Assessment of pre-harvest sprouting resistance in spring wheat in Norway

Pre-harvest sprouting is the precocious germination of kernels while still in the mother plant due to early breakage of seed dormancy, which usually occurs when humid weather conditions persist before harvest. It causes a serious problem throughout the world in some season, resulting in huge economic losses caused by downgrading of wheat quality from food to feed as well as reduction in yield. In the last few years, wheat quality and yield in Norway has been seriously affected by pre-harvest sprouting. Thus, pre-harvest sprouting resistant cultivars are needed in order to avoid losses in wheat quality and yield. Therefore, the objective of this study was (i) to compare different methods of PHS assessment in wheat and (ii) to find the markers that are associated with PHS resistance. Field experiment was conducted in Vollebekk, Ås, Norway in 2010 with a total of 159 spring wheat lines. Germination index (GI), falling number (FN) and dormancy index (DI) was used to assess the dormancy of wheat grains. The result showed a significant negative correlation for GI and FN (-0.456) and GI and DI (-0.575), and significant positive correlation for FN and DI (0.413). A total of 25 microsatellite markers previously identified in chromosome 3A, 3B, 3D and 4A were used to characterize the wheat lines. Highest number of significant markers was identified in the adapted lines and with GI. The important Norwegian wheat cultivars showed a very low level of dormancy and contained none or very few markers associated with dormancy. The best performing lines had low GI, high FN and high DI and carried 3 or more significant markers associated with dormancy, which could be useful as breeding parents for improving the resistance to PHS