Premium
The Mechanical Factors Determining the Shape of the Wheat Kernel
Author(s) -
Boshnakian Sarkis
Publication year - 1918
Publication title -
agronomy journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.752
H-Index - 131
eISSN - 1435-0645
pISSN - 0002-1962
DOI - 10.2134/agronj1918.00021962001000050003x
Subject(s) - citation , computer science , information retrieval , library science
The shape of the grain of wheat is affected by a number of spikelet characters, which are mainly : (I) The s.tiffness of the glumes, (2) the size and shape of the space in which the grain develops, (3) the number of grains in .the spikelet and their position, (4) density of the head, (5) the pressure caused by ~he growth of different parts of the head, and (6) the species which produces the kernel. Just as the interior surface of stone or hard-shelled fruits determines to a very large extent the shape of the enclosed seed, so the. character and form of the surroundings of the developing grain of wheat determine the shape of the mature kernel. An ideal wheat kernel whose free development has not been arrested by coming in contact with the surrounding parts of the spikelet should be symmetrical; that is, when. the grain is divided by a plane dorsi-ventrally passing through the crease, the two halves should be alike with the dimensions reversed. Such a grain is shown at A in figure 27. The position in the spikelet of, uniformly developed kernels is seer~ in figure 27 E. Symmetrical grains are very rarely found in nature. The types of k.ernel most frequently fou~nd are those shown in B and C of figure 27 ;,their relative positions on the spikelet are shown in Fb and Fc respectively. In these cases the plane .does not divide the grain into symmetrical halves. ’Grain B dorsally viewed is flattened on the left side, while in the case of C the opposite side is flattened. This flattening occurs always on the siide of the kernel which is nearer to the rachis, as shown in F. It is evident then that all grains which are flattened on the left side are produced by the florets on the left side of the spikelets, and those flattened on the right side are borne on the opposite side of the spikelet. This character, which is constant for all species, enables one to determine the side of the spik.elet on which different kernels were.produced.