IDENTIFICATION OF GENETIC-FACTORS INFLUENCING CHIP COLOR IN DIPLOID POTATO (SOLANUM SPP)

A genetic map was constructed with a combination of isozymes, restriction fragment length polymorphisms (RFLPs) and randomly amplified polymorphic DNA (RAPDs) to apply quantitative trait loci (QTL) analysis to identify genetic factors that contribute to chip color in potato. The diploid population used was a cross between a Solanum tuberosum haploid and S. chacoense hybrid used as female parent and a S. phureja clone used as male. Chip color was determined visually on samples fried from tubers stored at 10C. On a scale of 1 (light color) to 10 (dark color), the population ranged from 2 to 8 while the parents average chip color was 3.5. Based upon one-way ANOVAs (P < 0.05), 13 genetic markers showed significant associations which represent a total of six QTLs. A multiple locus model based upon the markers that have the largest effect per QTL explained 43.5% of the phenotypic variation for chip color in the population and increased to 50.5% when one significant epistatic interaction was included in the model. All the significant marker associations were identified in the S. tuberosum-S. chacoense hybrid. Through preliminary data, the results of this study suggest that additive effects contribute a significant portion of the genetic variation for chip color. The identification of these QTLs for chip color variation provides the means to apply marker-assisted selection to introgress these genes into the cultivated potato germplasm.