RELATIVE PERFORMANCE OF CLONES SOURCED FROM LOCAL TRIALS VERSUS INTER-REGIONAL SELECTION TRIALS

FINAL ASSESSMENT STAGE selection trials (FATs) in sugarcane breeding programs are expensive but critical in recommending new clones for cultivation within each major growing region. Traditionally, clones selected from local early stage trials were given priority for inclusion in final stage selection trials compared with clones selected from trials in other regions. However, research reported in 2007 suggested that genotype × region interactions were a relatively small source of variation in selection trials, compared with other (genotype × within-region) interactions. This led to a recommendation that the best clones identified in final assessment trials in any one region be directly entered into final assessment trials in all other regions. This differed from previous practice of including clones in final assessment trials only after either good performance in local stage 2 (CAT) trials or release as cultivars in other regions. This recommendation was at least partly adopted in all regional selection programs. Some results arising from this recommendation are examined here. Performance of clones selected from local (early stage) trials was compared with clones selected from trials in other regions. On average, clones selected via final stage trial data from other regions performed slightly better than clones selected on local stage 2 (CAT) trials. Correlations between performance of selected clones in local stage 2 trials and subsequent performance in final stage trials were consistently around 0.3 to 0.5 for key traits. The results suggest that inclusion of clones performing well in final assessment trials in other regions coupled with slightly increased selection intensity from local stage 2 (CAT) trials would likely result in superior populations being tested in final assessment trials. These results generally support the recommendation that clones performing well in final assessment trials in any region continue to be rapidly and directly included into final assessment trials in all regions. Further work is required to identify the optimal proportions of locally selected clones to include in final assessment trials.