Comparison of multivariate methods for the analysis of genetic resources and adaptation in Phytolacca dodecandra using RAPD |
| |
Authors: | K Semagn A Bjornstad B Stedje E Bekele |
| |
Institution: | Addis Ababa University, Institute of Pathobiology, P.O. Box 1176, Addis Ababa Ethiopia; aau-ipb@telecom.net.et Fax: +2511-755296, ET Agricultural University of Norway, Department of Horticulture and Crop Sciences, P.O. Box 5022, N-1432, ?s, Norway, NO University of Oslo, Botanical Garden and Museum, Trondheimsveien 23B, N-0562,Oslo, Norway, NO Addis Ababa University, Department of Biology, P.O. Box 1176, Addis Ababa, Ethiopia, ET
|
| |
Abstract: | The extent of genetic differentiation among 17 Ethiopian populations (249 individuals) of Phytolacca dodecandra (Endod) sampled along altitudinal gradients that varied from 1600 to 3000 m was investigated using random amplified polymorphic
DNA (RAPD). The populations were classified into three altitude groups: lowland (1600–2100 m), central-highland (2101–2500
m) and highland (2500–3000 m). Seventy polymorphic loci scored from 12 RAPD primers, singly or in combination with ecogeographical
variables (altitude, longitude, latitude, temperature and rainfall), were used for principal component, discriminant, correlation,
and stepwise multiple regression analyses. Principal component analysis (PCA) clearly differentiated lowland and the central-highland
populations from those of the highlands independent of their geographical regions. Canonical discriminant analysis separated
the lowland plants from those of the highlands with the central-highland plants being intermediate. Classificatory discriminant
analysis corrected classification of 92.8% of the 249 plants into their respective three altitude groups. Multiple regression
analysis identified a strong association between some RAPDs and altitude, temperature and rainfall, while the variation in
most RAPDs was explained by combinations of the different ecogeographical variables. It is hypothesised that the different
altitude groups may be (1) chemical and/or physiological ecotypes produced as a result of complex interactions of altitude
with climatic and/or edaphic factors, or (2) different in ploidy levels. The significant correlations obtained between population
means from some RAPDs and altitude and temperature as well as the strong association of some RAPDs with the ecogeographical
variables in the multiple regression analysis suggest that part of the RAPD polymorphism could be adaptive, and responsive
to environmental selection.
Received: 15 December 1999 / Accepted: 12 February 2000 |
| |
Keywords: | Altitude differentiation Environmental selection Phytolacca dodecandra RAPD |
本文献已被 SpringerLink 等数据库收录! |
|