Improving hexaploid spring wheat by introgression of alleles for yield component traits from durum wheat

Hexaploid bread wheat (Triticum aestivum L.) and tetraploid durum wheat (Triticum durum Desf.) have been cultivated in similar geographic areas for similar to 10,000 yr. The crossing barrier caused by ploidy difference suggests that different favorable alleles for yield-related traits may have accumulated in the two crops. Previous work allowed identification of favorable alleles at six quantitative trait loci (QTL) from durum wheat in a recombinant inbred line (RIL) population from a cross of 'Mountrail' durum and 'Choteau' spring wheat. The purpose of this study was to determine the impact of six durum alleles at yield component QTL in several spring wheat backgrounds. Three spring wheat cultivars were crossed with six hexaploid lines derived from the original Choteau/Mountrail cross to generate RILs. Heterozygous RILs, containing both the durum and the bread wheat alleles, were identified for each of the QTL. The heterozygous RILs were used to develop near-isogenic lines (NILs) for the six introgressed QTL. The NILs were grown in five environments under irrigated and rainfed conditions in Montana in 2017 and 2018. A durum allele QTL on chromosome 3B resulted in increased kernel weight in all five environments. The introgressed durum QTL alleles caused pleiotropic interactions among yield component traits. Environment and genetic background significantly affected the stability of introgressed QTL on yield components for four of the six QTL. Results suggest that alleles from durum may be useful for yield improvement of hexaploid spring wheat. However, interrelationships of yield components, pleiotropic interactions, and environment will affect the value of durum wheat alleles in hexaploid wheat backgrounds.