Location: Sugarcane Field StationTitle: Genotypes Using Best Linear Unbiased Predictors. Journal of American Society of Sugar Cane Technologist
|TAHIR, M - Sugar Crops Research Institute|
|KHALIL, I H - Sugar Crops Research Institute|
|MCCORD, PER - Former ARS Employee|
Submitted to: American Society of Sugar Cane Technologists
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/17/2014
Publication Date: 11/17/2014
Citation: Tahir, M., Khalil, I., Mccord, P.H., Todd, J.R. 2014. Genotypes Using Best Linear Unbiased Predictors. Journal of American Society of Sugar Cane Technologist. American Society of Sugar Cane Technologists. 34: 44-56.2014.
Interpretive Summary: New sugarcane varieties are important for farmers in Florida to maintain yields. Selection is difficult in the early stages of the sugarcane breeding program because of small unreplicated plots. A statistic that has been utilized sucessfully by animal breeder called Best Linear Unbiased Predictors (BLUPs) was applied to data in an early stage of the sugarcane breeding program at the USDA-ARS Sugarcane Field Station in Canal Point, FL. The estimated BLUPs did improve the yield means of selected individuals over the overall mean but were less than the selection method currently used at the station.
Technical Abstract: Varietal improvement program at the United States Department of Agriculture-Agricultural Research Service (USDA-ARS), Field Station at Canal Point, Florida consists of 4 stages. Stages I and II consist of unreplicated sugarcane (Saccharum Spp.) genotypes advanced from seedlings while Stages III and IV consist of replicated highly selected genotypes. Although new genotypes are unreplicated in Stage II, checks are replicated in an augmented design. Best Linear Unbiased Predictors (BLUPs), primarily used in animal breeding, could be used in the breeding program to select genotypes having improved characters. The present study was conducted to determine whether selection indices incorporating BLUPs would improve the Stage II selection program. Basic statistics and frequency distributions showed the presence of variability in brix, sucrose, purity, recovery, stalk weight, stalks per plot, commercial recoverable sucrose (CRS), and tons of cane per ha (TCH). However, analysis of variance showed significant differences only for stalk weight and the contrast of checks versus new genotypes. Path analysis revealed highest direct effects for stalk weight and stalks per plot. The selection index comprised of stalk weight, stalks per plot, and CRS. The results showed that although selection indices estimated using Estimated BLUPs (EBLUPs) improved means of the individual genotype selection, values were lower than the means obtained using the selection method used at the USDA-ARS Field Station at Canal Point. However, selection indices calculated using raw data gave lower mean values when compared to EBLUPs. The present study shows promising results with regard to use of BLUPs in the selection index method. Index selection screened genotypes based on multiple characters and were better in performance than the rest of the genotypes. These results could be improved by including an equal number of checks across all blocks for Stage II experiments. Furthermore, culling on the basis of disease ratings should precede the index selection procedure.