The Inheritance of Gossypol Level in Gossypium I. Additive, Dominance, Epistatic, and Maternal Effects Associated with Seed Gossypol in Two Varieties of GOSSYPIUM HIRSUTUM L.

TUDIES in quantitative inheritance are generally conducted as the analysis of the effects of groups of genes acting in concert to produce the character under consideration. Rarely can the number of loci involved be knc". It is thus of some interest when the number o i genes involved in the production of a character can be known through the use of a method (which allows for discrimination among units of expression by qualitative assays, yet have the genes express themselves in some other way, the nature of which is quantitative. The character, expression of pigment gland size and number in the plant body and seeds of various species of Gossypium, fits into this category. A normally glandular plant of Upland cotton (Gossypium hirsutum var. Zatifolium Murray) displays pigment glands in the leaves, stems and carpel walls in undiminishing numbers throughout the lifespan of the plant. When such a plant is crossed to a plant devoid of glands, the resulting F, is approximately intermediate in glandulosity. The F, generation displays a continuous array of glandulosity ranging from a very few glands about the margins of the cotyledons to types which appear to be normal. In addition there are a few glandless individuals. MCMICHAEL (1960) compared the F, progenies stemming from the cross of a glandless straiin to several accessions of Upland cotton. He concluded from the relative numbers of glandless seedlings in each progeny that the concerted action of alleles at two independent loci produced the glandless character. LEE (1962) devised a inethod for separating the active, gland-producing loci through inspection of the pattern of glands on the cotyledons of week-old seedlings. The two monomeric genotypes produced in this fashion proved to be strikingly different in their relative abilities to sustain gland production through various phases of plant development. Pigment glands in cotton contain a variety of polyphenolic substances (STAN-