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 60 Co‐γ‐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 61 M 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.