Maximizing Maize (Zea mays L.) Crop Yield via Matching the Appropriate Genotype with the Optimum Plant Density

Aim: The objective of this investigation was to match the functions of optimum plant density to produce the highest possible grain yield per unit area with the greatest maize genotype efficiency.

Study Design: A split plot design in randomized complete block arrangement was used with three replications. The main plots were assigned to plant densities, and sub-plots to maize genotypes.

Place and Duration of Study: This study was carried out at the Agricultural Experiment and Research Station of the Faculty of Agriculture, Cairo University, Giza, Egypt in 2012, 2013 and 2014 seasons.

Methodology: Six maize inbred lines differing in tolerance to high density (D) [three tolerant (T); L-20, L-53, Sk-5, and three sensitive (S); L-18, L-28, Sd-7] were chosen for diallel crosses. Parents and hybrids were evaluated under three plant densities: low (47,600), medium (71,400), and high (95,200) plants ha-1.

Results: The T×T hybrids were superior to the S×S and T×S hybrids under the high D in most studied traits across seasons. The relationships between the three densities and grain yield per hectare (GYPH) showed near-linear regression functions of increase for inbreds L-53, L-28, Sk-5 and Sd-7 and efficient non-responsive and inefficient responsive groups of hybrids with the optimum density of 95,200 plants ha-1, near-linear regression of increase for inbred L-18 with optimum density of 47,600 plants ha-1 and a curvilinear relationship for inbred L20 and the rest of the hybrids with the optimum density of 95,200 plants ha-1 for in-efficient non-responsive crosses and 88,000 plants ha-1 for inbred L20 and efficient responsive hybrids.

Conclusion: Growing the tolerant hybrid L20×L53 under high-D gave the highest grain yield (17.05 t ha-1) in this study with a superiority to the best check (SC 2055) of 27.0%.