The Relationship Between Productivity And Some Components Of Canopy Structure In Ryegrass (Lolium Spp.)
Productivity and percentage conversion of light energy were measured in (
Under infrequent cutting (28–34 days) the tiller population selected for erect tillers and rigid leaves was more productive than those selected for prostrate tillers and rigid leaves, and prostrate tillers and lax leaves. Under frequent cutting (14–17 days), however, the populations with prostrate tillers were most productive.
Considerable differences existed in the productivity of the S. 321 families, and their relative performance differed under the two cutting frequencies. Under infrequent cutting the highest yielding family was 17% more productive than the base population, whilst under frequent cutting the yield of the most productive family was 19% greater than that of the base population.
The heritability of sward yield was 0·64 under infrequent cutting and 0·86 under frequent cutting.
The most productive genotypes, populations and families under infrequent cutting had the highest leaf-area index (LAI) at complete light interception and the lowest extinction coefficients for visible radiation (
The physiological basis of differences in productivity is discussed in relation to canopy characters whioh may be used as selection criteria for increasing the efficiency of light utilization in herbage grasses.