1 No. 156. 2971 Experiment Station. Oct, '08. Kansas State Bulletin No. 156-October, 1908. Botany Department. The Yellow Berry Problem in BOARD OF REGENTS. HON. A. M. STORY (1909), President..... ...Manhattan, Riley county HON. EDWIN TAYLOR (1911).. Smith Center, Smith county .Hays, Ellis county Edwardsville, Wyandotte county . Anthony, Harper county E. R. NICHOLS, President of College, (ex officio) Secretary....Manhattan MISS LORENA E. CLEMONS, Assistant Secretary. Experiment Station at the Kansas State Agricultural College, Manhattan. Bulletin No. 156-October, 1908. Botany Department. H. F. ROBERTS, M. S., Botanist. G. F. FREEMAN, B. S., Assistant Botanist. The Yellow Berry Problem in Kansas Hard PART I. ONE of the most serious problems which the wheat-growers of the Kansas hard wheat districts have to contend with is that of the so-called "yellow berry." The wheat of this region produces normally a hard, flinty, translucent grain, of medium size and of a clear dark reddish-amber color. By the term "yellow berry" is meant the appearance, in wheat of the above description, of grains of a light yellow color, opaque, soft and starchy. These opaque yellow grains, constituting what are called the "yellow berries," may have this character throughout; but sometimes from a small fraction to half of a grain will be yellow and starchy, while the remainder of the kernel will be hard, flinty and translucent. The difference in color between the flinty grains and the "yellow berries" is due to difference in the structure and contents of the cells of the endosperm. According to Hackel,1 if the albuminoids so fill up the intervals between the starch grains that the latter seem to be imbedded in cement, the albumen appears translucent, and the fruit is called "corneous"; but if the union is less intimate there remain numerous small air-cavities, the albumen is opaque, and the fruit is mealy. 1. E. Hackel, "The True Grasses," p. 26. Lyon and Keyser,2 as the result of their studies on the internal structure of the wheat kernel, say (p. 35): "The protoplasmic network of the cells in the sections from the very horny kernels showed only an occasional vacuole; sections from the markedly yellow kernels showed very much more numerous and larger vacuoles, measuring on the average less than 0.001 millimeter. Medium yellow berry kernels had fewer and smaller vacuoles than the markedly yellow kernels." These writers also found that in the yellow berries the starch grains in the cells were larger in diameter than in the flinty kernels, although not so large as in the typical starchy wheats. The following table indicates the range: This agrees with Cobb, who says: "It is noticeable that when the grain is rich in nitrogenous matter the number of large starch granules is smaller." The yellow berry may then possibly be regarded as an imperfect product, in which the spaces in the cells which are normally filled with proteids (gluten) contain merely water, which, drying out with the ripening of the kernel, leave airspaces which are responsible for the opaque appearance of the kernel. In addition to this fact is the further one that per unit of volume of the yellow berry kernel there may be a smaller amount of starch than in the flinty grains, on account of the greater size of the individual starch grains. From the standpoint, therefore, of both gluten and starch, the yellow berry is probably an inferior kernel, and from the economic standpoint it may be regarded as a degenerate product. It should further be emphasized that the bleached opaque grains, due to weathering, are not "yellow berries." In weathered kernels the grain has an opaque and rather dirty grayishyellow aspect, which appearance affects the grading of the grain adversely, but is not necessarily associated with an in 2. Winter Wheat. T. L. Lyon and A. Keyser, Nebraska Experiment Station, Bull. 89 (June, 1905). 3. Cobb, N. A., in Agricultural Gazette, New South Wales, vol. XV, part 6, p. 512. ferior condition of the kernel, although such frequently is the result of exposure to the weather. This distinction between weathered grains and yellow berry has been dwelt upon, because, to judge from the literature upon the subject, much confusion concerning these characters exists, not only among farmers but also among experiment station men. The yellow berry, then, appears to be distinctly a physiological growth product, due to certain conditions thus far not clearly analyzed or satisfactorily explained in any of the experiment station publications, and the causes of which have constituted the object of the investigations which this bulletin reports. PHYSICAL CHARACTERS OF THE YELLOW BERRIES. In addition to, and in consequence of, the structural characters alluded to, viz., the presence of numerous vacuoles in the endosperm-cells, filled with air, which in the corresponding flinty grains of the same variety are filled with gluten (proteids), there are found to exist some interesting and important conditions with respect to weight and specific gravity. The presence of air-vacuoles doubtless accounts for the lighter weight and the uniformly lower specific gravity of the yellow berry kernels. Owing to the higher specific gravity of the carbohydrates in the wheat kernel (starch 1.53, sugar 1.60, cellulose 1.53), as compared with the proteids (gluten 1.297), it would necessarily follow that the true starchy wheats are the heaviest wheats and possess the highest specific gravity. Compiled from reports of the U. S. Dept. of Agriculture. The degree of correspondence that there may be between the particular kind of starchy grain appearing in hard wheat and 4. Körnicke und Werner, Handbuch des Getreidebaues, vol. 2, p. 120 (1884). |