The flowering responses of crop and pasture species in Australia I. Factors affecting development in the field of Lolium species (L. rigidum Gaud., L. perenne L., L. multiflorum Lam.)

Abstract

Cultivars of three species of ryegrass (Lolium rigidum Gaud., L. perenne L., and L. multiflorum Lam.) were grown in the open and in the glasshouse at Melbourne (lat. 38° S.), with additional lighting and vernalization when required. They were sown at different times through the year and were compared for times of flower initiation and heading and for leaf numbers to heading. They included two early cultivars (Wimmera, Kangaroo Valley), four mid-season ones (Victorian, Grasslands Ruanui, Tasmanian No. 1, Grasslands Paroa), and one late one (S.23) from England.

For all cultivars studied, some cold was required for flower initiation, while long days hastened it somewhat; development between initiation and heading was hastened by both warmth and long days. The early group with a small cold requirement initiated in winter and spring and headed in spring and summer. The mid-season group with a larger cold requirement initiated only in spring, and headed in mid spring to early summer. The late cultivar headed scantily or not at all, the winter temperature being too high for initiation.