Genetic characterization of angular leaf spot resistance in selected common bean landraces from Tanzania

Abstract

Angular leaf spot disease (ALS) caused byPseudocercospora griseola is one of the most important bean diseases in Tanzania. The bean landraces Beti-10, Nanka, Nanavala and Nkanamna used in this study have been identified as resistant to ALS but the nature of inheritance and mechanisms of resistance against ALS in those potential sources has not been elucidated. This information is crucial and a necessary first step for a successful breeding programme. The objective of this work was to study the inheritance of ALS resistance in those landraces and to identify the mechanisms of genetic resistance using Simple Sequence Repeat (SSR) markers. Crosses were made between resistant bean landraces and a susceptible bean cv Kablanketi. The parents, F 1 , F 2 and backcrosses derived plants were used for inheritance studies and for molecular marker screening using 30 SSR markers. Results indicate that, a single dominant gene control resistance against ALS in each of the four landraces; also the SSR marker Pv-ag004 was found to be polymorphic between Beti-10 and Kablanketi and linked to the disease resistance. The resistance were validated by checking the F 2 population of the cross between Kablanketi × Beti-10. Therefore, since marker Pv-ag004 is polymorphic and linked to ALS resistance, the Beti-10 landrace might be a potential source of ALS resistance. However, a detailed study with more markers need to be done on these landraces with a view to opening the possibilities of identifying new markers linked to ALS resistance and mapping of genes associated with resistance to ALS.

Artificial intelligence and deep learning based technologies for emerging disease recognition and pest prediction in beans (phaseolus vulgaris l.): A systematic review

“…Considering Tanzania as an example, the symptoms has been testified to spread from low to high altitudes above sea level where the common beans are grown (Hillocks et al, 2006) which covers the northern zone, the lake zone, the western regions and the southern regions. ALS has been extensively studied in various previous studies (Wani et al, 2022;Tryphone et al, 2015;Mongi et al, 2016;Mongi, 2018;Chilagane, 2017). Common bean rust is one of the major diseases in the common bean growing areas caused by the fungus called Uromyces appendiculatus (Fromme, 1924;Stavely and Pastor-Corrales, 1989).…”