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Accueil du site → Master → Kenya → 2021 → Phenotyping Mungbean (Vigna Radiata (L.) Landraces for Resistance and Stability to Common Bacterial Blight (Xanthomonas Axonopodis Pv. Phaseoli) Under Semi-Arid Conditions of Kenya

Egerton University (2021)

Phenotyping Mungbean (Vigna Radiata (L.) Landraces for Resistance and Stability to Common Bacterial Blight (Xanthomonas Axonopodis Pv. Phaseoli) Under Semi-Arid Conditions of Kenya

Tollo, Joyce Awino

Titre : Phenotyping Mungbean (Vigna Radiata (L.) Landraces for Resistance and Stability to Common Bacterial Blight (Xanthomonas Axonopodis Pv. Phaseoli) Under Semi-Arid Conditions of Kenya

Auteur : Tollo, Joyce Awino

Université de soutenance : Egerton University

Grade : Master of Science Degree in Plant Breeding 2021

Résumé
Common bacterial blight (CBB) caused by Xanthomonas axonopodis pv phaseoli L. is one of the major biotic constraints affecting mungbean (Vigna radiata) production globally. In Kenya, it is a major disease in areas where legumes are grown year after year and seeds recycled making it more devastating for smallholder legume farmers. The objectives of this study were to ; (i) identify sources of resistance to common bacterial blight in mungbean genotypes, (ii) determine genotype by environment interaction and stability of common bacterial blight (CBB) resistance in mungbean germplasm and (iii) validate the resistance of selected resistant genotypes from field trials to CBB under artificial inoculation in the greenhouse. Two experiments were carried out in this study ; the first experiment involved evaluation of 240 genotypes for CBB resistance in four semi-arid regions of Kenya for two cropping seasons (2019 and 2020). In the second experiment, twelve genotypes identified as being resistant from experiment one alongside four checks were evaluated under greenhouse conditions to validate their resistance. Disease severity was observed for CBB score at 10 days after inoculation (DAI), 17 DAI and 31 DAI and expressed as Area Under Disease Progress Curve (AUDPC). Results from the field experiments revealed significant main effects for genotype (G), environment (E) (combination of cropping season and location) and genotype by environment interaction (GE) (p < 0.01) for all the traits. From GGE analysis, Kambi Ya Mawe (KYM) location in SR 2019/2020 was revealed as the most suitable environment for evaluation of CBB resistance. Genotypes GBK 004852, GBK 004789, GBK 026986, GBK 004970, GBK 004961, GBK 004882 and GBK 043573 were identified as high and stable resistance across the tested environments. Greenhouse results revealed significant (p<0.01) effects due to main effects of genotypes and cropping cycles, respectively, for CBB score at 10 DAI, 17 DAI, 31 DAI and AUDPC. However, genotype by cropping cycle interaction effect was non-significant for all the traits measured. The results confirmed the outcome of the field experiment (experiment one) as genotypes GBK 004828, GBK 004890, GBK 022540, GBK 017437, GBK 004820, GBK 004789, Local variety, Biashara and GBK 051334 were identified as resistant genotypes. The identified genotypes are recommended for use in breeding programmes aimed at improving preferred susceptible mungbean varieties for resistance to CBB. Besides, such promising genotypes would be submitted for National Yield Trial (NPT) for future deployment as resistant varieties.

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Page publiée le 16 mai 2022