African Journal of Biotechnology Vol. 6 (12), pp. 1387-1392, 18 June 2007   

ISSN 1684–5315 © 2007 Academic Journals        

Full Length Research Paper

Intragenomic diversity and geographical adaptability of diploid cotton species revealed by cytogenetic studies

Alishah Omran¹, Ahmadikhah Asadollah²*, and Nasrollanejad Saeid³

¹Cotton Research Institute of Iran, Beheshti St., P. O. Box 49175483 Gorgan, Iran.

²Department of Agronomy and Plant Breeding, Gorgan University of Agricultural Sciences and Natural Resources, Bassij Sq., P. O. Box 4913815739, Gorgan, Iran.

³Department of Plant Pathology, Gorgan University of Agricultural Sciences and Natural Resources University, Bassij Sqr., 4913815739, Gorgan, Iran.

*Corresponding authors E-mail: ahmadikhah_a@gau.ac.ir. Tel: (+98171) 4426082. Fax: (+98171) 4420438.

Accepted 7 May, 2007

Cotton is one of the most important crops in Iran, and is cultivated in different regions of the country. Gossypium herbaceum is one of the A-genome cottons, which is a potentially important genetic resource for cotton breeding programs. Collecting native cultivars of this species growing in different regions is a vital step in broadening variability of the gene pool. The G. herbaceum is one of the two cultivated species under cultivation in Iran, which is specifically adapted to a given environment and includes more than 40 ecotypes, named as landrace cottons. The present paper reports the intragenomic characteristics analysis of 42 G. herbaceum cultivars in the cotton genebank using cytological methods. The karyological studies showed variations within the species in the size of chromosome, chromosome volume and karyotype formulae. All cultivars possessed 2n=26 chromosome, but varied with regard to number of SAT-chromosomes (ranging from 1 to 3) and the chromosomes carrying secondary constructions. Karyotypes were of symmetrical type, having small chromosomes. Analysis of variance revealed significant differences between the cultivars as well as the chromosomes. Cluster analysis could group the cultivars in four distinct clusters. The present study indicates genomic differences among diploid G. herbaceum cultivars, which can be used in cotton hybridization programs in Iran or other countries.

Key words: Gossypium herbaceum, Intragenomic diversity, Adaptability, Karyotype.