Effect of Seed Rates and Sowing Dates on Productivity of Wheat (Triticum aestivum L.)

A field experiment was conducted at the Agronomy farm of Nepal Agricultural Research Council (NARC), Khumaltar, Lalitpur to evaluate the effect of sowing dates and seed rates on yield and yield attributes of wheat. The experiment was laid in a split-plot design with three replications treated with 4 sowing dates as the main plot factor (12th Nov, 27th Nov, 12th Dec, and 27th Dec) and 4 seed rates as subplot factor (100 kg ha-1, 120 kg ha-1, 140 kg ha-1 and 160 kg ha-1). Results revealed that the leaf area index was significantly affected by sowing dates and was comparatively superior in 2nd sowing date (27th Nov) wheat. Similarly, in the case of seed rates, the leaf area index was influenced significantly and was recorded to be increasing with an increase in seed rates. Phenological parameters like days to 50% heading, flowering, and maturity were observed maximum (116, 123, and 179 days, respectively) in early sown wheat and reduced with the subsequent delay in sowing. Maximum values of yield and yield attributes like effective tillers per meter square (635.6), spike length (9.56 cm), grains per spike (41.49), grain yield (7.59 Mt ha-1), and straw yield (9.58 Mt ha-1) were observed in the wheat sown in 2nd date (on 27th Nov) which differed significantly to wheat sown on other dates. Seed rates had no significant influence on grain yield and yield attributes. Thousand-grain weight was found maximum (46.26 g) in early sown wheat (on 12th Nov sown wheat, reduced with the subsequent delay in sowing, and the harvest index was observed as maximum (0.51) under December 27 sown wheat. Though the yield and its attributes were not influenced significantly by seed rate, the maximum yield (6.18 Mt ha-1) was observed in wheat sown at the rate of 120 kg ha-1. Considering seed yield and its parameters, 2nd date of sowing wheat (27th Nov) and seed rate of 100 kg ha-1 could be the best option to uplift the productivity of wheat in rainfed lowland conditions of Lalitpur, Nepal.