*mpsilva@inia.org.uy

Wheat (Triticum aestivum L.) is a globally distributed crop due to its wide adaptability which in turn is a consequence of the large variance in phenology among cultivars. The genetic diversity governing phenological traits, such as days to flowering, enables the selection of optimal combinations of cultivar and sowing date for each environment, crucial for maximizing yield potential in local conditions.

Additionally, morphological characteristics, especially reduced plant height, have played a fundamental role in the "Green Revolution," enhancing grain yield by mitigating lodging and optimizing partitioning to reproductive organs. Understanding the effect of allelic variation in phenological and morphological traits, including the VERNALIZATION (VRN), PHOTOPERIOD (PPD), EARLINESS PER SE (EPS) and REDUCED HEIGHT (RHT) gene family pathways, is essential for breeding programs to target specific environments.

In this study, we analyzed 19 wheat genotypes, including cultivars and advanced breeding lines, with allelic variations in VRN-1, PPD-1, EPS-D1, RHT-1, and RHT-2 genes from the Wheat Breeding Program of the National Institute of Agricultural Research (INIA-Uruguay). Field trails with seven sowing dates in the 2023 growth season were used to assess the combined effects of the allelic variation on days to flowering, days to physiological maturity and grain yield.

A wide range of sowing dates was explored, from early to late, resulting in a range of days to flowering from 321 to 728 degree days, with variation among genotypes being explained by the interaction between allelic combinations and environment.

This work presents the findings of our investigation, aimed at advancing the development of wheat germplasm with heightened adaptability to Uruguayan environmental conditions.