Root growth of interspecific sunflower seedlings derived from wild perennial sunflower species

Abstract

Early root and hypocotyl growth and root branching patterns were characterized for five genetically diverse interspecific sunflower hybrids derived from wild perennial Helianthus species and two cultivated hybrids. Seedlings were grown in polyethylene pouches at 25 °C in the dark for 10 d. The hybrid and days after sowing (DAS) were sources of variation for primary and lateral root length, number of lateral roots, root branching density, root fresh weight, and hypocotyl length and fresh weight. There were high positive correlations among root growth characteristics that should be helpful in selecting sunflower hybrids adapted to arid conditions. The wild interspecific sunflower hybrids derived from wild perennial species possessed less-than-expected variability in early root growth. Nevertheless, there appears to be adequate genetic variability for further selection and genetic improvement. Key words: Helianthus species, growth pouch, primary roots, lateral roots, branching density, hypocotyl