The Effect of Earliness per se (Eps) Genes on Flowering Time in Bread Wheat

Abstract

Photoperiod (day-length) response, vernalization (response to extended periods of cold) and earliness per se (Eps) genes regulate flowering time in wheat. The vernalization and photoperiod response genes are relatively well studied. However, the role of Eps genes is yet to be fully understood but the current assumption is that Eps genes regulate flowering independent of vernalization and photoperiod. While some Eps genes have been cloned in both Hordeum vulgare and Triticum monococcum, none has been cloned in Triticum aestivum to date. The use of near isogenic lines (NILs) in both T. monococcum and Triticum aestivum has enabled Eps effects to be studied in more detail and candidate genes have been proposed for Eps effects in both species. Eps loci are reported to be involved in fine tuning flowering time and are also responsible for controlling spikelet number and size hence could be manipulated to increase wheat yield. This mini review summarises our current understanding of Eps and how manipulation of Eps genes can be used in predictive wheat breeding.