Differential Fluorescent Banding in 11 Varieties of Gossypium hirsutum L. from Bangladesh

Abstract

Eleven varieties of Gossypium hirsutum L. (cotton) released by the Bangladesh Cotton Development Board, viz., CB-1 (Cotton Board-1), CB-2, CB-3, CB-4, CB-5, CB-6, CB-7, CB-8, CB-9, CB-10 and CB-11 were investigated cytogenetically by differential fluorescent banding for authentic characterization. The 11 cotton varieties represented a broad spectrum of variation for several phenotypic and agronomic traits. The 11 cotton varieties were found to possess 2n=52 chromosomes, of which most were metacentric. A wide range of CMA-positive bands (5–20) was found in the metaphase chromosomes of the 11 varieties. Different numbers of satellites, such as 2 (CB-4, CB-7), 3 (CB-6), 4 (CB-1) and 6 (CB-2, CB-3, CB-8, CB-10), were found after CMA-staining. The differential staining property of satellites revealed the stain-specific nature of these satellited portions. Entirely DAPI-fluoresced chromosomes were frequent in these varieties. The number, location and distributions of GC- and AT-rich repeats are specific for each variety. Some CMA- and DAPI-bands were so unique that these chromosomes could easily be isolated from the rest and may be used as marker chromosomes for the respective varieties. Fluorescent banding revealed the occurrence of genomic alteration within these varieties. Therefore, each variety could be characterized authentically by fluorescent banding analysis.