Yield improvement in spring oats

Summary Grain yields of 14 spring oat varieties grown at two levels of nitrogen in three seasons at two locations were compared. A genotype × environment analysis demonstrated that the more recent varieties not only had higher yields but also were better adapted to high-yielding environments. Modern varieties demonstrated a yield improvement of 30% over the older varieties. Examination of components of yield by a series of simple correlations indicated that improvement in varieties by breeding has been associated with shortened straw and higher harvest indices. Within varieties, 1000-grain weight was the most stable character and harvest index the character which varied most consistently with variations in grain yield.