Useful heterosis and combining ability for grain yield and resistance to downy mildew disease (Prenosclerospora sorghi) in some new yellow inbred lines of maize.
Abstract: ABSTRACT: Sixteen new inbred lines of yellow maize with wide genetic diversity were top-crossed with two narrow and one broad genetic testers to obtain 48 top-crosses in 2002 growing season. These crosses and two commercial check hybrids were evaluated at two locations Sakha and Nubaria Agriculture Research Station to estimate combining ability and useful heterotic effects for grain yield, its components and percentage of resistance to downy mildew disease (DMR %) in 2003 season. The obtained results revealed that, additive genetic variance (σ2GCA) was more important than non-additive genetic variance (σ2SCA) in the inheritance of days to 50% silking, ear position, No. of kernels/row, 100-kernel weight, grain yield ard/fad and DMR%. Meanwhile, σ2SCA played an effective role in the expression of plant height, ear height, ear length, ear diameter and grain yield/plant. The magnitude of the interaction of σ2SCA by locations (σ2SCA×Loc) was markedly higher than those of σ2GCA×Loc. for ear length, ear diameter, kernels/row, 100-kernel weight, grain yield ard/fed and grain yield/plant. While, σ2GCA was more sensitive to environmental conditions than σ2SCA for days to 50% silking, plant height, ear height, ear position and rows/ear. Inbred lines Sk-7008/7 and Sk-7008/12 exhibited good general combiners for grain yield and DMR%. Also, inbred line Skug-10 was the best combiner for earliness, ear position, grain yield and its related traits. Nine inbred lines are found desirable and inherited favorable alleles of DMR% in their top-cross progenies. Narrow genetic base was the most efficient and effective than those of broad genetic base for evaluating combining ability of most studied traits. Positive and significant heterotic effects over the commercial checks were detected via six top-crosses, i.e., Skug-10 × SC155 (27.16%), Sk-7008/12 × SC155 (19.46%), Sk-7008/7 × B-73 (17.89%), Skug-3 × SC155 (17.48%), Sk-7001/1 × SC155 (11.62%) and Sk-7001/2 × SC155 (11.54%) for grain yield and DMR% suggesting these yellow hybrids are prospective genetic materials for yielding ability with resistance to downy mildew disease in future maize breeding program.
Key words: Maize, Grain yield, Downy mildew, Combining ability, Heterosis, Additive and non-additive variances
Publication year 2005
Pages 273-292
Availability location معهد بحوث المحاصيل الحقلية - مركز البحوث الزراعية - ش الجامعه – الجيزة
Availability number
Organization Name
serial title J. Agric. Res. Tanta Univ., 31 (2):273-292.
Author(s) from ARC
Agris Categories Agricultural research
Publication Type Journal
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