| Cotton is an important economic crop, and the improvement of cotton fiber yield and quality is always the challenge for the researcher in this field. The appearance of an transgenic cotton gemplasm line with iaaM, IF-11,which characterized by high lint percentage, reveal the possibility to improve lint percentage and mocronaire simultaneously. Therefore, studying on this IF-11gemplasm line and the heterosis with other cotton varieties for new germplasm breeding, fiber production increasing, and fiber quality improving has an important theoretical and practical significance.In present research, IF-11was mainly used to reciprocal cross with Ekang-10,TM-1,J-14,IF-11(wu).Then through the field investigation, stratified survey, sample test and so on, agronomic traits, yield traits, quality traits, photosynthetic rate, DNA methylation, etc. of parents and reciprocal cross F1, were measured and investigated. The main results were as follows:(1) On one hand, IF-11would not significantly affect the plant height and the first fruit branch position, on the other hand, it could protect the excellent traits. Also, taking IF-11as the male parent resulted in the obviously improvement of the lint percentage in low-lint genotypes. For Single boll weight, almost all the orthogonal Fi showed an apparent increase compared with female parent because of the increasing of lint percentage, except Ekang10xuan/IF-11. For example. Youzhi-1/IF-11improves18.6%compared with the female parent. Increase of lint percentage could also improve cotton yield. For instance, in this study, TM-1/IF-11improved24.26%, IF-11(WU)/IF-11improved16.08%and J-14/IF-11improved9.95%compared with the female parent. For the trait of lint yield, TM-l/IF-11, J-14/1F-11, Youzhi-1/IF-11, IF-11(WU)/IF-11were all higher than female parents, and that with a extent higher than cotton yield.(2)For the improvement of fiber quality, IF-11, as male parent, could effectively lead the micronaire of female parent into a higher grade. Almost all the orthogonal Fi showed lower micronaire than male parent except TM-1/IF-11, also, all reciprocal F1 showed reduced trend when compared with their male parent. Although decrease extent of micronaire didn’t show a statistically significant level, but it upgraded the standard in micronaire value of every experimental material.(3) For the middle heterosis and high heterosis of reciprocal cross cotton hybrid F1, some materials demonstrated good performance. For instance, On the inner dimension of effective bolls, boll weight, seed cotton yield and lint yield, various combinations demonstrated positive heterosis.(4)On the DNA methylation, reciprocal cross cotton hybrid Fi of J-14with IF-11were with higher methylation rate than their parents. The female parent indicated significantly lower methylation than the male, F1hybrids were higher than both the parents. Genetic methylation frequency of male parent was higher than the female parent, and genetic methylation frequency of anti-cross F1was higher than orthogonal F1. In this study, anti-cross F1, taken IP-11as the female parent, was with higher DNA genetic methylation frequencies than those materials taken IF-11as the male parent. Hence, it was inferred that iaaM gene may enhance the genetic of DNA methylation. |
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