A Study of Reciprocal Hybrids Between Upland Cotton (Gossypium hirsutum L.) and Experimental Lines with Cytoplasms from Seven Other Species1

Genetically or cytoplasmically uniform crops may be vulnerable to disastrous pest infestations. Upland cotton (Gossypium hirsutum L.) cytoplasm is present in most of the cotton cultivars grown commercially in the U.S. However, experimental breeding material has been developed from Upland cotton hybrids with cytoplasms from seven other species of Gossypium. The most uniform and productive progenies within each of these seven cytoplasms were selected for making reciprocal backcrosses to Upland cotton cultivars. Backcrosses with cytoplasm from two tetraploid species (G. barbadense L. and C. tomentosum Nutt.) showed no significant differences from their reciprocal hybrids with Upland cytoplasm, but similar backcrosses with cytoplasm from each of the five diploid species (G. herbaceum L., G. arboreum L., G. anomalum Wawra & Peyr., G. harknessii Brandagee, and G. longicalyx Hutchinson and Lee) differed significantly from their reciprocal hybrids.