Research On The Differentiation Development Of Tassel And The Utilization Of Heterosis In The Photoperiod-thermo-sensitive Tassel Deficiency Line I17 In Maize

The material of the photoperiod-thermo-sensitive tassel deficiency line I17 in maize with unique characteristics-photoperiod-thermo-sensitive tassel deficiency,and the transformation fertility were obvious,planted the I17 maize in the spring in changsha and the tassel developed normally,planted the I17 maize in the summer in changsha and the tassel developed abnormally.In order to research the I17 maize genetic traits of the tassel deficiency,the cross and backcross experiments were carried out in the hybrid combinations with B73,Mo17;in order to research the differentiation developme-nt characteristics of the tassel,the different sowing date experiments of the I17 maize were carried out in the spring and in the summer;in order to evaluate the strength of the I17 maize heterosis and screen the new hybrid maize combinations with good agronomic characters and high yield,utilized the other 14 maize inbred lines (IZheng-58,B73,I478,Zheng58,308,344,H37-2,IXin3,Xin3,Qi319,24-2,G13,H25-2,Z58) with the 117 maize and preparated for the F1 combinations,identifying the agronomic traits,the phot-osynthetic characteristics,the yield characteristics of the F1 combinations in the field.The main results showed in the following:(1)The tassel of the F1 generation in the I17 maize differentiation developed normally,the tassel character of the F2 and BC1 generation in the I17 maize were separated in the summer,which could be divided into three types-the normal tassel,the short tassel and the tassel deficiency,and the study found that the performance of tassel deficiency in the I17 maize was recessive character,the genetic traits of tassel deficiency controlled by two pairs of recessive allelic gene.(2)The fertility transformation of I17 maize in the spring and in the summer were obvious.The tassel of the I17 maize in the spring developed normally,which could be observed and divided into five different morphological characteristics types.The tassel of the I17 maize in the summer developed abnormally,the young tassel developed deformitily in the early,which could be only observed and divided into two different morphological characteristics types.The tassel of the maize I17 in the summer stopped developing and dead deformitily at the protrusions of the growth cone and the elongation of the growth cone,and disabled to through the elongation of the growth cone normally,only left upright leaf developed deformitily in the late,forming the tassel deficiency at last.(3)The difference between the photosynthetic characteristics in the different combinations of maize was obvious,and there was no obvious regularility to follow,the correlation between the photosynthetic characteristics and the yield characteristics were no significant.The photosynthetic characteristics cluster analysis in different combinations of maizes in Changsha showed that the photosynthetic characteristics of the combinations 6(I17x308),7(I17x344),11(I17xQi319),13(I17xG13) were excellent,and the photosynthetic characteristics of Linao No.1,the combinations 2(117xIZheng58),4(I17×I478) and 14(I17xH25-2) were low,the photosynthetic characteristics of the rest of the combinations were general.The yield characteristics cluster analysis in different combinations of maizes sho-wed that the yield of Linao No.1,the combinations 3(I17×B73),7(I17×344),9(I17×IXin-3),11(I17xQi319) and 13(I17xG13) were higher,the agronomic and the ear characters were better;the yield of the combinations 10(I17xXin3) and 12(117x24-2) were lower; the yield of the rest of the combinations were general.The combinations 2(I17xIZheng58) belong to the early maturity combinations;the rest of the combinations might belong to moderate combinations;the comprehensive performance of the combinations 7(I17x344),9(I17xIXin3) and 11(117xQi319) were excellent,the yield of the combinations 3(I17xB73) was the highest,the yield increase 4.19% compared with the Linao No.1.(4)The preliminary research results indicated that the transformation fertility of the photoperiod-thermo-sensitive tassel deficiency line 117 in maize was obvious,the photosynthetic characteristics and the yield characteristics of the combinations 11(I17xQi319) and 13(I17xG13) were both excellent,so researching the heterosis utilization of the two-line with using the maize of 117 can open a new way to improve the production and modify the quality of maize.