ENHANCEMENT OF SEED GERMINATION IN THE AFRICAN EGGPLANT (Solanum aethiopicum)

Abstract

African eggplant (Solanum aethiopicum) is an important indigenous vegetable in Tanzania with seed dormancy problem. The overall objective of the study was to improve germination of African eggplant seeds. Two different seeds sources were from Agricultural Seed Agency (ASA) field. A lab experiment was carried out in KEFRI-Muguga. Treatments were completely randomized (CRD) in a growth chamber. Each source consisted of two varieties of this crop, DB3 and Tengeru white. Source one seeds were extracted from fruits harvested at different physiological maturity stages, when were red, yellow red and yellow green. Source two seeds were harvested after every two weeks (14 days) at full red stage between 30 and 72 days after anthesis(DAA). Source one seeds were subjected to the following Cardinal temperatures from 15oC, 20oC, 25oC, 30oC and 35oC to determine the optimum, minimum and maximum temperatures for germination of the crop which were found to be 25oC, 15oC and 30oC respectively for Tengeru white while DB3 germinated only at 30oC and 25oC.The data for source one seeds were subjected to ANOVA using GENSTAT package version 12.2. Seeds germination percentages were highly significant at P = 0.001 under all temperature regimes. Source one seeds were also subjected to alternating temperatures 30/25oCand 30/20oC in 24 h continuous light. Results indicated that, Tengeru white attained higher germination (87%) while DB3 attained 21% under 30/25o in continuous light. When DB3 subjected to GA3 (0.01%, 0.02% and 0.03%) and KNO3 (0.1%, 0.2% and 0.3%) at 30/25oC for 24 h continuous darkness, the effect of these chemicals were highly significant at P = 0.001 on influencing germination whereby higher germination (35.38%) was recorded with GA3 0.03%. When GA3 concentrations was raised to 0.05%, 0.08%, 0.1% and 0.2% at 30/25oC (24 h continuous light), germination increased significantly at P = 0.001to 68.45% at 0.1%. Source two seeds which were harvested at different physiological maturity stages, 30, 44, 58 and 72 days after anthesis were subjected to GA3 = 0.1%, 0.2% and 0.3% in alternating 30/25oC in both continuous darkness and continuous light for 24 h. The data generated were subjected to ANOVA using GENSTAT package version 12.2. Results indicated that, at 72 DAA, Tengeru white seeds attained 80.33% while DB3 seeds attained 38.04% without chemical treatment. When treated with chemical,Tengeru white recorded higher germination at 0.2% GA3, though this was not statistically different from control (33%). This suggests that, when harvested at its physiological maturity(72 DAA),Tengeru white can germinate well without chemical treatment. DB3 on the other hand, required GA3(0.1%) to attain higher germination percentage (68.45%) when harvested at 72 DAA. Seeds harvested between 30 DAA and 44 DAA recorded lower germination percentages. It is therefore recommended that, for seed production, both varieties should be harvested 72 DAA and germinated under alternating temperature 30/25oC in continuous light. Further research however needs to be done on breeding to reduce DB3 seeds dormancy and raise germination percentage for DB3 from 68.455 to 100%.