Growth indices of yield variability in wheat (Triticum aestivum L.) under varying degree of shades

Light is the main environmental factor which regulates growth and development of crop plants. Decrease in light intensity due to shading adversely affects plant growth and development. The present study was conducted to analyze the effect of varying degree of shades on growth characteristics and yield of wheat crop. Two shading treatments were applied i.e. 33% shading (L1) and 66% shading (L2) with full sunlight as control (L0). The experiment was conducted during the winter seasons of 2010–2011 in a split-plot design with three replications with shading treatments in the main plot and five varieties of wheat in the sub plots. The findings of the study showed that the mean crop growth rate, mean relative growth rate, net assimilation rate, leaf area ratio, leaf area index and specific leaf weight were significantly influenced by increasing shade. Grain yield of all the wheat varieties decreased with increase in shading. Varietal differences in grain under shading are discussed in relation to leaf area index and crop growth rate.