Japanese Civilization (Part 22) Part 1.

(From Journal of Japanese Trade & Industry (JJTI))

Byline: Kawakatsu Heita

R. A. SILOW made extensive investigations into the genetic aspects of taxonomic divergence in the diploid Asiatic cottons. He maintained that; (a) taxonomically, the relationship between two cultivated Asian species, G. arboreum and G. herbaceum, was similar to that of the New World species, which reached full fertility in the current generations. Sterility was developed and two species were disintegrated later, and (b) G. herbaceum and G. arboreum were not only separated by a genetic barrier, but by ecological adaptabilities as well. There are three independent lines of evidence to confirm Silow's findings: (1) The species integrity was maintained when cultivated cottons were grown with commercial crops; G. arboreum and G. herbaceum were commercially cultivated together in western India and in parts of Madras for many years without a breakdown of the species distinction; (2) Before the genetic distinction between G. arboreum and G. herbaceum was decoded, comprehensive and long-term efforts were made in Southern India to interbreed commercially acceptable cottons. These consistently failed to produce material of agricultural value, and it was remarked that "the better the single plant selection in any generation, the worse the segregates that appeared in its progeny." (3) In crosses made for the genetic analysis of species difference, a wide range of unbalanced types were created in segregating generations.

The Origin and Spread of the Old World Cottons According to George Watt, "no species of Gossypium is known, in its original habitat, to be annual." Historical and botanical evidence clearly shows that the primitive cottons were perennial. Since cotton plants were originally long-lived perennials, the natural limits of genus distribution were fixed by climatic conditions favorable to this habit of growth.

As mentioned previously (Part 19), differentiation in the Old World complex of cultivated cottons led to the establishment of two clearly defined species, G. arboreum and G. herbaceum. Concerning the origin of both species, one conjecture is that the Indus civilization in the middle of 3000 BC effectively divided the area which formed the primary ...