Ear: Stem ratio in old and modern wheat varieties; relationship with improvement in number of grains per ear and yield

Three field experiments were conducted over two seasons at three sites in Western Australia, to investigate the physiological basis of increased grain number per ear in some old and modern wheat varieties and lines isogenic for Rht dwarfing genes. Growth rates and relative growth rates of the stem and ear varied between varieties, but there were no discernible trends with date of introduction or maturity grouping. The ratio of ear: stem growth...