The effect of chaff of cereals on germination of seeds and on the growth of mold

1. Shelling seeds of several species and stocks of wheat and two varieties of "hull-less" barley resulted in a considerable increase in the percentage of germination, if shelling immediately preceded germination in petri dishes. For such stocks it would appear that storing seeds with the chaff on and shelling just before germinating would be the best way to prolong viability. 2. The ability of seeds of four varieties of common wheat to germinate in the chaff was correlated with their tendency, as reported by Harrington, to germinate in the stook. Thus, tests in petri dishes might be used to indicate the tendency of seeds of a variety to germinate before harvest or in the stook. 3. Shelled and unshelled seeds of three varieties of oats germinated about equally well in petri dishes, though shelled seeds germinated more quickly. 4. Seeds of "hulled" varieties of barley varied in their response to the removal of chaff, but in general, removal of chaff from seeds of "hulled" stocks did not result in as great a benefit to the seeds as it did with seeds of "hull-less" stocks. 5. Shelling had little effect on the germination of seeds of wheat stocks tested in soil, except that, as in petri dishes, shelled seeds germinated more quickly. 6. Unshelled seeds of oats germinated distinctly better than shelled seeds in soil, but, as in petri dishes, shelled and unshelled seeds germinated at about the same rate. Differences in the effect of chaff on germination in petri dishes and soil suggest that seed laboratory tests in petri dishes may not be as reliable as tests in soil in indicating the germinative ability of some seeds under farm conditions. 7. The effects of chaff in altering germination of wheat, barley, and oats were apparently dependent to a considerable degree on the age and viability of the seeds. Highly viable, fresh seeds usually grew whether they were shelled or not. 8. Storing seeds with naphthalene for 3 to 5 months resulted in a slight reduction in germination, more noticeable in the rate of germination than in percentage, of a stock of wheat seeds tested but did not account for the effect of chaff in reducing germination. 9. Unshelled seeds of three stocks of einkorn and one stock of barley were distinctly less liable than shelled seeds to mold. The other stocks of cereals tested were almost mold-free. 10. Aqueous solutions of extracts of wheat chaff were sometimes but not consistently effective in inhibiting germination of seeds and in inhibiting the growth of mold on shelled seeds.