|TAHIR, MOHAMMAD - University Of Agriculture - Pakistan|
|KHALIL, IFTIKHAR - University Of Agriculture - Pakistan|
|GLAZ, BARRY - Retired ARS Employee|
Submitted to: American Society of Sugar Cane Technologists
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/29/2014
Publication Date: 8/7/2014
Citation: Tahir, M., Khalil, I.H., Mccord, P.H., Glaz, B.S., Todd, J.R. 2014. Stability of genotypes and sources of variability in the Canal Point sugarcane cultivar selection program. Journal of the American Society of Sugar Cane Technologists. 34 pgs. 1-20.
Interpretive Summary: Breeders select plants adapted to different environments to increase the yield in the target environments. Mostly, plant genotypes do not respond the same across different environments and this results from an interaction between the environment and the genotype. If there is no interaction, breeders could select based on one location. In Florida, sugarcane is grown on two major soil types, sand and ‘muck’ (organic). Breeders need to select new varieties effectively, on either soil. Data was gathered from yield trials on sand and muck soils and was used to calculate the stability of important traits, including total yield and sugar yield, across soils and locations. The results indicated crop age (first, second, or third season) was the primary effect affecting variability and the primary interaction was crop age by location. This indicates that it is appropriate to evaluate sugarcane across locations and crops as it currently done in the final stage of breeding and may beneficial to expand locations in earlier stages. This information will aid in breeding program planning to increase the efficiency for selection for different environments.
Technical Abstract: Sugarcane (Saccharum spp.) is grown in muck and sand soils in Florida, which comprise of 78 and 22% of the hectarage, respectively. Field studies were conducted on muck and sand soils for one plant and two ratoon sugarcane crops in a cooperative genotype selection program based at Canal Point, Florida. The studies were conducted to determine the effects of muck and sand soils on the performance of sugarcane genotypes in the final stage (Stage IV) of testing in the breeding program in Florida. Data from six sets of 16 genotypes each from primarily the CP 04-, 05-, and 06- series and CPCL 95-, 02-, 05-, and 06- series in six trial locations on muck soils and three locations on sand soils were collected for three crop years (plant cane, first, and second ratoon). Analyses of mean squares on each soil separately, and for both soils combined, indicated that crop (plant crop, first, and second ratoon) made the highest contribution to the total mean squares. Crop × location was the interaction that made the most contribution to total mean squares. Tons of cane per hectare and tons of sugar per hectare showed crop × location interaction values of 2.95 and 4.38% on muck soils and 19.69 and 15.04% of the total mean squares on sand soils, respectively, which were higher than the other interaction components. Stability analyses indicated that only one genotype was stable for all characters in 2004 and 2005 on muck soils, while one each in 2005 and 2006 on sand soils. Similarly, only two genotypes were stable across both soil types. Usually genotypes that are stable are selected for release. These results indicate that it will be difficult for this program to consistently select genotypes with stable, high yields on both muck and sand soils. Separate tests with one set of genotypes selected from early stages on muck soils and a second set selected in early stages on sand soils are recommended for optimum genotype selection for each soil type. In these separate programs, Canal Point researchers should evaluate whether adding crop cycles to early selection stages and whether adding locations to the final selection stage on sand soils will improve selection decisions.