§201.58a. Indistinguishable seeds. — Inbound Citations

(4) For methods of determining pure seed percentages of annual and perennial ryegrass, refer to §§ 201.58(b)(10) and 201.58a(a).

(10) The germination test for fluorescence of ryegrass shall be conducted in light [not to exceed 100 foot candles (1,076 lux)] with white filter paper as the substratum. The white filter paper should be nontoxic to the roots of ryegrass and of a texture that will resist penetration of ryegrass roots. Distilled or deionized water shall be used to moisten the filter paper. The test shall be conducted in a manner that will prevent the contact of roots of different seedlings. Roots of some seedlings produce fluorescent lines on white filter paper when viewed under ultraviolet light. First counts shall not be made before the eighth day; at that time remove only normal fluorescent seedlings. Evaluation of fluorescence shall be made under F15T8-BLB or comparable ultraviolet tubes in an area where light from other sources is excluded. If there are over 75 percent normal fluorescent seedlings present at the time of the first count, break the contact of the roots of the nonfluorescent seedlings from the substratum and reread the fluorescence at the time of the final count. At the final count, lift each remaining seedling, observing the path of each root since sometimes faint fluorescence will show on the substratum as the root is lifted. Abnormal seedlings and dead seeds are not evaluated for fluorescence. See § 201.58a(a).