The effect of soil fertility on the contribution of main stem, tillers and kernel position to grain yield and grain protein content of wheat

The relative contribution of main stems and tillers, as well as the relative contribution of first, second and third kernels in spikeiets to grain yield and grain protein content, is seldom quantified. The grain yield of main stems, tillers and relative mass of kernels in the spikelet by floret position were determined in a long-term fertilization and irrigation experiment at the University of Pretoria. A randomized complete block design in a split-plot arrangement with three replicates was used. Main plots consisted of two different soil fertility levels and subplots were assigned to four cultivars. Mean grain yield of main stem (MS), first tiller (T1) and second tiller (T2) for the cultivar Kariega was 1.26 g, 0.98 g and 0.53 g respectively, 1.29 g, 0.78 g and 0.40 g for Carina, 1.63 g, 0.69 g and 0.09 g for Inia and 1.71 g, 1.10 g and 0.51 g for SST 86. Within a cultivar, the respective ears (MS, T1 and T2) did not differ in mean grain protein content, but significant differences were observed among th...