Gabriel Ddamulira
Makerere University Kampala
Uganda
Title: Screening for new sources of angular leaf spot resistance in common bean
Biography
Biography: Gabriel Ddamulira
Abstract
Developing common bean (Phaseolus vulgaris L.) varieties resistant to angular leaf spot (ALS), a fungal disease caused by Pseudocercospora griseola (Sacc), is still hindered by 1) existing exotic resistance sources which are not well adapted to environmental conditions in Uganda and 2) high variability of P.griseola which complicates ALS control. These two factors necessitate continuous identification of new and broad sources of resistance to quicken the process of developing resistant varieties to reduce on the current yield losses. Seventy four landraces, four commercial varieties, and two controls were screened with four P. griseola races (1:6, 17:39, 21:39, and 61:63) to determine their resistance to ALS. The experiment was conducted in pots in a screenhouse to identity resistant genotypes and the effect of growth habit and seed size on ALS resistance. The experiment was factorially designed in randomised complete block design with three replications. Analysis of variance showed significant (P<0.05) variation in resistance among bean genotypes. Landrace (U00297), showed consistent resistance to four P. griseola races used in this study. But for commercial varieties, only recently released NABE 13 was moderately resistant to the four P. griseola races while the rest were susceptible. Seed size and growth habit were observed to influence genotype resistance to only mild P.griseola race (1:6) but not to virulent races. The results showed that U00297 was resistant to ALS under screenhouse conditions. This information generated will guide breeding programs targeting developing bean varieties resistant to ALS.
