Division of Plant Physiology, Indian Agricultural Research Institute, New Delhi-110012
Based on (i) inverse partitioning pattern of dry matter (DM) between ear and stem under changing mother shoot dry matter per unit area at anthcsis (MSDMA) brought about as result of staggering sowing dates at fixed population levels in Sonalika (T. aestivum) and HD 4502 (T. durum); (ii) similar pattern of DM accumulation upto anthesis (TDMA) in most wheat cultivars under normal conditions and (iii) no change in harvest index (HI) of different shoots born on mother plant in pot experiment where growth conditions were conducive for tiller survival; it was concluded that HI would decline in a situation where MSDMA was raised. This would happen when population levels are increased or tillering is poor resulting in low ear number at harvest.
The above conclusion was confirmed on a trial with 13 semidwarf cultivars where grain yield remained positively associated with ear number and grain weight per ear (r =0.68 and 0.64 respectively). However, HI remained positively associated with ear number per unit area.
