75. Germination.—Wheat absorbs upon germination from five to six times its weight of water. Various experimenters have reported that dilute solutions of fertilizers and other salts accelerate germination. The salts dissolved in soil water probably exert a favorable influence. Whether this is a physical or physiological influence has not been proven, but it has been shown that absorption of water goes on as rapidly in dead seeds as in live ones.1 More concentrated solutions used to prevent smut have in some instances been reported injurious. Much less injury is done by soaking the seeds in the solution before sprouting than by bringing the solution in contact with the young plantlet. It has been shown that nitrate of soda and muriate of potash when used in too large quantities or not properly distributed in the soil may destroy germination, while fertilizers composed of lime and phosphoric acid are much less injurious. In no case should the seeds be brought in direct contact with nitrate of soda and muriate of potash. Sachs gives the minimum and maximum temperatures at which wheat will germinate as 41° F. and 108° F., and the most favorable temperature as 84° F. Haberlandt reports that wheat germinated at 41° F. at the end of six days, that the maximum temperature of germination was between 88° and 100° F., and that the most favorable temperature was somewhere between 61 to 88° F.3 Saunders determined the viability of three varieties of wheat during six years with the following average results: 80; 82; 77; 37; 15; 6 per cent. The germination ability showed a marked decrease at the end of four years, and at the end of six years was entirely lost in two of the three varieties. 1 Wyo. Bul. 39, p. 44. 2 U. S. Dept. of Agr., Div. of Bot. Bul. 24. 8 Landw. Vers.-Stat. XVII, 104. ▲ Can. Expt. Farms Rpt. 1903, P. 44. IV. WHEAT. I. BOTANICAL RELATIONS. 76. The Wheat Genus (Triticum L.).-The plants of this genus are all annuals. The commonly cultivated species have apparently been so changed from the wild type as to be dependent upon man's agency for their existence. Sir John Lawes was wont to say that if man should disappear from the earth wheat would follow him in three years. This is true, also, of the common field bean, maize, tobacco, and a few other less commonly grown species. Hackel divides the genus into two sections, viz., Egilops L. and Sitopyros. In the former the glumes are flat or rounded on the back, while in the latter they are distinctly keeled. To the latter section belong the cultivated species. 77. The Species of Wheat.-There are eight cultivated types of wheat which are usually considered of greater value than the variety type. Hackel recognizes but three true species and the other types are treated as subspecies.2 The structural relationship is much closer between Tr. sativum and Tr. polonicum than between Tr. monococcum and either of the former. The palea of Tr. monococcum falls into two parts at maturity, while in the other two species the palea remains entire. Tr. sativum spelta and Tr. sat. dicoccum are to be distinguished from the other four subspecies of sativum by the grains remaining enclosed in the glumes upon threshing and by the rachis breaking up at maturity. The common and 1 In the following division into species and subspecies Hackel has been followed. See The True Grasses. By Edward Hackel. Translated from Die Naturlichen Pflanzenfamilien by F. Lamson-Scribrer and Effie A. Southworth, pp. 179-187. 2 Ibid. club wheats are closely related to each other, as are likewise the poulard and durum wheats. Einkorn never, and the polish wheat rarely, gives rise to a fertile cross with common wheat. The subspecies of Tr. sativum readily cross with each other. The relationship of the eight types is shown in the following outline : 78. Einkorn (Tr. monococcum L.).—This species may be distinguished from the other species by the palea falling into two pieces at maturity. The joints of the rachis readily separate as in the case of the wild species of this genus. Usually only the lower flower of the spikelet matures. Each spikelet is awned and the spike is compact. The wild type is scarcely distinguished from the culti vated type. It is cultivated somewhat in Europe in poor and rough places unsuited for other varieties of wheat. Its cultivation is of great antiquity, as is proven by finding the (One-half natural size.) grain in the Lake dwellings belonging to the Einkorn. Stone Age. It is used for mush and cracked wheat, and as fodder for cattle, rather than for bread. 79. Spelt (Tr. sativum spelta Hackel).-Was largely and widely cultivated in ancient times. Hackel states that it was the chief grain in Egypt and Greece and was cultivated everywhere throughout the Roman Empire and distributed through its colonies. It is now sparingly cultivated in Europe except in northern Spain, where it is still an important crop. At present it is used almost exclusively as a stock food. It is not cultivated in this country except in an experimental way. There are both winter and spring varieties, but the winter beardless spelt, a white-spiked, awnless variety, is said to be the most profitable. Under ordinary conditions the yield is not equal to common wheat. Hackel states that it is more certain, liable to fewer diseases and not at all subject to the attacks of birds. Carleton says that it is especially liable to rust. He gives its desirable qualities as power to hold the grain in the spike, constancy in fertility, and hardiness of certain winter (One-half natural size.) varieties.1 The brittleness of the spike is an undesirable quality. Spelt. The Garton Brothers (England) have obtained good results by crossing spelt on common wheat to prevent shattering at harvest. 80. Emmer (Tr. sat. dicoccum Hackel).-Hackel states that this subspecies has been "cultivated from the most ancient times but always more sparingly than spelt and at present (1885) only in S. Germany, Switzerland, Spain, Servia and Italy.“ Carleton (1900) says: "Very little, if any, true spelt is grown in 1 The Basis for the Improvement of American Wheats. By M. A. Carleton TJ. S. Dept. of Agr., Div. Veg. Phys. and Path. Bul. 24, p. 34. Russia, though a rather large quantity of emmer is produced each year." This species is often incorrectly called spelt in the United States and the two species are thus sometimes confused. "The plants of this species are pithy or hollow, with an inner wall of pith; leaves sometimes rather broad, and usually velvety hairy; heads almost always bearded, very compact, and much flattened on the two-rowed sides. Common wheat: Turkish red variety on the left; Red The appearance in the field is therefore quite different from that of spelt. The spikelets, however, look considerably like those of spelt, but differ principally in the presence always of a short pointed pedicel. This pedicel, which is really a portion of the rachis of the head, if attached at all to the spelt spikelets, is always very blunt and much thicker. Besides, the emmer spikelets are flattened on the inner side, and not arched as in spelt, so that they do not stand out from the rachis as the spelt spikelets do, but lie close to it and to each other, forming a solidly compact head. The spikelets are usually two. grained, one grain being located a little higher than the other. The outer chaff is boat-shaped, keeled, and toothed at the apex. The grain is somewhat similar to that of spelt, but is usually harder, more compressed at the sides, and redder in color. "For the production of new varieties by hybridization emmer has qualities similar to those of spelt, but still more valuable. At the same time emmer, besides possessing harder grain, is more resistant to drought, and usually rather resistant to orange leaf rust. It is well adapted for cultivation in the northern States of the Plains and has already proved very valuable as a hardy forage plant in that region, |