BREEDING HIGH VALUE MELONS FOR ENHANCED FLAVOR, NUTRACEUTICALS AND DISEASE RESISTANCE THROUGH INTERSPECIFIC HYBRIDIZATION

The main goal of this project is to develop disease resistant, high quality melons that are nutraceutically enriched. We aim to characterize C. melo core collection and develop introgressed lines (IL) for Powdery Mildew (PM) and Fusarium Wilt (FW), involving interspecific hybridization by backcrosses of F1 of Charentais (Cucumis melo) X Cucumis callosus back with the recurrent parent (Charentais) for six generations through advancing by selfing in a speed growth chamber. From the sweet and juicy melo types to the refreshingly mild agrestis, subspecies diversity is a gastronomic delight and a testament to the species' adaptability and evolutionary success. However, even with such extensive variation, the melon genome presents certain limitations, particularly regarding resistance against common diseases like powdery mildew (PM) and fusarium wilt (FW). These diseases pose significant challenges to melon cultivation, often leading to reduced yields and compromised fruit quality. Powdery mildew, a fungal disease, manifests as white, powdery spots on leaves, while FW causes the wilting and eventual death of the plant. Despite numerous attempts to breed disease-resistant melon varieties, success has been limited, pointing to a genetic bottleneck for these specific resistances within Cucumis melo. Crossing Cucumis melo with closely related species, Cucumis callosus, a widely grown perennial herb in the state of Rajasthan, produces fertile F1 offspring when crossed withC. meloand is the wild progenitor from which melon was domesticated. Given the pressing need for disease-resistant melon varieties and the limitations of current breeding programs, interspecific hybridization offers a promising pathway for future research. Such endeavors could not only revolutionize melon agriculture but also contribute to food security by improving the resilience of this important crop.The small genome size of melon (350 Mbp) greatly facilitates genome research and gene discovery in this crop. The molecular dissection of complex traits through breeding approaches, coupled with the development of high-throughput parallel mapping analysis of gene expression, promises to add much to our understanding of the relationship between genes and phenotype. This three-year project aims to develop high-yielding, disease-resistant melon varieties with improved fruit quality by selective crosses with exotic melon types in conjunction with molecular-based gene-introgression tracking methodologies.This proposal uses these core germplasm accessions for genomic selection for fruit quality, resistance, and yield. Derivatives of this genomic selection will be utilized further for on-farm trails and additional participatory selection to rapidly generate improved varieties with small-farm market appeal. These activities, supported by intensive education and outreach, will disseminate existing prebreeding lines and interspecific derivatives to underserved communities. The current proposal will address the need to integrate modern technologies that can create common tools for genomics-assisted breeding with the objectives mentioned below.Introgression of disease-resistance genes into cultivated melons from the compatible wild relativesFine mapping and identification of candidate genes and underlying QTL explaining PM and FW resistance, major fruit shape, size, and nutraceutical traits for use in genomic selectionEvaluation of GS and IL derivatives for fruit yield, quality, and resistance traits and validation of QTL effectsParticipatory breeding-based selections