Data from: Genomic regions associate with major axes of variation driven by gas exchange and leaf construction traits in cultivated sunflower (Helianthus annuus L.)

Stomata and leaf veins play an essential role in transpiration and the
movement of water throughout leaves. These traits are thus thought to play
a key role in the adaptation of plants to drought and a better
understanding of the genetic basis of their variation and coordination
could inform efforts to improve drought tolerance. Here, we explore
patterns of variation and covariation in leaf anatomical traits and
analyze their genetic architecture via genome-wide association (GWA)
analyses in cultivated sunflower (Helianthus annuus L.). Traits related to
stomatal density and morphology as well as lower order veins were manually
measured from digital images while the density of minor veins was
estimated using a novel deep learning approach. Leaf, stomatal, and vein
traits exhibited numerous significant correlations that generally followed
expectations based on functional relationships. Correlated suites of
traits could further be separated along three major principal component
(PC) axes that were heavily influenced by variation in traits related to
gas exchange, leaf hydraulics, and leaf construction. While there was
limited evidence of colocalization when individual traits were subjected
to GWA analyses, major multivariate PC axes that were most strongly
influenced by several traits related to gas exchange or leaf construction
did exhibit significant genomic associations. These results provide
insight into the genetic basis of leaf trait covariation and showcase
potential targets for future efforts aimed at modifying leaf anatomical
traits in sunflower.