Development of a Cotton Plant with Glandless Seeds, and Glanded Foliage and Fruiting Forms1

Abstract

Pigment glands in cotton (Gossypium spp.) contain gossypol and related terpenoid aldehyde compounds and these glands are found throughout most aboveground parts, including seeds. These glands protect the plant from insect pests, but gossypol in the embryo of the seed is undesirable because it is toxic to nonruminant animals. The objectives of the present study were to identify a hexaploid cotton plant that possessed glands in most of the aboveground parts, except the seed, and initiate the transfer of this trait into a tetraploid cotton. A fertile hexaploid (2N= 78) plant from an interspecific cross of tetraploid (2N=52) Gossypium hirsutum L. ✕ diploid (2N=26) G. sturtianum Willis showed a phenotype having glandless seed, and glanded foliage and fruiting forms. This phenotype had flowerbud and seed gossypol percentages of 0.29 and 0.02, respectively. Fertile pentaploid F1 plants from crossing the hexaploid and the tetraploid G. hirsutum Texas marker‐1 (TM‐1) stock appeared to produce as much seed cotton as the tetraploid Texas marker‐1 at Brownsville, TX. However, the F1 plant produced 0.31% flowerbud and only 0.02% seed gossypol. The flowerbud and seed gossypol percentages of TM‐1 were 0.58 and 1.29, respectively. These results show that fertile hexaploid germplasm in cotton has been developed that possesses the unique characteristic of storing gossypol in glands in the vegetative foliar and fruiting plant parts but not in the embryo of the seed.