Alfalfa seed is ideally grown as an irrigated crop in warm, semi-arid regions with a long growing season. These conditions provide for optimum flowering and pollination of alfalfa; conversely, high humidity or untimely rainfall can reduce alfalfa seed production. To optimise seed production, irrigation practices must be tailored to fit local conditions.

Site and Soil Characteristics
Irrigation requirements for seed production depend on soil texture, soil depth, precipitation, temperature, evaporation, season length and farming practices. All of these factors influence the total amount of water applied, and the timing and quantity of irrigation. Soil texture and soil depth regulate the water holding capacity (WHC) of an individual soil. Sandy soils can “hold” about 10 cm of water per metre of soil at saturation (100 percent WHC), whereas some clays can contain over 16 cm/m (Figure 4). Alfalfa seed is successfully grown on a wide variety of soil types and depths. Deep, clay-loam soils require less-frequent irrigation, but sandy or shallow (< 1 m) soils require careful and frequent irrigations. For optimum alfalfa seed production, the moisture content of the upper of the upper 60 cm should be closely monitored.

Aside from the physical soil characteristics, climate and crop conditions determine the frequency and quantity of irrigation application. The rate of evapotranspiration (ET) from an alfalfa seed field varies depending on soils, temperature, wind speed, day-length and crop canopy. Typically in July, ET rates in alfalfa can be as high as 6 to over 7 mm per day (water loss to the air).

There are many technical ways describe and measure ET, but knowing the maximum potential ET (6 to 7 mm/day) is useful for crop management. For example, a saturated soil of 1-metre depth with a WHC of 12 cm/m would be completely dry in about 20 days (Figure 5). Obviously, to maintain good moisture in the upper 60 cm would require irrigation about every 10 days with adequate water to re-wet the upper 60 cm.

Irrigation Principles
An established alfalfa seed crop will require >120 cm of water (applied, precipitation and residual soil moisture) per year for optimum production. The timing and rate of irrigation should be based on anticipated crop growth and environmental conditions. For example, on deep soils in the northwest US, many growers can supply half of the water in fall, winter and early spring, with the other half applied in spring and early summer to promote slow steady growth. On heavier soils in that region, irrigation is only necessary until June when flowering commences, and then one or two more irrigations as needed. In contrast, shallow or course soils require more frequent irrigation to minimize crop stress. Two common practices used for irrigation timing are: 1) calendar date - 10 cm of water every 20 days after first bloom, and 2) full soil profile in the spring, then irrigation when “Pan Evaporation” exceeds 7.5 cm.

Irrigation Methods Alfalfa is successfully grown under all types of irrigation systems. Total water provided by sprinkler systems (10 cm, etc.) is easy to calculate and apply. Sprinkle irrigation is the ideal method to establish and grow an alfalfa seed crop, however during bloom there is some slight disturbance to pollinators due to irrigation and canopy humidity. Sprinkler irrigation is the most efficient method of irrigating sandy soils, however is initially more complicated and expensive. Sprinkler irrigation can be used on fields too steep or contoured for furrow irrigation, which is a major advantage.

Furrow irrigation is the most widely used form of irrigation for alfalfa seed. Furrow irrigation requires land that has a very uniform and slight slope. In order to estimate application rate, the farmer must know water flow rate and retention time in the field. Regardless of irrigation method, the goal is to put moisture into the soil rather than across the soil, at the proper time and in sufficient quantities.

Special Considerations for Alfalfa Seed. Alfalfa seed fields are best suited for deep, well-drained soils where crop water needs are controlled by irrigation. Sandy loam soils or other light soils are best for alfalfa seed. Good soil moisture is needed until bloom, then irrigation levels and timing are gradually cut back to mid-bloom; this causes the alfalfa plant to have a more synchronous bloom at the expense of additional vegetative growth. Seed growers have the “art” of knowing when to “stress” the alfalfa plant to maximize seed set. The soil should not have an impermeable layer to restrict root growth or limit the ability to “stress” the alfalfa at the appropriate time. Generally, high biomass production results in low seed yield. Tall (>1 metre) thick forage growth will produce less seed than shorter, vigorously blooming forage on the same soil. In some soils with a clay hardpan or a high water table, a common phenomenon is high seed production for one or two years, then in later years the alfalfa crop growth becomes more vegetative and tall with low seed yields, regardless of good irrigation management.

Figure 4. Generalized diagram of soil and water holding capacity (WHC). Depending on soil texture, WHC varies from 10 to 15 cm of water per metre of soil.

Figure 5. Generalized diagram of evaporation-transpiration (ET) losses of water from a saturated soil. ET rates from alfalfa in mid-summer are 6 to 7.5 mm/day.

PRINCIPLES OF SEPARATION AND SEED PROCESSING
Jim Stanelle, Colorado Crop Improvement Association, Fort Collins, Colorado, USA

“A seed is a living organism and it must be treated as one or it will not live to produce a future generation.”

Cleaning seed is the removal of all the particles in the seed lot that will not produce a viable plant of the desired crop. The purposes of seed cleaning are 1) the removal of contaminants, 2) upgrading and, 3) sizing. The first two purposes involve removal of those particles that will not produce a strong plant of the desired crop and the third, size grading, is used mostly to increase the ease of planting and decrease the variability of the seed lot. The discussion here will focus on the removal of those particles that will not produce a strong plant and not on seed sizing.

All the particles that exist in the seed lot fall into one of two categories. First, are the contaminants, weeds, trash, or other particles not specific to the desired crop and second, seed of the desired crop that for some reason is not strong or healthy enough to produce a viable plant. The process of seed cleaning will first identify those unwanted particles and second, remove them. Since each raw seed lot is different, it is important the lots be assessed before cleaning to understand what problems exist.

Pre-Cleaning Evaluation
How does one look at a raw seed lot to assess the problems that exist? The first thing seen are the seeds of the desired crop. They are probably the most numerous and should be uniform in size, shape and colour. The next set of particles that are noticed will probably be the larger light, chaffy pieces—these are often part of the seed plant such as awns, threshed heads, stems, or leaves. Another group of particles in the seed lot will be heavier particles that are closer in size to that of the desired seeds in the lot. This fraction could contain weed seeds, soil clods, and small stones. The last group of particles that will be found in a raw seed lot will be smaller particles. These pieces are usually found at the bottom of the seed mass after moving the larger particles away. This fraction will probably contain small weed seeds, fine dirt and broken seed kernels. This pre-cleaning examination is important to find out what exists in the seed lot and to determine how the problem impurities are to be removed.

Seed Processing
A number of different processes are available to clean or condition seed. Depending on seed condition and level of contamination, an operator will select the proper order and settings for the equipment. Separations of seed are based on seven physical characteristics of a seed lot (Table 1).

The easiest of the unwanted fractions to remove is the light, chaffy material. These particles have several characteristics that are drastically different from the desired seed and therefore relatively easy to separate. Their larger size with a greater amount of surface area in comparison to their weight makes it easy to separate in a column of air. The moving air will hit the surfaces of the chaff and blow it away from the seed mass. Even if the most dense of these particles do escape separation in the air column, they will be large enough to be removed by the scalping screen on the air screen cleaner.

The smaller particles are the next easiest to remove. The lightest of these particles will be blown out in the air column of the air screen cleaner and most of the rest will be small enough to drop through bottom or sifting screens on the cleaner. Only those small particles close in size to the desired seed will present a problem and will have to be dealt with later.

As with the smaller fraction, the larger particles are mainly dealt with on the scalping screens of the air/screen cleaner. Most of the larger particles will not fall through the screen perforations with the seed mass and they will be separated. Only those seeds that are very close in size to the desired seed will once again have to be dealt with in a more specific manner.

The last fraction to be dealt with is the seed fraction itself. Even though this fraction contains all the seed of the desired variety, some of those seeds could be damaged in a manner that will not allow the new plant to grow and produce a good quality crop. These damaged kernels, along with those impurities already mentioned that are just larger or smaller than the seed are the ones that must be separated from the seed lot in a more precise manner.

All of the impurities previously removed were taken out by either the air separation or the scalping and sifting screens of the air screen cleaner. The air/screen cleaner uses round hole screens to separate particles with respect to their width, and slotted or oblong screens to separate by thickness. In addition, the blowing air separates impurities on the basis of seed weight with respect to surface area. Since the remainder of the problem particles are close in size to the desired seed and have not been removed by the air/screen, they must be examined closer to understand how they can be removed.

Length Separations. A common impurity not removed by the air/screen cleaner is one that has a length that is different from the desired seed. Since the seed has already passed through the screens, the width and thickness can be assumed to be similar to that of the seed. Two possibilities would be a round seed and a stick in a wheat sample. If these three particles, the round seed, the stick and the wheat kernel, were viewed from the end, they would have similar width and thickness, but the stick would be longer and the weed seed shorter than the wheat kernel. A length grader must be used to make the separation, but since one particle is longer than the wheat seed and one is shorter, two different operations are necessary.

A length grader is a machine that utilizes the differences in length to separate impurities from a seed lot. Most length graders use long rotating drums with small indentations on the inside of the cylinder. Seed enters the cylinder and the downward slope and rotation of the cylinder moves the seed from one end to the other. As the seed mass moves through the cylinder, the individual particles slide into the indentations of the cylinder. Centrifugal force from the rotating cylinder holds the particle inside until gravity causes it to drop out. Any particle that is longer and has its centre of gravity outside of the indent will fall out sooner, while the shorter particles with their centre of gravity on the inside of the indentation will remain in the indent for a greater part of the revolution. An adjustable trough on the inside of the cylinder is set to catch those shorter seeds when they fall from the indents. Since the longer seeds have already fallen out, they will not land in the trough, but instead remain with the seed mass. So, a length grader is used to remove short particles from the seed mass. In the example of the wheat seed, the stick and the round weed seed, the length grader with small indents would hold the shorter round weed seed and remove in the method stated above. But, since the stick and the wheat kernel are both longer, the stick would still have to be removed from the seed mass by a second process. Since the length grader removes short particles from the seed mass, any shorter product has already been removed, so we must now change our perspective and look at the wheat seed itself as the short piece. A second cylinder with larger indentations would allow the wheat kernel to lay inside and be lifted into the trough while the longer sticks fall out and remain with the mass. With the first cylinder, the shorter weed seeds are lifted and trash is removed from the trough. In the second cylinder, wheat seed is lifted and collected in the trough while trash is discarded from the cylinder.

Specific Gravity Separations. Even after the air/screen cleaner and the length grader have cleaned the seed, some problem particles can still remain. Small stones or shrivelled seeds that are dimensionally similar to the desired seed could still be in the seed mass. The difference here is that the impurities are either heavier or lighter than the seed, and to remove these particles, a machine that can sense their weight must be used.

The gravity table has a surface or deck that is covered with seed. Air is blown from underneath causing the seed on the deck to act like a fluid. This means that it acts just as if it were in water, the lightest seed would float to the top of the seed mass and the heaviest would sink to the bottom. The gravity table deck is set at an angle and a sideways, reciprocating (back and forth) motion is applied to the deck. The deck slope causes the lightest material on the top to flow downhill while the back and forth motion carries the material nearest the bottom of the mass up the slope in a stair-step motion. The combination of the angle and the motion causes the lightest seed to be separated from the heaviest. In this way, the gravity table removes the heavy stones and the light, shrivelled seed from the good quality seed.

Since the gravity table uses weight per unit volume (specific gravity) to make a separation, it works best when the physical dimensions and shape of the seed and the impurities are similar. This means that seed should have been cleaned through both the air/screen cleaner and the length grader before using the gravity table. Additionally, most visible contamination problems in seed lots can normally be removed by the first two pieces of equipment, so the gravity table does less to remove contaminants but more to upgrade the quality of the seed lot. In conditions of stress such as drought or hot weather, seeds often do not develop to their full potential, and the resultant seeds might be lighter in weight and shrivelled causing lower viability. Since lighter seed is removed on a gravity table, test weight and germination of the seed lot are usually enhanced.

Surface Texture Separations. Even after some seed lots have been processed through the air/screen cleaner, the length grader and the gravity table, some persistent seeds could still be present. In alfalfa seed, for instance, dodder might still be present. The only useable difference that can be used here is surface texture. The alfalfa seed has a shiny, smooth seed coat while the dodder has a pitted, rougher coat. Other surface texture differences could include a weed seed with a pointed end in a lot of shiny, smooth seed.

A velvet roll mill is often used for this type of separation. The machine has several pairs of rollers each approximately two metres long and 10 centimetres in diameter. The parallel rolls are covered with a velvet material, the intake end is 10 degrees higher than the discharge end and the rolls rotate in opposite directions. The seed mixture is added to the top end and slides downward between the rolls due the rotation of the rolls. The rough surface of the dodder or other impurity gets caught in the velvet and is thrown over the edge of the rolls and discharged. The smooth alfalfa seed continues down between the rolls and is discharged at the end.

Another method developed for separation of dodder or other rough seeds from alfalfa, based on seed coat texture is the magnetic separator. A powder of iron is mixed thoroughly with a seed lot, and the mixture is fed into a magnetized mill that removes dodder, cracked seeds or other rough particles. It should be noted that both of these techniques are seldom 100 percent effective in removing dodder, and they also remove some good alfalfa seed. Therefore, dodder eradication consists of a combination of planting pure dodder-free seed, clean fields, field monitoring and weed removal, and as a last resort these special seed processors.

Again, a thorough pre-cleaning examination of each seed lot is important to determine the problems that exist in the lot, and the machines and settings to be used to separate the problem particles from the seed mass. Each piece of seed cleaning equipment capitalizes on one or more physical difference to remove the impurities.

Using the Air/Screen for Special Separations. For most crops, the use of the air/screen cleaner, the length grader and a gravity table will produce a high quality seed lot, but in some circumstances, all three of those pieces of equipment may not be available for use. In the case where only an air/screen cleaner is available there may be some options that can be used to make length and density separations. The air/screen cleaner is a very versatile machine and with some easy modifications it can perform the same separations as the length grader and the gravity table, although less efficiently. An air/screen cleaner is most efficient at separating particles based on weight with respect to surface area, as well as particle width and thickness. But since the machine is very versatile, it may be able to make a credible separation based on length or density if it is set up and operated correctly.

The air column on the air/screen cleaner acts similarly to a gravity table in that it uses moving air to weigh the seed and remove the lightest particles. The difference is that the air column in the air/screen is very short and the seed is only exposed to it for a second or so, while seed flows across the deck of the gravity table for a minute or more. In addition, seed being cleaned on a gravity table has been dimensionally sized so that all particles are of similar size during the process. So to use the air/screen to make a density separation, cleaned seed should be run through the machine a second time with the air separation set to remove a few seed kernels that are slightly less dense. This second run will improve the quality of the seed, but not as precisely as if it was done on a gravity table.

Since the air/screen is very versatile, it also can aid in the removal of particles by length. Once again this closer separation will have to be made when the seed is cleaned so it can be in conjunction with the closer density separation mentioned previously. A length separation is not easily made on an air/screen cleaner because longer particles tend to bounce around due to the screen movement, stand on end and fall through the perforations. So, if the amount of bouncing of the seed can be reduced and the number of opportunities that the seed has to be exposed to the perforations is reduced, then it may be able to remove some longer particles from the seed mass.

To prevent longer particles from standing on end it is obviously necessary to keep them laying flat. Placing a heavy cloth on the screen so that the seed passes between the cloth and the screen will keep the longer particles from standing up. The action of the screen may allow the shorter wheat kernels to stand up and fall through a round hole screen causing a separation based on length. Although this separation can be made, the air/screen cannot make it as completely and efficiently as the length grader. Since the air/screen machine is being used to make a separation it is less suited to perform, the capacity may be limited. Lower capacity means that fewer seeds are on the screen at any given time and this could create a problem where each particle has more opportunities to be exposed to perforations and be separated. Once the wheat is separated from the longer particles, it is necessary to remove it from the screen surface before it has a chance to find its way through subsequent perforations and recombine with the seed lot. To prevent this, these separated particles must be removed from the screens as soon as possible. One way to do this is to cover or blank some of the perforations in the lower portion of the screen so that any separations could not occur in that area.

Another way to decrease exposure time to the perforations is to increase the angle of the screen. This means that the longer impurities slide off the screen faster therefore decreasing the number of exposures to the perforations. Some of the larger seed cleaners will have screens with variable pitch screens, but to accomplish this on smaller machines, the intake end of the machine should be elevated approximately 5 cm. Conversely, to increase the exposure time to the perforations, the discharge end should be elevated. In either case, elevating one end of the cleaner will change the exposure times to all the screens on the machine. This may or may not be desirable.

Still another way to increase the exposure time of the seed on just the sifting screen is to install a screen dam. A screen dam is just a small board placed on the sifting screen about one-half of the way down the screen that covers the entire width of the screen. As seed travels down the screen, it builds up behind the dam until the depth is great enough for some seed to flow over the top. Since the seed is building up, it remains on the screen longer, increasing the time that the seed is exposed to the perforations. If the exposure time is greater, then the opportunity to be separated is greater for the impurity that has some different dimensions from the seed.

Sanitation
Good seed cleaning will remove most unwanted particles from the seed lot, but it is not the best way to insure a pure seed lot. The best way to keep unwanted impurities out of your seed is to never have them in the seed lot in the first place. This starts in the field. If possible, seed fields should be monitored for several years before the seed production occurs. Weed problems should be dealt with in that time period. Once the seed crop is growing, a programme of removing any unwanted plants from the field, rogueing, should be initiated.

Any equipment used to handle the seed should be free from contaminating impurities as well. Planting equipment, harvesters, trucks or wagons used to haul seed, storage facilities, and cleaning equipment must all be thoroughly cleaned before use. A combine that harbours fifty kilograms of grain can negate all the hard work performed in the purification of previous year’s parent seed production and many hours of field rogueing. It is not uncommon to have two people spend three to four hours cleaning all the impurities out of a combine before harvesting a seed field.

To clean the equipment used in seed production, it may be necessary to have a vacuum cleaner, air compressor and a generator to operate them. In addition, knives or screwdrivers are used to remove seeds from cracks and crevices, and brooms, brushes and shovels are used to clean up seeds from floors.

Personnel
Effective and efficient seed processing requires well-trained operators. These operators must have good technical and mechanical skills, as well as a thorough understanding of seed separation and process flow. In many seed conditioning facilities worldwide, the seed cleaning manager may be the single most important employee in charge of quality, efficiency and profit.

Figure 6. Laboratory-scale air/screen seed cleaner in Xinjiang.

A GUIDE FOR FORAGE SEED QUALITY TESTING
Chen Mingshun, Xinjiang General Grassland Station, Urumqi, Xinjiang, China

Seed Structure and Physiology. Most types of forage seed consist of a seed coat, the embryo and endosperm. The embryo is the most important part of seed, and it consists of the germ, radical, plumular axis and seed lobe. After germination, the radical, germ and plumular axis become the root, stem, and leaf structures, respectively. Therefore, the embryo is the origination of plant.

The endosperm is a tissue to store nutrients. During germination, these nutrients are digested, absorbed and utilized by embryo. The endosperm of some plants is absorbed and utilized for embryo growth during the period of seed development, thus, these kinds of seeds have no endosperm when they are mature. The major nutrients within seed are starch, fat and protein.

The seed coat is the protective covering for the seed. The thickness, colour of seed coat and number of seed lobes vary among species. The hilum and seed pore are found on the seed coat of mature seed.

Chemical composition and performance. The chemical composition of forage seed is rather complicated, primarily consisting of water, carbohydrate, fat, protein and other nitrogenous compounds. Also, there are small amounts of minerals, hormones, enzymes, and other compounds depending on species.

Seed performance is affected by the various chemical compounds present. Moisture is a medium for metabolic action within seed cells. During seed development, maturity, harvest and storage, moisture content is closely related with seed quality, seed physical condition and chemical performance. Carbohydrate and fat are the substrates for respiration. Protein is involved with the synthesis of protoplasm and the cell nucleus, but protein can also be used for respiration. Minerals supply nutrition for metabolic functions during the period of seed germination.

Formation and development of forage seed. During forage plant growth, reproduction is initiated by light, temperature, and hormonal effects. Flower buds develop first, then flowering, fertilization and seed set. During pollination of the flower, double fertilization occurs – the fertilized egg grows into an embryo, and the nucleus of the endosperm grows into the endosperm and the seed coat. Many environmental conditions during this process affect the number, size, and quality of the developing seed.

Seed dormancy. Many forage seed have seed dormancy, which means that mature and viable seed do not germinate. For some seed, a specific condition is required for germination, and when that condition occurs, germination will proceed (called forcible dormancy). Other seed will not germinate even if suitable conditions such as water, temperature and oxygen are provided. These seed are still viable, but remain dormant due to seed structure or physiological factors (called physiological dormancy).

Dormancy is an adaptive and evolutionary trait. Some species through natural selection have high dormancy to adapt to adverse environments. For many species, the degree of seed dormancy in a species is generally related to the ecological environment where its predecessor grows. Dormancy has contributed to species and germplasm prolongation. Wild or cultivated forage seed grow in harsh environments with some level of seed dormancy to maintain integrity of the species. Dormancy can be conducive to forage harvest. The dormant stage can maintain the viability of seed and prolong seed life span. During storage, a series of methodologies could be adopted to prolong dormancy so as to increase seed life span.

There are several specific types of seed dormancy. Mechanical dormancy is caused by the impermeable characteristic of the seed coat or mechanical restriction to air or water exchange. Many forage legumes such as alfalfa can have hard seed coats, which require scarification for germination. Physiological dormancy can result from incomplete differentiation of the embryo, or embryo growth restriction due to after-ripening processes. Chemical dormancy is caused by inhibitory substances such as ammonia, hydrogen cyanide, ethylene, aromatic oils, alkaloids and other compounds that prevent germination.

Methods for breaking seed dormancy. Several physical procedures are used to break seed dormancy by improving seed coat permeability. Temperature treatments such as freezing, high temperature or temperature gradients can improve oxygen exchange, and terminate seed dormancy. Mechanical treatments are used to scarify or physically break the seed coat. Water is able to enter into the seed, and seed dormancy is terminated. High-pressure treatment is used for some types of seed. For example, Oenothera seed is soaked, then maintained for two to three days at six to eight atmospheres. This enables water to seep into the cracks in the seed coat, which terminates dormancy and hastens germination. Other species such as sweet-clover or alfalfa are dried at indoor temperature and treated at 200 atmospheres.

Irradiation treatments can also be used to terminate dormancy and promote germination. The include X ray, gamma ray, beta ray, alpha ray, ultra-red ray, ultraviolet ray and laser.

Several chemical treatments are also effective in promoting germination. Inorganic treatments such as acid, alkali, or salt can disrupt the seed coat and improve germination. For example, dormancy of immediately-harvested seed of alfalfa can be eliminated by soaking in a solution of sulphuric acid with oxygen injection for a period of 30 minutes. Organic chemicals such as dichloromethane, acetone, thiourea, formaldehyde, ethyl, colchicine and malic acid can also terminate dormancy.

Several plant hormones can break dormancy. Giberellin is able to promote seed germination and improve seed germination ability. Kinin is able to terminate seed dormancy that is caused by abscisic acid.

Seed Quality
High-quality seed is defined as seed that adapt to all sorts of ecological environments, and utilizes light, water and natural land resource fully. Factors that govern seed quality are the clean (pure) seed percentage and the vigour of germination. The clean seed percentage is the amount of pure seed of the desired variety in a seed lot. During crop production, harvest, processing and storage there are many opportunities for damaging seed or introducing seeds from other crop or weed species. The pure seed percentage of seed lots is an important factor on seed price, safe storage, planting rate, the potential spread of insect, diseases or weeds.

Vigour of germination includes two indexes – total germination percentage and vigour. These two indexes ensure successful sowing, healthy seedling, good harvesting and high quality. Vigour of germination can be reduced in the process of maturing, harvesting, processing, curing, storage, transporting and fumigation. So, vigour of germination is one of the important indexes of seed quality.

Other factors indicative of seed quality are seed size, and the presence of disease or insect pests. A common measure of seed size (or seed weight) is 1000-kernel weight. Within a crop variety, seed maturity, vigour and viability are generally associated 1000-seed weight. Seed weight is useful for developing proper sowing densities, resulting in uniform and vigorous crop stands.

Factors affecting seed health are infections or infestations by plant diseases or insect pests. In many cases, very low levels of seed contamination by these pests can result in seed death, heating in storage and crop losses when the seed is planted. Control of these organisms is essential for high-quality seed.

For many grain crops, seed moisture is an important index relating to proper seed processing, storage, fumigation, transportation and price determination.

All of the above indexes have been proven after long term scientific experiments and practice, and they are important to assess seed quality. Standard seed classification and testing systems are necessary to ensure high-quality seed for domestic and international seed markets.

Seed quality law
The development of national and international seed trade has made necessary the creation and promulgation of seed laws to ensure seed quality for the planting industry. Currently, there are numerous agencies and regulations affecting seed, including plant breeder protection, crop seed laws, plant quarantine, and importation laws. The relevant seed laws in China are the Chinese Seed Management Rules & Crop Seed Implementing Regulations (implemented May 1989) and the China Seed Law (December 2000). A major effort is being made worldwide to develop uniform and relevant seed standards and regulations.

For implementation and enactment of seed regulations in China, numerous agencies and infrastructure are being developed (see following chapter). A major management organization is the regional seed testing laboratories (stations) responsible for seed testing and certification. These play an important role to ensure seed quality, protect farm producer benefits, and to promote the development of viable seed production and planting industries.

Forage Seed Testing
The purpose of forage seed testing is to adopt scientific methods, test, evaluate and analyse the quality of forage seed. Forage seed quality includes seed clean rate, pure seed percentage, plumpness degree, viability, germination percentage, moisture percentage and others. These testing qualities are very important to different segments of the seed industry, such as producers, processors, warehouse managers, businessmen, farmers, certification organizations and seed management institutes.

Forage seed quality reflects the prestige of the seed industry, seed management institutes, and the pride and diligence of farmers. The advanced testing methodologies will ensure continued improvement of seed quality. Proper testing will guarantee safe seed storage and transportation, control weeds, and prevent spread of disease and insect pests.

Sampling. The purpose of sampling is to take a small seed sample from a large lot of forage seed for testing. The sample must consistently represent the entire seed lot. Correct sampling is the first step of good seed quality testing. The validity of seed testing results and certificates depend on both proper sampling and appropriate testing procedures. If the sampling procedure is error, it would be impossible to get the correct sample. Thus, the testing results would be error even if the testing technology were correct. Generally, personnel who are qualified with a sampling certificate implement the activity of sampling.

Seed lot. A seed lot is defined as a specified quantity of crop seed of a particular variety. A seed lot is harvested at the same time from the same field. Maximum allowable seed lot quantities vary among species. For some big seed such as Chinese pea-shrub (Caragana), sainfoin, and vetch, the maximum quantity is 5,000 kg, for alfalfa 1,000 kg, annual bluegrass seed and crested wheat grass are below 1,000 kg.

Principles of sampling. Initially, the quality of seed in a lot should be uniform. If it is different, seed must be mixed thoroughly before sampling. Secondly, multiple sampling points should be distributed at all points within the seed lot. Thirdly, the sample amount that is taken from each sampling point must be identical, otherwise it will influence its representation of the whole sample. Fourthly, qualified staff must carry out all sampling activity.

Sample types. A primary sample is a small quantity of seed from one sampling point of the whole seed lot.
• A mixture sample (original sample) is the mixture of all primary samples from a whole seed lot.
• The test sample (average sample) is submitted to the Seed Testing Station, and is generally taken from the mixture sample.
• The experimental sample (work sample) is taken from the testing sample received by the testing laboratory. It is used for one testing item.
• A secondary sample is any subsequent sample taken from a mixture, test or experimental sample.

Sample dividing.
As described, the experimental sample is taken from the testing sample received at the seed testing station. The minimum weight of an experimental sample for the clean seed rate analysis is equivalent to 2,500 seeds. The weight of experimental sample for other crop seed is ten times of the experimental sample for clean rate analysis. Sample weight for moisture testing of whole seed is 50 grams or 100 grams if the seed requires grinding. All of the secondary samples will be representative as long as the technique of sample dividing is suitable and the procedure of sample dividing is correct. The methods of sample dividing include mechanical sample dividing, random sample dividing, improved sample dividing and hand sample dividing.

Sample storage. Minimal time between sampling and testing is desired. The sample should be stored in a cool and ventilated indoor site. High temperature and high relative humidity must be avoided. Samples are typically stored for one year.

Clean (Pure) Seed Analysis
The purpose of the clean seed analysis is to determine the percentage of forage seed after removing impurities, waste seed and other plant seed. Clean seed rate is an important index for testing seed quality and is also a scientific basis for deciding grade and price. In addition, the analysis of impurity and other plant seed types will help to select reasonable seed cleaning methods and improve seed quality. Clean seed selected from this analysis can be used as the sample for other quality tests, such as germination percentage and viability.

At present, the clean rate testing method in China is the accuracy method. The seed sample is a mixture of clean seed and impurities. Therefore, all types of constituent must be separated out during clean seed rate testing. Clean seed rate testing must be conducted according to the testing standard to get the correct testing result.

Clean seed is the main variety that is found during testing submitted by the sender. The characteristics of clean seed are as follows:
- A complete seed includes achene, similar grain, offshoot grain and floret.
- A broken seed, is bigger than half the size of the original seed.
- Caryopses of forage grass seed.

Waste seed are seed without embryos, broken seed pieces, germinated seed, or seed damaged by disease or insect pests. Other plant seed include weeds, other crops. For dodder, a 100-gram sample must be evaluated. Dead impurities includes vegetation or plant debris other than the crop seed, such as empty seeds, sterile florets, or broken seed that is less than half the size of the original seed.

Analysis procedure. Analyse the experimental sample once, then repeat. The weight of the sample evaluated depends on national standards. The experimental sample for clean rate testing must be divided into four parts: clean seed, waste seed, other plant seed and impurity. These are separated and weighed separately. If the weight is below 0.5 grams , three decimal places should be retained. If the weight is 1 to 9 grams , retain two decimal places, and for 10 to 99 gram samples, retain one decimal place. The weight of all parts must be converted into a percentage calculated according to the total weight of all four parts instead of the original weight of the experimental sample. However, the total weight of all four parts must be compared with the original weight to check for loss or error. Results from both tests must agree, or the test is repeated.

Report. The result of the clean rate should be given to one decimal place. The total percentage of all parts should be 100. If the content of one part is less than 0.05 percent , “Small Amount” should be filled in the report. The percentage of clean seed, waste seed, other plant seed and impurities should be reported on the testing certificate. If the content of one part is zero, “0.0” should be filled in. The amount of other plant seed or weed seed should be expressed as “number per kilogram”. If the percentage of weed seed exceeds 1 percent , it must be indicated on the certificate.

Seed number testing for purity (other plant seed)
Other plant seed includes weed seed or crop seed other than the clean seed of the sample. According to the requirement of the seed sender, all of the other plant seed can be identified and quantified. For international seed trade, presence and quantity of prohibited weeds or crop species must be tested.

The testing can be divided into complete testing, limited testing and simple testing. Complete testing is to test all of other plant seed from the experimental sample. The limited testing is to test appointed seed from the experimental sample. The simple testing is to test a part (one fifth) of the experimental sample.

A magnifying glass and illumination equipment is used to test the experimental sample. Separate all of the other plant seed or the appointed seed out and calculate the number of these seed. The results are expressed as seed number, or can be converted into a seed number per unit.

Germination Testing
Germination is the most important laboratory test, and generally expressed as germination percentage and vigour. Germination percentage is the percentage of seed germinated at the end of a specified germination test. Germination vigour is measured several ways, but generally accounts for germination rate during the primary period of the experiment.

The direct and real goal of a germination test is to predict potential field germination. However, field conditions of soil and climate vary among different areas and seasons. Therefore, germination tests were developed for laboratories with standard control of equipment, environmental conditions, and methods. Under these optimum conditions, the laboratory test provides for accurate prediction of potential field germination.

Germination equipment. Germination chambers provide for control of temperature, light and humidity. Numerous types of glass or plastic containers are used for the germination test. Beds within the chamber consist of germination paper, sand or soil. [

Standard germination test procedure.
Mix the experimental sample completely, and take at random four replicate samples of 100 seed (for large seed four replications of 50 seeds). According to the standard procedure, select the appropriate germination bed, then place seed on the moistened germination bed. A proper distance should be maintained between seed to reduce mutual influence and bacterial infection. Label all containers, noting date, sample number, seed name or breed name, and replicate number. Then, put a cover or a plastic film on the container.

Depending on crop, maintain temperature and light of the germination container at alternating 16-hours at 20° C in dark 8 hours at 30° C in light. During the period of seed germination, it is necessary to check the chamber daily to ensure a suitable condition for germination. Add water to the germination bed continuously so as to maintain suitable moisture. If fungal infections occur, remove and wash infected seed, or repeat the test

Monitoring and Recording. A minimum of two monitorings and recordings are needed during the germination period, the first counting and the last counting. If the final count is more than seven days, counting times should be increased to once every two or three days until the last count. During the period of the first count, rotten seed should be removed and counted. All of weak seedlings, defective seedlings and ungerminated seed should be kept on the original germination bed or moved to another germination bed. During the last recording, after weekly counts up to 28 days all normal seedling, abnormal seedlings, dead seed and ungerminated seed should be recorded respectively. After the experiment is finished, if variable or doubtful results occur because of dormant seed, seed decay or fungal infection, the experiment should be repeated. Also if there are some known errors on experimental conditions, seedling monitoring, counting or the result exceeds the limited difference, repeat the test.

Calculation and Reporting. After the experiment is finished, calculate the total number of normal seedling first, then calculate the percentage of normal seedlings, abnormal seedlings, impermeable seeds, ungerminated seeds and dead seeds that accounts for the total experimental seeds respectively.
Percent germination = (Number of normal seedlings at end of test/Number of seeds in sample) x 100

Calculate the average of the four replicates retaining one decimal point.

Viability testing
Besides the percentage of normal germinated seed, seed viability must be tested on all ungerminated seed to judge the total potential seed germination. In standard germination tests, seed dormancy may be terminated but germination may have not occurred during the test period. For the seed trade, the turnaround time for testing may be inadequate. For some crops (as example autumn-seeded) the time interval between harvest and sowing is very short. For these reasons, seed viability is tested quickly by a biochemical procedure using Tetrazolium.

The tetrazolium (TZ) dying technique uses the common reagent 2,3,5 -triphenyl tetrazolium chloride (C19H15N4Cl, molecular weight 334.8). The dry reagent is a white or light yellow powder that is soluble in water. The reagent should be mixed at concentrations of 0.1 percent for cut seed to 1.0 percent for whole seeds. The reagent is mixed with distilled water with a pH of 6.5 to 7.0 (outside this range, use phosphate buffers). Upon preparation, the TZ reagent is easily degraded. So it should be prepared frequently, and stored for short periods in a brown bottle and packed by black paper in a dark cabinet. Further, the test should be conducted in the dark.

The principle of the TZ analysis relies on the dehydrogenase enzyme present in viable embryos. The TZ has no colour, but TZ reacts with hydrogen, producing a red compound triphenyl formazan within viable cell tissue. Thus, stained tissue is viable and unstained tissue is not viable. Coloured embryo means viable seed, and uncoloured embryo means unviable seed. In addition, some seeds are not dyed completely, and this indicates that a portion of the seed is necrotic. The position and degree of necrotic tissue within a seed embryo determine seed viability.

There are two common methods for the TZ test. In many laboratories, all ungerminated seed in the germination test are tested with TZ. All stained embryos are counted and added with the germinated seed to calculate “pure live seed”. Alternatively, the TZ test can be conducted on a separate experimental sample. Four replicates of 100 seed are divided randomly from the experimental sample and pre-moistened. After the forage seeds have swollen, they can be treated by cutting and stabbing before dying, which is advantageous to TZ permeation. The seed are placed into a Petri dish, and the TZ solution is poured onto the seed. Dying occurs quickly at temperatures between 30 and 35º C. After staining is complete, wash the seed and view under a stero-microscope to count viable and unviable seed.

Moisture Testing
Seed moisture content is an important index of seed quality for many crops. Seed moisture content testing is very important for guiding activities such as harvesting, cleaning, fumigation, storage, transportation and marketing. Seed moisture is tested by an old and accurate method. Currently, moisture is rapidly determined in automated moisture metres. For the old standard procedure, the main equipment are a hot-air oven (the maximum temperature is 200º C), grinder, analytical balance (1 mg), sample box and desiccator.

For the low temperature/hot air oven method, weigh the desired number of drying containers, then place them into the oven for 1 hour drying with a temperature of 103±2º C. The sample containers are transferred to a desiccator for 30 to 45 minutes to cool. Weigh the sample containers and record their weight. Using replicates of each seed sample, place about 5 g each into drying containers, and record their exact weight. Next, all sample containers are returned to the oven with the lids removed. Drying temperature is 103±2º C for 17±1 hours. The sample containers are transferred to the desiccator for 30 to 45 minutes cooling after drying. Weights of the dried seed are recorded, and the relative humidity should be below 20 percent when weighing.

Seed moisture percentage = (M2-M3)/(M2-M1)×100

where M1 is the weight of sample box and cover (g), M2 is the weight of sample box and cover before drying (g), M3 is the weight of sample box, cover and sample after drying (g).

The high temperature/hot air oven method is similar to the low temperature/hot air oven method described. The difference is to increase oven temperature to 130 to 133 ºC, and reduce drying time to one hour.

Some large seeds require grinding before moisture determination. However, these seed must be dried prior to grinding if the moisture content is over 17 percent (typically the moisture content of forage grass seed can be more than 18 percent , and legumes more than 16 percent ). The twice-drying method consists of placing 20 grams of seeds into the oven at a temperature of 130º C for 5 to 10 minutes. The seeds are weighed after two hours cooling. The seed is then ground and replicate samples of 4.5 to 5.0 grams are weighed. Dry at 130±2º C, cool, re-weigh, and calculate moisture content from one of two equations:

Seed moisture percentage = ((W1*W2-W1×*W3)/W*W2)*100

where W is the weight of sample (grams), W1 is the weight of sample after drying in advance (g), W2 is the weight of ground sample (g), W3 is the weight of ground sample after drying (grams).

Seed moisture percentage = ((S1+S2)-(S1*S2))/100

where S1 is the moisture loss of whole seeds after the first drying ( percent ), S2 is the moisture loss of ground seeds after the second drying ( percent ).

Seed Health Testing
The development of forage seed trade at home and abroad increases the opportunities for spread of disease, insect and weed pests. Expanded production of superior seed and seed health testing is of utmost importance. Testing of seed for disease and insect pests ensures good quality for improved pasture and hay crops, and also guarantees good animal health. Infestation or infection by insects and bacterial or fungal pathogens can significantly reduce germination, stand health and crop yield. Further, harmful exotic pests could be introduced into a new area, requiring many years to control the problem.

Seed health testing is a comprehensive testing technology that involves knowledge of biochemistry, microbiology, entomology, and plant protection. Seed testing can limit pest spread during seed transportation and storage, and is also useful in the market to assess seed value. Seed health testing can involve both field testing and laboratory analysis. Field inspection is an objective appraisal of relative infestation by a disease or insect pest. Field evaluation is useful to identify potential pest problems, but quantification is done after harvest by numerous laboratory tests.

Seed insect pest testing should be carried out in accordance with the individual pest characteristics in different seasons and regulations. Some common testing methods are naked eye testing, microscopic examination, sieve testing, seed cut testing, dying and soft X ray testing.

Common methods employed for seed disease and testing are:
• Naked eye testing - used to examine for large pathogens in seeds.
• Sieving testing - used to separate and examine large pathogens such as galls, ergot or sclerotia bodies.
• Wash testing - to test for bacterial or fungal spores on seed surface.
• Funnel separating testing used to test for nematodes.
• Germination testing – used to test for sporulation of bacteria or fungi during seed germination.
• Isolation and culture testing - used to grow and identify specific seed pathogens.
• Bacteriophage testing
• Isolation planting testing – used to identify pathogen in seedlings.

Seed sampling and sample size for pest testing is similar for those described for the seed quality tests. One difference is that some sterilization, washing and drying of all apparatus must be done each time to avoid cross-contamination and to ensure that the results are correct. Seed health testing methods should be selected depending on the testing purpose, seed variety, research conditions, and the specific pathogen or insect. In is important for analysts to master the relevant knowledge and experience in testing methods, as well as constantly being vigilant to detect potentially new pests.

The quantity of the experimental sample is generally no less than 400 seeds. In addition, according to the test protocol, a whole testing sample or some part of it can be treated as an experimental sample, then sampling a small amount of seed that is equal to 400 seeds randomly. Results are calculated and reported by either the percentage of infected seed or the number of pathogen bodies present. The report must also include the sample size and method used.

Seed Processing Effects on Seed Quality
Moisture Alfalfa seed harvested under ideal conditions (appropriate desiccation, modern combine, hot-dry weather) has very little threat from losses. However in many cases, a significant amount of damp plant debris (immature seeds, green pods, stems, leaves, weeds) may be harvested with the seed. If this occurs, the seed crop should be dried immediately after harvesting to prevent potential heating, discolouration, germination, spread of detrimental micro-organisms, or other quality losses.

The basic principle of seed drying is to remove free water within seed rapidly so that it will not influence seed quality. Two methods of seed drying methods are natural drying and artificial drying. Natural drying is widely practiced in China, and requires spreading the seed in a thin layer on tarpaulins under the sun. The seed is raked or turned for several days until dry. Caution should be observed to prevent losses from rain or wind. Artificial drying can be accomplished by several methods. In arid conditions high volume fans blowing ambient air through a bin or container of alfalfa seed is sufficient. In some cases a drier has a fan equipped with a heater. In both cases seed in an artificial drier should be kept below 40 ºC to reduce quality losses.

Forage seed processing
Forage seed cleaning and processing uses specialized equipment based on the characteristics of seed such as size, density, or surface structure as described in the previous chapter. During the processing of Foundation seed or large lots of commercial seed, several of the laboratory tests are used as “preliminary” tests for the seed processor. For example, a preliminary purity test is often used to make partial payment to the seed farmer, with the balance due after bagging. The purity test identifies all contaminant weeds, and it is used to base the order or number of runs through the equipment. Therefore seed quality testing is not only the final evaluation of a seed lot, it is also useful during the cleaning and processing phase for high-quality seed.

Seed Storage
Scientific storage methods will prolong the life, viability and value of alfalfa seed. Seed life is the duration of seed viability under a specific environmental condition. Genetic characteristics, seed condition prior to storage, and the storage environment influence seed life.
Short-life seed is below 3 years.
Medium-life seed is 3 to 15 years.
Long-life seed is 15 to 100 years, or longer.

A major genetic characteristic for long seed life in alfalfa is its hard and semi-impermeable seed coat. At the time of storage, there are a number of physiological factors which can limit seed longevity. For alfalfa seed that is properly dried and clean, longevity should always be good. All mouldy or insect-infested seed must be removed by cleaning or chemical treatment.

Seed may be stored in bags made of gunny, cotton, paper, plastic film, or in bins made of metal or wood. Prior to processing, seed is typically stored in large bins or bulk (1,000-kg) bags. Most seed is conveyed and packed by automated or semi-automated machinery. At the final step seed is weighed and the bag is sown. Typical bag sizes for international markets are 22.7 kg (50 pounds) or 4.4 kg (100 pounds), and are either multi-layer paper bags with an inner polyethylene liner or woven polyethylene fabric. Certificate identification must be printed on the bag or a seed tag sown onto it, which should include variety name, production location, year, lot number, purity rate, germination percentage, and content and quantity of other crop or weed seed.

The primary objective for storage of commercial alfalfa seed is to prevent losses due to moisture, rodents, birds, insects, fire and theft. For small lots such as Breeder seed or germplasm resources, specialized storage containers that maintain low temperature and humidity. Due to cost, these are not applicable to large seed lots.

For commercial seed long-term storage is not necessary. Seed is stored in bins or bags, and these should be kept in closed, ventilated buildings. Ideal seed storage conditions are at temperatures below 15 ºC and below 50 percent humidity. Seed temperature and humidity will change with the varying of temperature and humidity in the storage facility. Fans or air conditioning devices can be installed to balance the temperature and humidity of indoor and outdoor. During summer months, storage facilities should be ventilated in if the temperature and moisture within the storage are higher than that outside. Ventilation can be as simple as opening windows or using fans to circulate air at ambient temperature.

Bagged seed should be stored on pallets above a concrete floor. For convenient management, the distance between stacks or between a stack and the wall should be about 50 centimetres. The height and width of the stack should be determined by the dry state of seed.

An accurate seed inventory should be maintained after the seed is put in storage. Initially, daily change of temperature and moisture in seed stacks should be monitored. Seed temperature will approximate ambient temperatures – high from March to August, and low from September to February. Daily change of seed moisture is generally lowest between 02.00 and 04.00 hours, and highest at 16.00 to 18.00 hours.

Seed temperature can be monitored by inserting a thermometer in various areas of each stack of seed bags. Moisture samples should be obtained for every 25 m3, consisting of three layers and five points from each layer. These seeds are mixed for an average moisture analysis.

Insect pests, rodents and mice should be monitored constantly. Check for torn bags, droppings, claw prints, droppings, or dead animals in the storage area. During periodic quality tests, the seed can be sieved and observed for droppings and insect pests. During normal storage conditions, germination tests are not required. However, if seed is stored for more than one year it should be re-tested for seed germination rate before the seed is sold. During storage, comprehensive records should be maintained with the seed inventory.

International Seed Testing and Marketing Associations
International marketing of forage seed is rapidly expanding, and there is a great need to have realistic, logical and uniform seed quality standards. Seed quality testing methods (similar to those described in this manual) are widely used, but often the interpretations, reports or seed label requirements vary among countries. A number of organizations, such as the Association of Official Seed Analysts (AOSA) are involved with the effort to standardize seed test protocols and interpretation. Further, this effort is encouraged by several seed trade organizations, because of the importance of labelling and seed quality standards for import-export markets. These include the International Seed Testing Association (ISTA), American Seed Trade Association (ASTA) and the Canadian Seed Trade Association (CSTA).

Major reference resources for seed testing are the Seed Viability Testing Method Handbook (edited by AOSA and ISTA), Principles and Techniques of Seed Testing (Agriculture Publishing House, Yan Qi Chuan) and Seed Viability (Scientific Publishing House, Tao Jia Lin, Zheng Guang Ju). International marketing of seed is rapidly changing, therefore seed analysts are encouraged to research and stay abreast with advances in seed testing or reporting methods. Previous traditional seed analyses are adequate to assure for high-quality seed for local farmers. However, in the near future there is great potential for exporting seed from Xinjiang to other provinces or internationally. Therefore every effort should be made to create seed testing standards consistent with (or exceeding) those used internationally.

MAINTENANCE AND QUALITY CONTROL IN A DEVELOPING FORAGE SEED INDUSTRY
Chen Mingshun, Xinjiang General Grassland Station, Urumqi, Xinjiang, China

• Forage seeds are critical production goods for grass and forage land development, feed production, ecotype building and afforesting cities and the surrounding areas. The demand for forage seed is soaring with the implementation of the Western Development Campaign, the project for bringing sand blown by wind under control in Beijing, Tianjing and their surrounding areas, other ecological construction projects, and the structural adjustment of the planting industry in farming areas. At present the supply of forage seed in China is insufficient and has the general characteristic of poor quality. The seed market is in chaos and flooded with counterfeit seed (mislabelled or misrepresented), and this will definitely harm the common interests of our country, farmers, herdsmen, and construction projects.

• For many years, China had limited laws and regulations concerning forage seed quality standards and marketing. There are many problems in the forage seed industry, such as deficient seed supply, poor farming techniques and low quality. The efficient production and operation of a successful forage seed industry require some basic standards, regulations, quality inspection and control, and supervision. All of these greatly influence the industrialization of forage seed and the economic development based on forage seed.

Challenges for Production and Operation of the Forage Seed Industry in China

Scale of seed farms. Generally, alfalfa and other forage seed fields are small in scale, poorly managed, and low-yielding. Presently, there are around 1,400,000 ha of alfalfa in China and most seed is harvested from dual-purpose fields. The average yield of alfalfa seed is 100 to 300 kg/ha because of forage harvest and other management factors. In Xinjiang, forage seed production is about 100 tons annually, but the demand for planting seed is about 1,000 tons. Since the seed demand outstrips the supply, the price is skyrocketing and there are numerous other problems.

Poor quality. Most seed marketers are not licensed, farmers do not sow as requested and seldom apply scientific methods in field maintenance, and seed processors lack necessary equipment and skills for seed storage and cleaning. Consequently, most seeds produced do not conform to the quality standards and have poor survival rate. The circulation of those seeds in the market exerts severe influence on the quality of forage land and cause unnecessary losses.

According to the information provided by the Supervision, Inspection and Testing Centre (Urumqi) for Forage Seed, Agriculture Ministry, in 1999 only 15 percent of all samples meet the standards. In 2001, the Animal Husbandry Department issued the Implementation Outline for Specialized Inspection on the Capital Goods Market of Animal Husbandry in accordance with the Working Scheme for Joint Law Enforcement Activities: Fighting with Counterfeits in the Market of Farm-oriented Materials issued by State Bureau of Industrial and Commercial Administration and Agriculture Ministry. At the same time a work team focusing on fighting with counterfeits was established. By 2001, about 41 percent of inspected seed samples met minimal quality standards. It is obvious that the quality of forage seed is indeed poor from these results.

A major factor affecting the quality of alfalfa seed in Xinjiang is the damage caused by dodder (Cuscuta spp.). This parasitic weed has significantly reduced alfalfa seed production, and severely limits potential new areas of production. Further, the quality of imported seed is extremely variable.

Seed industry in chaos. For people driven by private interests, there are some problems in seed maintenance caused by the current disorder and speculation. Some vendors do not provide any quality certificate when selling seeds. In recent years the supply of forage seed falls short of demand and the price is not stable. Some vendors illegally purchase and sell counterfeit seeds, mix bad seed with good seed, bid up prices and reap fabulous profits. This directly results in interfering with the maintenance of an orderly forage seed market and harms forage land construction and feed production. Additionally, the producers and proprietors never forecast the market, and production and distribution are not coordinated.

Currently, there are 104 issued Operation Certificates of Forage Seed and 47 issued Production Certificates. However many operators are not certified.

Strengthening and Regulating the Seed Market
It is easy to find the direct relationship between the disorder in the forage seed market and loose maintenance. With the implementation of the Seed Law, PRC, the maintenance of forage seed has gradually moved towards a more legitimate system. Forceful measures should be taken to ensure the healthy development of a viable forage seed industry in China.

Maintain quality standards. Seed quality is of great importance for agricultural and social benefits to farmers and herdsmen. The standardization of seed maintenance is the guarantee for seed quality. Carrying out the standard maintenance of forage seed is to put the Seed Law, PRC into effect and continually improving and perfecting policies concerning seed quality. It is necessary to establish a sound mechanism of quality supervision and inspection in order to strictly authenticate seed quality, and supervise the whole process from production to distribution.

Item No. 76 of the Seed Law, PRC governs all activities concerning forage seed and edible mushroom such as maintenance of seed resources, seed selection, production, operation, and utilization. It furnishes the basis for establishing and perfecting the legitimate system for forage seed maintenance. So in order to put what is regulated on Item No. 76 into practice, it is essential to link the primary principles of the Seed Law with concrete conditions of seed maintenance together and map out special regulations fit for seed maintenance. Recently Maintenance Measures for Forage Seed has been developed by the Agriculture Ministry and will be put into effect soon. Meanwhile Interim Maintenance Measures (Trial Use) for Forage Seed issued by the Ministry of Farming, Animal Husbandry and Fisheries on Oct. 25th, 1984 will be abolished.

Standardize Forage Seed Production
It is indispensable to implement state inspection standards for forage seed, strengthen the inspecting bodies, equip with advance machinery for inspection and processing and maintain the national generation attestation system for different varieties of forage seed. Three grades of seed are Breeder, Foundation (base) and Certified. Seed conforming to the national grade standards for forage seed will be issued certificates which guarantee seed quality.
Breeder seed is grown from parent material by a plant breeder, and is the firsthand seed for new varieties
Base (Foundation) seed is the first generation offspring derived from planting Breeder seed
Certified seed is the offspring derived from planting the base seed, and grown in quantities for commercial sale
(Unauthenticated seed is called common seed)

Prohibit the Marketing of Counterfeit Seeds
After the maintenance infrastructure is initiated, the system of inspection and supervision activities should be started. Regulations according to the Production License of Forage Seed, Operation License of Seed, Business License, and Certification of Inspection should be enforced. These rules restrict operation without business license, standardize forage seed marketing and completely eradicate the production and circulation of counterfeit seed in the market. Violators of related law and regulations should be punished severely to safeguard the legitimate rights and interests of the producers, distributors and users.

Second, the production and marketing of counterfeit seeds and seeds of inferior quality should be prohibited. This would include intentional mislabelling of variety name, type, or production area. Seeds of inferior quality are those inferior to national or local standard of seed, quality is inferior to the label, weed seed content exceeds the label, or contain a mix with harmful life-forms which are the target of national quarantine.

Third, the authority for forage seed maintenance is the Animal Husbandry Bureau attached to the PRC Agriculture Ministry. Further, the animal husbandry departments (farming and animal husbandry departments) attached to the governments above the level of counties, according to the Management Measures for Forage Seed.

Seed Quality Inspection Agencies
Forage seed should be inspected according to International Technical Standards of Seed Inspection and the inspection is undertaken by quality-admitted organizations. Quality inspection organizations should have qualified inspectors. Sample seed should be extracted only by qualified inspectors. Quality Inspection Reports should be completed by inspectors with qualification certificate, signed by the juridical person of inspections organizations and stamped.

China established six inspection centres for forage seed for the first time in 1985, and the Xinjiang Inspection Centre for Forage Seed was established then. At present there are more than ten all throughout China, including three at the Ministry level in Urumqi, Xinjiang, Lanzhou, Gansu Province and Huhhot, Inner Mongolia.

Item No. 37 of the newly issued Management Measures for Forage Seed specifies that quality inspection of forage seed should conform to International Technical Standards of Seed Inspection. It is for regulating inspection procedures, ensuring seed quality and approaching towards international standards. Currently, technical standards of seed inspection in China lag behind other areas in the world. This needs to be corrected before it is realistic to apply International Technical Standards of Seed Inspection. Many advanced equipment and technologies have been introduced in China to improve technical levels of seed inspection. In the very near future, many of the current limitations will be overcome, and domestic forage seeds will have the same level of quality and quality control as those in international markets.

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