Estimation of the introgression level in Populus nigra L. populations by means of isozyme gene markers
1999
Benetka, V. | Mottl, J. | Vackova, K. | Pospiskova, M. | Dubsky, M.
Three enzyme systems (6-PGD, LAP, GPI) were tested in the progeny of a controlled crossing of Populus x canadensis x Populus nigra with the object of distinguishing hybrids in a population of P. nigra. Segregation ratios of 1:1 for 6- PGD and LAP were determined among phenotypes corresponding to P, nigra (homozygote) and P. x canadensis (heterozygote). The segregation ratio for GPI was 3:1 in favour of the homozygote. No linkage was found between the polymorphic loci of 6-PGD and LAP. Experimental results proved that it is possible to identify hybrids of the P. x canadensis x P. nigra type from spontaneous populations of P. nigra. These results enabled analyses of three populations of P. nigra. In the generative progeny of the female trees of P. nigra no hybrids were ascertained. Hybrids morphologically different from P. nigra were identified in a population of two-years-old seedlings. In a population of trees 10 to 18 years of age 9.7% were hybrids with P. x canadensis yet riot different from P. nigra morphologically. The extent of introgression in the progeny of female P. nigra is discussed.
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