Stability and Adaptability of Yield, Oil Content and Leaf Specific Weight, and their Relationships under Multi-Environment Conditions in Maize

The present study was carried out to evaluate the stability and adaptability of maize genotypes and identify the relationship between grain yield and each of seed oil ratio and leaf specific weight under two different environmental locations for two seasons. The field experiments consisted of 5 parents and 10 hybrids and were conducted in randomized block design during autumn and spring seasons at each location of Kalar and Khanaqeen. Genetic analysis of stability and adaptability according to the methodology of Eberhart and Russel regression coefficient (bi) and Francis and Kannenberg coefficient of variability (CV) along with simple linear regression analysis for correlations between parameters were performed based on the average of all environments. For grain yield, the hybrids P2P4 and P2P3 were found to be adaptable, and parent P5 was stable over the environments. The parents P3, P4 and P5 along with the hybrids P2P1, P4P1 and P5P3 have a good performance and stability. Regarding oil ratio, the hybrids P1P3 and P5P1 were adaptable, and hybrids P2P3 and P2P5 were stable according to Eberhart and Russell methodology. The parents P2 and P5, and hybrids P2P4, P2P5 and P5P4 have good performance and stability. The hybrid P2P3 was stable, and the hybrid P5P3 was adaptable according to Eberhart and Russell methodology. According to Francis and Kannenberg coefficient of variability (CV), the genotypes P1, P3, P5, P2P1 and P4P1 were confirmed as having good performance and being stable. Therefore, these genotypes could be further studied and used in breeding programs under different environmental conditions. Simple linear regressions showed positive significant correlation between grain yield and leaf specific weight, and a trend for a significant relationship with oil ratio which indicates the importance of these traits to assess yield potential of maize crop and use them as a selection criterion in breeding programs.