The Inheritance of An Ultra-Dwarf Mutant in Upland Cotton and Its Gene Location

Dwarf plant resources are very rare in upland cotton. An ultra-dwarf mutant from upland cotton was identified at experiment field at Nanjing, China, in 2004. The genetic analysis showed that the traits was controlled by a pair of negative qualitative genes.It was designed as du. Up to now, no similar mutation have be found in upland cotton. The mutation could not normally flower and produce bolls under natural condition, and reached last height only 10.5cm. If treated with exterior GA₃, it could flower and set bolls.

Meanwhile, linkage inheritance of gene du based on SSR markers was carried out. Seventy pairs of polymorphic primers were identified from 1350 primers between parents and near-isogenic lines, and then mapped with F₂ population from intraspecific crosses of “Ultra-dwarf No.1” and “Xinluzao 16” by bulked segregation analysis. Linkage analysis showed du was linked to seven co-dominant SSR markers (NAU2679、NAU2749、NAU905、NAU2838、NAU5373、NAU2238 and NAU4946) on chromosome 6 and was located between NAU2238 and NAU4946,which were from 3.5cM and 1.5cM, respectively.