2009 Annual Report 1a.Objectives (from AD-416) To develop and provide U.S. Department of Agriculture, Agricultural Research Service (ARS) chromosome substitution lines of cotton with whole chromosomes or parts of chromosomes from Gossypium tomentosum and G. mustillinum substituted into G. hirsutum in a TM-1 common background for use in molecular mapping of agronomic, fiber, and pest resistance genes in cotton. 1b.Approach (from AD-416) Rooted cuttings of chromosome deficient or substitution lines will be made as each backcross is developed and supplied to ARS at Mississippi State, MS. When 5 backcrosses have been completed in the substitution program, the euploid substitution lines will be developed by selfing and supplied to ARS for use in introgressing genes from these wild tetraploid species into G. hirsutum breeding germplasm. ARS will genotype with special molecular markers to confirm specific chromosomes involved in substitution lines when necessary. Development of chromosome substitution lines from G. tomentosum will be emphasized first, followed by substitution lines from G. mustillinum. 3.Progress Report New chromosome substitution lines with chromosomes from Gossypium tomentosum were developed, cloned plants were sent to ARS at Mississippi State University for keeping in the greenhouse, and seed were produced by ARS for field evaluation of fiber and agronomic traits. The ADODR monitored this project by quarterly contact with the scientist assigned to this project.