GENERAL AND SPECIFIC COMBINING ABILITY OF NEW WHITE MAIZE INBRED LINES FOR SOME AGRONOMIC TRAITS

Seven new white maize inbred lines were crossed with three testers in 2021 growing season at Ismailia Research Station. The resulting 21 crosses plus four standard checks were evaluated in 2022 growing season at three locations (Ismailia, Sakha and Sids) to estimate combining ability effects and identify the superior crosses. A randomized complete block design (RCBD) with three replications was used. The data were collected on number of days to 50% silking, ear height, plant height, number of rows per ear, number of kernels per row and grain yield. Mean squares due to locations were significant or highly significant for all studied traits. Mean squares due to crosses and their partitions; lines, testers and lines × testers interaction were significant or highly significant for all studied traits, except testers for number of kernels per row. The parental lines (Ism7246 and Ism7253) possess high desirable GCA effects for grain yield, earliness and lower ear placement. The two single crosses (Ism6084×Sk13) and (Ism7246×Sk13) and the three three-way crosses (Ism8093×SC10), (Ism6084×SC131) and (Ism7253×SC131) out-yielded the standard checks SC10 and TWC321, respectively. Ear height and plant height were controlled mainly by additive gene effects meanwhile, number of days to 50% silking, number of rows per ear, number of kernels per row and grain yield were controlled by non-additive gene effects.