Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 11/30/2015
Publication Date: 2/8/2016
Citation: Emendack, Y., Burke, J.J., Xin, Z., Burow, G.B., Hayes, C.M., Chen, J., Chopra, R. 2016. Dhurrin content relates to sorghum [sorghum bicolor (L.) Moench] seedling growth in marginal soils [abstract]. Southern Association of Agricultural Scientists. Paper No. 33.
Technical Abstract: Dhurrin content in leaves of mature sorghum plant is a quantitative measure of the level of pre-and postflowering drought tolerance (Burke et al., 2013). Postflowering drought tolerance in sorghum is linked to the staygreen (delayed senescence) trait (Howarth, 2000; Rosenow et al., 1977) which has been associated with decreased lodging, less susceptibility to charcoal rot, increased stem carbohydrates during and after grain filling, and improved grain filling and grain yield under stress. Thus, early enhanced screening of grain sorghum lines for high dhurrin levels will be an important component of breeding for improved post-flowering drought tolerance. Sorghum genotypes of known dhurrin levels, determined from mature leaves at the late vegetative stage, were grown in four soil-nutrient combinations: potting soil Mix 1 plus nutrient irrigation (GM1), play sand plus nutrient irrigation (GM2), potting soil Mix 1 plus water irrigation (GM3), and play sand plus water irrigation (GM4). Fresh seedling weight (Fsw), seedling length (Fsl), dhurrin and sugars (Sucrose, Glucose and Fructose)contents were determined at 5 and 10 days after emergence (DAE). Genotypes with high dhurrin (HD) levels show higher fresh seedling weights and lengths than low dhurrin (LD) level genotypes only at 10 DAE, grown under play sand and water irrigation. Pooled low dhurrin genotypes show significant negative correlations between seedling dhurrin content and Fsw and Fsl, at 5 and 10 days after emergence. No genotypic variation in dhurrin levels was observed using either seedling dhurrin content or sugar contents irrespective of soil-nutrient combinations and days after emergence. This study concludes that at 10 days after emergence and under marginal soils, sorghum genotypes with staygreen and thus postflowering drought tolerance potential (high dhurrin levels) will outperform genotypes with senescence or pre-flowering drought tolerance potential.