Author
Ulloa, Mauricio | |
HUTMACHER, ROBERT - UNIV. OF CA, SHAFTER, CA | |
DAVIS, MICHAEL - UNIV. OF CA, DAVIS, CA | |
WRIGHT, STEVEN - UNIV. OF CA, TULARE, CA | |
Percy, Richard |
Submitted to: Journal of Cotton Science
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 12/13/2005 Publication Date: 7/5/2006 Citation: Ulloa, M., Hutmacher, R.B., Davis, R.M., Wright, S.D., Percy, R.G., Marsh, B. 2006. Breeding for Fusarium wilt race 4 resistance in cotton under field and greenhouse conditions. J. Cot. Sci. 10:114-127. Interpretive Summary: Fusarium oxysporum f. sp. vasinfectum (FOV) Atk. Sny & Hans represents a continuing threat to cotton production in the U.S. that warrants attention in plant breeding efforts. Several troubling developments concerning this pathogen (e.g., newly-recognized Australian FOV races and race 4 FOV identification in CA) highlight the need for additional comprehensive research to provide improved host plant resistance to this pathogen. In order to assess the U.S. cotton gene pool and study host plant resistance against FOV race 4, field and greenhouse evaluations were conducted in 2003, 2004, and 2005 on more than 150 Pima (Gossypium barbadense) and Acala and non-Acala Upland (G. hirsutum) entries. Pima cottons inoculated with race 4 developed more severe symptoms than the Acala and non-Acala Upland cottons. However, some Acala and Upland cottons were severely infected. Germplasm highly resistant to FOV race 4 was identified in some Pima entries. The current genetic base for resistance for commercial Pima cultivars in California is limited. Host-plant resistance is the most economic and effective strategy for Fusarium wilt control in cotton. This research identified potentially new improved resistant germplasm for release in the near future for public incorporation into California cotton cultivars. In addition, this research provided information about the susceptibility of commercial and improved germplasm of cottons, allowing growers to make informed decisions regarding the choice of cotton cultivar to plant in fields infested with race 4. Development of highly resistant germplasm and genetic mapping of populations are ongoing to develop and/or identify molecular markers to assist in the breeding process for FOV resistance in cotton. Technical Abstract: Fusarium oxysporum f. sp. vasinfectum (FOV) Atk. Sny & Hans represents a continuing threat to cotton production in the U.S. that warrants attention in plant breeding efforts. Several troubling developments concerning this pathogen (e.g., newly-recognized Australian FOV races and race 4 FOV identification in CA) highlight the need for additional comprehensive research to provide improved host plant resistance to this pathogen. In order to assess the U.S. cotton gene pool and study host plant resistance against FOV race 4, field and greenhouse evaluations were conducted in 2003, 2004, and 2005 on more than 150 Pima (Gossypium barbadense) and Acala and non-Acala Upland (G. hirsutum) entries. A population of 32 Pima recombinant inbred lines (RILs) and six F1 combinations of hybrids developed between susceptible and resistant entries were also assayed. Pima cottons inoculated with race 4 developed more severe symptoms than the Acala and non-Acala Upland cottons. However, some Acala and Upland cottons were severely infected. Germplasm highly resistant to FOV race 4 was identified in some Pima entries. Resistance against FOV race 4 in Pima cottons was more complete than expected, and may be determined by a single dominant major gene and one or more modifying minor genes which may provide the trangressive segregation observed in some RILs. However, variability for FOV resistance in Acala and non-Acala Upland cottons may be more complex, and has been suggested to be inherited in a quantitative manner by several major genes and minor modifying genes. This research identified potentially new improved resistant germplasm for release in the near future for public incorporation into California cotton cultivars. In addition, this research provided information about the susceptibility of commercial and improved germplasm of cottons, allowing growers to make informed decisions regarding the choice of cotton cultivar to plant in fields infested with race 4. Development of highly resistant germplasm and genetic mapping of populations are ongoing to develop and/or identify molecular markers to assist in the breeding process for FOV resistance in cotton. |