Effects of manipulation of number of tillers and water supply on grain yield in barley

Abstract

SummaeyThe effects of several detillering treatments on dry-matter production and grain yield in barley were investigated in a series of pot experiments using two water regimes. When ample water was provided, even quite severe reductions in the number of tillers only slightly reduced grain yield in spite of large effects on total shoot dry weight. When all the plants were grown with the same amount of water, however, the plants with few tillers tended to have greater grain yield, higher water use efficiency (in terms of grain yield) and higher harvest index than the plants permitted to tiller freely. This effect was probably related to the greater transpiration rates from the freely tillering plants which led to their suffering a greater degree of water stress than the plants with few tillers. This led to the freely tillering plants having a greater proportion of sterile ears and a lower harvest index. Water stress apparently had no effect on the grain yield of the main shoot or first tiller. It is concluded that genotypes which produce few large tillers having a high rate of survival should be able to achieve relatively high yields in drought conditions without sacrificing yield potential under optimal conditions.