COMBINING ABILITY, HETEROTIC GROUPING, CORRELATION AND PATH COEFFICIENT IN MAIZE
Document Type : Original research
10.12816/ejpb.2023.301683
Abstract
Combining ability analysis was performed using line × tester design for sixteen new white maize inbred lines which were crossed with two inbred lines as testers in 2020 growing season at Sakha Research Station. The resulting 32 top crosses along with two check hybrids were evaluated at three locations in 2021season. Mean squares due to locations were highly significant for all studied traits. Mean squares due to crosses and their partitions into lines, testers and lines × testers interaction were highly significant for all studied traits, except testers for ear height and line × tester for plant height. The parental lines Sk5002/1, Sk5004/7, Sk5007/10, Sk5008/12, Sk5008/13 and Sk5009/17 possess high GCA effects for grain yield and Sk5008/13 possess desirable GCA effects for earliness, long ear and large ear diameter. The two crosses Sk5007/10× Sd7 and Sk5009/17×Sk12 had desirable SCA effects and high mean performance for grain yield compared to the standard check SC10. These two crosses will be evaluated on a large scale in Egypt. Moreover, it is recommended that the two crosses, previously identified based on mean performance, were undergo further evaluation on a large scale for the commercial release to improve white maize hybrids in Egypt. Number of days to 50% silking, plant height and ear diameter were controlled mainly by additive gene action. Meanwhile, ear height, ear length and grain yield were controlled by non-additive gene action. The inbred lines, based on grain yield and heterotic group using specific and general combining ability (HSGCA) method, were classified into two heterotic groups as follows: group-1 (Sd-7) included Sk5008/15, Sk5009/17, Sk5009/18 and Sk5012/22. While, group-2 (Sk12) included Sk5003/5, Sk5004/7, Sk5007/8, Sk5008/13, Sk5008/14, Sk5008/16, Sk5009/19 and Sk5010/21. These groups could be used in breeding programs for selecting the best parents in developing new crosses. Grain yield showed highly significant and positive correlations with each of ear length, ear diameter, ear height and plant height. It is worthy to note that the effect of ear length and ear diameter proved to be the most effective selection criteria in maize breeding programs aiming at high grain yield capacity.
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