0673-B4

MACROPROPAGATION OF Oxytenanthera abyssinica (A.Rich) Murno From Culm Cuttings in the Nursery

Eiman Elrasheed Eltayeb Diad ¹ & Ahmed ElHouri Ahmed ² & Syadat Eltigani Mohamed ³

Abstract

Bamboos are versatile row material, which can be used for food, building materials, artifacts and raw materials for production of pulp and paper products. Unlike most of the other forest tree species Bamboos are fast growing and capable of annual returns. In Sudan, there are two indigenous species i.e. Oxytenanthera abyssinica (A.Rich Murno) in the plains and at the foothills in the high rainfall savannah and Arundinaria alpina (K.Schuni) in the Imatong mountains and is of less importance than the former. The problem of Oxytenanthera abyssinica is that it has a very long vegetative phase of growth before it flowers. Flowering is followed by the death of the clump. This vegetative phase is estimated to last 30 -40 years. Since seeds are produced at long intervals, vegetative propagation was resorted to for propagation of the species in the nursery at ordinary conditions (macro- propagation) of temperature at 40ºCat summer and 14 ºC in winter, provision of irrigation, silt and sand for potting mixture and shading at the early stage. The rooting percentage of cuttings was 42% in winter, which was significantly better than that in the summer, which was 30%. The two-noded cuttings were significantly better than one -noded cuttings. Also cuttings taken from the basal part of the culm were best in rooting followed by those taken from the middle, while those taken from the top failed to root. Horizontal planting was better than vertical planting. When IBA was added to enhance cuttings to root; 4000 ppm of IBA gave 46% of rooting compared to 34.4 % when a concentration of 2000 ppm was applied. The 4000 ppm and 2000 ppm concentrations were significantly different at p < 0.05 than those treated with 1000 ppm and the control. Cuttings do not root without IBA application.

1. Introduction

Bamboos cover large areas of tropical and sub tropical regions and had been subjected to depletion by bad management or lack of it. As a result, regeneration cannot keep pace with exploitation and there is a need for development of management practices to secure regeneration, protection, and maintenance of sustained production.

In Sudan, there are two indigenous species i.e. Oxytenanthera abyssinica (A.Rich Murno) and Arundinaria alpina (K.Schuni). The former is more important as it has a wider distribution and therefore commonly used than the later, which has a limited distribution in the higher lands of the Imatong Mountains .A part from taxonomic studies, very little work was done on the indigenous bamboos of the Sudan (Elamin, 1990). This work, therefore, concentrates on the problems of Oxytenantherea abyssinica, which shall be referred to in the text as the species.

In the Sudan, increasing areas were used for agricultural crop production without regard for the negative environmental impact. Rotations and inputs to restore soil fertility were rarely used except to a limited extent in the modern irrigated sector (El Houri, et al., 2001). The needs for food and forests products increased with increasing populations, which put tremendous pressure on the natural resources of forests and rangelands. The situation has been worsened by social conflicts and civil strife in the Sudan and neighbouring countries, which resulted in a large number of displaced people in the country and refugees from neighbouring countries. The displaced persons and refugees have immediate needs for wood particularly for energy and shelter. Bamboos are perennial woody grasses that are fast growing and capable of producing utilizable annual production, which is not normally the case with other forest tree species. It could meet part of the needs of the population for construction, furniture, energy, pulp and paper products in the future .The problem of Oxytenanthera abyssinica is that it has a very long vegetative phase of growth before it flowers and this is followed by the death of clump. This vegetative phase is estimated to last 30 -40 years (Sharma, 1980; Kigomo, 1988; ElHouri, 1997). Therefore seeds are rare and not easily available. It became necessary, therefore, to resort to vegetative methods for propagation for reproduction and multiplication of the species for production of seedlings for various purposes including afforestation, agroforestry and other purposes.

Bamboos can be propagated using vegetative parts such as rhizomes, culms, branches and nodal buds. Bamboos could be propagated from branch cuttings Which is applicable for most bamboo species e.g. Dendrocalamus asper, Gigantocheoa aspera, and G. ligulata. Thick walled bamboo species have large and dominant primary branches consisting of root primordia and dormant buds at the base of the branch (Rungnapar, 1988). Also successful propagation of bamboos from the main culms were reported for many species e.g. Bambusa vulgaris (Khan, 1966). B. balcoa,B. nutani. Dendrocalamus hamittoni, D. hookeri (Das, 1988). Bambusa textitils var fasca, B. multiplex, B. gilla, B. chungii, (Zhang et al., 1997).

2. Objectives

The main objective is to find the optimum method for successful propagation of the species from culm cuttings at normal nursery conditions. The detailed objectives are to find:

1) The effect of the season when cuttings were prepared on the success of propagation from cuttings.
2) The effect of type of cuttings (one noded and two noded cuttings) on the success of propagation.
3) The effect of method of planting (horizontal-vertical planting) on propagation.
4) The effect of position where cuttings were taken from the culm (top-middle-basal part of the culm) on propagation.
5) The effect of auxin concentrations Indol-butyric acid (IBA) concentrations (0-1000-2000-4000ppm) on the regeneration from cuttings

3. Materials and methods

1. Source of cuttings

Culm cuttings were prepared from new culms (less than one year old) from clumps of a plantation of Oxytenanthera abyssinica at Abu Gaili Forest near Sinner (Blue Nile State at latitude 13º 36ˉ and longitude 23º 36ˉ). The plantation was established 1994 and therefore it was about 4 years old at the time of the experiment.

New culms usually have active buds whereas old culms usually carry dormant buds. The new culms were examined morphologically to ascertain the existence of buds, which may grow and form culms.

2. Type and position of cuttings

Two types of cuttings were prepared:

a) One-noded cuttings, approximately 25cm in length and 5cm in diameter.
b) Two-noded cuttings, approximately 40cm in length and 5cm in diameter.

The cuttings were defoliated and the axillary buds were left intact. Approximately equal proportions of the internodes were left on both sides of the single-noded and two noded cuttings. Cuttings were prepared from the top, middle and basal part of the culms.

3. Medium used and method of planting

The prepared cuttings were planted in a soil medium consisting of a thin layer of silt covered with sand. This mixture was placed on concrete beds of 150x50x30 cm (length x width x depth). The beds were covered with plastic sheets laid on a metal frame about 30-50cm above the ground to create suitable conditions for rooting e.g. diffused light and to maintain high relative humidity.

Two methods of planting the cuttings were used:

a) Vertical method, where one-node was buried in the soil.
b) Horizontal method, where cuttings were buried horizontally and covered with a thin layer of the soil.

4. Auxin treatment

Indol-3-butryic acid (IBA) was the auxin used throughout the experiments. The concentrations used were 4000ppm, 2000ppm, 1000ppm and 0ppm as control. The dip method was used throughout the experiment; the basal ends of the prepared cuttings were dipped in the prepared auxin solutions, which were put in a plastic tray. The treated cuttings were left for 16-20hrs in the solutions at laboratory temperature (24-25ºC). Then the cuttings were planted as described above and watered daily and kept moist by watering whenever necessary.

The experiments were conducted in summer and winter where the mean maximum temperature was about 40ْºC during summer and the mean minimum temperature was about 14-10ºC ْin winter season.

3. Experimental design and statistical analysis

The layout adopted was randomised complete block design with ten replicates for each treatment.

The following parameters were recorded every 4 weeks

1. Percentage of cuttings with sprouting shoots.
2. Shoot length.
3. Root length.
4. Percentage of rooting cuttings.

4. Results and discussion

4.1 effect of season on the performance of cuttings:

Table (1) shows the percentage of cuttings with sprouting shoots, which reached 32% and 49.2% for those, prepared in summer and winter respectively after five months in the nursery. Whereas the percentage of rooting cuttings reached 30% and 42% in summer and winter respectively for the same period in the nursery.

The percentage achieved by cuttings with sprouting shoots and rooting prepared in summer and winter after 1, 2, 3, 4, and 5 months in the nursery are shown in Fig (1) and Fig (2) respectively. Shoot length of the cuttings taken in summer which reach 22cm and those taken in winter reach 32 cm, which is significantly different at P< 0.05. The root length of the cuttings taken in winter (18.1cm) was significantly greater at P<0.05 than those taken in summer (12.6 cm). The root number of the cuttings taken in 4.8 was also significantly greater at P< 0.5 than in those taken in summer 2.4 all these differences were statistically significant at P< 0.05.Cuttings started to initiate roots in the second month after planting in winter whereas in summer the cuttings started to initiate rooting at the third month after planting. These results agreed with Lin (1995), who recommends that cuttings taken from Bambusa odonii should be taken in winter season. Also, Sirikalyanon et al. (1997) concluded that the best season for planting cuttings is winter for Dendrocalamus hamiltonii.

Table (1): Effect of season on performance of the cuttings of Oxytenantherea abyssinica, after five months in the nursery.

Fig (1): The percentages of sprouting and rooting cuttings of Oxytenanthera abyssinica in summer, after five months in the nursery.

Fig. (2): The percentages of sprouting and rooting cuttings of Oxytenanthera abyssinica in winter, after five months in the nursery.

4.3 The effect of type of nodes:

Table (3) shows that the percentage of sprouting cuttings in summer and winter season for one noded cutting reached 33% and 38% respectively. The differences in percentages was significant at P<0.05. Double noded cuttings reached 54%and 68% of sprouting cuttings in summer and winter season, and the differences in percentages was significant at P<0.05.Also, the percentages of rooting cuttings was significantly greater at P<0.05 in double noded cuttings 33.4 and 44.7 in summer and winter seasons respectively compared with 25.9 and 35.2 rooting cuttings percent in the single noded cuttings in summer and winter season respectively Fig (4).

Table (3): The effect of type of cuttings on the performance of cuttings of Oxytenanthera abyssinica in summer and winter season, after five months in the nursery.

Fig. (4): The effect of Type of cuttings on the percentages of rooting cuttings of Oxytenanthera abyssinica in summer and winter, after five months in the nursery.

Table (3) shows the effect of type of nodal cuttings (single node and double nodes) on the shoot and root length and root number of cuttings. It appears that there was no significant difference at P<0.05 in the length of shoots of the cuttings with double nodes in summer and winter seasons. However, in summer season, the numbers of roots in the cuttings produced from the double noded cuttings were significantly greater at P<0.05 than those produced in the single noded cuttings viz. 4.2 and 2.7 respectively

The same sequence occurred in winter season, where the number of roots from propagules of single noded cuttings were significantly less at P< 0.05than those of double noded cuttings viz. 2.9 and 5.1 respectively. These results agree with the results reported by Bohidar (1989) who recommended that the two noded cuttings were usually more successful that one noded cuttings. In contrast with the result obtained by Das (1988) who found a success rate of 80% from single noded culm cuttings in Bambusa nutans compared with 60% in the two noded cuttings of the same species . These results confirm the results obtained by Castillo (1990) who recommended the use of cuttings having at least two nodes for Dendrocalamus merrillianu

4.4 The effect of IBA concentrations:

Table (4) shows that the percentage of sprouting in the untreated cuttings and those treated with IBA at concentration 1000ppm were significantly different at P<0.05 than those treated with 2000ppm and 4000ppm in the summer and winter season.

Fig (5) shows the percentage of rooting cuttings in those treated with IBA hormone with different concentrations in the summer and winter season. It appears that the percentage of rooting cuttings is highly significant in the cuttings which where dipped in the various concentrations of IBA.

Cuttings treated with IBA at 4000ppm initiated higher percentage of rooting cuttings 41.4% and 46.2% in summer and winter seasons respectively. Those were significantly different at P< 0. 05 than those treated with IBA at 2000ppm, which initiated rooting percentage of 28.1% and 34.4% in summer and winter seasons respectively. The untreated cuttings failed to initiate roots and those treated with IBA at concentration of 1000ppm initiated roots with percentage of rooting of 10, 16.5 in summers and winter season respectively.

Shoot lengths of the cuttings treated with IBA concentrations (1000, 2000, 4000ppm) reached 26, 27, 31cm respectively. They were significantly different at P<0.05 than the shoot lengths of untreated cuttings, which reached 16.8cm shoot length in summer season. The same sequence occurred in winter season where the shoot lengths of the cuttings treated with IBA at concentrations of 4000, 2000 and 1000ppm reached 33, 30, 27cm respectively, which were significantly difference at P<0.05 than the shoot length of untreated cuttings.

The root lengths of the cuttings treated with IBA concentrations at 2000, 4000ppm were significantly different at P<0.05 than those treated with IBA at concentration of 1000ppm, which reached 4.2cm in summer.

Cuttings treated with IBA at concentrations 2000, 4000ppm reached root lengths 14.1 and 16.3cm respectively in summer season. The same pattern appeared in the winter season. There were no significant difference at P<0.05 between the lengths of root produced from cuttings treated with IBA concentrations of 2000, 4000ppm. They produced a length of 15.7 and 17.7cm for winter respectively. However there were significantly different at P<0.05 from those cuttings treated with IBA concentration of 1000ppm, which reached a root length of 6.0cm and 4.2cm in winter and summer respectively. Both in summer and winter season, the number of roots produced from cuttings treated with IBA with concentrations 2000, 4000 ppm, were significantly different than those treated with IBA with concentration of 1000ppm.

These results are in line with McClure (1986) who recommended the use of IBA, which increased the ability of cuttings to initiate roots, which reached up to 54%of rooting in Bambusa textis. The findings are also in line with Surendern et al. (1985) who reported that IBA and NAA as effective hormones increasing the success rate to 80% in B. arundinacea , 70% in Dendrocalamus strictus and 50% in D. scrpteria. The results agree also, with Abd. Razak and Aminuddin (1995) who showed that the use of IBA at 2000 ppm promoted the growth of the cuttings of Gigantochloa levis.

The results are also confirmed by Nagariaiah (1994), who reported an increased rooting percentage of the cuttings of Bambusa vulgaris by using growth regulating substances.

4.5. Effect of method of planting:

The method of planting vertically or horizontally, produced significant effect on the percentage of sprouting, rooting cuttings, the shoot and root length. The cuttings planted horizontally gave successful propagules whereas the vertically planted ones especially the two noded cuttings failed to sprout successfully in summer and winter seasons (Fig. 6). So the recommended method of planting would be horizontally, and this agrees with Dong et al. (1999) and Pyare et al.(1998) who reported that, the best method of planting cuttings is to plant them horizontally.

Plate (1) shows successful, rooting cuttings of the species treated with 4000ppm, five months after planting in winter. Also Plate (2) shows successful rooting cuttings of the species taken from the basal part of the current year culms with addition of 4000ppm of IBA, four months after winter planting. Plate (3) shows successful rooting cuttings, treated in the same manner with 4000ppm of IBA in winter 9, 12months after planting.

Table (4): Effect of IBA concentrations on the performance of cuttings of Oxytenanthera abyssinica after five months in the nursery.

Fig:(5) The effect of IBA concentrations on the percentages of rooting cuttings of Oxytenanthera abyssinica in summer and winter, after five months in the nursery.

Fig:(6) The effect of method of planting on percentages of sprouting cuttings of Oxytenanthera abyssinica in summer and winter, after five months in the nursery.

5. Conclusions

a) One year or less old culms are more suitable as explants for cuttings.
b) Winter is the best season for propagation from cuttings where the percentage of rooted-cuttings reached 42% while it reached 30% in summer.
c) Cuttings taken from the basal and middle part of the culm gave a higher rooting percentage 36.8 and 44% respectively than the cuttings taken from the upper part of the culm, which failed to produce roots.
d) Two-noded cuttings gave the highest rooting cuttings, which reached 44.7% while those from one-noded cuttings reached 33.2%. Hence it is recommended that 2-noded cuttings be used for propagation followed by one-noded cuttings.
e) Horizontally planted cuttings rooted while those vertically planted failed to root. It is therefore recommended that cuttings be horizontally planted for propagation from cuttings. f) In winter season cuttings treated with IBA at 4000, 2000, 1000ppm gave 46, 34.4, 16.5 percentage of rooted cuttings respectively while cuttings treated with no IBA (control) failed to root. It is recommended to use 4000ppm followed by 2000ppm and only 1000ppm in case of scarcity of IBA.

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¹ National Centre for Research Institute of environment and Natural Recourses Box 6096
² University of Khartoum. Faculty of Forestry.
³ University of Khartoum. Faculty of Sciences.