engleski

GEI for some poplar clones in the early stage of growth in eastern Croatia

Research into phenotypic stability, adaptability and productivity of poplar clones at plantation age 2 + 3 was conducted in the lower course of the River Drava and the tributary of the River Danube in the east of Croatia. In this area, the construction of river infrastructure has led to severe changes in the water regime. It is for this reason that the selected poplar clones should be adapted to the specific new condition of low groundwater levels. The parameters of dbh and survival were measured in eight poplar clones planted in three experimental plots. Measurements included the clones P. ×canadensis (’Pannonia’, ’Bl Constanzo’, ’I-214’, ’M 1’), and the P. deltoides clones (’710’, ’S 6-36’, ’S 6-20’, ’S 1-8’). According to the obtained results, the locality 25b in the Forest Office of Valpovo had the poorest site quality, followed by the locality 7k, while the locality 5g in the Forest Office of Osijek was found to be the best. The interaction of a genotype and the environment (GEI) in which a particular genotype (clone) may exist results in different phenotypes. This in fact represents the extent of reaction of a particular genotype to the intensity of external factors. The extent of reaction of a particular clone is genetically determined and so is phenotypic stability of this genotype. A phenotypically stable genotype is a clone in which the phenotypic value of a particular trait is very similar in different environments. Its usable value does not depend only on its maximal productivity, but also on its ability to retain certain traits (e.g. increment) at a relatively high level and in different environments. The results of this research confirm that even at such a young age the quality of a particular habitat has conditioned modifications in average clone values of dbh and survival. They also indicate the amount of production to be expected from the mixture of these clones or from the cultivation of a particular clone. As a rule, the most suitable clones that cause optimal modifications, from a silvicultural aspect, are those with high phenotypic instability, whose cultivation is justifiable in optimal habitats, but also in less suitable habitats provided that agrotechnical measures and adequate plant protection are applied. The obtained results and the value of the regression coefficients and regression analysis in particular show that at this plantation age the tested clones may be divided into two groups in terms of phenotypic stability, adaptability and productivity: a) Phenotypically very unstable clones of high productivity with specific adaptability to optimal sites/environment (’S 1-8’, ’710’ and ’Bl Constanzo’) ; b) Phenotypically very stable clones with medium or low productivity with the tendency to adapt to all sites/environment (’Pannonia’, ’I-214’, ’M 1’, ’S 6-36’, ’S 6-20’).

GEI; Poplar Clones

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