Morphological Identification and Evaluate the Combining Ability and Heterosis of Some Inbred Lines of Maize and Its Crosses

Abstract

In 2016 five maize inbred lines were crossed in all possible combinations without reciprocals by using a half diallel crosses mating design to obtain 10 single crosses. Parental inbred lines and their F 1 single crosses were evaluated through 2017 season to evaluate the role of general and specific combining ability, heterosis and the morphological characteristics. A randomized complete block design with three replicates was used. Results showed that mean squares of genotypes, general combining ability (GCA) and specific combining ability (SCA) were highly significant for all studied yield traits. The GCA/SCA ratio was less than unity for all studied traits, this means that these traits are predominantly controlled by non-additive gene action. Positive significant GCA effects were found for all studied traits. Based on GCA estimates, it could be concluded that the best combiners were Inb 209 and Inb 239 for most of studied traits. This result indicated that these inbred lines could be considered as good combiners for improving yield and its attributes. Positive significant SCA effects were found for all studied traits. Based on SCA effects, the best crosses for ear diameter, 100-kernel weigh and kernel number/row was C1; for ear length was C10 and for ear weight/plant, grain weight/plant and shelling percentage was C8. Results showed positive significant heterosis values for all studied yield traits. The best crosses over both their mid-parents and betterparents for ear diameter and 100-kernel weigh was C2; for ear length and kernel number/row was C5; for ear weight/plant and grain weight/plant was C9 and for shelling percentage was C8.

Evaluation of Inbred Lines of Maize in a Diallel Cross under Normal Condition and Drought Stress

“…All the crosses under either of the two irrigation treatments showed positive additionally significant or highly significant heterobeltiotic effects for grain yield (ardeb/feddan), except the cross (P-86×P-137) under normal irrigation, the crosses (P-24×P-171) and (P-53×P-171) under drought stress, and the hybrids (P-17×P-24), (P-17×P-171), and (P-53×P-96) under the two irrigation regimes. Several studies have also shown significant levels of heterosis over better parent for grain yield in maize under normal irrigation and drought conditions (Fayed et al 2019).…”