Quality Analysis Of Reciprocal Backcross Population Of BC₃ And Construction Of CSSLs Between Huangzaosi And YE 478

To improved quality and increase yield in maize, cultivation of new variety is the key.Huangzaosi and Ye 478 as parents each other selected from the foundation inbred lines used in maize breeding in China was materials in the present study, respectively derived from Tangsipingtou and Reid, constructed two introgression lines populations. One introgression lines was in BC₃S₁ for Ye 478 as recurrent parent, the other was in BC₃ for Huangzaosi as recurrent parent. Based upon the reciprocal backcross populations of BC₃ for the variation and correlation of quality traits, including the contents of starch, protein, oil, lysine in maize kernels were systematically analyzed. It is supply the foundation for the future research, at the same time provide a reference and basis for improving the quality of Maize. In addition, introgression lines used molecular assisted selection (MAS) in BC₃ for Ye 478 as recurrent parent. Chromosome segment substitution lines (CSSLs) were consisted of Ye 478 as donor parent, and Huangzaosi as receptor, as well as evaluated on segments. This study was based on multiple comparison between BC₃S₁ and Ye 478 through SAS 9.0 software and QTL mapping used IciMapping 3.0 software. The main results are as followed:1. Based upon the reciprocal backcross populations of BC₃ derived from two elite maize inbred lines of Huangzaosi and Ye478, the variation and correlation of quality traits, including the contents of starch, protein, oil, and lysine in maize kernels were systematically analyzed. The results are as followed:(1) Between starch content of inbreds reached significance, the inbred with higher starch content (Huangzaosi) could significantly increase the starch content of the lower one (Ye 478), and the starch content of maize kernels could be improved through direct selections.(2) Between protein content of inbreds reached significance, affected by the genetic background and the complicated relationships with other quality traits, the inbred with lower protein content could significantly increase the protein content of the lower one, and the protein content of maize kernels could be improved through indirect selections.(3) Though the content of oil and lysine reached non-significant level, but the starch content negatively correlated with the contents of protein and lysine (P <0.01); the protein content positively correlated with the contents of lysine (P <0.01); the starch content negatively correlated with the contents of oil, and reached level of significance in BC₃/Y(P<0.05), non-significance in BC₃/H(P<0.05); the oil content negatively correlated with the contents of protein and lysine in BC₃/H(P<0.01), on the contrary, the oil content positively correlated with the contents of protein and lysine in BC₃/Y(P<0.01). Those relationships could improve the content of oil and lysine in maize 2. The population of chromosome segment substitution lines (CSSLs) was developed with Ye478 as the recurrent parent, Huangzaosi as the donor parent, respectively through backcross and self. In this process, we carried out maker-assisted selection by using 106 simple sequence repeat (SSR) maker covering the whole genome of maize. In this population of CSSLs, the average length of a single introgressive segment was 62.5 cM, varying from 41.95 to 87.12 cM. The total segment length was 6624.61 cM with coverage of 80.33% of chromosomes. The construction of CSSLs will play an important role of molecular breeding, which supply the foundation for maker-assisted breeding and fine mapping.3. Through SAS 9.0 software, we used multiple comparison between BC₃S₁ and Ye 478. The results that plant height and tassel primary branch number only have one family reached level of significance; 10-kernel length has 14 families reached level of significance; 10-kernel width has 5 families reached level of significance; ear weight has 6 families reached level of significance; cob weight has 4 families reached level of significance; kernels per row has 2 families reached level of significance; ear length and 100-kernel weight only have one family reached level of significance; non-significance in other traits (P<0.01). We selected a few families, which have more homozygous in background with few untargeted fragments and reach level of significance (P<0.01). This is supply an important material for breeding.4. We preliminary mapping 9 QTLs about related traits, including 3 QTLs in kernel width, 1 QTL in ear diameter, 2 QTLs in 100-kernelweight, 1 QTL in plant height, 1 QTL in ear height, 1 QTL in tassel primary branch number.