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在以08-641(R08)为轮回亲本的BC2F2材料中,以种子形状和颜色是否类似R08为标准,选出供体不同的两个典型材料,一个种子形状和颜色类似R08(编号为A,供体为CN962);另一个种子形状和颜色不类似R08(编号为B,供体为8065)。分别自交两代得到79个不同株系(BC2F4),A材料自交分离得到的株系群体称A株系群,B材料自交分离得到的株系群体称B株系群。把A、B株系群分别按上述标准进行双向分类,得到AR、ANR和BR、BNR共4个次级分类株系群。通过对这些不同分类群回交后代株系的田间出苗率与大斑病抗性鉴定和配合力分析,探讨不同选择方向对轮回亲本R08的改良效果。结果表明,79个回交后代株系中,26个株系的出苗率显著或极显著高于R08,29个高抗大斑病。不同选择方向的回交后代比较显示,对R08田间出苗率和大斑病抗性的改良,以种子形状和颜色不似R08为标准选择得到的回交后代株系优于以种子形状和颜色类似R08为标准选择得到的回交后代株系。因此,回交过程中在加强改良目标性状的基础上,采取多向选择策略可能有利于提高回交改良的育种效率。
In BC2F2 with recurrent parent 08-641 (R08), two representative materials with different donors were selected based on whether the seed shape and color were similar to R08. One seed was similar in shape and color to R08 (numbered A, Donor is CN962); the other seed is not similar in shape and color to R08 (number B, donor 8065). A total of 79 different lines (BC2F4) were obtained from two generations of inbred lines, respectively. Lines belonging to group A and group B were self-isolated and named as group B. A, B strains were bi-directional classification according to the above criteria, AR, ANR and BR, BNR a total of four secondary classification strains. Through the field emergence rate, the identification of the disease and the analysis of the combining ability of the backcross generations of these different taxa, the improvement effect of different selection directions on the recurrent parent R08 was discussed. The results showed that among the 79 backcrossed progenies, the emergence rate of 26 lines was significantly or extremely significantly higher than that of R08 and 29. Backcross progenies of different selection directions showed that improvement of emergence rate and leaf blight resistance in field R08 was better than backcross progeny lines whose seed shape and color were not similar to R08, R08 is a backcross progeny selected by the standard. Therefore, on the basis of strengthening the target traits in the backcrossing, adopting a multi-directional selection strategy may be conducive to improving improved backcross breeding efficiency.