Relationships between the duration of phases in the pre-anthesis life cycle of spring barley

Abstract

Ear development and ear growth were studied in the progeny of two crosses between a six-row and two two-row spring barley varieties. There were no differences in the rates of primordium initiation amongst the progenies and parents. Duration of ear initiation and ear growth varied amongst the genotypes, and there was a strong negative correlation between the duration of these phases. Duration of ear initiation was correlated with number of leaves, as was the length of life cycle from sowing to anthesis. Survival of spikelets was related to the number of spikelet primordia initiated. However, the proportion of spikelet primordia that survived to form grains was less in ears with most spikelet primordia. This may be due to competition for resources in the ear. It is suggested that optimal ear size and life-cycle duration may be achieved by breeding for appropriate durations of the component phases of the life cycle.