小麦-黑麦代换系间、代换系与易位系间杂交后代染色体易位系的选育

Selection of Wheat-rye Chromosome Translocation Lines between Substitution Lines or between Substitution Lines and Translocation Lines

为了选育有经济价值的易位系,探讨小麦-黑麦间产生易位的频率,本研究以小麦-黑麦代换系DS5R/5A和DS6R/6A为母本,以小麦-黑麦易位系克珍(Kezhen)和带有杀配子染色体的代换系DSGC1为父本,分别进行田间杂交。结果表明:DS5R/5A、DS6R/6A与DSGC1(2S)杂交结实率低,平均为27.7%,与克珍(T3B.3R)杂交结实率高于前者,平均结实率为59.3%,二者均好于远缘杂交的结实率,这也表明带有杀配子染色体的亲本影响结实率;对选出的54株DS5R/5A×DSGC1、DS6R/6A×DSGC1杂种后代与80株DS5R/5A×克珍、DS6R/6A×克珍杂种后代进行C-分带、原位杂交和分子标记鉴定后发现,二者的易位频率分别为11.1%和8.8%,并且多为染色体端部小片段易位,这种小片段易位可能是代换系间杂交部分同源染色体交换产生的。此外,也表明杀配子染色体在引起染色体断裂后可发生染色体易位。本研究共获得T5RL.5AS、T5RS.5DL、T5RS.5BL、T6RL.6DS、6RL.6BS以及T6RS.6BL等13个易位系,平均易位频率为9.6%。

In this study, we made crosses by choosing wheat-rye substitution line DS5R/5A and DS6R/6A as maternal parents, and wheat-rye translocation line Kezhen and substitution line DSGC1 harboring gametocidal chromosome as paternal parents, in order to breed translocation lines with economic significance and investigate the frequency of translocations generated by wheat-rye hybridization. Results showed that DS5R/5A and DS6R/6A had a low seed-setting rate with an average of 27.7% when crossed with DSGC1 （2S）, whereas a relatively higher seed-setting rate with an average rate of 59.3% when crossed with Kezhen （T3B.3R）. Both of which were better than that of distant hybridization. This indicated that seed-setting rate should be affected by parents with gametocidal chromosomes. Subsequently, we conducted C-banding analysis, in situ hybridization and molecular markers identification on 54 progenies derived from DS5R/5A×DSGC1 and DS6R/6A×DSGC1, and 80 progenies derived from DS5R/5A×Kezhen and DS6R/6A ×Kezhen. The results showed that translocation frequencies were 11.1% and 8.8%, respectively. In addition, most of these translocations were small fragments and occurred at the ends of chromosomes, which might be generated by recombination between homologous chromosomes of substitution lines. The results indicated that translocations could occur after chromosomes breaking caused by gametocidal chromosomes. A total of 13 translocation lines （T5RL.5AS, T5RS.5DL, T5RS.5BL, T6RL.6DS, 6RL.6BS, T6RS.6BL etc.） were obtained in this study, with an average translocation frequency of 9.6%.