<i>Ef-cd</i> locus shortens rice maturity duration without yield penalty

Abstract

The contradiction between "high yielding" and "early maturing" hampers further improvement of annual rice yield. Here we report the positional cloning of a major maturity duration regulatory gene, <i>Early flowering-completely dominant</i> (<i>Ef-cd</i>), and demonstrate that natural variation in <i>Ef-cd</i> could be used to overcome the above contradictory. The <i>Ef-cd</i> locus gives rise to a long noncoding RNA (lncRNA) antisense transcript overlapping the <i>OsSOC1</i> gene. <i>Ef-cd</i> lncRNA expression positively correlates with the expression of <i>OsSOC1</i> and H3K36me3 deposition. Field test comparisons of early maturing <i>Ef-cd</i> near-isogenic lines with their wild types as well as of the derivative early maturing hybrids with their wild-type hybrids conducted under different latitudes determined that the early maturing <i>Ef-cd</i> allele shortens maturity duration (ranging from 7 to 20 d) without a concomitant yield penalty. <i>Ef-cd</i> 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 <i>Ef-cd</i> matured significantly earlier. Therefore, <i>Ef-cd</i> could be a vital contributor of elite early maturing hybrid varieties in balancing grain yield with maturity duration.