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Effective population size as a parameter closely correlating with the genetic and genotypic diversity of the seed orchard output is an important indicator of seed orchard functioning. It is determined by the variation of male and female gametic contributions of parental genotypes (including those outside the seed orchard), influenced by the variation in male and female gamete production, reproductive phenology, pollen dispersal within seed orchard and other factors. We assessed male and female fecundity, as well as temporal course of male and female flowering in two seed orchards of Pinus nigra ARNOLD and Fraxinus excelsior L./F. angustifolia VAHL. in Slovakia. In both cases, male and female gametic contributions of plus-tree clones were modeled on the basis of fecundity and flowering phenology, and were used to calculate status number as an estimator of effective population size. In the seed orchard of Pinus nigra, marker-aided verification of clonal fidelity revealed unexpectedly high proportion of misplaced ramets (29.9%) and alien genotypes (44.4%). Monitoring of reproductive processes in 2002 and 2003 showed high variation in both male and female fecundity, and pollen shedding preceding female receptivity in Pinus nigra. All these factors contributed to a very low relative status effective number, representing 8.6% to 38.6% of the population census (depending from the management option in relation to misplaced and alien genotypes). In the mixed seed orchard of Fraxinus excelsior and F. angustifolia, the proportion of misplaced and alien genotypes was much lower (22.4% and 12.3%, respectively). However, a high fecundity variation and protogyny resulted in a low relative status number (18.8% to 29.5% of the census number of clones) also in this seed orchard. Practical implications of these findings are shortly discussed and practical management options are proposed.

Response of 16 oilseed rape genotypes to B (boron) toxicity was analyzed by comparing the results of two experiments conducted in a glasshouse. In Experiment 1 plants were grown in standard nutrient solutions with 10 µMB (control) and 1000 µM B. Relative root and shoot growth varied from 20-120% and 31-117%, respectively. Variation in B concentration in shoots was also wide (206.5-441.7 µg B g-1 DW) as well as total B uptake by plant (62.3-281.2 µg B g1). Four selected genotypes were grown in Experiment 2 in pots filled with high B soil (8 kg ha-1 B; B8). Shoot growth was not affected by B8 treatment, while root and shoot B concentration was significantly increased compared to control. Genotypes Panther and Pronto which performed low relative root and shoot growth and high B accumulation in plants in Experiment 1, had good growth in B8 treatment. In Experiment 2 genotype NS-L-7 had significantly lower B concentration in shots under treatment B8, but also very high B accumulation in Experiment 1. In addition, cluster analyses classified genotypes in three groups according to traits contrasting in their significance for analyzing response to B toxicity. The first group included four varieties based on their shared characteristics that have small value for the relative growth of roots and shoots and large values of B concentration in shoot. In the second largest group were connected ten genotypes that are heterogeneous in traits and do not stand out on any characteristic. Genotypes NS-L-7 and Navajo were separated in the third group because they had big relative growth of root and shoot, but also a high concentration of B in the shoot, and high total B uptake. Results showed that none of tested genotypes could not be recommended for breeding process to tolerance for B toxicity. Izvod Odgovor 16 genotipova uljane repice na toksičnost B (bora) analizirana je poređenjem rezultata dva ogleda izvedenim u stakleniku. U Ogledu 1, biljke su gajene u hranljivim rastvorima sa dva tretmana B: 10 µM B (kontrola) i 1000 µM B (toksična koncentracija). Vrednosti za relativni porast korena i nadzemnog dela varirale su od 20-120% i 31-117%, po redu. Koncentracija B je takođe značajno varirala (206.5-441.7 µg B g-1 SM) kao i ukupno usvojena količina B po biljci. Na osnovu rezultata dobijenih u Ogledu 1 odabrana su četiri genotipa koja su u Ogledu 2 gajena u posudama sa zemljištem kome je dodat B preračunato za poljske uslove u količini od 8 kg ha-1 (B8) uz kontrolu..Toksične količine B nisu negativno uticale na porast biljaka, dok je koncentracija B u korenu i nadzemnoj masi značajno povećana u poređenju sa kontrolom. Iako su u Ogledu 1 zabeležene velike razlike u porastu biljaka i koncentraciji B u suvoj masi, rezultati dobijeni u Ogledu 2, nisu pokazali da je kod bilo kog genotipa prisutna tipična reakcija na osnovu koje bi bili svrstani u grupu osetljivih ili tolerantnih na tiksičnost B. Genotipovi Panther i Pronto kod kojih je u Ogledu 1 zabeležen mali relativni porast korena i nadzemnog dela, kao i velika koncentracija B u biljci, imali su dobar porast u tretmanu sa 8 kg ha-1. U Ogledu 2, kod genotipa NS-L-7 zabeležena je značajno niža koncnetracija B u nadzemnom delu biljaka, ali i velika akumulacija B u Ogledu 1. Kluster analizom genotipovi su podeljeni u tri grupe na osnovu relativnog porasta korena i nadzemnog dela, koncentracije B u njima i ukupnom usvajanju B po biljci, ali tako da ne ukazuju na eventualno postojanje otpornosti na toksičnost B. Istraživanje je pokazalo da ni jedan od 16 testiranih genotipova ne može da bude preporučen za proces oplemenjivanja za otpornost na toksičnost B.