In a surve)' of the incidence ol Crondrtinjn ribicoLi in Romania, this parasite was lound to be present all over the country, except in mountain regions.The heaviest attacks occurred in Ribcs nigrum and n\ young plantations of Ptnus strobus, whereas old plantations of P. sirobirs and other pine species were iree from bhster rust, as were natural populations oiPi}i!is tcmbra, Ribcs alpmiim. and R. pclraeiDn in the Carpathians.

No abstract

Summary After the nursery testing, twelve Swiss stone pine (Pinus cembra L.) provenances from the Alps and Carpathian Mountains were planted out at two sites located at high elevation in the Southern and Northern Carpathians. Total height growth (H), annual height growth (h), root collar diameter (RCD), branches per whorl (BW) and survival (SV) were measured and analyzed. Analysis of variance showed highly significant (p < 0.01; p < 0.001) differences between provenances for all traits, except survival, suggesting that selection at the provenance level could be possible. Also, over locations analysis revealed significant genotype x environment interaction, demonstrating that some provenances react differently to environmental conditions and, selection should take this into account. The phenotypic coefficient of variation was moderate for growth and high for number of branches per whorl suggesting that selection within provenance can also be applied. Finding of significant and highly significant age-age and trait-trait phenotypic correlations indicated that early and indirect selection in Swiss stone pine species is possible. According to DUNCAN’s multiple range test the best performing provenances of the two mountain ranges were selected for operational planting and breeding programmes. The results of this study validate that a very slow growing species, such as Swiss stone pine may still possess very high genetic variation in growth rate; consequently, this trait can be improved. Finally, an attempt has been made to develop a seed transfer guidelines for the species by using the pattern of geographic variation as a basis.

SummaryThis experiment consists in a controlled crossing according to a factorial design performed between 7 female trees of P. strobus and 4 male trees of P. wallichiana to combine the rapid growth of former species with high resistance to Cronartium ribicola of the latter one. The hybrid families were artificially inoculated at age 2, and field planted at age 6. Blister rust resistance (BRR), tree survival (TS), total height growth, (H) annual height growth (h), diameter (D), basal area (BA), stem volume (V), stems straightness (SS) and branch thickness (BT) were the traits measured at age 17. Statistical analysis produced the results presented below. Significant (p<0.05) and highly significant (p<0.01; p<0.001) differences were found among hybrid families. Differences among female effects were highly significant (p<0.001) for all tested traits including BRR, suggesting that nuclear additive genes controlled these traits. Significant differences were found among male parents for H but no significant differences for BRR; therefore, all four male parents transmitted a similar level of resistance. The ratio σ2GCA/σ2SCAvariance accounted for 8.1 for BRR, 8.5 for H, 3.5 for V, 9.3 for SS and 1.9 for BT. Similarly, the ratios of σ2GCA-F/σ2GCA-Mvariance due to female parents were 70.5 for BRR, 23.6 for H, 1.0 for V, 0.4 for SS and 1.0 for BT, were found. Narrow-sense heritabilities, at individual level, were low to moderately high, ranging between 0.085 for BT and 0.421 for BRR. By comparison with the mean of P. strobus parent species, the BRR heterosis was highly positive, but negative for all growth traits. If the hybrids will be used in operational planting programs, a significant genetic gain for BRR and growth traits could be achieved.

A full diallel mating design (10 parents) was carried out in a Swiss stone pine panmictic population from the Carpathian Mountains. At age six, after nursery testing, the progenies were field planted to one site, using a completely randomized block design with 100 families, four replicates and a 15 tree row-plot per replication, spaced 2.5 x 2.5 m. Total and annual height of all individuals of this test was assessed at successive ages, between ages eight and 16. In addition, weight of 100 seeds and cotyledon number were considered in correlation analyses. Significant differences occurred in total height for general and specific combining ability effects. Variance components, heritabilities, genetic correlations and genetic gains on growth traits and survival at age 16 were estimated. Across the field testing period, GCA 3) variance increased with time, accounting for 65 % of plot mean phenotypic variance by age 16. In contrast, SCA variance declined as the progeny test aged accounting for only 9 % by age 16. The time trend of the four heritability estimates for total height increased with age across the testing period reaching their highest level between age 14 and 16. Genetic correlations over time for total height rose from 0.85 at age two to 0.94 at age six and then leveled off across the field test indicating that if the goal is to improve 16-year height, early selection can be considered at age six. By selecting the best 10 %, 15 % and 20 % of individuals within the best fullsib families, a genetic gain in total height of 12.4 %, 11.0 % and 9.9 % respectively, could be achieved at age 16. A higher gain can be obtained if the best general combiner parents are selected and intermated.