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ARS Home » Plains Area » Lubbock, Texas » Cropping Systems Research Laboratory » Plant Stress and Germplasm Development Research » Research » Publications at this Location » Publication #327045
Title: Sorghum recombinant inbred lines segregating for stay-green QTL's and leaf dhurrin content show differential reaction to stalk rot diseases

Author
item ADEYANJU, ADEDAYO - Kansas State University
item YU, JIANMING - Iowa State University
item LITTLE, CHRISTOPHER - Kansas State University
item ROONEY, WILLIAM - Texas A&M University
item KLEIN, PATRICIA - Texas A&M University
item Burke, John
item TESSO, TESFAYE - Kansas State University

Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/17/2016
Publication Date: 3/18/2016
Citation: Adeyanju, A., Yu, J., Little, C., Rooney, W., Klein, P., Burke, J.J., Tesso, T. 2016. Sorghum recombinant inbred lines segregating for stay-green QTL's and leaf dhurrin content show differential reaction to stalk rot diseases. Crop Science. doi:10.2135/cropsci2015.10.0628.

Interpretive Summary: The association between post-flowering drought tolerance and the stay-green phenotype in sorghum is well established. More recent studies link the stay-green phenotype with levels of dhurrin and soluble sugars in the leaves. Post-flowering drought response has always been associated with stalk rot resistance, especially charcoal rot. However, apart from the common knowledge that charcoal rot requires a dry environment, the mechanisms governing these associations is not clear. This study evaluated which genes contribute to stalk rot resistance. When genes associated with the stay-green trait stg 1 and stg 3 resistance to stalk rot was observed. Other stg genes such as stg2 and stg4 did not have an effect on stalk rot resistance caused by the pathogen. Furthermore, stalk rot resistance had no significant association with levels of dhurrin and soluble sugars in the leaves.

Technical Abstract: The association between post-flowering drought tolerance and the stay-green phenotype in sorghum is well established. More recent studies link the stay-green phenotype with levels of dhurrin and soluble sugars in the leaves. Post-flowering drought response has always been associated with stalk rot resistance, especially charcoal rot. However, apart from the common knowledge that charcoal rot requires a dry environment, the mechanisms governing these associations is not clear. The objective of this study were to determine the effects of major stay- green QTLs on response to infection by two stalk rot pathogens, M. phaseolina and F. thapsinum, and to examine the possible relationship between levels of dhurrin and soluble sugar in the leaves and response to stalk rot diseases. Fourteen genotypic groups derived from the Tx642 × Tx7000 recombinant inbred line (RIL) population carrying a combination of stay-green quantitative trait loci (stg QTL) were evaluated under three environments in four replications. The results revealed that stg QTLs have variable effects on severity of stalk rot diseases. Genotypes carrying either stg1 or stg3, or their combination stg1+3 expressed high levels of resistance to M. phaseolina. But, resistance to F. thapsinum required a combination of stg1 and stg3. Other stg QTL blocks such as stg2 and stg4 did not have effect on stalk rot resistance caused by either pathogen. Furthermore, stalk rot resistance had no significant association with levels of dhurrin and soluble sugars in the leaves.