EFFECT OF BLENDED NPSB FERTILIZER RATES ON GROWTH, YIELD AND YIELD COMPONENTS OF SESAME (Sesamum indicum L.) VARIETIES AT KONSO, SOUTHERN ETHIOPIA MSc

Abstract

Sesame is an important cash and food oil crop in the low lands of Ethiopia. Declining soil fertility and inadequate extension and demonstration of improved high yielding varieties are the major constraints for sesame production at the study area. Thus, Sesame varieties response to rates of blended NPSB fertilizer was studied at Konso, Southern Ethiopia, during 2019/2020 cropping season to determine sesame varieties and blended NPSB fertilizer rate on growth, yield, and yield components. The experiment consisted of three sesame varieties (Setite-1, Setit-2, and Gonder-1) and five blended NPSB fertilizer rates (0, 50, 100, 150 and 200kg NPSB ha-1). The experiment was laid out in Randomized Complete Block Design (RCBD) with three replications. The collected data were to days to 50% flowering, days to physiological maturity, plant height, number of nods plant-1, number of branches plant-1, number of capsules plant-1, number of seeds capsule-1, 1000 seed weight, above ground dry biomass, harvest index, seed yield, oil content and oil yield. The collected data was subjected to analysis of variance (ANOVA) using Statistical Application Systems (SAS) software version 9.0. Significant difference among the means was separated using Least Significant Difference (LSD) at 5% probability level. Results of analysis showed that days to 50% flowering, days to physiological maturity, plant height, number of nods plant-1, number of branches plant-1, number of capsules 1, number of seeds capsule-1 and 1000 seed weight and oil content were significantly (p˂0.05) affected due to sesame varieties and blended NPSB fertilizer rates while their interaction were not significant. Above ground dry biomass, harvest index, seed yield and oil yield were significantly affected due to sesame varieties and blended NPSB fertilizer rates as well as interaction of both. Maximum number of days to 50% flowering (63) and physiological maturity (97) were recorded from Gonder-1 variety and oil content (56.84%) was recorded from variety Setit-1. Variety Setit-2 showed maximum plant height (153.83cm), number of nods plant-1 (31), number of branches plant-1 (8), number of capsules plant-1 (129), number of seeds capsule-1 (67) and 1000 seed weight (3.52g). The highest number of days to 50% flowering (54), days to physiological maturity (93) and plant height (146.17cm) were recorded at 200kg NPSB ha-1. The highest oil content (58.51%) was recorded at 200kg NPSB ha-1. The highest nods plant-1 (32), number of branches plant-1 (8), number of capsules plant-1 (141), number of seeds capsule-1 (68) and thousand seed weight (3.87g) were recorded at 100kg NPSB ha-1. The highest above ground dry biomass (4298.96kg ha-1), harvest index (25.6%), seed yield (1099.33kg ha1) and oil yield (616.16 kg ha-1) were recorded from variety Setit-2 with 100kg NPSBha-1. Economic analysis indicated highest net benefit (23,085ETB ha-1) with Marginal Rate of Return (MRR) (827.13%) was recorded from variety Setit-2 with application of 100 kg NPSB ha-1. Thus, blended fertilizer at rate of 100kg NPSB ha-1 and Setit-2 would be tentatively suggested for the study area even though further study could be carried out-over seasons and locations to make a conclusive recommendation