Genetic Diversity in Elite Cotton Germplasm Determined by Morphological Characteristics and RAPDs

Abstract

Limited interspecific introgression has been achieved in the breeding of the two primary cultivated species of cotton (Gossypium hirsutum L. and G. barbadense L.). Genetic diversity of 16 near-homozygous elite cotton genotypes derived from interspecific hybridization was investigated at the DNA level with the random amplified polymorphic DNA (RAPD) procedure and at the phenotypic level with stable and highly heritable morphological characters. Eighty random decamer primers were used to amplify DNA via the polymerase chain reaction (PCR) and 135 RAPDs were generated. Nineteen morphological traits were measured on the genotypes in field experiments in 1992 and 1993. Morphological characters were chosen that easily distinguish typical G. hirsutum (upland cotton) from G. barbadense (Pima cotton). Dendrograms were generated for genetic distance from the RAPDs and average taxonomic distance from the morphological data. Both procedures produced two clusters with one resembling G. hirsutum and one G. barbadense. Classification of all genotypes based on the two methods gave similar results with a correlation of 0.63 between the genetic distance and taxonomic distance. Several genotypes were identified that were genetically and phenotypically distant from typical G. hirsutum and G. barbadense. The level of polymorphism exhibited by these genotypes could be exploited in genetic mapping populations to tag economically important traits, such as fiber quality. These genotypes also could serve as a germplasm source of unique alleles in G. hirsutum that are derived from G. barbadense. This experiment demonstrates for the first time that RAPD analysis can reliably determine genetic relationships within a diverse array of Gossypium germplasm. E XTENSIVE INTERSPECIFIC genetic variation is present within the genus Gossypium and this variation is distributed among approximately 43 species (Percival and Kohel, 1990). The primary cultivated species are G. hirsutum and G. barbadense. The successful introgression of genes via interspecific introgression has resulted only after extensive recombination and selection (Stalker, 1980). Meredith (1991) and Niles and Feaster (1984) reviewed the transfer of desirable genes from exotic intraspecific and interspecific germplasm sources into contemporary upland cotton breeding programs. Genetic improvements in fiber quality have been achieved by exploiting Beasley's Triple Hybrid germplasm [(G. thurberi Tod. × G. arboreum L.) × G. hirsutum L.] (Culp et al., 1979). This was part of the Pee Dee germplasm program in South Carolina that employs population development procedures based on recombination and cyclical selection. Triple Hybrid germplasm has been introgressed into Acala 1517 germplasm in New Mexico Dep.

RETRACTED: Study of Genetic Diversity in Germplasm of Upland Cotton (<i>Gossypium hirsutum</i> L.) in Pakistan

“…Within-boll yield components were determined by direct measurement or through calculations. Tatineni et al [7] and Kumar et al [8] studied genetic variation among cotton genotypes resulting from interspecific hybridization at the DNA level with the random amplified polymorphic DNA (RAPD) method. Pathak and Singh [9] used six populations of different cotton cultivars (P 1 , P 2 , F 1 , F 2 , BC 1 & BC 2 ).…”

Identification of common bean (Phaseolus vulgaris) duplicates using agromorphological and molecular data

“…Another multivariate technique is principal component analyses which uses aims at visualizing the proximity of accessions and any links between the analyzed descriptors. However, Tatieni et al (1996) argue that the phenotypic traits traditionally used for the characterization and estimation of genetic divergence may be of limited importance because they are generally influenced by the environment and the developmental stage of the plant. Isoenzyme and DNA markers which are little influenced by the environment are therefore more adequate for germplasm characterizations.…”

Molecular Markers in Cotton Improvement

“…RAPD techniques have been used for many purposes in cotton including assessment of, diversity, genome mapping, phylogentic studies (Rahman et al, 2002;Zhang et al, 2002;He et al, 2008;Rahman et al, 2008;Rana and Bhat, 2004), genetic variations or diversity studies (Tatineni et al, 1996Chalmers et al, 1992, Xu et al, 2001and Chaudhary et al, 2010, DNA fingerprinting (Multani et al, 1995) and determining the relationship between the genotypes of different and same species (Wajahatullah et al, 1997), also used to evaluate the genetic relationship among cotton genotypes (Shu et al, 2001), to identify the QTLs for stomatal conductance (Ulloaand Meredith, 2000), to construct linkage mapping and QTL analysis in cotton (Zhang et al, 2003and Lin et al, 2009. RAPDs were used to distinguish the cotton varieties resistant to jassids, aphids, and mites (Geng et al, 1995).…”