OPTIMISING CROP AGE IN THE INITIAL SELECTION STAGES OF THE NSW SELECTION PROGRAM IN AUSTRALIA

摘要

THE MAIN aim of this project was to obtain the basic information required to implement an efficient and effective breeding and selection program for the sugarcane-growing region of Broadwater, New South Wales (NSW) in Australia, with particular reference to problems associated with mixed one- and two-year cropping. Eighty seedlings from each of 40 families were planted in a family (Stage 1) trial. Two replicates of this Stage 1 trial were harvested as family plots after one year, and compared with two other replicates, which were harvested after two years growth. Twenty clones from forty families (800 clones) also were planted as 4-sett plots in families to simulate Stage 2 trials, and in 10 m plots to simulate Stage 3 trials. In the first ratoon crop of the Stage 2 trials, clonal measurements were taken to estimate the yield potential for each clone. This estimated value was then correlated to the data obtained during harvest of the Stage 2 trials. The results suggested that, in areas where two-year crops predominate, selection should be based on the data from two-year old crops. In addition, there was a strong correlation between the estimated and calculated selection index in both the one-year and two-year Stage 2 crops. However, the correlation between the one-year estimated selection index and the two-year calculated index was not significant. The results also show that family selection combined with visual selection in Stage 2 was generally more effective to identify elite clones in Stage 3 than family selection alone. Additionally, when the Brix of clones was taken into account, the efficiency of identifying elite clones was increased even further. These results have been used in conjunction with other research to rationalise the NSW selection program.