Association mapping for melon traits

Eighty five melon types belonging to the USA and eastern Europe were evaluated for their growth and fruit traits for three seasons starting from the year 2005. The genotypic data was generated by 250 mapped SSRs, gathered from various published reports that cover all the twelve chromosomes to resolve population structure and LD. The population structure was explored to identify discrete subpopulations based on allele frequencies. Twenty five LD blocks were found across the melon genome. Association mapping was performed using GLM and MLM to resolve marker-trait associations. Identified associations were subjected to Bonferroni correction. Previously published QTLs positions pertaining to the fruit yield, fruit weight, number of fruits, soluble solids, fruit length and width could be validated across the seasons. New candidate QTLs were identified for several traits. Common markers were identified for fruit yield and soluble solids that can be used for marker assisted selection to simultaneous improvement of yield and high quality.  Seven markers were identified to be linked with the resistance of powdery mildew. We used Best Linear Unbiased Prediction (BLUP) to predict breeding values of melon collections taking into consideration of QTL genotype X environmental interactions. We will present details LD, association mapping and BLUPs that can through light on heritable genetic variance.