Nl. Shaw et al., GERMINATION AND SEEDLING ESTABLISHMENT OF SPINY HOPSAGE IN RESPONSE TO PLANTING DATE AND SEED-BED ENVIRONMENT, Journal of range management, 47(2), 1994, pp. 165-174
Reestablishment of spiny hopsage (Grayia spinosa [Hook.] Moq.) in the
shrub steppe requires development of appropriate seeding technology. W
e examined the effect of planting date and seedbed environment on germ
ination and seedling establishment of 2 seed sources at 2 southwestern
Idaho sites. Seedbeds were prepared by rototilling. In 1987-88, seeds
collected in 1986 were drilled at 66 viable seeds m-1 of row at Birds
of Prey in late fall, winter, and early spring and at Reynolds Creek
in late fall, early spring, and late spring. Seeds collected in 1986 a
nd 1988 were broadcast at 400 viable seeds m-2 at both sites in late f
all, early spring, and late spring 1988-89. Seeds in nylon bags were a
lso planted at each site in late fall, winter, and early spring in 198
7-88 and in late fall, winter, early spring, and late spring in 1988-8
9. On each succeeding planting date and in early summer, 5 bags of eac
h seed source from each of the earlier planting dates were recovered.
Water content, viability, and germination were compared among seeds fr
om previous plantings and control seeds stored in the laboratory. Each
year, first-year seedling establishment at both sites was favored by
late fall compared to other planting dates. In 1988, seedlings establi
shed only from late fall plantings at a density of 1 m-2 at each site.
In 1989, late fall planting at the 2 sites increased seedling establi
shment 6 (51 vs 8 M-2) and 20 (41 vs 2 m-2) times compared to early sp
ring planting. Germination was generally greater for seeds incubated a
t field sites compared to controls. Germination total and rate increas
ed 6-11 times and 13 days from late fall 1987 to early spring 1988, 1-
6 times and 4 and 9 days from winter 1988 to early spring 1988,17 time
s and 10-11 days from late fall 1988 to winter 1989, and 4-7 times and
11 days from winter 1989 to early spring 1989. Late fall or early win
ter planting is essential to permit early spring germination when surf
ace soils are moist.