Effect of dwarfing genes on yield and yield components of tall Indian wheat varieties

The effects of 3 dwarfing genes Rht 2, Rht 3 and Rht 1, 2 obtained from Tobari 66, Tordo's, Norin 10, Olesen, 0 6899 and S 948A was studied on the expression of yield and yield components of 4 commercially grown tall Indian wheat varieties K 68, Hybrid 65, NP 846 and NP876. Though, almost all the dwarfing genes reduced the plant height and enhanced the expression of grain yield, but the contribution of Rht 1, 2 in combination, from the source 06899 with NP 846 was observed to be the highest (28.3%) followed by Rht 3 gene from Tordo's source (20.0%) with K 68. However, the Rht 1,2 in combination. The increase in yield of the dwarf versions of the tall Indian varieties resulted primarily from an increase in the number of spikes per plant as also from the increase in the number of grains per spike.