NEWS for North Dakotans
Agriculture Communication, North Dakota State University
7 Morrill Hall, Fargo, ND 58105-5665
September 28, 2000
Sprout damage in small grains that resulted from rain-delayed harvest in some parts of North Dakota may reduce the performance of grain used for seed, according to a North Dakota State University plant scientist.
Effects of sprouting can be detrimental to seed viability and seedling vigor, so growers should determine the potential impact on productivity before planting damaged seed, says Michael Peel, NDSU extension agronomist.
Sprouting, or the germination process, generally only occurs when a kernel has matured to a harvest ripe stage. Germination begins when a kernel takes up water, which activates enzymes that break down starch and proteins.
The process can be initiated multiple times in wheat and barley, Peel says. Each time, test weight is lowered and the viability of the seed will be reduced.
Sprout damage can be identified by visual inspection. Peel says visible indicators of sprouting include a weathered appearance, seed swelling, a split seed coat leaving the embryo exposed, and emergence of the coleoptile and radicle (the seedling shoot and root).
In wheat, a falling number test is used to measure the amount of enzyme activity. A test result with a falling number below 300 generally indicates pre-harvest sprouting has occurred.
Research indicates that kernels with sprout damage but no visible damage to the germ perform well in standard germination tests. Seed with low levels of damage can have germination almost as good as that of undamaged seed, but following aging the percent germination can drop dramatically.
Seed with an exposed germ or ruptured seed coat performs less well in germination tests. Seed with exposed germ structures is also susceptible to physical damage during handling.
Seedling mortality from severely sprout damaged grain, with exposed germ and shoots, can be about two-thirds of the total planted seed, compared to typical seedling mortalilty in the range of 10 to 20 percent with undamaged wheat or barley.
Planting sprout damaged seed can compound any problems that impeded the ability of a new seedling to emerge and produce active leaves required for good seedling vigor, Peel says. These conditions may include waterlogged soils, dry soils and crusting.
Seed sprouted to the point that the seed coat has split may also be damaged by the seed treatments typically used in North Dakota, says Peel.
Peel says damaged seed should be tested for germination before using. When the germination falls below 90 percent, consider using different seed, he says.
Peel lists a few simple guidelines to determine the potential impact of using sprout damaged seed:
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Source: Michael Peel, (701) 231-8037
Editor: Gary Moran, (701) 231-7865