| Abstract | Istraživanje je provedeno u dvije klonske sjemenske plantaže poljskog jasena (Čazma, Nova Gradiška) na genotipovima koji pripadaju dvijema sjemenskim regijama. Genetička varijabilnost ispitana je s osam mikrosatelitnih biljega. Provedena su fenološka opažanja listanja i cvjetanja kroz tri sukcesivne godine (2014., 2015., 2016.). Na osnovu razvojnih faza listanja procjenjeni su kvantitativni genetički parametri, kao što su genotipska, okolišna i fenotipska varijanca, te nasljednost u širem smislu. Ispitane su ekotipske forme i utjecaj klimatoloških čimbenika na početak listanja (temperatura, oborine, insolacija). Kroz fenološka opažanja cvjetanja istraživana je dinamika cvjetanja, te oblici spolnosti poljskog jasena. Cilj istraživanja bio je utvrditi razinu unutarpopulacijske i međupopulacijske varijabilnosti, procjeniti vrijednosti nasljednosti za kvantitativno svojstvo listanja, utvrditi postojanje ekotipskih formi i utjecaj klimatoloških čimbenika na početak listanja, te dinamiku cvjetanja kroz trogodišnja fenološka opažanja. Na osnovu mikrosatelitnih biljega istraživani genotipovi ne pokazuju statistički značajnu međupopulacijsku genetičku različitost. Najviša genetička varijabilnost pripada unutarpopulacijskoj razini strukturiranosti. Procjenjeni kvantitativni parametri početka listanja ukazuju na umjerene vrijednosti nasljednosti, te na porast genotipske i smanjenje okolišne varijance srazmjerno sa starošću istraživanih genotipova. Svojstvo početka listanja poljskog jasena pokazuje tendenciju razdvajanja na dvije ekotipske forme (rana i kasna). Od ispitanih klimatoloških varijabli insolacija pokazuje najbolju statističku značajnost. Ispitane su mogućnosti primjene modela Growing Degree Days i Dynamic Model Chilling Portions, te je prag temperaturnih suma za sjemenske plantaže iznosio 13 °C, odnosno 15 °C, sa početkom mjerenja od 1. studenoga, dok za negativne temperaturne sume nije dobivena statistički značajna razlika. Istraživanjem spolnosti i cvjetanja u klonskim sjemenskim plantažama utvrđeno je postojanje muških i hermafroditnih cvatova, dok ženski cvatovi nisu utvrđeni. Zapažena je i promjena spola kod istih genotipova tijekom istraživanih godina |
| Abstract (english) | The narrow-leaved ash (Fraxinus angustifolia Vahl) is one of the three indigenous ash species in Europe. The largest continuous complexes of the narrow-leaved ash in the Republic of Croatia are located along the Sava river (80% of the total area). Over the recent years, the dieback of the narrow-leaved ash had a decreasing trend on natural regeneration, both in Europe and in the Republic of Croatia. Research into the genotypic and phenology variability was conducted in two clonal seed orchards (Čazma, Nova Gradiška) on a total of 92 genotypes belonging to two seed regions (seed region Upper Posavina, Middle Croatia and Pokuplje, and seed region Middle Posavina). Genetic variability was tested with eight microsatellite markers (Femsatl 4, Femsatl 8, Femsatl 10, Femsatl 11, Femsatl 16, M2-30, FR639485, FR646655). Phenological observations of the flushing and flowering were conducted over three consecutive years (2014, 2015, 2016), and performed in regular seven-day intervals from the beginning of February until the end of June. Flushing and flowering were classified into six development phases (six phases of flushing and six phases of flowering). Based on the development phases of flushing, quantitative genetic parameters were estimated, such as genotypic, environmental and phenotypic variance, and broad-sense heritability. Ecotypic forms and the impact of climate factors (temperature, precipitation, insolation) on the beginning of flushing were studied. Phenological observations of flowering were used to study the dynamics of flowering and the forms of sexuality of the narrow-leaved ash. The aim of the study was to determine the level of intra and interpopulation variability, assess the values of heritability for the quantitative trait of flushing, establish the existence of ecotypic forms and impact of climate factors on the beginning of flushing, and the flowering dynamics through three-year phenological observations. Based on microsatellite markers, the studied genotypes do not express a statistically significant interpopulation genetic variability (FST = 0.007; p = 0.018). The highest genetic variability belongs to the intrapopulation level of structure (99.30 %). The estimated quantitative trait of the beginning of flushing suggest moderate to high values of heritability (H2 = 0.20 to 0.63), and an increase in genotypic and decrease in environmental variance in proportion with the age of the studied genotypes. The property of the beginning of flushing of the narrow-leaved ash expressed a tendency of separation into two ecotypic forms (early and late), where the forms differ/separate by 12 days on average. The Čazma clonal seed orchard contains a considerably larger share of genotypes expressing a tendency for later flushing (69 %), unlike the clonal seed orchard of Nova Gradiška, where the majority are early flushing genotypes (64 %). Of the studied climate variables, insolation expressed the best statistical significance with regard to the variable of the beginning of flushing (CSO Čazma, r = 0.89; CSO Nova Gradiška, r = 0.96). The possibilities of applying the models of Growing Degree Days and Dynamic Model Chilling Portions were studied, and the temperature sum threshold for seed orchards was 13°C (CSO Čazma) and 15°C (CSO Nova Gradiška), with the measurements beginning on November 1, whereas for negative temperature sums no statistically significant difference was obtained (p = 0.854). Research into the sexuality and flowering in clonal seed orchards resulted in the establishment of the existence of male and hermaphrodite inflorescences, whereas female inflorescences were not found. Also observed was a change of sex in the same genotypes over the studied years. |
