Assessing genetic diversity among six populations of Gossypium arboreum L. using microsatellites markers

Abstract

Among the four cultivated cotton species, G. hirsutum (allotetraploid) presently holds a primary place in cultivation. Efforts to further improve this primary cotton face the constraints of its narrow genetic base due to repeated selective breeding and hence demands enrichment of diversity in the gene pool. G. arboreum (diploid species) is an invaluable genetic resource with great potential in this direction. Based on the dispersal and domestication in different directions from Indus valley, different races of G. arboreum have evolved, each having certain traits like drought and disease resistance, which the tetraploid cotton lack. Due to lack of systematic, race wise characterization of G. arboreum germplasm, it has not been explored fully. During the present study, 100 polymorphic SSR loci were used to genotype 95 accessions belonging to 6 races of G. arboreum producing 246 polymorphic alleles; mean number of effective alleles was 1.505. AMOVA showed 14 % of molecular variance among population groups, 34 % among individuals and remaining 52 % within individuals. UPGMA dendrogram, based on Nei's genetic distance, distributed the six populations in two major clusters of 3 populations each; race 'bengalense' was found more close to 'cernuum' than the others. The clustering of 95 genotypes by UPGMA tree generation as well as PCoA analysis clustered 'bengalense' genotypes into one group along with some genotypes of 'cernuum', while rest of the genotypes made separate clusters. Outcomes of this research should be helpful in identifying the genotypes for their further utilization in hybridization program to obtain high level of germplasm diversity.

Genome-Wide Mining and Characterization of SSR Markers for Gene Mapping and Gene Diversity in Gossypium barbadense L. and Gossypium darwinii G. Watt Accessions

“…The AMOVA results estimated 38% variation among population of accessions and 62% genetic variation within the populations of both species. A similar previous study indicated 14% variation among populations and 52% variation between individuals of G. arboreum [56].…”

Genotyping-by-Sequencing of Gossypium hirsutum Races and Cultivars Uncovers Novel Patterns of Genetic Relationships and Domestication Footprints

“…3-5 However, the high genetic similarity among G hirsutum accessions has hindered opportunities for breeding new cotton cultivars with improved agricultural traits such as higher yield, ease of harvest, and stronger resistance to pest, diseases, and environmental stresses. 6-10…”

“…[3][4][5] However, the high genetic similarity among G hirsutum accessions has hindered opportunities for breeding new cotton cultivars with improved agricultural traits such as higher yield, ease of harvest, and stronger resistance to pest, diseases, and environmental stresses. [6][7][8][9][10] Seven genetically related accessions of G hirsutum, including Latifolium, Palmeri, Marie-Galante, Richmondi, Yucatanense, Morrilli, and Punctatum, have been identified based on their locations of origin. 11 These races have distinct characteristics that are common to wild cotton but not to cultivated G hirsutum, such as sensitivity to a short-term light cycle, greater disease resistance and drought tolerance, hard seed coats, and variable seed size, and are genetically compatible with domesticated cottons.…”

Molecular Characterization of Desi Cotton Hybrids using SSR Markers for Boll Size Improvement

“…Studies evaluated the genetic diversity of landraces in G. arboreum L. race by using simple sequence repeats (SSRs) (Liu 2007), where the result of these studies revealed a higher level of genetic variation at the DNA level among the G. arboreum accessions than that among G. hirsutum L. accessions. The transition of intraspecific and interspecific hybridization of allelic diversity from different cotton germplasm services to the main cotton breeding gene pools would be an important step in this direction (Sethi et al, 2015). The current study focuses on genetic improvement by using molecular breeding approaches for the production of highly desirable desi cotton verities with traits of interest.…”