Evaluating natural infection of fungal, bacterial and viral pathogens to dry bean genotypes under field conditions

Summary

Fungal, bacterial, and viral diseases are economic foliar diseases that cause yield losses, between 40% and 100%, in commonly grown dry bean cultivars across the world. Development of disease resistance genotypes is a complex interaction between genetic and environmental factors. This study focused on determining the natural infection of disease-causing pathogens of angular leaf spot, powdery mildew, bacterial blight, and bean common mosaic virus in different agro-ecologies in relation to grain yield. The diversity of 211 bean genotypes was tested at two different disease hot spots areas under incomplete block design, with two replications for two cropping seasons in Tanzania. Disease severity was significantly different (p<0.001) for genotypes and their interactions with the environment and season. Higher disease severity was observed at the Lyamungo site than the Selian site. Effects of genotypes by environment were observed with a maximum yield of 2170 kg/ha to a low yield of 398 kg/ha with a grand mean of 1151.54 kg/ha. High annual rainfall and relative humidity contributed to disease development in the tested environments. Five genotypes (FEB 189, A774, NUA 16, KG 71-4, and DOR 766) expressed traits of resistance to the above diseases and their incorporation into breeding programs to enhance dry bean productivity is recommended.

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