Validation of effectiveness marker-assisted gamete selection for multiple disease resistance in common bean

Abstract

Plant breeding is the most cost-effective, practical and environmentally friendly strategy for reducing losses associated with bean diseases, especially in low-input agricultural systems because no additional investment is required from farmers. However, incorporating resistance to one pathogen may not result in a significant change because several diseases co-infection beans at the farm level. Consequently, breeding varieties with multiple disease resistance is a more appropriate, reliable and sustainable approach. In such context, gamete selection is the more appropriate breeding method because it allows simultaneous selection for multiple traits; though as originally proposed and validated, it is largely based on phenotypic evaluation for agronomic traits, which leads to delay in variety development and strong dependence on erratic weather conditions. The objective of this study was to validate 26 F 1.8 elite bean lines selected for resistance to angular leaf spot (ALS), anthracnose, root rots, common bacterial blight (CBB) and bean common mosaic virus (BCMV), from inter-racial and inter-gene pool populations developed using molecular markers on the gamete selection method in early generations. Pathogens were isolated from diseased plants collected from various locations in central Kenya, multiplied on appropriate media and used to inoculate the test lines in a greenhouse at Kabete Field Station, University of Nairobi. Data on disease incidence and severity were collected at 14, 21, 28 th days after inoculation, using the 1-9 CIAT scale; except for the root rot experiments for which data were recorded once at 21 st day after seedling emergence. Results showed that five of the 26 elite lines possessed multiple resistance to five pathogens, eight to four pathogens, nine to three pathogens, three to two pathogens and one was resistant to one pathogen. This implied that markers, used in early generations, were effective in the identification and transfer of resistance genes to susceptible commercial varieties. However, there were no significant correlations in the reaction of tested genotypes to pathogens in this study, except between BCMV and ALS (r=0.3942*). This suggests that resistance genes are in different chromosomes and are assorted independently. The presence of genotypes with multiple disease resistance among test elite lines, confirms the effectiveness M.J. MONDO et al. 586 of inter-racial crosses and marker-assisted gamete selection to concurrently improve the resistance to common bean major diseases in Eastern Africa.

Genetic analysis of resistance to bean leaf crumple virus identifies a candidate LRR‐RLK gene

“…These efforts have provided molecular tools to accelerate the selection of resistant germplasm through MAS (Meziadi et al., 2017). Recent studies underline the effectiveness of MAS for introgression of multiple disease resistances in breeding programs (Mondo et al., 2019; Rezene et al., 2019). In this study, we identified a set of SNP markers that can be readily used for MAS of BLCrV resistance and could be complementary in the breeding effort against other begomovirus‐related diseases.…”

New Challenges and Future Perspectives in Nutrition and Sustainable Diets in Africa

“…The crops have dense macro-and micronutrients content (Mibei et al, 2016;Ngugi et al, 2016;Ontita et al, 2016;Ali et al, 2021); can effectively provide solutions to the double malnutrition challenge experienced on the African continent, and proponents have recommended the need to intensify research on traditional crops. However, research has put more focus on crops such as maize, wheat and rice (Mondo et al, 2018;Mwizerwa et al, 2018;Gitari et al, 2019;Odingo, 2019;Owade et al, 2019;Ichami et al, 2020;Jekayinoluwa et al, 2020;Mukami et al, 2020;Malavi et al, 2021;Wagaba et al, 2021). As a result, many of the traditional food crops remain undocumented, and the few documented crops have not been exploited sufficiently to attain their full potential considering all the activities along the food system value chain (Sibanda and Mwamakamba, 2021).…”

Gaps and opportunities in research on food systems; a micro-institutional analysis of the University of Nairobi

“…The crops have dense macro-and micronutrients content (Mibei et al, 2016;Ngugi et al, 2016;Ontita et al, 2016;Ali et al, 2021); can effectively provide solutions to the double malnutrition challenge experienced on the African continent, and proponents have recommended the need to intensify research on traditional crops. However, research has put more focus on crops such as maize, wheat and rice (Mondo et al, 2018;Mwizerwa et al, 2018;Gitari et al, 2019;Odingo, 2019;Owade et al, 2019;Ichami et al, 2020;Jekayinoluwa et al, 2020;Mukami et al, 2020;Malavi et al, 2021;Wagaba et al, 2021). As a result, many of the traditional food crops remain undocumented, and the few documented crops have not been exploited sufficiently to attain their full potential considering all the activities along the food system value chain (Sibanda and Mwamakamba, 2021).…”