IS DWARFING IN PEAR ROOTSTOCKS DUE TO ANEUPLOID GENETIC STRUCTURES?
The INRA pear rootstock breeding programme is dealing with interspecific hybridization between the INRA pear rootstock Pyriam as female and Pyrus species as male parents in order to introduce new agronomic traits. INRA Pyrus species germplasm contains a large range of phenotypes and the pear rootstock breeding programmes have led to a wide range of dwarfing to vigorous selections. Cytogenetic characterization, done by flow cytometry, has shown that the analyzed Pyrus species are diploids as well as the released rootstocks. It has also shown that the group of perry pears, belonging to the P. nivalis species, contains diploid and triploid genotypes. As P. nivalis dwarfing rootstocks selections are aneuploids, further investigations by evaluation of the total DNA content and chromosome number counting have been done. The results demonstrate that dwarfing in Pyrus is linked with an aneuploid structure found in hybrids between a P. nivalis triploid genotype and a Pyrus species diploid one.
Simard, M.H., Guisnel, R., Daguin, F., Demilly, D., Billy, B. and Honoré, D. (2011). IS DWARFING IN PEAR ROOTSTOCKS DUE TO ANEUPLOID GENETIC STRUCTURES?. Acta Hortic. 909, 59-66
pear rootstocks, Pyrus, aneuploidy, cytogenetic structure, dwarfing