I'^IELD CROPS. 43 



Improving wheat by selection, N. A. Cobe {Af/r. Gaz. TV. S. W., T 

 {1894), Xo.'I, pp. L^o9-;150). — The aiifclior's chief object was the selection 

 of rust-proof or rust-resistant plants. lie discusses the characters which 

 must be combined in a wheat in order that either its rust resistance may 

 be increased or that its agricultural and commercial valne may be 

 augmented. To ascertain the amount of rust the author recommends 

 the use of his scale, by means of which it is possible to determine the 

 proportion of tlie surface of blade, sheath, and stem that are affected by 

 rnst. Wheat plants with purple straw sliow a greater tendency to rust 

 than those with straw of other colors. Selected plants, besides escaping 

 rust, should combine, among other desirable qiTalities, the following 

 characteristics: Productiveness, well-shaped grain, stiff, short straw, 

 and narrow, erect, tongh, and glaucous foliage. The author insists 

 that selection should be made of whole plants and not of single heads, 

 and in judging a plant he believes it necessary to consider 36 points, 

 the more important of which are noted below. 



The plant should stool abundantly, bear all of its ears at the same 

 height, and these should rii^eu simultaneously. Ko ear with sterile 

 spikelets should be selected. If the grains in a spikelet are small they 

 should be the more numerous. A top-dressing with soluble manures, 

 followed by timely rains, when the heads are just appearing, tends to 

 produce spikelets Avith a large number of grains. The more nearly 

 spherical a grain of wheat the snniller the percentage of bran. On the 

 other hand, long grains, though giving a smaller proportion of flour 

 are richer in gluten, a desirable characteristic. If the bran is thin a 

 long grain may be chosen, but if the bran is thick a short grain is 

 desirable. A pointed grain contains more gluten in proportion to its 

 starch. " The deeper the crease the more there is of both bran and 

 gluten, but the grain increases in value with the depth of crease up to 

 any extent yet known to occur." 



The thickness of the gluten layer just under the bran varies, and a 

 wheat with a thick gluten layer as determined by microscopic exam- 

 ination should be selected. Small grains contain a larger proportion 

 of gluten than large ones. The less brush there is on a grain the 

 better. The straw of selected plants should be neither flexible, brittle, 

 nor long, but short, stiff, and large. Varieties with long straw are 

 liable to shelling by wind. Beards diminish shelling by lessening the 

 shock of impact against other heads. 



The chaff should not be weak, as shown by its thinness and trans- 

 lucency, nor yet brittle, since both of these characteristics are the chief 

 causes of shelling. A stiff chaff, which is desirable, is usually white or 

 yellow and glazed on the surface and has a color of its own independent 

 of the inclosed grain. Oominict and upright heads shatter less easily 

 than loose and leaning heads. Varieties with red chaif, with a few 

 marked exceptions, are esj^ecially liable to shelling. 



In judging of the ripeness of wheat it is claimed to be always neces- 



