A revised map of chromosome 15 in Gossypium hirsutum

Abstract

Three translocations involving chromosome 15 (H15) in cotton, T4R;15L 1040, T11L;15L 1058a, and T15R;20R SL15, were tested against the H15 marker genes okra leaf [Formula: see text] and veins fused (vf). The latter gene was also tested against T15L;16L 2767. Duplication deficiencies monosegmental for H15 (easily recognized by their narrow distorted bacteoles) showed that [Formula: see text] is in the right (R) arm distal to the SL15 breakpoint (bp-SL15) and cannot be distal to bp-1040 or bp-1058a in the left (L) arm. Recombination frequencies between the three bp's and [Formula: see text] showed that the order is (L) bp-1058a–bp-1040–centromere–bp-SL15–[Formula: see text]. [Formula: see text] is approximately 28 cM (centi-Morgan) from the centromere. The L and R arms of H15 defined by translocations correspond, respectively, to the long and short arms defined by telosomes. Duplication deficiencies monosegmental for H15 showed that vf is not distal to either the L arm or the R arm bp's in H15. Therefore vf and the genes Lg, s, and cr, which are closely linked to vf, cannot be located on H15 as had been assumed. "Linkage group II" thus contains genes located on two different chromosomes. We suggest retaining linkage group II for Lg and genes closely linked to it and designating the group of genes on H15 linked to [Formula: see text] as linkage group XIX.Key words: cotton, translocations, linkage maps, duplication–deficiencies, okra leaf, veins fused.