Development of pyramided mung bean lines carrying resistance genes for Cercospora leaf spot disease and bruchids

Cercospora leaf spot (CLS) disease and bruchids are the common disease and insect pest causing yield loss in mung bean (Vigna radiata (L.) R. Wilczek).'KUML4' is an improved mung bean cultivar grown in Thailand having high yield, early and highly synchronous maturity, large seed size, but susceptible to CLS disease and bruchids.This study was conducted to improve 'KUML4' through introgression of VrTAF5 for CLS resistance and VrPGIP2 for bruchid (Callosobruchus maculatus) resistance from landrace mung bean accessions 'V4718' and 'V2808', respectively, by marker-assisted backcrossing (MABC).In the MABC, foreground selections were performed using VrTAF5-and VrPGIP2-specific markers.The BC3F3 pyramided lines with KUML4 background carrying both VrTAF5 and VrPGIP2 genes were developed and evaluated for agronomic and yield-related traits, CLS resistance, and bruchid resistance.Three BC3F3 lines, KUML4-2020-21, KUML4-2020-23, and KUML4-2020-60, exhibiting superior agronomic and yield-related traits, CLS resistance, and bruchid resistance than 'KUML4' were successfully obtained via MABC.Under the CLS outbreak, these lines showed 248.5%-331.7%higher seed yield than 'KUML4'.The lines expressed nearly perfect resistance to bruchid (< 5% seeds damaged).These lines can be developed into new resistant mung bean cultivars in the future.