# title
Sorghum RILs Segregating for Stay-Green QTL and Leaf Dhurrin Content Show Differential Reaction to Stalk Rot Diseases

# abstract
<jats:p>The association between postflowering drought tolerance and the staygreen phenotype in sorghum [<jats:italic>Sorghum bicolor</jats:italic> (L.) Moench] is well established. Recent studies link the staygreen phenotype with levels of dhurrin and soluble sugars in the leaves. Postflowering 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 mechanism governing these associations is not clear. The objectives of this study were to (i) determine the effects of major staygreen (<jats:italic>stg</jats:italic>) quantitative trait loci (QTL) on response to infection by two stalk rot pathogens, <jats:italic>Macrophomina phaseolina</jats:italic> and <jats:italic>Fusarium thapsinum</jats:italic>, and (ii) 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 <jats:italic>stg</jats:italic> QTL were evaluated under three environments in four replications. The results revealed that <jats:italic>stg</jats:italic> QTL have variable effects on severity of stalk rot diseases. Genotypes carrying either <jats:italic>stg</jats:italic>1 or <jats:italic>stg</jats:italic>3, or their combination <jats:italic>stg</jats:italic>1+3 expressed high levels of resistance to <jats:italic>M. phaseolina</jats:italic>. But, resistance to <jats:italic>F. thapsinum</jats:italic> required a combination of <jats:italic>stg</jats:italic>1 and <jats:italic>stg</jats:italic>3. Other <jats:italic>stg</jats:italic> QTL blocks, such as <jats:italic>stg</jats:italic>2 and <jats:italic>stg</jats:italic>4, did not have an 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.</jats:p>

# authors[].organizations[].label
College of Agriculture and Life Sciences

# authors[].organizations[].label
College of Agriculture and Life Sciences

# keywords[]
30 Agricultural, Veterinary And Food Sciences

# authorList[]
Adeyanju, A., Yu, J., Little, C., Rooney, W., Klein, P., Burke, J., & Tesso, T.