The yield and survival of lucerne lines in the upper south-east of South Austrialia

Thirty lines of lucerne from regions with Mediterranean and temperate climates were grown on a degp and infertile sandy soil in the Upper South East of South Australia. One trial (A) was cut at the frequency usually recommended for lucerne, and the other (B) was cut twice as often. Both trials were sown in spring 1965 in drills 35 cm apart, and were maintained as pure lucerne stands. The yield of dry matter of the tops was measured in Trial A between November 1966 and November 1969, and in trial B for one year from November 1966. The row cover attained by the plants was measured in each year. In trial A, yields rose to maximum values in spring and declined during the summer months to minimal values in autumn. At most harvests there mere significant differences between lines. Mediterranean lines gave good yields in the early phase of the trial, and were the most productive lines through each late summer to winter period. Lines from cool temperate regions, e.g. Rhizoma, gave low initial yields and low winter yields, but gave largest yields in spring 1968. Two Portuguese lines consistently gave high yields : they were the only lines to produce significantly more total dry matter than Hunter River over three years. All lines adequately survived a very dry year (1967), and most plant losses occurred in the final year of the trial. In 1969, six Mediterranean lines showed poor survival, each had less than 50 per cent row cover. Dry matter yields were smaller in trial B. Lines from cool temperate regions maintained 80 per cent row cover throughout and gave the largest yields. Three Mediterranean lines were eliminated after two years of frequent cutting, and the row cover of five other lines was reduced to less than 50 per cent.