Research Projects

India, the second-largest pumpkin producer after China, faces low average productivity due to biotic and abiotic stresses, with diseases caused by begomoviruses being the major limiting factors. Begomoviruses, a single-stranded DNA virus, are transmitted by whiteflies and infect predominantly dicot plants. They have a wide host range, high evolution rates, and a large population of vectors during humid-rainy seasons, causing crop loss. Identifying and developing resistant germplasm is the only reliable, viable, economical, and ecological way to manage these diseases. A resistant line, PVR-1343, was identified and released as "Punjab Nawab" by PAU Ludhiana. Genetic expression of the trait varies with the source material, so QTLseqr and QTL-seq t al 2020 were employed to identify candidate genes/QTLs governing begomovirus resistance in Punjab Nawab. It was found that resistance against begomoviruses (sLCCNV and ToLCNDV) in Punjab Nawab is digenic recessively inherited, with two begomovirus resistant loci qMI-sq/To7.1 and qMI-sq/To17.1 conferring resistance. Nine polymorphic sNPs identified within the highly significant qMI-sq/To7.1 region were converted into KAsP markers, narrowing down the qMI-sq/To7.1 interval to 103Kb. Identifying tightly linked markers from both loci will facilitate marker assisted selection/introgression into elite lines. However, more efforts are required for an additional cycle of self-pollination to identify homozygous recessive individuals from progeny tests and a cumbersome whitefly mediated artificial inoculation phenotypic process for screening and identification of resistant plants. The current proposal aims to narrow down/fine map both QTLs (Chr7 and Chr17), develop markers for marker assisted selection (MAs), and conduct expression analysis of the putative identified resistant genes to gain insight into the molecular mechanism underlying begomovirus resistance in pumpkin.