GERMINATION PHYSIOLOGY OF AFRICAN BIRD’S EYE CHILI SEED

Abstract

Seed germination parameters may be determined by stage of seed maturity and the level of dormancy. These parameters subject the seed to varied responses on sensitivity to environmental factors that stimulate germination such as gibberellic acid, priming treatments, light and the range of temperature over which germination can occur. Capsicum frutescens seeds show erratic physiological maturity with low germination and vigour besides being physiologically dormant. The overall objective of the study was to determine the effects of fruit harvesting stage and seed treatments on physiological quality of seeds as well as the best conditions for seed germination. Seed samples were subjected to different germination regimes of constant temperatures (15oC, 20oC, 30oC and 35oC) and alternating temperatures (20oC/30oC and 25oC/30oC) under different photoperiodic regimes. Seed samples from differently matured fruits were subjected to priming using KNO3 (concentrations of 0.2%, 0.5% and 0.8%), and polyethyl glycol (PEG6000) (concentrations of -0.2Mpa, -0.6Mpa and 1Mpa); and gibberellic acid treatments (concentrations of 0.02%, 0.05% and 0.08%). Germination assays were done under light and temperature conditions. Fruits were tagged at flowering and seeds harvested at different fruit maturity dates from 20 days after flowering to 75 days after flowering with a step of five days. Percentage germination, mean germination time, first count, 1000 seed weight, seed moisture content, seed dry weight and electrical conductivity tests were performed. The experimental data obtained from different parameters tested was subjected to analysis of variance (ANOVA) and separation of means was done by Contrast Comparison at 95% level of significance. Temperature had significant effect on germination (p≤.001), with the highest percentage germination of 57% being recorded at a temperature of 25oC. Primed seeds and seeds treated with gibberellic acid had high percentage germination and germination vigour as compared to controls irrespective of the fruit colour and germination conditions (p<.001). The highest values were recorded from seeds that were harvested from red fruits and germinated under darkness (p<.001). Seeds that were harvested from fruits at 75 days after flowering when the fruits were red in colour had maximum germination and vigour values. For maximum seed vigour and germination, seeds should be harvested from red fruits and germinated under constant optimum temperatures of 25oC. Where priming is a necessity, potassium nitrate is the most suitable at concentrations of 0.5%. Treatment with GA3 should be done at a concentration of 0.08% and germination is more optimum if treatments are germinated in high temperatures in the presence or absence of light.