Plant & Animal Genomes XVIII Conference

January 9-13, 2010
Town & Country Convention Center
San Diego, CA

LD Mapping For Melon Fruit Related Traits

Yan R Tomason^{1, 2} , Padmavathi Nimmakayala¹ , Gopinath Vajja¹ , Mariia I Tomason² , Umesh K Reddy¹

¹   Department of Biology, Gus R. Douglass Institute, West Virginia State University, Institute, WV 25112-1000, USA

²  Department of Plant Breeding, Dnepropetrovsk State Agrarian University, Voroshilov 25, Dnepropetrovsk 49600, Ukraine

Thirty eight melon types belonging to Ukraine and other world collections that were selfed for four consecutive generations were evaluated for their growth and fruit traits for five seasons (2003-2007). Conventional breeding approaches focusing on improvement for yield and fruit quality parameters lacked precision and power as these traits are typically represented by poly genes with lot of environmental interaction. The genotypic data generated by mapped SSRs gathered from published reports/ several hundred of AFLPs together with information on various morphological traits was utilized to resolve population structure using STRUCTURE program. The population structure was explored to identify discrete subpopulations based on allele frequencies. Clustering and population structure showed three major groups based on their existing convar characterization. The phenotypic variability analyzed through univariate statistic showed high amount of genetic variance for the fruit yield and other quality traits. The AMOVA revealed 76% within population and 8% among population variance. Putative polymorphisms were used to analyze genotype-phenotype associations to identify several QTLs, using TASSEL software. The stability of QTLs across the seasons and across the models (GLM with PCA, GLM with structure, MLM with PCA and MLM with structure) was compared. The significance and complexity of marker-trait associations for all the traits investigated will be presented and discussed