Ef-cd locus shortens rice maturity duration without yield penalty

The contradiction between 'high-yielding' and 'early-maturing' hampers further improvement on annual rice yield. Here we reported the positional cloning of a major maturity duration-regulatory gene, Early flowering-completely dominant (Ef-cd), and demonstrated that natural variation in Ef-cd could be used to overcome the above contradictory. The Ef-cd locus gives rise to a long noncoding RNA (lncRNA) antisense transcript overlapping the OsSOC1 gene. Ef-cd lncRNA expression positively correlates with the expression of OsSOC1 and H3K36me3 deposition. Field test comparisons of early-maturing Ef-cd near-isogenic lines (NILs) with their wild types as well as the derivative early-maturing hybrids with their wild-type hybrids conducted under different latitudes determined that early-maturing Ef-cd allele shortens maturity duration (ranging from 7 to 20 days) without a concomitant yield penalty. Ef-cd facilitates nitrogen utilization and also improves the photosynthesis rate. Analysis of 1,439 elite hybrid rice varieties revealed that the 16 homozygotes and 299 heterozygotes possessing Ef-cd matured significantly earlier. Therefore, Ef-cd could be a vital contributor of elite early-maturing hybrid varieties in balancing grain yield with maturity duration. Overall design: Total RNA was extracted from the fresh leaf blades of 40 d seedling of early-maturing NIL D248 (BC5F11) and its recurrent parent SH881 (Shuhui881) using TRIzol reagent (Invitrogen, USA). 2 biological replications were collected.