Proceedings of the 9th Alps-Adria Scientific Workshop, 12–17 April 2010, Špičak, Czech Republic – PHYSIOLOGICAL PROCESSES

Abstract

Pre-harvest sprouting resistance in wheat depends on the level of grain dormancy at harvest time as well as on certain spike characteristics including the level of water soluble germination inhibitors found in wheat bracts. The objectives of the present study were: (i) to evaluate the influence of germination temperature on inhibitory effect of water bract extracts on wheat germination and (ii) to compare different germination criteria for measuring germination inhibition. Samples of bracts were taken at harvest ripeness from 30 wheat cultivars grown in the field. Germination tests were performed at 20C or 30C using nondormant seeds of the cultivar Banica and 5 ml of bract extracts of 30 genotypes or 5 ml distilled water as a control. Three criteria were used to characterise a seed as germinated: 1) rupture of the pericarp over the embryo (P), 2) at least one rootlet >3mm in length (1R) and 3) three rootlets 3mm in length (3R). Mean germination percentage (GP) and germination index (GI) in bract extracts were significantly lower compared to GP and GI in water for both germination temperatures but the inhibition was stronger at the higher germination temperature. Comparing the three germination criteria the highest inhibition of germination was observed using 3R and 1R for GP and GI, respectively. Significant differences among cultivars for germination inhibition were observed for both germination temperatures.