Evaluation of pre-harvest sprouting in triticale compared with wheat and rye using a line source rain gradient

Abstract

Field grown triticales, wheats and ryes were subjected to an artificial rain gradient with the aim of discriminating among different genotypes on the basis of their tolerance to wetting, measured as change in falling number (FN) and alpha-amylase activity (AA). Below-canopy gravity irrigation throughout the growing cycle ensured stress-free conditions. The rain gradient was created by overhead irrigation from a central water line or line source. Plots were sown perpendicular to the line source and sampled for AA throughout the gradient and over sampling dates. The gradient was also analysed for FN 30 days post physiological maturity (PM+30). Based on change in AA over both the gradient and sampling dates and change in FN at PM+30, genotypes tolerant to wetting were identified. The factors rnost important in conferring tolerance to wetting among triticales were spike angle, thousand-grain weight and FN levels. Whilst the line source offered good discrimination among triticales on the basis of change in FN and AA, it was not effective in distinguishing between wheat and rye lines.