Associations Among Oat Traits and Their Responses to the Environment

Desirable qualities of milling oat varieties include low hull content (high groat content), high beta-glucan content, high groat protein, low oil concentration, low kernel breakage, high grain yield, and superior yield stability. The objective of this study was to develop a graphical method for understanding the influence of environment on genetic relationships among traits. Associations among agronomic and quality traits in 67 oat (Avena sativa L.) performance trials conducted during 1996-2003 across Canada and some northern US states were studied using a trait-association by environment biplot, which allows visual study of pair-wise trait associations in multiple environments (year-location combinations). Based on the differential association of yield with days to heading and plant height, the North American spring oat growing regions can be divided into Northern mega-environment (Canadian Prairies plus North Dakota and Idaho) and Southern megaenvironment (Minnesota, South Dakota, and Ontario). We also found that the following trait associations were relatively stable across environments: (1) negative association of protein content vs. oat yield, (2) positive association of beta-glucan vs. groat oil, (3) positive association of beta-glucan vs. protein content, and (4) negative association of beta-glucan vs. breakage. All trait-associations were of moderate magnitude and were responsive to the environment. This suggests that breeding for superior oat varieties with desired trait combinations is possible, but it must be achieved through direct selection for multiple traits in representative environments.