Analysis of the Relationship Between the Key Parameters of Grain Yield in Two Maize ( Zea Mays L. ) Genotypes

We studied the relationship between key components of maize grain yield using two maize populations derived from two strains (BLC and JNE genotypes) with contrasting values of yield components. The BLC genotype has higher grain filling rate and heavier kernels while the JNE genotype has longer effective filling period and larger number of kernels per ear. In both populations, we observed a highly significant relationship between grain filling rate and kernel weight (r ≥ 0.90, p<0.001). Kernel weight was also correlated with effective filling period, but at a lower magnitude (r=0.29 for JNE genotype, and 0.30 for BLC genotype, p<0.05). These observations clearly showed that selecting for higher grain filling rate had a strong additive genetic effect on kernel weight. However, final grain yield per plant was much more influenced by number of kernels than kernel weight at a planting density of 42000 plants ha-1. A principal component analysis reveals that larger number of kernels and longer effective filling period are characteristics of the JNE genotype that had higher grain yield. Higher grain filling rate and heavier kernels were attributes of the BLC genotype that had comparatively lower grain yield.