Screening of thirty new Genotypes and five Land Races of Cowpeas for Resistance to Cercospora Leaf Spot Disease in Uganda

Abstract

Cowpea, Vigna unguiculata (L.), is an important grain legume grown majorly in Africa and constitutes a valuable source of protein in the diets of millions of people. Some abiotic and biotic stresses adversely affect its productivity. This study aimed at screening for host plant resistance against a biotic stress, Cercospora Leaf Spot (CLS) among 35 cowpea genotypes collected from IITA, Ghana and from within Uganda. The major breeding objective of this study is contributing towards the breeding programme for genotypes with improved yield and CLS resistance. The experiment was carried out at Makerere University Agricultural Research Institute - Kabanyolo (MUARIK). The thirty-five (35) cowpea genotypes were evaluated for resistance to CLS disease in a 6x6 alpha lattice design with two replications under natural field conditions. Data on Cercospora severity, plant vigor, number of seeds per pod, number of peduncles per plants, 100 seed weight, number of pods per plant and yield (kg/ha) were collected and analysis of variance within genotype and their genotype mean performance was also obtained. The genotypes differed significantly on the basis of Cercospora severity, plant vigor, number of peduncles, 100 seed weight and number of pods per plant. Genotypes such as Hewale x NE 5-SF4:6/13 C2 Brown, Hewale x NE 5-SF4:6/17 Brown, NE 55 x Hewale-SF4:6/19, WC 2 x IT90K-S277-S2-SF4:6/8 Brown, and the land race, WC 35C, were significantly resistant to CLS, while, genotypes; NE 55 x Hewale-SF4:6/17 Brown, WC 2 x IT90K-S277-S2 SF4:5/11 were relatively tolerant to CLS, despite their high levels of CLS. Therefore, the above varieties with high level of resistance and tolerance could be considered in the breeding programme since they had great yields despite the presence of CLS.