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ARS Home » Southeast Area » Charleston, South Carolina » Vegetable Research » Research » Publications at this Location » Publication #404908
Research Project: Genomics and Genetic Improvement of Disease Resistance and Horticultural Characteristics of Watermelon, Broccoli, and Leafy Brassicas

Location: Vegetable Research

Title: Genome-wide association study of soluble solids content, flesh color, and fruit shape in citron watermelon

Author
item KATUURAMU, DENNIS - US Department Of Agriculture (USDA)
item Levi, Amnon
item WECHTER, WILLIAM - Clemson University

Submitted to: The Plant Genome
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/29/2023
Publication Date: 9/18/2023
Citation: Katuuramu, D.N., Levi, A., Wechter, W. 2023. Genome-wide association study of soluble solids content, flesh color, and fruit shape in citron watermelon. The Plant Genome. 16(4). Article e20391. https://doi.org/10.1002/tpg2.20391.
DOI: https://doi.org/10.1002/tpg2.20391

Interpretive Summary: Watermelon is an important vegetable crop grown worldwide. Fruit quality traits are key drivers for consumer acceptance and repeat purchase of new watermelon varieties. Information on phenotypic and genetic variability (molecular markers) is needed to develop watermelon varieties with fruit quality attributes demanded by growers and consumers. There is limited information on the inheritance and genetic control of fruit quality traits (soluble solids content, flesh color, and fruit shape) in watermelon. In this study, a collection of USDA citron watermelon accessions was extensively evaluated for fruit quality traits under field conditions over two seasons. A genetic mapping methodology called genome-wide association study was utilized to locate genomic markers and candidate genes associated with fruit quality traits. The new molecular markers will be crucial in improving watermelon for fruit quality traits via marker-assisted breeding. The information will be useful to university and seed company plant breeders and researchers.

Technical Abstract: Fruit quality traits are major determinants of consumers’ willingness to purchase watermelon produce making them major goals for breeding programs. There is limited information on genetic underpinnings of fruit quality traits in watermelon. A total of 125 citron watermelon (Citrullus amarus) accessions were genotyped using single nucleotide polymorphisms (SNPs) molecular markers generated via whole-genome resequencing. A total of 2,126,759 genome-wide SNP markers were used to uncover marker-trait associations using single and multi-locus GWAS models. High broad-sense heritability for fruit quality traits was detected. Correlation analysis among traits revealed positive relationships except fruit diameter and fruit shape index which was negative. A total of 37 significant SNP markers associated with soluble solids content, flesh color, and fruit length, fruit diameter, and fruit shape index traits were uncovered. These peaks SNPs accounted for 2.1 to 23.4 % of the phenotypic variability explained showing the quantitative inheritance nature of the evaluated traits. Candidate genes relevant to fruit quality traits were uncovered on chromosomes Ca01, Ca03, Ca06, and Ca07. These significant molecular markers and candidate genes will be useful in marker-assisted breeding of fruit quality traits in watermelon.