Seed maturity and harvest time effects seed quantity and quality of Hordeum brevisubulatum

Hordeum brevisubulatum (Trin.) Link is one of the more desirable alkaline-tolerant native perennial grass species in northern China. Propagation is hampered by excessive seed shedding at maturity which prevents its introduction and utilization in alkaline areas. The primary objective of this study was to investigate and evaluate the indices of quantity and quality of seed remaining on the spikes and to develop a visual indicator for the seed manager based on viable seed yield. The experiment was conducted at the Ecosystem Field Station of the Institute of Grassland Science at Songnen Grassland in 2002 and 2003. After heading began, the plants were observed daily to determine the growth stages of peak anthesis and seed shedding. Ten random sample plants were collected every 3 days from 5 to 29 days after peak anthesis. The number (Ns) and weight (Ws) of seed retained on 30 random spikes from each plant were recorded. The percentage germination (PG), speed of germination (SG), thousand seed weight (TSW) and electrical conductivity (EC) of seed leachate were tested. Seed retention declined rapidly on the first 3 days of the shedding period and slowly thereafter. According to the percentage of viable seed number and seed weight, the optimum harvest time for this species was between 4 days before seed shedding and 2 days after shedding. Acceptable viable seeds can be harvested after accumulating at least 160 GDD after peak anthesis.