Effects of differences in date of ear emergence and height on yield of winter wheat

Abstract

SUMMARY Early and late, and short and tall lines were selected from a cross between the winter wheat varieties Norman and Talent. All short selections carried the Rht 2 dwarfing gene while the tall ones did not. The selections were compared in field experiments at the Plant Breeding Institute in Trumpington and at The Murrays Experimental Farm of the Scottish Crop Research Institute near Pathhead. In one of the experiments at Trumpington the plots were automatically sheltered from rain and the effects of withholding water before anthesis and withholding water during grain filling were studied. In all trials the early selections gave grain yields equal to or greater than the late selections. There were no differences in number of ears/m 2 or in number of grains per ear between the early and the late selections. Mean weight per grain of the early selections was greater than that of the late selections. The short selections gave grain yields equal to or greater than the tall selections, except when water was withheld during grain filling in the sheltered experiment. There were no differences in number of ears/m 2 between the short and the tall selections. The number of grains per ear was greater and mean weight per grain was less for the short selections than for the tall selections. It is concluded that for general fitness to U.K. conditions, new varieties should be semi-dwarf, but earlier than current varieties.