A similar pattern was observed among clones from the very early stages of selection in a study reported by Jackson and McRae (2001). This study involved measuring cane yield and CCS of random clones derived from original seedling populations from two active breeding programs in the Burdekin region in Australia. The clones were evaluated in large plots (six rows 20 m) in order to estimate cane yield precisely.While a number of the clones were identified with higher cane yields than the two commercial cultivars included in the experiment (Q117 and Q96), none of the random clones had higher CCS than the two standard clones (Fig. 4).
The above data indicate that breeding programs have improved cane yield in the past but gains in CCS have been small or zero. Examination of genetic material generated and under evaluation in selection trials in breeding programs (Figs. 3 and 4) suggests that under current practices this trend is likely to continue. An important question, given the high economic importance of CCS, is whether it is possible to achieve greater improvements in CCS as well as cane yield?