Adaptation and stability of vegetable soybean genotypes in Uganda

Abstract

Vegetable soybean (Glycine max L. Merr.) is a specialty soybean, harvested as a vegetable when seeds are immature (R6 stage) and have expanded to fill 80 to 90% of the pod. The objective of the study was to assess the adaptation and stability of vegetable soybean genotypes in different agro-ecological zones of Uganda to enable selection of genotypes. A total of 21 genotypes were planted in Uganda for two consecutive seasons. Genotypes PI615437-B had the highest number of pods, while AGS 329 matured earliest in 64 days. Only AGS 292, AGS 329 and AGS 338 had 100 seeds weight above 30 g. G10427 was the ideal genotype in terms of adaptation and stability for fresh seed yield, with mean yield of 4281kg ha-1; followed by G2843 with 4039 kg ha-1. PI615437-B came third with fresh seed yield of 4024 kg ha-1. The least stable and adapted genotype was AGS 329 with only 1609 kg ha-1. Nakabango 1 and MUARIK 1 were the ideal environments, which were the most discriminative and representative. We recommend that G10427 be used as a test genotype and for improvement to produce a variety with good attributes, especially large seed, high yield and adaptable to Uganda.

Key words: Discriminative, Glycine max, specialty bean