Evidences of local adaptation in quantitative traits in Prosopis alba (Leguminosae)

BESSEGA, C.F.; POMETTI C.L.; EWENS, M.; SAIDMAN, B.O.; VILARDI, J.C.

GENETICA

SPRINGER

Lugar: Berlin; Año: 2015 vol. 143 p. 31 - 44

0016-6707

Signals of selection on quantitative traits can bedetected by the comparison between the genetic differen-tiation of molecular (neutral) markers and quantitativetraits, by multivariate extensions of the same model and bythe observation of the additive covariance among relatives.We studied, by three different tests, signals of occurrenceof selection in Prosopis alba populations over 15 quanti-tative traits: three economically important life historytraits: height, basal diameter and biomass, 11 leaf mor-phology traits that may be related with heat-tolerance andphysiological responses and spine length that is veryimportant from silvicultural purposes. We analyzed 172G1-generation trees growing in a common gardenbelonging to 32 open pollinated families from eight sam-pling sites in Argentina. The multivariate phenotypes differsignificantly among origins, and the highest differentiationcorresponded to foliar traits. Molecular genetic markers(SSR) exhibited significant differentiation and allowed usto provide convincing evidence that natural selection isresponsible for the patterns of morphological differentia-tion. The heterogeneous selection over phenotypic traitsobserved suggested different optima in each population andhas important implications for gene resource management.The results suggest that the adaptive significance of traits should be considered together with population provenancein breeding program as a crucial point prior to any selectingprogram, especially in Prosopis where the first steps areunder development.