Inheritance of Gossypol Level in Gossypium. IV. Results from the Reciprocal Exchange of the Major Gossypol‐Gland Alleles Between G. hirsutum L. and G. barbadense L.1

Abstract

Cultivars of Gossypium barbadense L. commonly assay 2.00 to 2.50% terpenoid aldehydes (gossypol and methoxgossypol) in dried meals from whole seeds, whereas Upland cultivars of G. hirsutum L. commonly average 1.00 to 1.50%.G landlesss eeds of both species are virtually free of gossypol. Using glandless stocks as recipient parents, the gossypol‐gland alleles of the two species, Gl2 and Gl2 were exchangedr eciprocally using the G. hirsutum cultivar, ‘Empire’, and the G. barbadense stock, AS‐2 Sea Island, as donors. AS‐2 made homozygous for alleles from Empire averaged about the same level of gossypol in seeds as the control (2.06% vs. 2.10%). Empire made homozygous for AS‐2 alleles likewise stabilized near its control (1.20% vs. 1.23%). Neither of the introgresseed monomeric stocks (Gl2Gl2gl3gl3 and gl2gl2Gl3Gl3) showed parity of expression between the gossypol‐gland alleles characteristic of “pure” G. barbadense. Rather, both showed the G. hirsutum type of expression wherein the Gl2 monomeric stores 2.5 to 3.0 times as much terpenoid substances as the Gl3 monomeric The high‐terpenoid G. hirsutum stock, however, 3‐T, showed a nearparity level of the substances between its monomerics after introgression with AS‐2 alleles. No cytoplasmic effects were detected.