Association of the Allelic Variations in Hd1, OsPRR37, Ghd7 and DTH8 With Major Agronomic Traits in Korean Rice (Oryza sativa L.) Cultivars

Understanding the complex genetic mechanisms controlling rice heading is crucial for rice breeding that aims to promote heading while minimizing adverse impacts on other agronomic traits. However, the allelic variations of major heading date genes in Korean rice cultivars and their effects on key agronomic traits remain unclear. Therefore, we catalogued the allele types of four major heading date genes (Hd1, OsPRR37, Ghd7 and DTH8) in 292 Korean commercial rice cultivars and investigated their individual and combined effects on major agronomic traits over 4 years under natural long-day conditions. Our study showed that non-functional hd1 allele have been extensively adopted in developing early maturing cultivars, whereas the alleles associated with early heading in OsPRR37, Ghd7 and DTH8 and their combinations have been rarely used in Korean rice breeding programmes. Alleles within the same functional group exhibited distinct effects on major agronomic traits, highlighting the need for more precise evaluations under isogenic backgrounds. Our study provides useful insights for breeding early maturing rice cultivars that maintain high yield by exploring under-utilized alleles of heading date genes and their combinations.