Genotypic Differences in Grain Protein, Oil and Starch Content and Yield of Maize (Zea mays L.) under Elevated Plant Density

The use of high plant density (PD) along with tolerant genotypes to high PD would overcome the negative impacts of competition stresses and lead to maximizing maize yield of grain (GYPH), protein (PYPH), oil (OYPH) and starch (SYPH) from the unit land area (ha). The main objective of the present investigation was to study Diallel crosses among diverse maize genotypes along with their parents were evaluated in the field for such characters under three plant densities, i.e. 47,600, 71,400 and 95,200 plants/ha, using a split plot design with 3 replicates in two growing seasons. Results combined across seasons revealed that elevated PD from 47,600 to 95,200 plants/ha caused a significant reduction in GYPP (29.98%), GPC (1.24%) and a significant increase in GYPH (38.48%), PYPH (36.80%), OYPH (40.70%), SYPH (38.43%) and GOC (0.74%). The F1 hybrids were lower in GPC than inbred lines, but were higher than inbreds for the rest of studied traits under all densities. Variation in GPC was from 9.3% (Sd7) to 14.38% (L18) among inbreds and from 9.5% (L20 x L53) to 11.58% (L18 x L28), while in GOC and GSC it was narrower than in GPC under all densities. Some genotypes were identified as high yielding and of high quality, high yielding of high tolerance and density efficient and responsive. Comparing with the best check (SC 2055) under high PD, the cross L20 x L53 gave higher GYPH (22.92%) and SYPH (24.9%) and the cross L53 x Sd7 gave higher PYPH (20.9%) and OYPH (12.2%).