Exploring the trait-yield association patterns in different oat mega-environments of Canada

This article presents a graphical method to visually analyze the trait-yield association (TYA) patterns based on data from multi-location, multi-year crop variety trials, exemplified using oat data from trials conducted across Canada from 2017 to 2022. Each year a new set of 60-66 oat (Avena sativa L.) breeding lines were tested in replicated yield trials at 9-11 locations, and data for yield, key agronomic and quality traits, and crown rust scores were collected at all or some of the locations. Pearson correlation coefficient was calculated between yield and each trait for each trial. The correlation coefficients from different locations and years were arranged in a TYA x trial (TYT) two-way table. This table was subjected to singular value decomposition, and the resulting first two principal components were used to generate a TYT biplot. The TYT biplot revealed three oat mega-environments (MEs) in Canada, consistent with the conclusion from previous ME analyses, indicating that each ME had its characteristic TYA patterns. It was found that yield was consistently and positively correlated with crown rust (Puccinia coronata var. avenae) resistance, test weight, kernel weight, and groat content in ME1 (the crown rust-prone regions of Ontario); yield was correlated positively with plant height but negatively with oil content in ME2 (the northern regions of eastern Canada). Interestingly, crown rust resistance was found to contribute negatively to yield in ME2. No strong and consistent TYAs were found in ME3 (the Canadian prairies). Different types of TYAs have different uses in genotypic selection. A trait-yield association x trial (TYT) biplot was introduced to reveal trait-yield association patterns.TYT biplots revealed different oat mega-environments in Canada, each with unique trait-yield association patterns.Trait-yield association patterns can be used to guide visual selection.Crown rust resistance was shown to be counterproductive in the non-rust regions.Different types of trait-yield associations have different uses in genotypic selection.