Dry Matter Partitioning between Plant Organs in Wheat Cultivars Differing in Productivity and Drought Resistance

In microplot field experiments conducted over the course of 12 years, the accumulation of dry matter was recorded in the leaves, stems, and ears of the primary shoots of plants of four cultivars of spring wheat (Triticum aestivumL.) differing in productivity and drought resistance. The contribution of organs to the accumulation of dry matter by the shoot from emergence to anthesis was calculated, and relative changes in the weight of the ear after anthesis were assessed. In all the cultivars, the contribution of the leaves was the same; however, the share of the ear was greater in short-stem cultivars of the intensive type in which the leaves were more active during the time of grain filling. Furthermore, this load increased, and the relative increment in the ear weight after flowering decreased in the years of drought, because the contribution of the leaves did not depend on water supply during the growing season. During these years, the contribution of the ear increased in the plants of all the cultivars. The authors conclude that, in arid regions, in addition to drought resistance, the cultivar should display such a ratio between the ear weight and the weight of leaves that would still ensure satisfactory grain filling