Study On Patterns And Techniques Of Maize High Yield Breeding In Jilin Province

This dissertation propounded the plan for high yield breeding, according to the ecological character of Midwest area in Jilin province .It innovated new heterotic group and studied on it deeply and wildly ,based on excellent synthesized characters of China ,America and subtropical germplasm .The results showed: Reid group×Tang group and Reid group×Lvdahonggu group were heterotic patterns in middle area of Jilin province.The high-yield and steady-yield breeding should be put up according to the pattern of Lancaster group×Tangsipingtou in the Western area of Jilin province, where exist obvious heterosis between PN group and Tang group; PN group and Lvdahonggu group; Lancaster group and Tangsipingtou group; Reid group and Lvdahonggu group; Reid group and Tangsipingtou group.The combination that crossed by J1285 and J853 was adapt to the Western area, and the combination of J1782 and Dan8415 was adapt to middle area .The heritabilities of ear row number ,ear height and plant height were high, the kernel length and grain weight per plant were low and these characters conformed to additive-dominance-epistatic genetic model.The main results show as followed:1.According to the ecological characteristics of Jilin province, the security of china grain and the strategic station of maize in national economy, it put forward the plan for high-yield breeding which Reid group×Tangsipingtou group and Reid group×Lvdahonggu group were the heterotic patters for middle area, the Lancaster group×Tangsipingtou group was the heterotic patters for the Western area.2.Analyzing the process of maize breeding, the author regarded that three periods profoundly influence on maize breeding and production in China in recent years. China went into hybrid universal stage after the importation of Mo17 and the breed of Huangzaosi. With Ye107 and Ye478, China maize production entered into Half density-resistant period .Following the hybrid Zhengdan958 breed successfully China maize production entered into density-resistant popularize period .The importation and improvement of PN78599 contributed to maize production and breeding.3.The author put forward the content that Reid group×Tangsipingtou group, Reid group×Lvdahonggu group,Lancaster group×Tangsipingtou group, internal group×foreign group were key heterotic pattern in maize production for North-east region.4.The author innovated new Lancaster group , Reid group and Lvdahonggu mixed with Tangsipingtou group based on synthesized good character and favorable gene of China, America and subtropical germplasm .The key representative of inbred line were J1285, J1782, J210, J376, J385, J5918.5.The new structured heterotic patterns including PN group×Lvdahonggu group, Reid group×Lvdahonggu and Lancaster×Tangsipingtou Lvdahonggu and Tangsipingtou have obvious heterosis .The PN group×Lvdahonggu group, Reid group×Lvdahonggu adapt to the middle area of Jilin province, while the Lancaster×Tangsipingtou adapt to the Western area of Jilin province.6.The combinations including J1285×J853, J1782×Dan8415, J5918×Dan8415, which were crossed by the inbred lines that breeding from the new created heterotic groups .These combinations have obvious superiority of four diallel crossing trail and they have already been applied in maize production.7.The result of heritability analysis showed that the estimated values of combinations were different in different diallel crossing, but they have the same tendency. Among all characters, the general heritabilities and narrow heritabilitiy of ear row number ranked the highest, and the two kinds heritability of ear height and plant height were in the next place, whereas the two kinds heritability of ear-kernel weight and kernel length were lowest. Hence when improving characters, the ear row number and ear height should be selected in S₀-S₁ generation, the ear-kernel weight and kernel length should be selected in S₄-S₅ generation according to the performances of plant type.8.Genetic model test on ear characters adopted four augmented NCâ…¡designs in this experiment. The results showed that the heredity of ear-kernel weight, 100-grain weight, kernel length, ear length , ear width ,ear row number did not conform to additive-dominance genetic model and there exists epistatic effect. The results of genetic model test that used two generation mean analysis experiment according with the former. It shows that these characters conformed to additive-dominance- epistatic genetic model, and the dominance effect was the most important for ear-kernel weight, and the additive and epistatic effect was important in the heredity of ear length and 100-grain weight .The result of model test on plant-type and growth stage characters, the results showed that dominance effect was important in plant heredity, and the additive effect was in dominant position and also exists epistatic effect. 9.The genetic diversity of self-select inbred lines, The Fifth key inbred lines and the crossed hybrid were analyzed through RAPD method .The result showed that J1285, Mo17, J1037 and improved Suwan1 were belong to Lancaster heterotic group; J5918 and 599-20 were belong to PN heterotic group ;The hybrid JiYu85(J1285xJi853), Jidanl80 and Jidan342 were divided into one group ,because they have the same genetic base. The study revealed that the clusters classified by ISSR and RAPD reached the same result.10.The result of the cluster analysis of 18 RAPD primers used to detect genetics diversities among 13 inbred lines and 9 hybrids was in accordance with practical production. This showed that RAPD method was a reliable option to cluster single inbred line and hybrid and ISSR has some effect on the analysis of maize genetics diversities, but it has some limitation at the same time.