Evaluation of early (S5) generation inbred line by using line × tester method was conducted in maize involving 29 lines and 3 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 with high SCA effect for grain yield, L18×BIL28, L22×BIL106 and L26×BIL31 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.
Maize inbred lines, Linextester method, GCA and SCA
November 2009
Variety and Species
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.
Twenty nine S5 generation inbred lines (as female parents) and 3 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 87 cross combinations in rabi 2009 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 2009. The unit plot size was 5.0 × 0.75m. Spacing adopted was 75 × 20 cm between rows and hills, respectively. One healthy seedling per hill was kept after proper thinning. Fertilizers were applied @ 250, 120, 120, 40 and 5 kg/ha of N, P205, K20, S and Zn, respectively. Standard agronomic practices were followed (Quayyum, 1993) and plant protection measures were taken as required. Two border rows were used at each end of the replication for minimize the border effect. Ten randomly selected plants were used for recording observations on yield contributing traits viz. days to 50% tasseling, days to 50% silking, days to maturity, plant height, ear height and grain yield (t/ha). The combining ability analysis was carried out as per the method suggested by Kempthorne (1957
Research report 2009-2010
The inbred parents L-1, L-2, L-4, L-8, L-12, L-14, L-15, L-18, L-19, L-20, L-21, and L-22 have been identified as the best general combiner due to their good combining ability effects and also their ability to transmit characters to their progenies for most of the characters. The cross L2 ×BIL106, L2 ×BIL28, L10×BIL106. L14×BIL31, L18×BIL106, and L18×BIL28 were identified as the best combinations due to their desired SCA effects for different traits.
Report/Proceedings