The Effect of Temperature on Seed Set and Seed Development in Detached Spikelets of Perennial Ryegrass (Lolium perenne L.)

Abstract

In perennial ryegrass seed yield is low. Pollination, fertilization and early stages of seed development are critical periods for the realization of the yield potential. As intact plants are difficult to handle, we used detached spikelets to study effects of temperature and genotype on seed set and seed development.Plants of four cultivars were grown in pots. Just prior to flowering, spikelets were detached from the ears and put on water. After pollination, various spikelets of each plant were placed at different temperatures (14/14, 17/12 or 20/15°C). Seven days after pollination the percentage seed set and the length of the developing seeds (caryopses) were assessed. Only florets in the four basal positions were used.For each cultivar an analysis of variance for unbalanced data was carried out. There were highly significant difference among genotypes for seed set and caryopsis length. There was no evidence for genotypic variation for tolerance to low temperatures. Neither temperature nor floret position had an effect on seed set. The caryopsis length, however, increased with increasing temperature and basal florets produced longer caryopses than distal florets. The detached spikelets proved to be a useful experimental tool.