Studies on the response of grape genotypes in relation to different levels of moisture stress

Abstract

A pot trial experiment was conducted on six grape genotypes (Dogridge, Saltcreek, 1613, St. George, Vitis champini clone and cultivar Thompson Seedless) with three levels of moisture stress for a period of 14 days. Of the six grape genotypes studied, the rootstocks, 1613, St. Geroge, Vitis champini clone along with cultivar Thompson Seedless did not survive the stress under 100 per cent moisture stress condition. However, all of them survived under 50 per cent stress condition. Under 100 per cent stress, all the genotypes showed general reduction in Relative Water Content (RWC), Osmotic Potential (OP), Leaf Water Potential (LWP), Transpiration rate (AE), Net Photosynthetic Rate (Pn) and Stomatal Conductance (Gs). Under 50 per cent mositure stress RWC, AE, Pn, Gs, reduced in all the genotypes. Whereas, they wre on par with the OP and LWP. Leaf temperature (LT) increased in all the genotypes at both the stress levels. The N, P and K content reduced in all the genotypes as a result of moisture stress. However, in Dogridge the N content in the leaves of stressed plants was almost on par with the well watered plants. Another experiment conducted on the diurnal variation of leaf RWC, OP and LWP were maximum in the morning in all the three genotypes (Dogridge, Saltcreek and Thompson Seedless) studied and reduced considerably by noon and slightly recovered in the afternoon under complete moisture stress. Soil mositure content was reduced in all the genotypes due to mositure stress. In the root development studies with six grape genotypes the highest root dry weight among all the categories of roots was found in Dogridge. Similarly, the dry weight of the shoot as well as the plant height were maximum in the rootstock Dogridge.