RFLP ANALYSIS OF GENOMIC REGIONS ASSOCIATED WITH RESISTANCE TO PREHARVEST SPROUTING IN WHEAT

Resistance to preharvest sprouting (PHS) is difficult to incorporate into new varieties because heritability is low and selection is limited to one generation per year. Our objective was to identify genomic regions containing quantitative trait loci (QTL) associated with resistance to PHS in two recombinant inbred (R) populations of white wheat (Triticum aestivum L. em. Thell.) by restriction fragment length polymorphism (RFLP) markers. One population consisted of 78 RI lines from the cross of NY6432-18 (NY18) x 'Clark's Cream' (CC). The second population consisted of 138 RI lines from the cross between sib lines NY18 and NY6432-10 (NY10). The NY18/CC and NY18/10 populations were evaluated for PHS in six and seven environments, respectively, by examining physiologically mature spikes under simulated rainfall. The three parental lines were surveyed for polymorphism with 195 low-copy RFLP clones. Individual RI lines from the NY18/CC and NY18/NY10 populations were probed with 37 and 27 polymorphic clones, respectively. Eight regions of the genome (four from each population) were significantly associated with resistance to PHS. Based on multiple regression, specific sets of markers and their interactions accounted for 44% of the genetic variance for PHS in the NY18/CC and 51% in the NY18/NY10 populations. These markers could find utility in breeding programs as indirect selection criteria for improvement of PHS resistance.