Effect of Water Deficit on Accumulation of Dry Matter, Carbon and Nitrogen in the Kernel of Wheat Genotypes Differing in Yield Stability

Water stress effects on accumulation of dry matter, carbon andnitrogen in grains were analysed in varieties and species ofwheat differing in yield stability. Variable water environmentswere generated using a line source sprinkler system. Althoughlarge fluctuations occurred in the water potentials of the flagleaf and ear, grain growth remained relatively buffered undermoisture stress. Developing grains were at a lower moisturelevel throughout grain growth in plants subjected to moisturestress relative to the unstressed plants. Carbon content decreasedmore than the nitrogen content in the stressed grains of thespecies and varieties. Reduction in the duration of grain growthand the rate of dry weight accumulation induced by water stresswas more prominent in T. aestivum var. C306 and T. sphaerococcum.Grain yield was reduced significantly under water stress, themaximum being in the high yielding cultivar HD2329. Both grainnumber and grain weight were reduced in response to stress,the extent of reduction being different in different genotypes.Copyright1994, 1999 Academic Press Water deficit, yield stability, C and N accumulation, heat degree days