Author
Zhao, Duli | |
DAVIDSON, WAYNE - Florida Sugarcane League | |
BALTZAR, MIGUEL - Florida Sugarcane League | |
Comstock, Jack | |
McCord, Per | |
Sood, Sushma |
Submitted to: Agronomy
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 7/28/2015 Publication Date: 8/1/2015 Citation: Zhao, D., Davidson, W., Baltzar, M., Comstock, J.C., Mccord, P.H., Sood, S.G. 2015. Screening for sugarcane brown rust in first clonal stage of the Canal Point sugarcane breeding program. Agronomy. 5:341-362. Interpretive Summary: Sugarcane is an important crop in south Florida. Consistent development of high-yielding sugarcane cultivars with resistance or tolerance to biotic and abiotic stresses is critical for commercial sugarcane production. Although the Canal Point sugarcane breeding and cultivar development program has made great progress for disease resistance, brown rust disease is still a challenge for the sugarcane production in Florida. A better understanding of sugarcane genotypic variability in response to brown rust will help optimize breeding and selection strategies for disease resistance. We conducted this study to determine sugarcane brown rust rate among genotypes in the first clonal selection stage (Stage I) in 2012 and 2013. Data were collected from all 14,272 (2012) and 12,661 (2013) genotypes and four check cultivars (CP 78-1628, CP 80-1743, CP 88-1762, and CP 89-2143; each had more than 40 replicated plots) in July-August. Mean rust rating, % of infection, and rust severity on the base of each family and female parent and their coefficients of variation within and among families (females) were further estimated. Results indicated that considerable variation exists in rust tolerance among families or females. The families or females for their progenies with the high susceptibility or resistance to brown rust were identified and ranked. The findings of this study are useful for evaluating sugarcane crosses and parents for rust disease and can help breeders use desirable parents for crossing and improve genotypic resistance to brown rust. Technical Abstract: Sugarcane (Saccharum spp.) brown rust (caused by Puccinia melanocephala H. & P. Sydow) was first reported in the United States in 1978 and is still one of great challenges for sugarcane production. A better understanding of sugarcane genotypic variation in response to brown rust will help optimize breeding and selection strategies for disease resistance. Brown rust ratings were scaled from non-infection (0) to severe infection (4) with intervals of 0.5 and routinely recorded for genotypes in the first clonal selection stage of the Canal Point sugarcane breeding program in Florida. Data were collected from 14,272 and 12,661 genotypes and replicated check cultivars in 2012 and 2013, respectively. Mean rust rating, % infection, and severity in each family and progeny of female parent were determined and their coefficients of variation (CV) within and among families (females) were estimated. Considerable variation exists in rust ratings among families or females. The families and females for their progenies with high susceptibility or resistance to brow rust were identified and ranked. The findings of this study can help scientists to evaluate sugarcane crosses and parents for brown rust disease, to use desirable parents for crossing, and to improve genotypic resistance to brown rust in breeding programs. |