Abstract
The main objective of this study was to verify the association between the coefficient of parentage estimates and multivariate techniques which were used as measures of genetic diversity in cultivars. Thirty cotton cultivars were used for this purpose among which genetic diversity was estimated by means of the parentage coefficient (CP) and also through multivariate techniques employing microsatellite markers (SSR). The correlation between genetic distances obtained by CPs and SSRs for cultivars was positive and significant, with a value of 0.25. The 18 ancestors evaluated in the current study contributed with 69% to the genetic constitution of the 30 cotton cultivars. The evidence that few ancestors actually contribute to the genetic constitution of the cotton cultivars used in Brazil indicates that new alleles should be introduced into the gene pool of these cultivars in order to broaden the genetic base of cotton.
Highlights
IntroductionPlant breeders have been assessing the levels of genetic diversity either through pedigree analysis or multivariate analysis which is undertaken based on some plant attributes (morphological features, agronomic performance, isozymes and polymorphisms at DNA level) (Van Esbroeck et al 1999).Similarity or genetic diversity have been estimated by means of pedigree analysis for a great number of crops, such as wheat (Kim and Ward 1997), barley (Graner et al 1994), maize (Messmer et al 1993), rice (Xu et al 1999) and cotton (Bowman et al 1996, Van Esbroeck et al 1998, Van Esbroeck et al 1999)
Plant breeders have been assessing the levels of genetic diversity either through pedigree analysis or multivariate analysis which is undertaken based on some plant attributes (Van Esbroeck et al 1999)
The objectives of this study were: (1) to verify the association between the estimates of coefficient of parentage and the multivariate technique calculated based on microsatellite markers employed as measures of genetic diversity in cotton cultivars and, (2) to evaluate the genetic contribution of ancestors to some cotton cultivars used in Brazil
Summary
Plant breeders have been assessing the levels of genetic diversity either through pedigree analysis or multivariate analysis which is undertaken based on some plant attributes (morphological features, agronomic performance, isozymes and polymorphisms at DNA level) (Van Esbroeck et al 1999).Similarity or genetic diversity have been estimated by means of pedigree analysis for a great number of crops, such as wheat (Kim and Ward 1997), barley (Graner et al 1994), maize (Messmer et al 1993), rice (Xu et al 1999) and cotton (Bowman et al 1996, Van Esbroeck et al 1998, Van Esbroeck et al 1999). Plant breeders have been assessing the levels of genetic diversity either through pedigree analysis or multivariate analysis which is undertaken based on some plant attributes (morphological features, agronomic performance, isozymes and polymorphisms at DNA level) (Van Esbroeck et al 1999). The method features the following disadvantages: 1) lack of detailed information in connection with pedigree genotype, and 2) the fact that the parentage coefficient, which is used to estimate genetic similarity, is calculated based on unrealistic preassumptions, such as (i) all lines, including parental and ancestral lines, are homozygous and homogeneous; (ii) lines without known common parentage are unrelated to each other and (iii) a line derived from a cross obtained half of its genes from each parent. Relationships between methods that use molecular markers and parentage coefficient to estimate genetic diversity varied depending on the species under study and the sampled plant material (Kim and Ward 1997)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
