Variability in habit, flowering and seed production within the Kangaroo Valley cultivar of Lolium perenne when grown in a range of environments

Abstract

Diversity of flowering and seed production characteristics were measured within and between seven populations of Kangaroo Valley perennial ryegrass. The hypothesis that these characteristics would not change when grown in diverse environments was tested. The average time from seedling emergence to spike emergence was similar for each of three biotypes that represented early, intermediate and late flowering populations. This occurred in spite of variation in this character of 54 to 72 days between plants within each of these biotypes. When data from all seven populations were combined, they formed a normal distribution with respect to time of flowering. Distinctive components of seed production were found for the different populations. Early flowering populations had higher seed yields and more but shorter spikes than late flowering populations. Wide variation in habit occurred within populations but there was a high correlation between erect habit and early flowering. Spikes of erect plants emerged 27 days earlier than prostrate plants. The seed formation characteristics of an early flowering population were unaltered when grown for three generations in diverse environments. The spike emergence and anthesis times for each of the seven populations were not changed when grown in new environments. We conclude that seed production of Kangaroo Valley ryegrass in environments similar to those described in these experiments will not significantly alter the population characteristic. For changes in the character of the population to occur, the new environment would have to be so severe to (a) restrict growth and select out a proportion of the progeny or (b) cause a change in the time of seed harvest.