Mass production of intergeneric chromosomal translocations through pollen irradiation of Triticum durum-haynaldia villosa amphiploid

Haynaldia villosa possesses a lot of important agronomic traits and has been a powerful gene resource for wheat improvement. However, only several wheat - H. villosa translocation lines have been reported so far. In this study, we attempted to develop an efficient method for inducing wheat - H. villosa chromosomal translocations. Triticum durum-Haynaldia villosa amphiploid pollen treated with 1 200 rad Co-60-gamma- rays was pollinated to Triticum aestivum cv. ` Chinese Spring'. Ninety-eight intergeneric translocated chromosomes between T. durum and H. villosa were detected by genomic in situ hybridization in 44 of 61M(1) plants, indicating a translocation occurrence frequency of 72.1%; much higher than ever reported. There were 26, 62 and 10 translocated chromosomes involving whole arm translocations, terminal translocations, and intercarlary translocations, respectively. Of the total 108 breakage-fusion events, 79 involved interstitial regions and 29 involved centric regions. The ratio of small segment terminal translocations (W.W-V) was much higher than that of large segment terminal translocations ( W- V . V). All of the M-1 plants were self-sterile, and their backcross progeny was all obtained with ` Chinese Spring' as pollen donors. Transmission analysis showed that most of the translocations were transmittable. This study provides a new strategy for rapid mass production of wheat-alien chromosomal translocations, especially terminal translocations that will be more significant for wheat improvement.