The effectiveness of phenotypic selection in natural populations: a case study from the Peruvian Amazon

Abstract

Phenotypic selection is commonly used in agroforestry, both in genetic improvement and as a component of “good practice” in seed collection. In the first case, the aim is to secure genetic gain. In the second case, selection is used to ensure that seed supplies meet given minimum quality standards, or that poor quality sources are avoided. Here we examine the effectiveness of phenotypic selection in natural forest stands of the Amazonian timber and multipurpose treeCalycophyllum spruceanumBenth.. We ask (a) whether mothertrees with high estimated annual height and diameter increments had faster growing progeny than mothertrees with low values; (b) whether forked mother-trees tended to have higher proportions of forked progeny than unforked trees; (c) whether spatially isolated mother-trees tend to produce slower growing progeny than mother-trees growing together with conspecifics. In each case, we found no evidence of differences between the respective groups. We offer explanations for these findings and discuss their implications for tree improvement and seed collection.

Puesta en valor del fruto “Ushun” mediante la caracterización botánica, fisicoquímica y fitoquímica, Cullaspampa, distrito de Caraz - Ancash

“…Una de ellas es la domesticación. Esta es una actividad que se ha realizado de forma tradicional en los huertos familiares, principalmente en especies forestales con fines de obtención de frutos (Cornelius y Ugarte, 2010). En el caso del "Ushun" existe evidencia arqueológica que demuestra que este árbol frutal nativo fue utilizado en culturas peruanas donde predominó las actividades de manejo y producción en chacras familiares como Mochica y Guitarreros (Fernandez y Rodriguez, 2007).…”

Efficiency of early selection in Calycophyllum spruceanum and Guazuma crinita, two fast-growing timber species of the Peruvian Amazon

“…We ignore genetic gain from mother-tree selection, as it is likely to be minimal in the 165 case of selection for growth in wild stands (Cornelius 1996;Cornelius et al 2011). Standard errors were calculated for the heritabilities with Dickerson's approach (Dieters 176 et al 1995), using the asymptotic variance-covariacne matrix generated by SPSS.…”

Domestication of native tree species for timber plantations: key insights for tropical island nations

“…Harvesting seed from desirable phenotypes can help to avoid truly poor seed sources (Cornelius et al 2011), but such phenotypic selection is not always reliable. For instance, Weber et al (2009) tested low-intensity phenotypic selection in Calycophyllum spruceanum in the Amazon, and found low heritability amongst progeny from selected versus randomly chosen trees.…”