Adaptive genetic variation in water-use efficiency and gum yield in Acacia senegal provenances grown on clay soil in the Blue Nile region, Sudan

• Published in: Forest ecology and management Vol. 226; no. 1; pp. 219 - 229
• Main Authors: Raddad, El Amin Y., Luukkanen, Olavi
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.05.2006; Elsevier
• Subjects: Acacia senegal; Animal and plant ecology; Animal, plant and microbial ecology; Biological and medical sciences; clay soils; Drought tolerance; Fundamental and applied biological sciences. Psychology; genetic variation; gum arabic; Gum arabic belt; gum production; Gum yield; mass spectrometry; measurement; provenance; sandy soils; soil water content; stable isotopes; Synecology; Terrestrial ecosystems; tree and stand measurements; tree growth; Water-use efficiency; yields; δ13C; Sudan; Senegal; Africa; Africa, Blue Nile R; δ 13C; Gum arabic belt; Gum yield; Drought tolerance; Water-use efficiency; δ13C; Wood; Growth; Water use; Plant leaf; Water use efficiency; Experimental study; Soils; Leguminosae; Dicotyledones; Acacia senegal; Angiospermae; Tree crown; Environment; Above ground plant part; Spermatophyta; Drought; Isotopes; Shoot; Adaptation
• ISSN: 0378-1127; 1872-7042
• DOI: 10.1016/j.foreco.2006.01.036

The genetic variation in shoot growth, water-use efficiency (as assessed by δ 13C) and gum production was compared among eight Acacia senegal provenances originating from contrasting conditions of the gum arabic belt in central Sudan. The experimental site was in the clay plain region. Carbon isotope ratios were obtained from leaves and branch wood samples of the dissimilar A. senegal provenances. The clay provenances were distinctly superior to the sand provenances in all traits studied but especially in basal diameter and crown width, reflecting their adaptation to the environment. Values of δ 13C were less negative in the sand group compared to the clay both in leaves and in branch wood. This suggests that sand provenances displayed conservative water use and high drought tolerance. Of the clay provenances, the local one displayed a high negative δ 13C value, which indicates less conservative water use that results in high productivity at this particular clay-soil site. Water use appears to correspond to the environmental conditions prevailing at collection sites for these provenances. Results suggest that A. senegal provenances in the clay part of the gum belt are adapted for fast growth rate and high biomass and gum productivity as compared with the provenances from the sand regions: a negative correlation was found between tree gum yield and δ 13C. The variation in water use and gum production was greater among provenance groups than within them, suggesting that selection among rather than within provenances would result in distinct genetic gain in gum yield.