Variation in Size and Development of Spikelets Within the Ear of Barley

Summary Carpel size at anthesis is known to vary with position along the ear in barley (Hordeum vulgare L.) and the aim of this work was to determine when differences in the size of spikelets at given developmental stages are established. The width of spikelet primordia at the double ridge stage was progressively less from the base to the tip of the developing ear and the difference in spikelet or floret size was maintained until the stage of stamen initiation. With the exception of the two lowest fertile spikelets measured, there was a good correlation between width of the spikelet at the double ridge stage and the final weight of the grain produced. The possible reasons for the differences in spikelet size are discussed.