Genetic analysis of photosynthetic characteristics of maize during late growth stage

Chinese. 了解玉米生育后期光合生理性状的遗传规律。选用8个光合速率差异较大的玉米自交系，按n(n+1)/2双列杂交法配制36个组合，采用GriffingⅡ和Hayman法对玉米4个光合生理性状进行配合力分析和遗传参数估算。所用材料中自交系鲁原92和A150是较好的高光效亲本，平均值较高的杂交组合的亲本中至少有一个是高光效的。光合速率的遗传符合“加性-显性”模型，而气孔宽不符合“加性-显性”模型，广义遗传力分别为95.73%、81.47%，狭义遗传力分别为28.33%、32.39%。光合速率和气孔宽这2个光合性状的遗传均以非加性效应为主，显性方向均指向增效，适合中高代选择和优势育种。叶绿素含量的遗传符合“加性-显性”模型，加性效应比非加性效应更重要，显性方向指向增效，广义遗传力为78.78%，狭义遗传力为57.03%，适合早代选择。不同光合性状的遗传规律不同，高光效育种工作中，应筛选一般配合力较大的自交系作亲本，同时进行广泛测交。

English. Maize genotypes have been shown to differ in photosynthetic characteristics. Grain yield of maize is mainly attributed to photosynthetic efficiency during grain-filling period. So it is important for improving photosynthetic efficiency to analyze genetic parameters and combining ability in major photosynthetic characteristics of maize during late growth stage. Eight inbred lines with different photosynthetic rate were used as parents to make 36 combinations by n(n+1)/2 diallel crossing model. Griffing Ⅱ and Hayman methods were used, and combining ability and genetic parameters were analyzed in 4 photosynthetic characteristics. The analysis of general combining abilities showed that two inbred lines (Luyuan 92 and A150) were regarded as ideal parents for improving photosynthetic efficiency of F1 generation. The comparison of the combinations with high photosynthetic efficiency showed that such combinations involved at least one parent with high positive GCA effect. The inheritance of photosynthetic rate also fit to additive-dominant model, but stomatal width did not conform to additive-dominant model. h2B% was 95.73% and 81.47%, respectively. h2N% was 28.33% and 32.39%, respectively. Both photosynthetic rate and stomatal width depended on the non-additive genetic effect. They could selected in middle or late generation and suited to be applied in heterosis breeding. It indicated that the inheritance of chlorophyll content fit to additive-dominant model, both of the h2B% and the h2N% of chorophyll content were 78.78% and 57.03%, respectively. Compared with non-additive genetic effects, additive genetic effects played an important role in the chlorophyll content inheritance, and can be selected in early generation. The genetic regularity of photosynthetic characteristics of maize are different. It is feasible to use photosynthetic efficient inbred lines to achieve combination with high photosynthetic efficiency. Making as many crosses as possible is necessary.