Gibberellic Acid Sensitivity among Common Bean Cultivars (Phaseolus vulgaris L.)

Authors

Alexander Pavlista, University of Nebraska, Panhandle Research and Extension CenterFollow
Dipak Santra, University of Nebraska, Panhandle Research and Extension Center, Scottsbluff, NEFollow
James Schild, University of Nebraska, Panhandle Research and Extension Center, Scottsbluff, NEFollow
Gary Hergert, University of Nebraska, Panhandle Research and Extension Center, Scottsbluff, NEFollow

Date of this Version

5-2012

Citation

HORTSCIENCE 47(5):637–642. 2012

Abstract

To lower seed yield loss from directly harvested common bean or dry bean, height of the lower pod-bearing nodes needs to be raised. The objective of this greenhouse study was to stimulate lower stem elongation by gibberellic acid (GA₃) of dry bean cultivars. Seeds of cv. Matterhorn, erect indeterminate Type II, and cv. Poncho, prostate indeterminate Type III, were dipped in GA₃ at 62.5 to 16,000 ppmand planted. After 14 d, the height of the unifoliate and first trifoliate nodes showed maximum stimulation of stem elongation by 1000 ppm GA₃ for ‘Poncho’ and by 2000 ppm for ‘Matterhorn’. Application of 1 mL of GA₃ at 0.031 to 2048 ppm to newly expanded unifoliate leaves showed cultivar differences. Whereas ‘Matterhorn’ was promoted at 64 ppm and reached a maximum height by 512 ppm GA₃, ‘Poncho’ was promoted at 0.25 ppm and reached a maximum height by 8 ppm GA₃. Flowering of ‘Matterhorn’ was unaffected by GA₃; flowering of ‘Poncho’ was completely inhibited by 128 ppm. The sensitivity difference of cultivars was verified with other cultivars. Type I cultivars, which are all determinate, showed a full range ofGA₃ sensitivity. Dry bean cultivars may be regrouped based on the GA₃ dose to which they respond. Individual response to GA3 rates of dry bean cultivars needs to be predetermined using a short-term, 2–3 weeks, greenhouse bioassay before field use of GA₃.