CHROMOSOMAL LOCATION OF PHOSPHOGLUCOMUTASE7 LOCUS IN GOSSYPIUM-HIRSUTUM

We report the first chromosomal assignment in the cotton genus, Gossyp ium, of a biochemical marker locus, specifically Phosphoglucomutase7 ( Pgm7). Isozyme polymorphism was detected between the inbreds TM-1 (G. hirsutum L.) and Pima 3-79 (G. barbadense L.). Analyses of these paren ts, their F-1 hybrid, and segregating F-2 and testcross progenies indi cated that Pgm7 determines the most cathodal phosphoglucomutase (PGM) isozyme bands and that the PGM isozymes are monomeric. Segregation ana lyses of self-progenies of monosomic BCnF1 interspecific hybrids and c hromosome substitution lines indicated that the Pgm7 locus is located in chromosome 12. Self-progenies from monotelodisomic (Te12Lo) F-1 int erspecific hybrids that were hemizygous for the short arm of chromosom e 12 segregated parental Pgm7 alleles, indicating that the Pgm7 locus is located in the long arm of chromosome 12. Testcrosses of the same m onotelodisomic as male parent segregated in a normal Mendelian fashion , indicating that the locus is 50 cM or more from the centromere in th e long arm of chromosome 12. The Pgm7 alleles of TM-1 and Pima 3-79 ar e probably identical to alleles Pgm7-2 and Pgm7-4, which have been des cribed in the biosystematic literature.