Comparison of phenotypic and molecular marker-based classifications of hard red winter wheat cultivars

Abstract

Genetic diversity is the basis for successful crop improvement and can be estimated by different methods. The objectives of this study were to estimate the genetic diversity of 30 ancestral to modern hard red winter wheat (Triticum aestivum L.) cultivars adapted to the Northern Great Plains using pedigree information, morphological traits (agronomic measurements from six environments), end-use quality traits (micro-quality assays on 50 g grain or milled flour samples for the six environments), and molecular markers (seed storage proteins separated using SDS-PAGE, 51 SSRs, and 23 SRAP DNA markers), and to determine the relationships of genetic distance estimates obtained from these methods. Relationships among diversity estimates were determined using simple (Pearson) and rank (Spearman) correlation coefficients between distance estimates and by clustering cultivars using geneticdistances for different traits. All methods found a wide range in genetic diversity. The genetic distance estimates based on pedigree had the highest values due to possible over-estimation arising from model assumptions. The genetic diversity estimates based on seed storage protein were lowest because they were the major determinants of end-use quality, which is a highly selected trait. In general, the diversity estimates from each of the methods were positively correlated at a low level with the exceptions of SRAP diversity estimates being independent of morphologic traits (simple correlation), SDS-PAGE, and SSR diversity estimates (rank correlation). However, SSR markers, thought to be among the most efficient markers for estimating genetic diversity, were most highly correlated with seed storage proteins. The procedures used to accurately estimate genetic diversity will depend largely upon the tools available to the researcher and their application to the breeding scheme.

Multivariate Analysis of Genetic Diversity among some Maize Genotypes under Maize-Albizia Cropping System in Indonesia

“…4 (Maize-Albizia cropping system). Morphological traits have been successfully used for estimation of genetic diversity and cultivar development since they provide a simple way of quantifying genetic variation (Fufa et al, 2005). In maize sole cropping system, clustering resulted in nine main clusters with a point Euclidian coefficient of 4.8, level of dissimilarity between genotypes is high in the dendogram with a genetic distance of 0-0.8.…”

Genetic diversity in the U.S. hard red winter wheat cultivars as revealed by microsatellite markers

“…Also, in the last 2-3 decades there has been increased collaboration between breeding programs, many use similar parents in their crossing program, and much sharing of germplasm (gene pool) has occurred between different breeding programs. There has not been a recent study to provide information on how genetic diversity has changed in modern HRWW cultivars except Fufa et al (2005), who reported a comparison between phenotypic and molecular marker-based approaches of estimating genetic diversity, using a set of 30 HRWW cultivars only from the Northern Great Plains of the USA. As a result, there is a need to quantify the genetic diversity existing among the different parts of the Great Plains HRWW cultivars released in the last several decades.…”

“…This information would help breeders to incorporate useful genetic variation into adopted gene pools by selecting for marker alleles linked to loci controlling important agronomic or quality traits (Tanksley and McCouch 1997). Several authors have studied genetic diversity in wheat by using different molecular markers, such as microsatellite (Devos et al 1995;Bohn et al 1999;Donini et al 2000;Manifesto et al 2001;Christiansen et al 2002;Huang et al 2002;Dreisigacker et al 2004;Fufa et al 2005), amplified DNA fragment polymorphism markers (Schut et al 1997;Barrett et al 1998;Manifesto et al 2001), and random amplified polymorphic DNA markers (Joshi and Nguyen 1993). Microsatellite markers, also known as simple sequence repeats (SSR), have proved to be the most suitable molecular markers for studying genetic diversity in wheat because of its multi-allelic nature, chromosome specificity, high polymorphism, and distribution throughout the genomes (Röder et al 1998a(Röder et al , 1998b.…”

Assessing the Genetic Variation of Bulgarian Bread Wheat Varieties by Biochemical and Molecular Markers

“…The high correlation obtained in the present study could be related to the fact that the biotypes of the cultivars were separated on the base of differences in storage protein PAGE patterns. Lower but signifi cant correlation between SSR and storage proteins PAGE diversity estimates r=0.42 (P<0.01) was reported for 30 US winter wheat cultivars studied by SDS-PAGE and 51 SSR markers (16). Therefore, another explanation could be that while many seed storage proteins are retained by selection, others, especially the gliadins, were neutral in selection similar to SSR markers.…”