Abstract
A field experiment was carried out using four inbred lines of maize BK112, Inb17, ZP607 and Zm6, as they were entered into half-diallel cross-breeding program in the fall season 2019, and 10 genotypes (6 crosses + 4 parents) were obtained according to the second Griffing method, the first model, in the spring season of 2020, the behavior of these inbreds and their hybrids were evaluated with three irrigation intervals with the aim of obtaining one or more distinct hybrids of pure strains derived from maize Zea mays L. under the irrigation interval and the study of hybrid vigor. The experiment was carried out in the fields of a farmer in Anbar Governorate, using the RCBD randomized complete block design (split – plot) with three replications. The irrigation interval (4, 8 and 12) days occupied the main plots, while the inbred and hybrids occupied the sub-plots. The results of the statistical analysis showed a significant effect of genotypes on the studied traits. The studied hybrids Zm6 × ZP607 were distinguished by their weight of 300 grains and the grain yield (85.83 g and 186.70 g) respectively. The plants grown under the irrigation interval 4 days outperformed the grain yield of the plant by giving it the highest yield of 156.03 g. It did not differ significantly with the 8-day irrigation interval, while the yield decreased significantly at the 12-day irrigation interval with a decrease of 120.8% and 120.5% than the 4 and 8 irrigation treatments, respectively. It was also found that the interaction was significant and reached the highest grain yield with an irrigation interval of 8 days, 224.0 g. The hybrid Zm6 × ZP607 gave the highest positive hybrid vigor for individual plant yield, which was 119.24%, 126.72% and 166.05% for the irrigation interval of 4, 8 and 12 days, respectively. Therefore, the plant breeder can use the characteristics of the yield components as selection guides with the superior hybrids in yield and the strength of the hybrid.
Determination of Combining Ability and Type of Gene Action Using Half-Diallel Cross Among Seven S6 White Maize Inbred Lines
