tailieunhanh - Báo cáo khoa học: "Genetic and phenological differentiation between introduced and natural populations of Quercus rubra"

Tuyển tập các báo cáo nghiên cứu về lâm nghiệp được đăng trên tạp chí lâm nghiệp quốc tế đề tài: Genetic and phenological differentiation between introduced and natural populations of Quercus rubra. | Ann Sci For 1993 50 Suppl 1 271S-280S Elsevier INRA 271s Original article Genetic and phenological differentiation between introduced and natural populations of Quercus rubra L JB Daubree A Kremer INRA laboratoire de génétique et d amelioration des arbres forestiers BP 45 33611 Gazinet France Summary Gene diversity within populations of o rubra was compared between 23 introduced stands and 9 geographic regions within the natural range for 4 enzymes encoded by 4 polymorphic loci. Gene diversity within populations was in general higher in introduced stands than in geographic regions due to differences in allelic frequency profiles. For 2 loci there were directional increases of frequencies of rare alleles in introduced stands as compared to geographic regions whereas the mean number of alleles was lower in the former populations. Similarly intraspecific variation among 15 introduced stands was compared to geographic variation among 18 origins in the natural range for bud flush and leaf coloration in experimental plantations established in France. There was a cli-nal latitudinal variation for both phenological traits in the natural range. The introduced populations occupied an intermediate position in the rankings for both phenological traits. A hypothesis of genetic differentiation between introduced and natural populations is proposed in light of the results obtained. allozymes I bud flush leaf coloration genetic differentiation Quercus rubra L Resume Differenciation génétique entre les populations introduites et cedes de I aire natu-relle du chêne rouge d Amerique Quercus rubra L . La diversité génétique intrapopulation Chez Q rubra L a été étudiée dans 23 peuplements introduits et 9 regions géographiques de I aire natu-relle avec I aide de 4 isozymes contrôlés par 4 locus polymorphes. Cette diversite est plus élevée dans les peuplements Introduits à cause des differences de profils des frequences alléliques alors que le nombre moyen d alleles par population est .