Identification of Elite Agronomic Traits using Chromosome Arm Substitution Lines of Triticum dicoccoides in the Background of Common Wheat

To effectively mine and utilize the valuable genes of wild emmer wheat (Triticum dicoccoides, 2n=4x=28, AABB), this study conducted an investigation of agronomic traits using two sets of chromosome arm substitution lines (CASLs) of wild emmer wheat in the backgrounds of the common wheat varieties Bethlehem (BLH) and Chinese Spring (CS). The results indicated notable differences in growth characteristics, including seedling agronomic traits, heading date (HD), and yield traits among the various CASLs in both the BLH and CS backgrounds. In both genetic backgrounds, the number of tillers in CASL6AL and CASL7BS was significantly less than that of the parents. Additionally, the average leaf width of six CASLs (2BS, 1AL, 7AL, 5BS, 4AS, and 2BL) was significantly smaller compared to the parents. Among CASLs in the CS background, CASL2BS exhibited a significantly narrower average leaf width and shorter average plant height compared to the parents and early-maturing CASLs. Conversely, CASL4AL had significantly more tillers and a shorter average plant height than other CASLs. In the BLH background, the spike phenotypes of all CASLs showed no significant differences from BLH. However, in the CS background, CASL6AS and CASL5AL demonstrated significantly longer spike lengths than CS. Moreover, CASL6BL had a more spikelets per spike than CS. CASLs 4AS, 4AL, 6BS, and 6BL exhibited short awns at the base and long awns at the top, while the remaining CASLs displayed no awns, consistent with CS. It is speculated that genes controlling physiological traits such as seedling tiller number, leaf width, plant height, and spike traits may be located on the corresponding chromosome arms.