Tropical Grasslands (2005) Volume 39,140151 Influence of storage conditions on survival and sowing value of seed of tropical pasture grasses. 2. Sowing value and storage strategies J.M. HOPKINSON AND B.H. ENGLISH Department of Primary Industries, Queensland Beef Industry Institute, Walkamin Research Station, Walkamin, Queensland, Australia Abstract
Evaluation of effects of storage conditions of seed
of 5 tropical pasture grass seeds (Panicum maximum,
Brachiaria decumbens, Brachiaria humidicola,
Setaria sphacelata and Chloris gayana)
was extended from laboratory tests (Part 1) to
seedling emergence and establishment tests in
greenhouse and field in north Queensland. Seed
cool-stored in woven bags at 10°C and 50% RH
mostly had higher field sowing value than comparable
open-stored seed, because the superior
preservation of viability and vigour tended to outweigh
the disadvantages of dormancy retention.
Exceptions occurred when dormancy persisted, as
it did inconsistently across seed lots, even within
a single cultivar. Reduction in storage moisture
content of seed sealed in moisture-proof packs
helped to preserve viability and vigour, particularly
with seed stored at ambient temperature.
However, very low moisture content (7.2%) prolonged
dormancy, with adverse effects on sowing
value. Dormancy delayed germination even when
not wholly preventing it. The benefits of retained
vigour and the restrictions of dormancy were displayed
in the field, but were masked in the more
benign environment of the greenhouse. Cold
storage at −12°C intensified dormancy of Gatton
panic, delaying germination of seed in the greenhouse
until the second and third seasons after
sowing.
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