Revisiting Domestication to Revitalize Crop Improvement: The Florigen Revolution

Most flowering plants have evolved to coordinate proper floral transition in shoot apical meristems at an appropriate time during development, referred to as “flowering time.” In domesticated crops, shoot life time has been manipulated to enhance productivity via synchronizing flowering time to the local environment, thereby creating a balance between vegetative and reproductive plant architecture during the year. Rice, a typical single transitional crop, has acquired balance between prolonged tiller growth and a relatively short reproductive phase on individual shoot, resulting in increasing yield. Crops with sympodial growth, such as tomato, which undergo multiple floral transitions on the main shoot, have been artificially selected for the determination of shoot growth by investigating the dosage sensitivity of florigen activation controlling flowering time on individual shoots. Here, we summarize recent genetic-molecular studies on tomato, which have been subject to genetic manipulation of flowering time in an effort to optimize seed productivity. We also review advanced genetic approaches as potential new tools for the enhancement of crop yield by manipulating flowering time via the dosage effect of florigen.