Varijabilnost morfoloških značajki žira hrasta lužnjaka (Quercus robur L.) i njihov utjecaj na nicanje, rast i razvoj sadnica u kontroliranim uvjetima

doctoral thesis

• Title (english): Variability of morphological traits of pedunculate oak (Quercus robur L.) acorn and their influence on germination, growth and development of seedlings under controlled conditions
• Author: Sandra Crnković
• Mentor: Damir Drvodelić (mentor)
• Committee member: Saša Bogdan (predsjednik povjerenstva)
• Committee member: Sanja Perić (član povjerenstva)
• Granter: University of Zagreb; Faculty of Forestry and Wood Technology; Zagreb
• Defense date and country: 2024-01-19, Croatia
• Scientific / art field, discipline and subdiscipline: BIOTECHNICAL SCIENCES; Forestry
• Universal decimal classification (UDC): 630 - Silviculture. Afforestation. Felling. Logging

Abstract

Utjecaji sve izraženijih klimatskih promjena na šume hrasta lužnjaka očituju se u smanjenju vitaliteta, sušenju, pojavi štetnika i bolesti i izostanku uroda žira. Budući da je urod žira već nekoliko godina slab ili djelomičan i nema ga dovoljno za potrebe gospodarenja, Hrvatske šume d.o.o. 2023. godine raspisale su natječaj za premještanje šumskog reprodukcijskog materijala hrasta lužnjaka, i sjemena i sadnica, iz zemalja Europske unije u Republiku Hrvatsku. Znanstvena istraživanja iz područja šumskog sjemenarstva, kao i uporaba kvalitetnog sjemena, od sve su većeg značaja jer su očuvanje ciklusa prirodne obnove, očuvanje genofonda i biološke raznolikosti izazovi za šumarske stručnjake, kako u znanosti tako i u praksi. U klonskoj sjemenskoj plantaži „Plešćice I“ od 2014. do 2018. godine opažano je vrijeme ulaska klonova u fenofazu produljenja pupova. Prema dobivenim podatcima svi klonovi su klaster analizom razvrstani u tri klastera ili grupe: ranolistajući, intermedijarni i kasnolistajući. Prema položaju matičnih, plus stabala u sastojinama, klonovi su podijeljeni u dvije grupe. Iz uroda 2015. godine sakupljeni su uzorci žira svih klonova i uzgojene su sadnice u kontroliranim uvjetima. Žir grupe ranolistajućih klonova imao je najveće prosječne vrijednosti morfoloških značajki koje označavaju krupnoću: širine, volumena i mase jednog žira dok su prosječne vrijednosti duljine žira bile jednake s vrijednostima grupe intermedijarnih klonova. Prosječne vrijednosti ovih značajki grupe kasnolistajućih klonova bile su najmanje, a razlika s ostalim dvjema grupama bila je statistički značajna za duljinu žira, volumen i masu jednog žira. Kod žira kasnolistajućih klonova, koji je imao najmanju krupnoću, nicanje je, u usporedbi s ostalim dvjema grupama, bilo sporije. Iako između prosječnih vrijednosti promjera vrata korijena, mase korijenskog sustava u suhom stanju, i Dicksonovog indeksa kvalitete, koje ukazuju na kvalitetu sadnice, nije utvrđena statistički značajna razlika između grupa, grupa ranolistajućih klonova imala je veće prosječne vrijednosti ovih varijabli od ostalih dviju grupa. Korelacija između širine, volumena, odnosno mase jednog žira i masekorijenskogsustava u suhom stanju, za sve klonove i za većinu grupa, bila je pozitivna, slaba, ali statistički značajna. Odvojenom sjetvom žira hrasta lužnjaka različite krupnoće i žira porijeklom od ranolistajućih i intermedijarnih odnosno kasnolistajućih klonova klonske sjemenske plantaže „Plešćice I“, u rasadniku mogu se uz pravilnu gustoću sjetve uzgojiti sadnice željene starosti koje će biti prilagođene određenim okolišnim uvjetima. Unos šumskog reprodukcijskog materijala visoke kakvoće, kategorije kvalificiran, na odgovarajuća staništa, jedan je od važnih preduvjeta uspješne obnove i kvalitete buduće sastojine.

Abstract (english)

The effects of increasingly pronounced climate changes on pedunculate oak forests are manifested in decreased vitality, dieback, onset of pests and diseases and the absence of acorn yield. For the past several years acorn yield has either been poor or partial, making it insufficient for management needs. For this reason, in 2023 the company Croatian Forests Ltd announced a tender for the transfer of forest reproductive material of pedunculate oak, including seeds and seedlings, from the European Union countries to the Republic of Croatia. Scientific research in the field of forest seed production, as well as the use of quality seeds, are increasingly gaining importance because the preservation of the natural regeneration cycle, as well as the conservation of the gene pool and biological diversity, set challenges to forest experts, both in science and in practice. In the clonal seed orchard “Plešćice I”, the time of entry of clones into the phenophase of bud elongation was monitored from 2014 to 2018. According to the obtained data, all clones were classified into three clusters or groups by cluster analysis: early-flushing, intermediary-flushing and late-flushing. The clones were divided into two groups according to the position of parent plus trees in the stands. Acorn samples of all clones were collected from the 2015 harvest and seedlings were grown under controlled conditions. The acorn from the group of early-flushing clones had the highest average values of the morphological traits that indicate size: width, volume and mass of one acorn, whereas the average values of acorn length were equal to the values of the intermediary clone group. The average values of these traits in the late-flushing clone group were the lowest, while the difference with the other two groups were statistically significant for acorn length, volume and mass. In the case of acorns of late-flushing clones, which had the smallest size, germination was slower compared to the other two groups. Although no significant differencewas found between the groups in terms of average values of the root collar diameter, root system mass in dry condition, and Dicken's quality index, which indicate seedling quality, the group of early-flushing clones attained higher average values of these variables in comparison with the other two groups. A correlation between the width, volume, and mass of one acorn and mass of the root system in dry condition for all clones and for the majority of the groups, was positive and weak, but statistically significant. By separately sowing pedunculate oak acorns of different sizes and acorns originating from early-flushing and intermediate or late-flushing clones from the clonal seed orchard “Plešćice I”, it is possible to grow seedlings of the desired age adapted to certain environmental conditions, provided the correct sowing density is applied. The introduction of high-quality forest reproductivematerial in thequalified categoryto appropriate sites is one of the important prerequisites for successful regeneration and quality of the future stand.

• Keywords: Šumski reprodukcijski materijal; klonska sjemenska plantaža; fenologija listanja; uzgoj sadnica u kontroliranim uvjetima
• Keywords (english): Forest reproductive material; clonal seed orchard; leafing phenology; growing seedlings under controlled conditions
• Language: croatian
• URN:NBN: urn:nbn:hr:108:093941
• Promotion: 2024
• Study programme: Title: Forestry and Wood Technology - postgraduate doctoral study - university; Study programme type: university; Study level: postgraduate; Academic / professional title: doktor/doktorica znanosti, područje biotehničkih znanosti, polje šumarstvo (doktor/doktorica znanosti, područje biotehničkih znanosti, polje šumarstvo)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Access restricted to students and staff of home institution
• Created on: 2024-06-18 12:06:20