Genotype x environment interaction of common bean (Phaseolus vulgaris L.) genotypes on reaction to four bean diseases

This study was carried out to assess the performance of advanced common bean lines (BC 2 F 6 ) to diseases (Angular leaf spot, Common bean blight and Bean common mosaic virus/Bean common mosaic necrosis virus) and yield and yield components in three different locations; Arusha, Mbeya and Morogoro. The experiment was arranged in split plot, main plots were locations (Arusha, Morogoro and Mbeya) and sub-plots were 32 genotypes (28 lines and 4 checks). The results from the experiment revealed high significant differences (p < 0.05) among genotypes and Genotypes x Environment interaction in days to 85 % maturity, pods per plant, seeds per pod, weight of seeds per plant, 100 seed weight and grain yield. There were no significant differences in diseases (Angular leaf spot and Common bean blight) scores and few genotypes had the Bean common mosaic virus/Bean common mosaic necrosis virus symptoms basing on the score of presence and absence. Among the lines that performed well basing on both diseases and yield were KT 13-1b, KT 4g-3c, KT 6-2d, KT 6-2c, KT 10-2d, KT 11-1a, KT 15a, KT 9-2b, KT 11-2d and KT 2b. Grain yield had a positive significant correlation with days to 50 % flowering, days to 85 % maturity, pods per plant, seeds per pod, weight of seeds per plant, 100 seed weight. This suggests that the traits have to be considered when breeding for higher grain yield. This study showed that the introgression of genes for resistance to the three diseases to preferred bean variety Kablanketi was successful since most of the lines were resistant to the diseases. However, this study needs to be repeated to verify the performance of these promising lines and planting should be done at the beginning of the season to ensure that there are favourable environments for diseases progress.Kirkhouse Trus