Water uptake in relation to pre-harvest sprouting damage in wheat: ear characteristics

Abstract

Wetting of mature wheat ears during simulated and natural rainfall and sprouting in the ear were studied in a group of c. 50 cultivars and in lines near-isogenic for awns, pubescence, glaucousness and club head. Cultivars differed by up to two-fold in ear water uptake over the first hours of exposure to simulated rain (2.6 mm h-1 in a misting chamber). Some of these differences were still evident after 30 h. Awns and their associated structures accounted for some of the varietal differences in ear water uptake. Those cultivars and near-isogenic lines with awns absorbed up to 30% more water. As well, sprouting in the ear was enhanced by at least 40%, and water penetrated more rapidly to the grain in ears of awned lines. Loss of free water on drying was little influenced by the awned character. The club head character enhanced ear water uptake by 25%. Pubescence and glaucousness had no effect on ear wetting. Cultivars can vary widely in post-harvest dormancy and plant breeders have utilized such differences in their selection for control of pre-harvest sprouting. However, further reduction of sprouting should also result simply from selecting for awnless cultivars.