Regenerating callus, roots and shoots of jatropha curcas (L) in-vitro and optimizing seed germination
Jatropha curcas is among the important tree crops in the world with a potential for biofuel production. The crop is drought resistant and thrives well in warm tropical climates. However, propagation material is a major production constraint. Currently seed and stems are the main materials used for propagation. Reports have shown that the seed has several aspects that constrain production efforts such as low viability, poor germination rates and varying cultivation information. Laboratory and greenhouse experiments were conducted to test for the best micro propagation and seed germination methods in the plant. Tissue culture trials using MS media with supplements of various hormonal concentrations including BAP, IBA, IAA, NAA, Kinetin, Zeatin and Adenine sulphate. From experiment 1, callus formation using explants (shoot tip, leaf and stem), the media containing BAP4mg/I+IBA2mg/1 gave the earliest callus formation date of mean of 8.3 on stems compared to BAP8mg/I+IBA4mg/I, NAA4mg/I+IBA2mg/1 and control(No treatment) and earliest days to shooting, mean 15 on shoot tips. The BAP4mg/I+1BA2mg/1 combination gave the highest callus amount of mean 2.3, and the longest shoots, mean 0.26 on shoot tips. In experiment 2, BAP8mg/I, IBA4mg/I, NAA2mg/1 and BAP8mg/I+NAA2mg/1 were used to culture stem, leaf and shoot tip explants. The BAP8mg/I+NAA2mg/1 combination gave the earliest callus formation dates of mean 8.3 on shoot tips, BAP gave highest amount of callus of 2.2 on shoot tip while shooting was only observed on shoot tip under BAP culture with a mean of 9.2 days to shooting. Experiment three involved using BAPlmg/I+IAAO.2mg/I,BAPlmg/I+KnO.5mg/I, BAPlmg/I+IBAlmg/I, BAPlmg/I+ZeatinO.5mg/I, BAPlmg/I+KnO.5mg/I+As2mg/1 applied on shoot tip, stem and leaf explants in Jatropha curcas. Only the shoot tips produced shoots with the earliest mean days to shooting of 7.47 and mean number of shoots of 3.4 in the BAPlmg/I+KnO.5mg/I+As2mg/1 combination. The fourth involved trials on four seed variety levels TS Morogoro, TZ Arusha, Pemba and Zanzibar cultured in BAP(lmg/l), IAA(O.2mg/I),NAA(O.2mg/l), IBA(lmg/l) ,Zeatin(O.5mg/I), Kinetin(O.5mg/I). BAP lmg/I gave the earliest mean days to shooting of 21 and highest mean number of shoot buds of 1.2, the longest shoots with mean 0.32cm and earliest days to rooting with a mean of 22 Experiment 5, four seed varieties, TS Morogoro, TZ Arusha, Pemba and Zanzibar cultured in BAPlmg/I+IAAO.2mg/l, BAPlmg/I+KnO.5mg/l, BAPlmg/I+IBAlmg/l, BAPlmg/I+ZeatinO.5mg/l, NAAO.2mg/I+KnO.5mg/1 and BAPlmg/I+KnO.5mg/I+As2mg/1. Cultures Morogoro variety in BAPlmg/I+IBAlmg/1 combination gave the earliest mean number of days to shooting of 17.2 and the highest mean shoot length of 0.32cm. The highest number of shoot buds with mean of 1.2 was obtained from the same variety under BAPlmg/I+IBAlmg/1 and BAPlmg/I+KnO.5mg/I+As2mg/1 combinations. The earliest mean of days to rooting, mean 20.6 was attained form the BAPlmg/I+IBAlmg/1 combinations with the Morogoro variety. Rainfed, Irrigated and Kitui varieties of Jatropha were subjected to four treatment levels; plastic pots covered with polythene paper, polythene bag container, the third plastic pots containing soil sand mixture and the fourth plastic pots only. The irrigated variety under polythene cover gave the best heights of mean 16.50cm at 14 days and 17.23cm at 21 days after planting. The rainfed variety under polythene bag container and the irrigated variety under polythene covered container gave the highest percent germination of mean 81.25%. Under polythene cover, the irrigated variety gave highest mean number of 3 leaves per plant at 14 days after planting and mean 3.75 leaves at 21days after planting. The earliest mean of germination days of 6.5 was obtained from Kitui variety under polythene bag containers. Seven seed varieties were tested for germination under five sets of treatment in the first experiment. Plastic pots covered with polythene paper, polythene bag container, the third plastic pots containing soil sand mixture, the fourth plastic pots only and the fifth had soil manure mixture in plastic pots. The earliest mean germination date of 10.25 were obtained from both polythene(TS Morogoro) and covered containers(TS Morogoro, Arusha and T3 Tanga) while the best mean height of 17.9cm was obtained from the covered plants(Pemba). Both the polythene container and covered trials had an equal mean number of 3 leaves per plant. The highest mean percentage germination was 100% and obtained from seeds germinated in plastic containers(TZ Arusha). In the temperature experiment, two seed types were subjected to 34,36,38 and 40 degree temperature treatments. At 40 degrees, the earliest mean of days to sprouting, the highest germination percentage of 88% ( irrigated variety), the highest mean stem length of 4.2cm and the highest number of leaves, 3(all varieties) were attained. On the laboratory desktop, seven seed varieties, were placed in two sets of base medium: petridishes aligned with filter paper and petridishes aligned with cotton wool. Each of the treatments attained a mean early sprouting date of 3 except the filter paper. Medium containing cotton wool base gave highest mean percent germination of 100% on the TZ Arusha variety. The highest mean root length of 1.7 cm was attained by presoaked Arusha variety while the cotton base gave the highest shoot length of 10.5cm. The experiments used the completely randomized design(CRD). Data was analyzed by ANOVA to detect significant differences between means. Means differing significantly were compared using Duncan's Multiple Range Test (DMRT) at 5% probability level.