746 



IOWA DEPARTMENT OF AGRICULTURE 

 TESTING PARTICULAR KINDS OF SEEDS. 



GENERAL CONSIDERATIONS. 



The work of seed testing is greatly facilitated by a general knowledge 

 of the conditions more or less peculiar to the seed of particular kinds of 

 crops. For illustration, the adulterants used with different kinds of 

 seeds differ in kind; the conditions of culture, of harvesting, and of prep- 

 aration for market tend to influence the condition of the seed; the kind 

 and source of the seed influence the character of its impurities. Kinds 

 of seed supplied to the market from both domestic and foreign grown 

 stocks should be considered with reference to their source. The signifi- 

 cance of the kinds of weed seeds as indicating the source of the seed is at 

 present chiefly applicable to the seed of the clovers and alfalfa. 



In the following remarks on the testing of particular kinds of seeds it 

 is assumed that the previously discussed methods of making seed tests 

 in general will be borne in mind, leaving the present discussion to relate 

 chiefly to conditions peculiar to the several kinds of seeds considered. 

 To avoid repetition, it may be stated that for the test sample of clovers, 

 alfalfa, and medium-seeded grasses seed equaling 12y 2 BB shots in weight 

 may be taken; of the smaller seeded redtop and blue-grasses half this 

 weight, equal to ^A BB shots, will suffice; of coarse seeds (as oats, bar- 

 ley, vetch, etc.), double the weight of 1214 BB shots may be used. Several 

 subdivisions of the larger sample may thus be required to segregate the 

 small test sample. A little care will insure accuracy in weighing the test 

 sample. 



TESTING RED CLOVER SEED. 



The yellow and violet colors of the seed, together with the triangular 

 form of individual seeds, distinguish fresh red clover seed. (See fig. 



22.) Old seeds are dull and 

 /■- " _ \ reddish brown. Imperfectly 



Mm£ . ^jT ' ;; -'-^_- .-•--". developed Si'C'ds nrr dull 



brown and more or less shriv- 

 eled. Empty perforated seed 

 shells in light screenings 

 show the work of the clover 

 seed chalcisfly. No evidence 

 of the so-called clover seed 

 midge is ever present in seed. 

 Note should be made of the 

 apparent relative quantity of 

 poor true clover seed in the 

 sample. 



Consider the matter of in- 

 tentional adulteration by the 

 use of (1) old red clover seed 

 which is sometimes disguised by oiling and polishing, but which will be 

 disclosed in the germination test; (2) yellow trefoil seed (figs. 3 and 23); 



Fig-. 22. — Seeds of red clover: 1, Side view 

 i rid, '2, edge view of seeds; 3, the trian- 

 gular form indicated; 4, a seed cut 

 lengthwise; 5, a seed cut crosswise, 

 showing the embryo; a, seed scar; 1», 

 stemlet (radicle) of the embryo; c, seed 

 leaves (cotyledons) of the embryo; 6, a 

 pod of red clover; 7, natural size of 

 seeds. 



