Association Analysis for Bacterial Spot Resistance in a Directionally Selected Complex Breeding Population of Tomato

• DOI: 10.1094/phyto-02-15-0051-r
• Publication Date: 2015-10-28T16:42:30Z
• Authors: Sung-Chur Sim; Matthew D. Robbins; Saranga Wijeratne; Hui Wang; Wencai Yang; David M. Francis
• Keywords: Association (psychology)

Bacterial spot of tomato is caused by at least four species Xanthomonas with multiple physiological races. We developed a complex breeding population for simultaneous discovery marker-trait linkage, validation existing quantitative trait loci (QTL), and pyramiding resistance. Six advanced accessions resistance from distinct sources were crossed in all combinations their F1 hybrids intercrossed. Over 1,100 segregating progeny evaluated the field following inoculation X. euvesicatoria race T1 strains. selected 5% most resistant susceptible evaluation as plots two subsequent replicated trials inoculated T3 (X. perforans) The estimated heritability was 0.32. In order to detect previously reported genes, well novel QTL, we explored methods correct structure analysis based on single markers or haplotypes. Both single-point haplotype analyses identified strong associations genomic regions known carry Rx-3 (chromosome 5) Rx-4/Xv3 11). Accounting kinship generally improved fit statistical models. Detection adding combination using Q matrix model-based clustering. Additional QTL detected chromosomes 1, 4, 6, 7 2, 6 (P < 0.01). Haplotype our ability trace origin positive alleles. These results demonstrate that both can be populations have experienced directional selection.