TY - JOUR
T1 - Comparing genetic diversity in agroforestry systems with natural forest
T2 - A case study of the important timber tree Vitex fischeri in central Kenya
AU - Lengkeek, Ard G.
AU - Mwangi, Alice Muchugi
AU - Agufa, Caroline A.C.
AU - Ahenda, Joseph O.
AU - Dawson, Ian K.
PY - 2006/7/1
Y1 - 2006/7/1
N2 - It is possible that current tree domestication practices undertaken by farmers reduce the genetic base of tree resources on farms, raising concerns regarding the productivity, sustainability and conservation value of agroforestry ecosystems. Here, we assessed possible changes in genetic variation during domestication in the important and heavily utilised timber species, Vitex fischeri Gürke (syn. Vitex keniensis), by comparing geographically proximate forest and farm material in central Kenya. Employing RAPD analysis, a total of 104 polymorphic markers revealed by five arbitrary primers were scored in a total of 65 individuals, 32 from forest and 33 from farmland. Despite concerns of possible genetic erosion, forest and farm stands did not differ significantly in levels of genetic variation, with H values of 0.278 and 0.269, respectively. However, Mantel tests did reveal greater geographically related associative genetic structure among individuals in farm rather than forest material, with r M values of 0.217 and 0.114, respectively. A more detailed analysis of structure suggested this could be due to local variation in origin of some on-farm trees. Implications of data for the genetic management of V. fischeri stands during farmer-led tree domestication activities are discussed. At present, there appears little reason to reject on-farm V. fischeri as a source of germplasm for future on-farm planting or for conservation purposes, although this situation may change and will require monitoring.
AB - It is possible that current tree domestication practices undertaken by farmers reduce the genetic base of tree resources on farms, raising concerns regarding the productivity, sustainability and conservation value of agroforestry ecosystems. Here, we assessed possible changes in genetic variation during domestication in the important and heavily utilised timber species, Vitex fischeri Gürke (syn. Vitex keniensis), by comparing geographically proximate forest and farm material in central Kenya. Employing RAPD analysis, a total of 104 polymorphic markers revealed by five arbitrary primers were scored in a total of 65 individuals, 32 from forest and 33 from farmland. Despite concerns of possible genetic erosion, forest and farm stands did not differ significantly in levels of genetic variation, with H values of 0.278 and 0.269, respectively. However, Mantel tests did reveal greater geographically related associative genetic structure among individuals in farm rather than forest material, with r M values of 0.217 and 0.114, respectively. A more detailed analysis of structure suggested this could be due to local variation in origin of some on-farm trees. Implications of data for the genetic management of V. fischeri stands during farmer-led tree domestication activities are discussed. At present, there appears little reason to reject on-farm V. fischeri as a source of germplasm for future on-farm planting or for conservation purposes, although this situation may change and will require monitoring.
KW - Conservation
KW - Genetic erosion
KW - RAPD
KW - Tree domestication
KW - Vitex keniensis
UR - http://www.scopus.com/inward/record.url?scp=33748109894&partnerID=8YFLogxK
U2 - 10.1007/s10457-005-5830-6
DO - 10.1007/s10457-005-5830-6
M3 - Article
AN - SCOPUS:33748109894
SN - 0167-4366
VL - 67
SP - 293
EP - 300
JO - Agroforestry Systems
JF - Agroforestry Systems
IS - 3
ER -