Conservation of mulberry germplasm on long-term basis requires huge resources and manpower and must be accompanied by effective utilization of germplasm resources on sustainable basis to justify long-term investments. In the backdrop of dwindling natural seribiodiversity with changing global climatic scenario, it is assumed that all genetic resources are potentially valuable and to be conserved for posterity. Present value of the existing resources cannot be assessed because of future developing technologies. This ends up in accumulating vast genetic resources in the field gene bank year by year. Hence, it is imperative to analyse the cost of the biodiversity conservation and its sustainable utilization. The documentation acts as sources of information to assist in the setting of the priorities, planning and operation of germplasm management. For effective information management of PGR, a complete inventory of the mulberry genetic resources of the nation with their Passport has to be developed. The information can be useful, meaningful and economical when it is properly analysed and logically organised to make it user friendly, easily available and retrievable.
Realizing the importance of information system in the germplasm management, CSGRC, Hosur developed an information system named Mulberry Germplasm Information System (MGIS) in international accepted language English (Fig-9) incorporating various facilities (Sekar et al. 1997). This system will work on MS-DOS platform and can be viewed on a VGA with resolution of 640 * 480 resolutions. While developing the system, the standard packages in the use at NBPGR, New Delhi and CYMMIT were taken into consideration so as to make the packages friendlier with scope for broad-spectrum o applications. In order to MGIS more meaningful and user friendly, the standard data format in terms of terminology and measurements with integrated database techniques were used. User-friendly menu driven facilities have been incorporated for easy data viewing, information retrieval, updating and report generation. Each file is linked to the National accessioning number which is a unique number assigned to each accession serving as primary key. The query module has the facility for identification and selection of accessions on the basis of certain desirable criteria up to 15 quantitative/qualitative characters has been developed as a separate module to facilitate breeders/users for utilization of information. The system is flexible enough to allow modification and insertion of new modules as per the changing needs of the scientists. In future, MGIS will be developed in Window platform using GUI (Graphic User Interface) technology.
The different descriptors on passport data, collection data, characterization data (morphological, leaf histological, reproductive behaviour, cytological and biochemical) and evaluation data (growth and yield parameters) and their detailed descriptor states are presented in Annexes 1-7. For standardization of the formats and data recording of different descriptors of characterization and evaluation, the standard methodologies are to be followed for comparison of the data.
3.2.1 Methodology for morphological characterization
The morphological data has to be recorded in the base collection of three years old plants, maintained as high bush/dwarf tree with spacing of 2.4 m ´ 2.4 m distance and crown height of 1.5 m with recommended cultural practices for high bush maintenance. The plants have to be pruned twice in a year i.e. in Feb-Mar and July-Aug for recording of data. The different morphological data has to be recorded after 75-90 day of pruning in both the seasons.
3.2.2 Methodology for reproductive characterization
The reproductive characterization has to be recorded in the main flowering season (February-March). Fully bloomed catkins of different accessions should be randomly collected and the length and breadth and the pedicel length of the different catkins should be measured. Number of flowers/catkin of different sexes should be counted by dissecting the individual flowers around the rachis of the inflorescence. Style length and stigma length, nature and type of the female flowers are to be recorded by dissecting them under stereomicroscope at receptive stage. The stigma is receptive from 8-12 days after floral initiation. The male catkins should be collected at 10 am in the morning at the time of anthesis in plastic bags and the stamen and the anther length should be measured under the stereomicroscope using ocular eyepiece micrometer. For studying the pollen diameter, viability and number of pollen germ pores, the mature pollen grains should be dusted on a clean slide from the male flowers and stained with 2% acetocarmine solution for 30 minuets and studied under the microscope. Fully ripened sorosis should be collected and different fruit characters like fruit length, breadth, pedicel length, weight, colour and taste to be recorded. For studying the different seed characters the fruits are to be soaked in water for over night and the seeds are properly cleaned with water. The floated seeds are rejected and only the healthy seeds, which are deposited in the bottom, are separated and dried on blotting paper. For calculating the seed set percentage prior to washing the number of acnes per fruit and number of seeds per fruit is to be recorded separately.
3.2.3 Methodology for leaf histology
Fully expanded leaves from 7th to 9th position in descending order from three months old pruned shoots in base collection are to be considered for the study. Small rectangular pieces should be taken from the central portion of the leaf blade avoiding veins and veinlets and preserve in the FAA solution. Quick fix replicas from adaxial and abaxial surfaces of the preserved leaf samples to be used for studying the stomatal size and idioblast frequency. While measuring the stomatal sizes care to be taken to avoid giant sunken stomata. For counting the number of chloroplast in the stomata, fresh epidermal peelings from 5th to 7th position leaf from the top of the branch in a descending order to be considered. For measuring the idioblast projection length, cystolith length, breadth and thickness of different layers such as cuticular, epidermal, palisade, spongy and total leaf thickness, thin hand sections of the preserved leaf material has to be taken and stained with 1% safranin and mounted in 50% glycerine. For all the characters three leaves per plant and three plants per accession are to be considered.
3.2.4 Methodology for cytological characters
The detailed karyotype studies can be made by selecting the well spread mitotic plates and all the chromosome measurements like short arm length, long arm length, total chromatin length, satellite bearing chromosomes are to be made from the camera Lucida drawings or from photomicrographs in mm and then converted to microns. All the measurements are to be tabulated separately and homologous pairs are to be arranged in the descending order of total length.
3.2.5 Methodology for growth and yield attributing parameters
The plants are to be maintained in row with 2.4 × 2.4 m spacing, as dwarf tree with crown height of 1.5 m. Recommended cultural operations for dwarf tree maintenance has to be followed. The plants are to be pruned twice in year in spring (February-Mar) and autumn (June-July). The data on different growth parameters has to be recorded when the plants attained three years of age and after 75-90 days of pruning considering at least three plants/accession. Moisture content of the excised leaves and moisture retention capacity (after six hours storage) has to be determined using equal number of top, medium and mature leaves by gravimetric method by using the formula.
The first ever catalogue on mulberry germplasm (Thangavelu et al. 1997) was published wherein the characterization and evaluation data of 328 mulberry germplasm accessions have been presented. The sample pages of mulberry catalogue are given in Annexure-10. The data is also available in the Website www.silkgermplasm.com. This website will be updated as and when the new data is generated. The sample pages of the website is given in the Annexure-11.
Mulberry plant genetic diversity is unevenly distributed over the globe and most of its diversity is concentrated in the tropical and subtropical geographical zones. No single country is self sufficient in PGR. The development of the global system on PGR began after the establishment of Communication on Genetic Resources for Food and Agriculture (CGRFA) by FAO. Presently 161 countries are the members of this commission. The main objectives are promotion and utilization of PGR by providing flexible framework for sharing information and developing networking activities, interaction, agreements, code of conduct, scientific standards and instruments for PGR management. The International Undertaking on Plant Genetic Resources (IUPGR) and CBD advocates the utilization of PGR with benefit sharing, on the contrary TRIPS and UPOV (Union for Protection of New Varieties of Plants) stressed on demand on ownership rights, which restricts the global exchange of PGR.
Morus diversity is rich in South Asian countries mainly in Japan, China, India, Thailand, Indonesia and Korea. The native genes of Morus species of continental America are untapped for sericulture development. The sharing of mulberry germplasm information and vis-à-vis utilization of genetic resources at global level is hitherto running at slow pace due to non coherence of international understandings over the issues related to plant genetic diversity and utilization. Today mulberry germplasm resources are available in 30 countries or more. There is an urgent need to establish the International Networking on Mulberry Germplasm Management and Utilization at global level. Japan is assisting developing countries through its JICA programme. However, special emphasis to be given for international training programmes on mulberry germplasm management under JICA.