| Understanding genetic regularity of photosynthetic characters in maize, it will be propitious to breeding for improving photosynthetic efficiency. 8 inbred lines (B38, B114, Chang 7-2, Mo17, Luyuan 92, Huangzao 4, Ye 502 and A150) with different photosynthetic rate were used to make 28 hybrids by (1/2)n(n-1) diallel crosses design. As GriffingⅡand Hayman methods were used, combing ability and genetic parameters were estimated in photosynthetic characters including potosynthetic rate, chlorophyll content and stomatal area at different developmental stage and different leaf positions (top leaf at male tetrad; 5th bellow ear leaf, ear leaf and top 2-leaf at silking stage; ear leaf at filling stage). The main results of this study were as follows:(1) Photosynthetic rate: Genes controlling photosynthetic rate differently expressed at different developmental stage and different leaf position. The results indicated the photosynthetic rate was mainly controlled by non-additive effect at different developmental stage and different leaf position. There had super dominance. The inheritance of potosynthetic rate of top leaf at male tetrad, 5th bellow ear leaf and top 2 leaf at silking stage did not fit in to additive-dominant model, and were controlled by many minor genes and few major genes. The inheritance of potosynthetic rate of ear leaf at silking and ear leaf at filling stage fit in to additive-dominant model, they were controlled by 1 major gene at least. The broad heritability raged from 85.04%~ 97.41%, it indicated that there was little environment influence on photosynthetic rate and it can be selected in early generation. The narrow heritability raged from 15.55%~47.98%, therefore photosynthetic rate was suited to heterosis breeding. The analysis of general combining abilities showed that 5 inbred lines (B38, Chang 7-2, Luyuan 92, huangzao 4 and A150) were bettern for improving photosynthetic rate of F1 generation than others. The analysis of total combining abilities showed that three hybrids (B38×Luyuan 92, Chang 7-2×Luyuan 92 and Huangzao 4×Mo17) were mostly high in photosynthetic rate at different developmental stage and different leaf position.(2) Chlorophyll content: Genes controlling chlorophyll content expressed resemblely at different developmental stage and different leaf position. The results showed that chlorophyll content was controlled by additive and non- additive genetic effects at different developmental stage and different leaf position. Compared with non-additive genetic effects, additive genetic effects played an important role on the chlorophyll content inheritance, showing part-dominant inheritance at male tetrad and silking stage, showing complete-dominant inheritance at filling stage. The inheritance of chlorophyll content of top leaf at male tetrad and ear leaf at filling stage fit in to additive-dominant model. The inheritance of chlorophyll content of 5th bellow ear leaf and ear leaf at silking stage fit in to additive-dominant model, the inheritance of chlorophyll content of top 2 leaf at silking stage did not fit in to additive-dominant model. Chlorophyll content at different developmental stage and different leaf positions were controlled by 1 major gene at least. Except broad heritability of chlorophyll content of ear leaf at filling stage was 78.78%, it can be selected in middle or late generation. The broad heritability was high, can be selected in early generation. The narrow heritability raged from 57.03%~ 65.75%。The analysis of general combining abilities showed that 3 inbred lines (B114, Luyuan 92 and A150) were regarded as ideal parents for improving the chlorophyll content of F1 generation. The analysis of total combining abilities showed that four hybrids (B114×Luyuan 92, B114×B38, A150×B114, A150×Luyuan92) were mostly high in chlorophyll content at different developmental stage and different leaf positions.(3) Stomatal area: Genes controlling stomatal area differently expressed at different developmental stage and different leaf position. The results indicated that the stomatal area was mainly controlled by non-additive effects at different developmental stage and different leaf position. The inheritance of stomatal area of top leaf at male tetrad stage fit in to additive-dominant model, it was controlled by many minor genes and few major genes. The inheritance of stomatal area of 5th bellow ear leaf and ear leaf at silking stage did not fit in to additive-dominant model, while the inheritance of stomatal area of top 2 leaf at silking stage fit in to additive-dominant model, The inheritance of stomatal area of different leaf position at silking stage were controlled by 1 major gene at least. The inheritance of stomatal area of ear leaf at filling stage did not fit in to additive-dominant model, it was controlled by many minor genes and few major genes. The broad heritability at male tetrad and silking stage were high, it indicated that there was little environmental effect on stomatal area and it was better for stomatal area to select in early generation. The broad heritability at filling stage was 82.39%, it was better for stomal area to select in middle or late generation. The narrow heritability raged from 12.51%~32.21%, stomal area suited to heterosis breeding. The analysis of general combining abilities showed that 4 inbred lines (B38, Chang 7-2, Luyuan 92 and A150) were regarded as ideal parents for increasing stomamal area of F1 generation. The analysis of total combining abilities showed that stomatal area of A150×Chang 7-2, A150×Huangzao 4 were mostly big at different developmental stage and different leaf position.The results would provide theoretical basis for future breeding in improving photosynthetic efficiency. |
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