Morphological Diversity of Populations of the Genus <i>Prosopis</i> in the Semiarid Chaco of Northern Cordoba and Southern Santiago Del Estero

Abstract

The objective of this study consisted in the characterization of morphological variability presented in the Prosopis population in the corridor that unites the semiarid with the arid region in Argentina. In this region, four species of Prosopis get in contact (P. chilensis, P. flexuosa, P. alba and P. nigra). Due to the fact that these species make fertile hybrids, this corridor has an enormous diversity. The mother's allowed the differentiation of five morphologic groups, which from the point of view of classic taxonomy have been classified in 16 taxa. Only groups 3 and 4 presented intermediate characteristics. The morphologic study of the descendants showed that the regrouping of the intermediate groups had a high error rate. This fact reaffirms the condition of intermediate groups. The canonical correlation analysis between the morphologic variables of the mothers and the seedlings revealed that each morphologic group had its own association of canonical variables between mothers and their seedlings, and that the variability observed in the set of the mothers and their seedlings follows a certain order. The enormous existing morphologic diversity in the Prosopis populations of the semi-arid Chaco of the north of Córdoba and southeast of Santiago del Estero was ordered in five morphologic groups. The descendant's morphologic studies confirmed the existence of the defined morphologic-genetic groups.

Morphological and molecular characterization of a hybrid zone between Prosopis alba and P. nigra in the Chaco region of northwestern Argentina

“…In this line, the Procrustean association metric between leaf and fruit characters retrieved the lowest value for site 3. In other hybridization studies carried out in P. chilensis and P. flexuosa (Verga 1995, Joseau et al, 2013, Teich et al, 2015, hybrids presented intermediate characteristics to both pure species; however, those studies did not report decoupling between fruit and leaf variables detected here. Although the novel phenotype appeared in few individuals in relation to the total sampled, the morphological decoupling between fruit and leaf variables, and the emergence of a novel phenotype give support to the importance of hybrid areas as active sites of evolutionary changes, in which hybridization may cause the emergence of new ecotypes or species (Goulet et al, 2017).…”

“…The inclusion of additional markers in future studies will allow us to conclude on the genetic status of these individuals. Anyway, according to the reviewed literature (Verga 1995, Joseau et al, 2013, Ferreyra et al, 2013, this is the first time that this type of decoupling has been detected in fruit and leaf characters in Prosopis. In this line, the Procrustean association metric between leaf and fruit characters retrieved the lowest value for site 3.…”

“…Fruit colour (FrC) was classified as: uniform yellow (class 1); yellow with some violet spots (class 2); numerous violet spots on a yellow background (class 3); totally black (class 4). The classes of the last three variables (FSh, FESh and FrC) represent a continuum in shape (from straight to curly) and in colour (from yellow to black) and are therefore considered ordinal (Joseau et al, 2013). Additionally, each tree was classified based on fruit characters following Burkart (1976) and Palacios & Brizuela (2005) as a typical P. alba (light coloured, straight shape and edges) or P. nigra (darker fruit, more twisted and with strangulations).…”

“…Its uses as timber resource are restricted because it is heavily attacked by wood boring insects, affecting wood quality. Previous studies on Prosopis hybridization were conducted using morphological characters (Palacios & Bravo 1981, Joseau et al, 2013, isozymes and random amplified polymorphic DNA (RAPDs) (Saidman 1990, Verga 1995, Bessega et al, 2000a, Vega & Hernandez 2005, Ferreyra et al, 2013, and recently with microsatellite markers (Mottura et al, 2005, Teich et al, 2015. Vega & Hernandez (2005) studied a putative hybrid area between P. alba and P. nigra using morphological traits and RAPDs.…”

Características evolutivas en Prosopis spp.: citogenética, genética e hibridaciones

“…Mientras que los límites genéricos y la división en secciones son generalmente aceptados; hay debates en cuanto a la variedad en términos de especies como Burkart definió (Joseau et al 2013). Pasiecznik et al (2001) (Hunziker et al 1986;Saidman et al 1996).…”