M. Shalim Uddin
Senior Scientific officer
Plant breeding division
BARI,Gazipur
Evaluation of early (S4) generation inbred line by using line × tester method was conducted in maize involving 34 S4 lines and 2 testers for grain yield and its components to determine the general combining ability (GCA) and specific combining ability (SCA) effects. Highly significant genotypic differences were observed indicated wide range of variability present among the genotypes. The crosses exhibited significant SCA effects involved high x high, high x low, low x high, average x low and low x low general combining parents. The crosses with high SCA effect for grain yield, CZ 2370-45-2 × CML 480, CZ 2370-18-2 × CML 480, CZ 2370-27-2 × CML 486, CZ 2370-7-2× CML 486 and CZ 2370-56-3× CML486 evolved from high x low general combiner parents were reveled additive x dominance type of gene action. The cross combinations with significant positive SCA effect having high mean values might be used for obtaining high yielding hybrids. The information on the nature of gene action with respective variety and characters might be used depending on the breeding objectives.
LinexTester, Combining ability, heterosis, GCA, SCA
November 2008
Variety and Species
Combining ability is one of the powerful tools in identifying the best combiner that may be used in crosses either to exploit heterosis or accumulate fixable genes. The present study involving a line × tester analysis aimed to determine the general combining ability (GCA) and specific combining ability (SCA) of crosses for different traits and to explore heterotic hybrid combinations.
Thirty four S4 generation inbred lines (as female parents) and 2 testers (as male parents, one from heterotic group A and another from heterotic group B) of maize were selected and crossed in line × tester fashion to generate 68 cross combinations in rabi 2007 at Bangladesh Agricultural Research Institute, Joydebpur. Seeds of all the parents, their F1 hybrids and one check variety BARI Hybrid maize 5 (BHM 5) were sown in the same farm following RCBD with 2 replications in rabi 2008.Ten randomly selected plants were used for recording observations on yield contributing traits viz. days to 50% tasseling (DFT), days to 50% silking (DFS), days to maturity (DM), plant height (PH), ear height (EH) and grain yield (t/ha). The combining ability analysis was carried out as per the method suggested by Kempthorne (1957).
Research report 2008-09
24000
From the study, seven lines (CZ 2370-45-2, CZ 2370-18-2, CZ 2370-10-2, CZ 2370-7-2, CZ 2370-7-2, CZ 2370-56-3, CZ 2370-24-3) and one tester (CML 480) exhibited significant positive SCA and possessed comparatively well per se performance. Though, these parents could use for developing high yielding hybrids. The crosses posses high yield with significant SCA effects could be used for better hybrid selection. The information on the nature of gene action with respective variety and characters might be used depending on the breeding objectives.
Report/Proceedings