Yield, leaf-area index and photosynthetic rate in some perennial ryegrass (Lolium perenne L.) selections

Abstract

Yield, critical LAI and apparent photosynthetic rate per unit leaf area were measured in four families selected from L. perenne S. 321. Differences in yield were attributable to differences in canopy structure producing differing critical LAI. The most productive family, which was 33% more productive than the base population, produced the largest critical LAI but had the lowest photosynthetic rate.