Characterization of a Triticum aestivum-Dasypyrum villosum T2VS·2DL translocation line expressing a longer spike and more kernels traits.

KEY MESSAGE: By using 2V-specific EST-PCR markers and sequential GISH/FISH analysis, we identified four homozygous CS-2V translocation lines, including a novel compensating T2VS·2DL translocation line NAU422. This translocation line has longer spikes and produces more grains per spike than its recurrent parent CS and three other translocation lines, which could be a valuable resource in wheat yield improvement. Dasypyrum villosum (2n = 14, VV), the wild relative of wheat, possesses novel and superior alleles at many important loci and should be utilized to improve the genetic diversity of cultivated wheat and may be very helpful for the improvement of wheat yield. In this study, four homozygous Chinese Spring (CS)-D. villosum translocation lines containing different fragments of chromosome 2V were characterized from a pool, including 76 translocations that occur in chromosomes 1 V through 7 V of D. villosum by both molecular markers and cytogenetic analysis. A rough physical map of 2V was developed which included nine markers in three segments of the short arm and ten markers in the long arm. The photoperiod response gene of D. villosum (Ppd-V1) was physically mapped to the FL 0.33-0.53 region of 2VS, while the gene controlling bristles on the glume ridges (Bgr-V1) was mapped to 2VS FL 0.00-0.33. A novel compensating Triticum aestivum-D. villosum Robertsonian translocation line T2VS·2DL (NAU422) with good plant vigor and full fertility was further characterized by sequential genomic in situ hybridization and fluorescent in situ hybridization and the use of molecular markers. Compared to its recurrent parent CS and three other translocation lines, the T2VS·2DL translocation line has longer spikes, more spikelets and more grains per spike in two season years, which suggested that the alien segment may carry yield-related genes of D. villosum. The developed T2VS·2DL translocation line with its morphological and co-dominant molecular markers could be utilized as a novel germplasm for high-yield wheat breeding.