Afterripening in curly mesquite seeds

Abstract

Curly mesquite (Hilaria belangeri Steud.) Nash) is a palatable nutritious range grass in the southwestern United States. Early research assumed no afterripening occurred in caryopses of this species and suggested that all seed could germinate immediately. Germination trials were conducted at 1, 6, 12, 18, 24, 30, and 36 weeks after harvest using seed cleaned either at harvest or just prior to each trial. Average increases in germination from 59 to 92% and 55 to 87% demonstrated an afterripening period of 12 weeks in seeds from 2 populations of curly mesquite. Maximum germinations of 94 and 90% occurred after 12 weeks for seeds cleaned at harvest and cleaned prior to each trial, respectively. Seeds not separated from fascicles at harvest displayed a rapid decline in total germination percentage after 24 weeks even though fascicles were removed just prior to germination trials. The extent and timing of the decline are greater if the fascicles are not removed prior to storage. Effects of the fascicle on germination remain unclear. Our findings suggest that seed storage periods and conditions should be taken into consideration when attempting to establish curly mesquite by seeding.