abstract
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Wheat (Triticum ssp.) yields need to increase by at least 60% by 2050 to meet the increased demands. Numerous studies have identified yield component genes in hexaploid wheat; however, fewer yield evaluation studies have been performed in tetraploid wheat. A potential source for allelic variation for wheat improvement is cultivated emmer (T. turgidum ssp. dicoccum). We evaluated three populations of tetraploid recombinant inbred lines derived from crosses between North Dakota durum wheat varieties and cultivated emmer wheat accessions under field conditions to identify quantitative trait loci (QTL) for yield components and seed morphology. The three populations were developed from the following crosses: Ben × PI 41025 (BP025), Divide × PI 272527 (DP527), and Rusty × PI 193883 (RP883). Plants were grown in the summer of 2017 and/or 2018 in a randomized complete block design in hill plots under non-irrigated conditions at the North Dakota State University research site in Prosper, ND. We identified QTL associated with yield components on every chromosome except 4B in these populations. In the BP025 population, QTL for spikelets per spike, grain weight per spike, and grain width, and in the RP883 population spikelets per spike were associated with the domestication gene Q. In the RP883 population, the Vrn-A1 locus was significantly associated with thousand kernel weight, days to heading, grain area, and grain width. Interestingly, neither of these two genes were associated with yield components or seed morphology in the DP527 population. In all three populations, the durum parents contributed alleles for increased kernels per spike and grain weight per spike. Beneficial alleles for other yield components and seed morphology traits were contributed by either cultivated emmer or durum depending on the cross/trait combination, and for some, both parents contributed beneficial alleles. The findings from this study will provide insights into the traits that differ between these two tetraploid wheat subspecies, along with developing tools breeders can use to introgress these traits into their breeding lines.