Association between genetic distances in wheat (Triticum aestivum L.) as estimated by AFLP and morphological markers

Abstract

Molecular and morphological data analyses matrices are very informative tools for the estimation of genetic distances. We used AFLP markers, morphological traits and combined analysis to estimate the genetic distances between wheat genotypes and ascertain any associations between the two techneques. Nineteen wheat (Triticum aestivum L.) genotypes were analyzed using amplified fragment length polymorphism (AFLP) markers and field evaluated for two years. The matrices obtained by morphological and molecular marker data analyses revealed a significant but moderate correlation (r = 0.47), indicating that such techniques sample distinct genome regions. The combined analysis was found to be highly correlated with AFLP (r = 0.97) and moderately correlated with morphological (r = 0.59) markers. A possible explanation for such results is a bias caused by the much higher number of AFLP (229) than morphological (17) markers. Thus, it is evident that the combined analysis is not efficient when a very dissimilar number of markers are used in each isolated technique. Therefore, to obtain a better knowledge of the degree of divergence among genotypes it is necessary to consider each analysis separately.

Morphological, pedigree, and molecular distances and their association with hybrid wheat performance

“…The dendrograms presented in Figure 1 show a good fi t between the graphical representation of distances and their original matrices, where medium to high cophenetic correlation coeffi cients were obtained (0.70, 0.76, 0.75, and 0.90 for morphological, molecular, combined morphological plus molecular, and pedigree data, respectively). In general, cophenetic correlation coeffi cients above 0.70 are considered effi cient for the graphical representation of contrasts between genotypes (Vieira et al, 2007).…”

“…Some studies on wheat have reported the association between hybrid performance and morphological (Cruz et al, 2004), molecular (Roy et al, 2004), combined morphological and molecular (Franco et al, 2001;Vieira et al, 2007), and pedigree-based distances (Almanza-Pinzón et al, 2003). Such tools are important auxiliary techniques for the selection of the best parental combinations and for a more rational use of germplasm.…”

“…Such tools are important auxiliary techniques for the selection of the best parental combinations and for a more rational use of germplasm. However, many studies indicate that the usefulness of such distance measures in selecting parental genotypes may be related to the genotype pool and the number of traits evaluated, as well as to the cultivation environment, and genotype x environment (GXE) interactions (Corbellini et al, 2002;Bertan et al, 2007;Vieira et al, 2007). Roy et al (2004) reported that the correlation between genetic distances estimated for wheat, using amplifi ed fragment length polymorphism (AFLP) markers and 14 morphological characters, was 0.072, indicating an association close to null.…”

“…Likewise, Autrique et al (1996) assessed the dissimilarity of 113 local genotypes of durum wheat using restriction fragment length polymorphism (RFLP), morphological characters, and inbreeding coeffi cients and did not fi nd any signifi cant correlation between these techniques. However, Vieira et al (2007) evaluated 19 wheat genotypes using AFLP and morphological markers and found a moderate correlation between morphological and molecular matrices, a high correlation between the matrices of the joint analysis (molecular and morphological markers) with the morphological matrix, and a moderate correlation between the matrices of the joint analysis with the morphological matrix.…”

Estimativa da divergência entre ecótipos de braquiária baseada em descritores quantitativos e qualitativos

“…O algoritmo que permite a análise simultânea de dados quantitativos e qualitativos foi proposto por GOWER (1971), embora poucos trabalhos têm utilizado esta estratégia para quantificação da dissimilaridade genética, sendo relatados estudos na literatura com Brassica napus L. (RODRÍGUEZ et al, 2005), Triticum aestivum L. (VIEIRA et al, 2007) e Solanum lycopersicum H. Karst. (ROCHA et al, 2010).…”