Growth, yield and phenological response of wheat cultivars to delayed sowing

A pot experiment conducted with 12 diverse wheat cultivars involving traditional tall and modern semi-dwarf to examine the impact of delayed sowing on growth, yield and some morpho-physiological and phenological characters revealed that delayed sowing in general caused marked reduction in growth and morpho-physiological characters such as plant height, leaf area per shoot and pot, number of shoots per pot, spike length, total dry weight per pot and dry weight per shoot of all the wheat cultivars at anthesis. Delayed sowing hastened the emergence of seedling, maximum tillering stage, emergence offlag leaf and spike, resulting in shortening the total growth duration of wheat plants. Delayed sowing caused significant reduction in biological and economic yields, through reduction in the number of spikes per pot, number of grains per spike, 1000 grain weight and grain and total dry weight per shoot without affecting some characters like grain spike ratio, spike weight ratio, harvest index and grain growth rate. Among the cultivars, traditional tall C 306 and K 68 manifested higher biological as well as economic yields than semi-tall and semi-dwarf cultivars under normal (D1) and 30 days late sown condition (D2), while failed to show superiority under 60 days delay of sowing (D3). The detrimental effect of delayed sowing on grain yield was maximum through reduction in the number of grains per spike followed by 1000 grain weight and number of spikes per pot.