Agriculture Reference
In-Depth Information
Phenol Test for barley (
Hordeum vulgare
), bluegrass (
Poa
spp
.
), oats (
Avena
spp.), ryegrass (
Lolium
spp
.
)
and Wheat (
Triticum
spp
.
)
Refer to AOSA Handbook 28, “A Standardized Phenol Method for Testing Wheat Seed for Varietal Purity,”
when testing wheat seeds. In checking the varietal purity of seeds with the phenol test, it is important to
establish the color reaction of the stated variety by using an authentic check sample of known varietal
purity. One advantage of the phenol test is that it is not dependent on the ability of the seed to germinate.
Procedure
1. Place two layers of ilter paper in distilled water.
2. Pour off excess water and place the seeds on the ilter paper (50 seeds/9 cm petri dish).
3. Cover the petri dish and allow seeds to soak overnight (15-24 h) at 25°C.
4. Prepare a 1.0% phenol solution by adding 5.0 g carbolic acid crystals to 500 ml distilled water.
Store the phenol solution in an amber glass container in a cool location; do not use phenol solution
that has been prepared for more than 3 months.
5. Place two layers of dry ilter paper in the petri dish and add enough 1.0% phenol solution (about
2 to 3 ml/9 cm petri dish) to soak the ilter paper.
6. Spread seeds uniformly over the surface of the moistened ilter paper and close the petri dish.
7. After 24 h (4 h for wheat and 2 h for oats), record the color reaction of the seeds and compare
with the check sample (Fig. 9.11). Seeds treated with Thiram require a longer reaction time than
nontreated seeds.
