Submitted to: American Society of Sugar Cane Technologists
Publication Type: Abstract Only
Publication Acceptance Date: 4/17/2006
Publication Date: 7/1/2006
Citation: Glaz, B.S., Miller, J., Tai, P., Deren, C., Kang, M., Lyrene, P., Gill, B.S. 2006. Sugarcane genotype repeatability in replicated selection stages and commercial adoption. [abstract]. Journal American Society of Sugar Cane Technologists. 26:45. Interpretive Summary:
Technical Abstract: The sugarcane (interspecific hybrids of Saccharum spp.) breeding and selection program in Canal Point (CP), Florida recently increased the number of genotypes in its final selection stage, Stage IV, from 10 or 11 new genotypes with 1 or 2 reference cultivars to 13 or 14 new genotypes with 2 or 3 reference cultivars. This change resulted from findings that replications could be decreased without reducing experimental precision in Stage IV. The major purpose of this study was to determine if increasing the number of new genotypes in Stage IV would improve the likelihood of identifying successful cultivars. A secondary objective was to determine if genotypes could be expected to have similar yields in Stage IV and the penultimate stage, Stage III. Data were reviewed from 24 cycles of Stage III and 16 cycles of Stage IV. Genotype correlations between Stage III and Stage IV were significant but low for sugar yield (Mg sugar per ha) (r = 0.27) and economic index ($ ha per ha) (r = 0.28). No genotype that ranked worse than 15th in both sugar yield and economic index in Stage III was later used on more than 1% of Florida’s annual sugarcane acreage. Several high yielding genotypes are often not advanced from Stage III to Stage IV due to disease susceptibility, poor agronomic type, or low sugar content. Therefore, it is usually necessary to select from genotypes ranking worse than 15th in Stage III to advance as few as 10 new genotypes to Stage IV. It is unlikely that advancing more than 10 or 11 genotypes to Stage IV would improve the likelihood of identifying productive commercial cultivars until other changes in the program improve the quality of genotypes advanced to Stage III.