Analysis on combing ability and estimation of genetic parameters for chlorophyll content in maize

Chlorophyll closely related to photosynthetic capacity and developmental stage in crops. In order to reveal the genetic characters of chlorophyll content in leaf above ear, ear leaf and leaf under ear (three-ear-leaves) of maize, ten inbred lines from five different heterotic groups were selected to make crosses by a completely diallel cross design. The combining ability analysis and genetic parameters estimations of chlorophyll content of three-ear-leaves were carried out. The results showed that highly differences existed among ninety F1 crosses including reciprocal crosses, the general combining ability (GCA) effects and special combining ability (SCA) effects were different and p<0.01. The inbred lines No.10 (Xu178), 1(Ye478) and 7(Dan340) were observed with positive GCA effects while other inbred lines showed negative GCA effects. The crosses 4×9 (Chang7-2×8085Tai) and 6×9 (Zi330×8085Tai) with significantly positive SCA effects were found. The cross 4×6 (Chang7-2×Zi330) appeared maximum negative SCA effect for three-ear-leaves investigated in this study. The GCA effect of inbred lines was not corresponding to the SCA effect. The correlation coefficients between three-ear-leaves were all more than 0.7 which were highly positive correlations. Chlorophyll content showed reciprocal crosses differences (p<0.05). Broad sense heritability and narrow sense heritability were about 55 and 33.5% respectively. The additive effect was greater importance than non-additive effect.   Key words: Maize, chlorophyll content, reciprocal effect, heritability.