Identification of new QTLs for quality traits and yield using tetraploid wheat interspecific backcross inbred lines

The wild tetraploid wheat Triticum turgidum var. dicoccoides is a valuable source of genetic variation for improving disease resistance, drought tolerance, and grain protein quantity and quality in cultivated wheat. However, little is known about the genetic basis of DNA introgression from wild relatives into cultivated backgrounds. Because wild germplasm contains both favorable alleles and undesirable agronomic traits, understanding segregation and recombination patterns is essential for its effective use in breeding. This study aimed to evaluate a population of backcross inbred lines (BILs) derived from T. turgidum var. dicoccoides to identify quantitative trait loci (QTL) associated with grain quality and yield-related traits.

The BIL population was evaluated in replicated field trials for grain protein content, fiber content, and yield components. Genomic analysis characterized the distribution of introgressed segments from T. turgidum var. dicoccoides within the durum wheat genome. QTL mapping identified 24 QTLs associated with variation in grain protein (12 QTL), fiber content (5 QTL), and yield traits (7 QTL). QTLs were detected on nine chromosomes (1B, 2B, 3 A, 4 A, 4B, 5 A, 5B, 6B, and 7B), with several loci consistently expressed across environments and years, highlighting stable genomic regions controlling key traits.

The study demonstrates that BIL populations are effective tools for a rapid introgression of beneficial alleles from wild wheat relatives, as it is the case for the fiber content and its implication for nutritional quality. The detected QTL provide a foundation for developing near-isogenic lines (NILs) to investigate individual locus effects and facilitate the incorporation of valuable wild alleles into future wheat breeding programs.