Genetic variation in wood density and correlations with tree growth in Prosopis africana from Burkina Faso and Niger

Abstract

Abstract• Variation in wood basic density and its correlation with tree growth were investigated at 13 years in a provenance/progeny test of Prosopis africana in Niger. The test included progeny from 256 trees sampled from 24 provenances in the Sahelian ecozone of Burkina Faso and Niger.• Variation in wood density was significant due to provenances and families within provenances. Individual tree heritability was higher for wood density than for growth traits. Provenance means for wood density increased from the more humid to the drier parts of the sample region. Phenotypic correlations indicated that larger trees tended to have denser wood.• Clines suggest that natural populations of P. africana from the drier parts of the sample region have the genetic capacity to produce denser wood, compared with populations from the more humid parts of the region. Correlations and heritability estimates suggest that selection of faster-growing trees may produce a small gain in wood volume but little (if any) gain in density in the subsequent generation. Multi-location provenance/tests are needed to confirm this tentative conclusion. Mots-clés :Sahel / adaptation / conservation / amélioration des arbres Résumé -Variation génétique de la densité du bois et corrélations avec la croissance de l'arbre chez Prosopis africana provenant du Burkina Faso et du Niger.• La variation de la densité du bois et sa corrélation avec la croissance de l'arbre ont été étudiées à l'âge de 13 ans dans un essai de provenances/descendances de Prosopis africana au Niger. L'essai a inclus les descendances de 256 arbres mères provenant de 24 provenances de l'écozone sahélienne du Burkina Faso et du Niger.• La variation de la densité du bois a été significative en relation avec les provenances et les familles à l'intérieur des provenances. L'héritabilité a été plus élevée pour la densité que pour les caractères de croissance de l'arbre. La densité moyenne des provenances a augmenté des sites les plus humides aux sites les plus secs de la région échantillonnée. Les corrélations phénotypiques ont montré que les plus grands arbres ont eu tendance à avoir le bois le plus dense.• Les clines suggèrent que les populations naturelles de P. africana des sites les plus secs de la région échantillonnée ont la capacité génétique de produire du bois plus dense que les populations des sites les plus humides de la région. Les corrélations et les héritabilités estimées suggèrent que la sélection d'arbres à croissance rapide peut produire un faible gain en volume de bois et très peu de gain en densité du bois dans la génération suivante. Des essais de provenance/descendance dans plusieurs sites sont nécessaires pour confirmer cette conclusion provisoire.

Potential of Genome-Wide Association Studies and Genomic Selection to Improve Productivity and Quality of Commercial Timber Species in Tropical Rainforest, a Case Study of Shorea platyclados

“…The differences in heritability values obtained for the same trait among these studies might be due to differences in the estimation methods, numbers of families and environmental interactions. Like the two cited studies, we also found that heritability of wood density was as higher as found in diameter and height growth, in accordance with general tendencies for wood properties of tropical hardwoods to have higher heritability than their growth traits [90]. Moreover, gene-environment (G × E) interaction effects are generally strong for traits with low heritability and weak for traits with high heritability.…”

Evidence for important genetic differentiation between provenances of Parkia biglobosa from the Sudano-Sahelian zone of West Africa

“…Similar clinal responses have been observed in other sahelian tree species e.g. Prosopis africana (Weber et al 2008;Sotelo Montes and Weber 2009), Acacia senegal (Larwanou et al 2010), Faidherbia albida (Billand and De Framond 1993) and Balanites aegyptiaca (L.) Delile (Weber and Sotelo Montes 2010). Raebild et al (2003a, b, c, d) also found significant provenance variation in Acacia spp., which suggests that differentiation between populations (provenance variation) is likely to be a general feature of Sahelian tree species.…”

“…Still, transfer of P. biglobosa seeds for planting and conservation purposes should probably be made from the drier zones to the humid ones (north to south) since northern provenances had better survival. This general recommendation was also made by other researchers (Weber et al 2008;Sotelo Montes and Weber 2009;Weber and Sotelo Montes 2010).…”

Morphological variation in Balanites aegyptiaca fruits and seeds within and among parkland agroforests in eastern Niger

“…For example, natural selection related to rainfall gradients in the West African Sahel may produce clinal variation in adaptively important traits among populations (Weber et al 2008;Sotelo Montes and Weber 2009;Weber and Sotelo Montes 2010;Sotelo Montes et al 2010), and seed size and shape may be adaptively important (Maranz and Wiesman 2003). In addition, selection by humans can produce significant differences in fruit size within and among regions (e.g., Maranz and Wiesman 2003;Leakey et al 2004Leakey et al , 2005bAssogbadjo et al 2005).…”