ABSTRACT
Most of the calories which feed humankind are derived from crops in the plant family Poaceae, the grasses. In natural populations, asynchrony of seed/grain maturity can be a selective advantage, reducing both the susceptibility of the genotype to climatic disasters, and the impetus for coevolution of pest populations with plant growth cycles. In the semiarid tropics which represent the likely centers of origin for many important grain crops, short daylength serves as a cue by which plants coordinate seed development with the season of optimal rainfall. Modern agriculture is based almost entirely on less than 50 major crops. Reduced seed dispersal is characteristic of virtually all cultivated grasses, and represents an obstacle to utilization of many potential new crops. However, the degree to which seed dispersal has been restricted is variable among different crops. Exceptions to the high level of correspondence among “domestication quantitative trait loci” may provide opportunities for crop improvement.
