The effect of tiller removal and tiller defoliation on competition between the main shoot and tillers of spring barley

摘要: SUMMARY In glasshouse and field experiments the source-sink relations of main shoot plants spring barley were modified by tiller removal defoliation. Decreasing competition promoted growth residual its component parts, earlier tillers removed greater was effect. Stem dry weight increased four-fold in early doubled experiment. The grain yield ear 26 – 30% compared with tillering control this due to larger grains all spikelet positions. On other hand increasing regular defoliation had relatively little effect on development study, but reduced 10% control. tillers. In survived repeated defoliation, continued be produced, majority produced fewer smaller per than plants. Tiller supported import assimilate from accompanied an increase photosynthetic rate leaves. defoliated died within 4 wk. These responses are discussed terms physiological interrelations between