Association mapping of mesocotyl and coleoptile length in rice using various genome-wide association study models

The mechanized direct seeding of rice (Oryza sativa L.) is a major trend nowadays. The elongation of rice mesocotyl and coleoptile can facilitate the rapid emergence of seedlings under deep mechanized sowing. Currently, most of the cultivated rice accessions have short mesocotyls or coleoptiles, with only a few related genes cloned. However, understanding and enhancing the ability of rice seedlings to rapidly emerge from deep sowing depths is crucial. Herein, we assessed 745 core rice germplasm accessions sown under a soil cover depth of 10 cm and found few long mesocotyl and coleoptile germplasms. We conducted genome-wide association study using six models to obtain three or more multi-model co-localization candidate regions and calculated F_st between the phenotypes of extreme samples to determine genetic differences. The candidate regions associated with mesocotyl and coleoptile lengths were identified by integrating F_st and multi-model localization results. This multi-model localization method may accelerate the mining of genes related to the mesocotyl and coleoptile, providing valuable targets for functional validation and marker-assisted selection in rice breeding programs.