Combining ability of Chilo partellus resistant maize inbred lines for mid-altitude environment of Kenya
Gakunga, J.
Combining ability of Chilo partellus resistant maize inbred lines for mid-altitude environment of Kenya - African Crop Science Society : 2011 - p. 293-294
Abstract only
Maize (Zea mays L.) is an important staple food crop in the developing world. The spotted stem borer, Chilo partellus Swinhoe causes significant maize yield losses in the mid-altitude ecology of Kenya. Host plant resistance is a preferred option to reduce yield losses. Knowledge of gene action conditioning resistance is key in breeding for insect resistance. The objectives of this research were to determine the level of resistance of 45 maize hybrids to C. partellus, agronomic performance of the hybrids in the target ecology, general and specific combining ability and the heterotic groupings of the inbred lines. Ten maize inbred lines were crossed in a diallel scheme to generate 45 single cross hybrids, which were evaluated using alpha lattice design in four sites for two rainfall seasons in 2009 and 2010. Ten plants in every plot were infested with five C. partellus neonates while the rest were protected using beta cyfluthrin (Bulldock). Data were recorded on grain yield, leaf damage, and number of exit holes, tunnel length, and ratio of tunnel length to plant height, and Analysis of Variance conducted using GLM procedure of SAS. Results showed variability (P<0.001) among the lines for resistance to the pest, grain yield and agronomic performance. Additive gene effects were more important than non-additive gene effects for grain yield and leaf damage, number of exit holes, tunnel length and tunnel length-plant height ratio, while genotype x parameter interactions were observed among traits. Parents 1 and 2 showed good GCA for grain yield, 3 and 4 had good GCA for leaf damage, exit holes, tunnel length and tunnel length-plant height ratio, while parent 9 showed good performance for both. Parents 1, 2, 3, 5, 8 and 10 were classified into heterotic group B, parent 6 into group A and parents 4, 7 and 9 into heterotic group AB. There was no variability in reaction to gray leaf spot, Exserohilum turcicum, rust and maize streak virus among the hybrids. It would be possible to develop viable F1 hybrids resistant to C. partellus and with desirable agronomic traits. Breeding for resistance to C. partellus should adopt a recurrent selection method to utilize the additive nature of gene effects. Inbred lines 1, 2 and 9 would be useful breeding stock for further breeding work. Potential for use of molecular markers in identification of QTLs associated with resistance should be explored.
English
Combining ability
Gene action
Resistance
Combining ability of Chilo partellus resistant maize inbred lines for mid-altitude environment of Kenya - African Crop Science Society : 2011 - p. 293-294
Abstract only
Maize (Zea mays L.) is an important staple food crop in the developing world. The spotted stem borer, Chilo partellus Swinhoe causes significant maize yield losses in the mid-altitude ecology of Kenya. Host plant resistance is a preferred option to reduce yield losses. Knowledge of gene action conditioning resistance is key in breeding for insect resistance. The objectives of this research were to determine the level of resistance of 45 maize hybrids to C. partellus, agronomic performance of the hybrids in the target ecology, general and specific combining ability and the heterotic groupings of the inbred lines. Ten maize inbred lines were crossed in a diallel scheme to generate 45 single cross hybrids, which were evaluated using alpha lattice design in four sites for two rainfall seasons in 2009 and 2010. Ten plants in every plot were infested with five C. partellus neonates while the rest were protected using beta cyfluthrin (Bulldock). Data were recorded on grain yield, leaf damage, and number of exit holes, tunnel length, and ratio of tunnel length to plant height, and Analysis of Variance conducted using GLM procedure of SAS. Results showed variability (P<0.001) among the lines for resistance to the pest, grain yield and agronomic performance. Additive gene effects were more important than non-additive gene effects for grain yield and leaf damage, number of exit holes, tunnel length and tunnel length-plant height ratio, while genotype x parameter interactions were observed among traits. Parents 1 and 2 showed good GCA for grain yield, 3 and 4 had good GCA for leaf damage, exit holes, tunnel length and tunnel length-plant height ratio, while parent 9 showed good performance for both. Parents 1, 2, 3, 5, 8 and 10 were classified into heterotic group B, parent 6 into group A and parents 4, 7 and 9 into heterotic group AB. There was no variability in reaction to gray leaf spot, Exserohilum turcicum, rust and maize streak virus among the hybrids. It would be possible to develop viable F1 hybrids resistant to C. partellus and with desirable agronomic traits. Breeding for resistance to C. partellus should adopt a recurrent selection method to utilize the additive nature of gene effects. Inbred lines 1, 2 and 9 would be useful breeding stock for further breeding work. Potential for use of molecular markers in identification of QTLs associated with resistance should be explored.
English
Combining ability
Gene action
Resistance