Relationship between plant anatomical traits and yield among different winter wheat genotypes in dry environments

Crop functional traits have changed along with increased yield over the course of crop breedingunder changing environments. But the effects of yield improvement on anatomical traits have not been studied extensively. We investigated the relationships between wheat yield and anatomical traits in two different dry environments, Zhuanglang and Dingxi, Gansu, China. We selected different dryland wheat genotypes(Triticum aestivumL.) and performed a field study to measure their yields. Root and leaf traits were measured with photomicroscopy and image analyses after sectioning with a microtomein the elongation and flowering period. Yield was positively correlated with seminal root cross-sectional xylem area at anthesis in both Zhuanglang and Dingxi. Root respiration was negatively correlated with yield, but positively correlated with cortex area in Zhuanglang at anthesis. Although yield has no significant correlation with flag leaf mesphyll area, leaf vein area and leaf vein density in Zhuanglang and Dingxi, it was negatively correlated with stomatal length, but positively correlated with abaxial stomatal density at thesis in Zhuanglang, showing that smaller but more abaxial stomata could promote increased yield. Our results suggests that larger root xylem area, decreased root cortical tissue with lower root respiration, higher abaxial stomatal density with smaller but more stomata in the flag leaf have contributed to increased yields in dry environments. Below- and above-ground anatomical traits are integrated. This anatomical trait-based study that unravel trait variation along with yield improvement advance our knowledge for further increases in yieldunder changing environments.