Sowing date effects on phenology and yield of white maize genotypes during Kharif season under subtropical environment

This study was aimed at evaluating the effect of planting dates on the phenology, morphology, and yield of white maize varieties under a subtropical environment. Four varieties, V1: PSC 121, V2: Yangnuo-7, V3: Youngnau 30 and V4: Changnuo-6 and three planting dates, S1: 29 May 2017, S2: 21 June 2017, and S3: 6 July 2017 were the treatment variables. The experiment was laid out following Randomized Complete Block Design (RCBD) with three replications. Data on various phenological, morphological, and yield and yield-related attributes were collected. May sowing took longer days to attain 6-collar leaf and 10-collar leaf stages. The 50% tasselling and 50% silking showed at least 4-5 days early for late sowing in July. Days to maturity were not remarkably affected by the sowing dates, but varietal differences existed. Yungnuo-30 took the longest days to maturity in May sowing. The highest plant height was measured in PSC-121 followed by Changnuo-6 sown in May. The genotype Yungnuo-30 showed a 28.7% reduction in plant height in July sowing. The sowing date had little effect on the number of leaves, but varietal differences in producing leaves were highly significant. It is remarkable that the genotype PSC-121 developed the maximum leaf area at 60 DAS for May planting but produced the least at 90 DAS for June planting. The total dry matter decreased to a great extent for June sowing irrespective of genotypes. The highest dry matter weight was observed from May sowing for the PSC-121 genotype followed by July sowing for the same genotype. Crop sown in May recorded the highest ear weight, the number of grains per cob, grain weight, and seed yield, which were statistically similar with July sowing but June sowing significantly reduced all those parameters. The June planting experienced moisture stress at the early stage of stand establishment. The genotype PSC-121 performed better for all those parameters for May and July sowing, followed by the genotype Yungnuo-30. The highest seed yield (7.35 t ha-1) was obtained in PSC-121 followed by Yungnuo-30 for May sowing. The higher seed weight for May sowing was attributed to higher ear weight and the number of grains per ear. Therefore, sowing of white maize in Kharif season depends of the yield potential of the genotypes and weather conditions for achieving higher production