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Posljednjih godina sve više raste interes za konzumacijom mladih izdanaka. Mladi izdanci izuzetno su bogati mineralnim tvarima, klorofilom te vitaminima. Način proizvodnje značajno utječe na njihov nutritivni sastav. Vrsta svjetla smatra se vrlo važnim okolinskim čimbenikom koji utječe na fotokemijske procese kod biljaka, koji utječu na koncentraciju mineralnih tvari, klorofila i karotenoida. Cilj istraživanja bio je utvrditi mineralni sastav te sadržaj klorofila i karotenoida kod mladih izdanaka heljde uzgojenih pod FLUO i LED osvjetljenjem. Mladi izdanci uzgajani pod FLUO osvjetljenjem imali su veći sadržaj P, K, Mg i klorofila b, dok je kod mladih izdanaka uzgajanih pod LED osvjetljenjem utvrđen veći sadržaj Fe i klorofila a.

Viroidi su male kružne nekodirajuće RNA molekule. Patogeneza viroida povezana je s poremećajem staničnog metabolizma i obrambenih signalnih putova, kroz transkripcijsku ili posttranskripcijsku modulaciju ekspresije gena. Istražili smo signalne putove u krumpiru (Solanum tuberosum L.) usredotočivši se na signalni put jasmonske kiseline (JA) u odgovoru na infekciju viroidom vretenastog gomolja krumpira (PSTVd). U istraživanju smo koristili transgene JA- deficijentne (StOPR3-RNAi) i JA-neosjetljive (StCOI1-RNAi) linije i biljke divljeg tipa (WT). Dinamika akumulacije viroida i analiza ekspresije gena uključenih u obrambeni odgovor biljke praćena je od 1 do 8 wpi, metodom PCR u stvarnom vremenu. Od 2 do 6 wpi, razina viroidne RNA bila je značajno veća u sistemski zaraženim listovima opr3 biljaka u usporedbi s coi1 i WT biljkama, što ukazuje na povećanu osjetljivost JA-deficijentnih biljaka na PSTVd. Geni povezani s patogenezom, PR1 i PR2, bili su jače eksprimirani u JA- deficijentnim i WT biljkama, a manje u JA- neosjetljivim mutantama. Komponente JA signalinga kao što su geni COI1, JAZ1, MPK4 i PAL, bili su manje eksprimirani u zaraženim biljkama svih ispitanih linija, a posebno u JA-neosjetljivim biljkama. Analiza transgenih linija također je otkrila smanjeno nakupljanje vodikovog peroksida i kaloze, što je u skladu s obrascima ekspresije gena za peroksidaze i kaloza sintazu. Čini se da inhibicija JA odgovora u coi1 biljkama rezultira privremenom odgodom razvoja simptoma.

Cilj rada bio je utvrditi prikladnost za uzgoj sorata ‘Topfirst’, ‘Topfive’, ‘Top 2000’ i ‘Jojo’ cijepljenih na podlozi WaxWa određivanjem pomoloških značajki plodova. Sorte su zasađene u voćnjaku pokušališta Jazbina Agronomskog fakulteta u Zagrebu (lok. 45°51.320’ SGŠ, 16°00.217’ IGD) bez sustava za navodnjavanje i zaštitnih mreža. Na temelju provedenog istraživanja sorta ‘Top 2000’ imala je najsitnije, najbrojnije plodove i najmanju košticu, no pokazala je najveću osjetljivost utvrđenu najvećim brojem oštećenih plodova. Sorta ‘Topfirst’ imala je najkrupnije plodove, dok je randman plodova bio najveći kod sorata ‘Top 2000’ i ‘Topfive’. Sorte ‘Jojo’ i ‘Topfive’ su imale najveću količinu suhe tvari.

Gustoća sjetve direktno utječe na broj klasova po m2 , a posljedično i na druge komponente uroda pšenice. Stoga je važno utvrditi optimalnu gustoću sjetve za određeni genotip koja će rezultirati maksimalnim urodom. Cilj ovog istraživanja je bio utvrditi utjecaj gustoće sjetve na formiranje komponenti uroda i urod različitih genotipova ozime pšenice. U istraživanje je bilo uključeno deset genotipova ozime pšenice: sorte AFZG Karla, Kaja, Mara i Antonija te šest oplemenjivačkih linija uzgajanih u dvije gustoće sjetve, 400 zrna/m2 i 650 zrna/m2 . Analizom je utvrđeno da gustoća sjetve značajno utječe na broj klasova po m2 , urod zrna po klasu i žetveni indeks, dok je interakcija genotip × gustoća bila značajna jedino za urod zrna po klasu. Masa 1000 zrna kao i hektolitarska masa najstabilnije su komponente na koje gustoća sjetve nije značajno utjecala.

Cilj istraživanja bio je utvrditi utjecaj različitih citokinina: 6-benzilaminopurin-a (BAP), metatopolin- a (mT) i tidiazuron-a (TDZ) te dva tipa osvjetljenja (flourescentne lampe- FLUO ili LED diode s omjerom crvenog i plavog svjetla 70 % : 30 %) na stopu multiplikacije i sadržaj klorofila u izdancima kapara uzgojenim in vitro. Tretmani citokininima signifikantno su utjecali na broj izdanaka (P

Garlic (Allium sativum L.) is a vegetatively propagated vegetable extensively studied due to its beneficial health effects. The cultivation and use of garlic is a part of Croatian tradition and each region or even village has their own landraces preserved for generations. In a relatively small area, a high phenotypic diversity could be observed and therefore the aim of this study was to assess a genetic diversity of collected Croatian garlic accessions. We genotyped 43 accessions from three Croatian regions (Istria, Dalmatia and continental Croatia) along with 14 foreign landraces using six polymorphic SSR markers. The number of distinct genotypes has been determined and the genetic structure and relationships among the accessions have been accessed. This is the first attempt to evaluate a large set of garlic accessions maintained by Croatian institutions as a part of the National program for conservation and sustainable use of plant genetic resources for food and agriculture. Accompanied by morphological and biochemical description, the results of this study will contribute to better knowledge on garlic genetic resources and foster effective and sustainable management of Croatian collections.

Bajam zbog svoje izuzetne hranjive i energetske vrijednosti s najvećom primjenom u prehrambenoj (konditorskoj) industriji, ali i širokoj primjeni u farmaceutskoj industriji i proizvodnji kozmetike ima desetljećima veliku potražnju kao i visoke otkupne i maloprodajne cijene. Uz povoljne klimatsko-edafske čimbenike u kombinaciji s odgovarajućim sortama i podlogama te primjenom suvremene tehnologije uzgoja, mogao bi se ostvariti prinos koji bi zadovoljavao vlastite potrebe. Današnja proizvodnja u Hrvatskoj zadovoljava samo petinu vlastitih potreba. U zadnjih deset godina ostali smo na uzgojnoj površini od svega 400 ha, točnije u 2016. godini uzgojna površina iznosila je 430 ha, s prinosom bajama u ljusci od 0, 4 t/ha. Ukupan prinos bajama u ljusci u 2016. godini iznosio je 155 t. Analizirajući podatke od 1992. godine do danas površina uzgoja bajama je prepolovljena, a proizvodnja je smanjena na približno deset posto tadašnje. Teško je povjerovati da smo 1951. godine imali proizvodnju bajama u ljusci od čak 5 680 t koja se sukcesivno smanjivala na 4 602 t u periodu od 1961. do 1970., na 2 156 t od 1971. do 1979. da bi se danas spustili na nezapamćeno nisku razinu proizvodnje. Otvoreno je pitanje kako aktualizirati povećanje proizvodnje bajama u Hrvatskoj budući je jezgra bajama toliko cijenjen i tražen proizvod.

Pre-harvest sprouting (PHS) in wheat can cause a reduction in grain yield, test weight and grain quality. The level of seed dormancy at harvest maturity is the main component of PHS resistance in wheat. In the present study, recombinant inbred line (RIL) mapping population developed by single seed descent from the cross ‘Bezostaja 1’ (weak PHS resistance, non-dormant) × ‘Klara’ (high PHS resistance, dormant) was used to analyse seed dormancy. The RIL population and parental genotypes were grown in replicated trials in two different environments. The genetic and the genotype × environment component of variance accounted for 71 and 20% of the phenotypic variance for seed dormancy, respectively. The estimated heritability of the trait was 0.85. In the RIL population, transgressive segregation was observed mostly in the direction of low seed dormancy, while only a few lines had more pronounced seed dormancy than the dormant parent ‘Klara’. A genetic map has been developed based on the RIL population while QTL analysis using composite interval mapping (CIM) and multiple interval mapping (MIM) allowed the identification of putative quantitative trait loci (QTLs) controlling seed dormancy.

Heljda (Fagopyrum esculentum Moench) je pseudožitarica porijeklom iz Kine, a u sjeverozapadnoj Hrvatskoj tradicionalno se uzgaja više od stoljeća. Donedavno je uzgajana na vrlo malim površinama, no proteklih godina povećava se interes za proizvodnjom ove kulture, kako za zrno, tako i za zelenu gnojidbu. Budući da na sortnoj listi Republike Hrvatske ne postoji ni jedna sorta heljde, javila se potreba za prikupljanjem postojećih lokalnih populacija heljde preostalih na području Varaždinske i Međimurske županije. Cilj ovog istraživanja bio je usporediti prikupljene populacije heljde (6 populacija) sa sortama susjednih država Darjom i Novosadskom. Genetskom analizom utvrđeno je razdvajanje domaćih populacija od referentnih sorti, iako je unutar samih populacija utvrđen visok stupanj genetske varijabilnosti. Morfološka i agronomska svojstva populacija, kao i sorti varirala su ovisno o sklopu (60, 80 i 100 kg/ha), roku sjetve (glavni i postrni usjev) i načinu uzgoja (ekološki i konvencionalni). Nutritivne vrijednosti odabranih populacija bile su u razini standarda sorte Darja. Iznimka je sadržaj cinka, za koji su u većini uzoraka zabilježene više vrijednosti kod odabranih populacija. Na osnovu genetskih, agronomskih i nutritivnih parametara odabrane su populacije 3. i 6. koje će se prijaviti kao čuvane sorte te biti umnažane kao Varaždinske populacije heljde.

Na otoku Pagu, u botaničkom rezervatu u Lunu nalazi se oko 80.000 stabala maslina od kojih je oko 1.500 divljih maslina i divljih maslina na koje je nacijepljena ‘Oblica’. U radu je praćena cvatnja i određena uspješnost klijanja peluda maslina od osam stabala (genotipova) samoniklih divljih maslina, 'Oblice' nacijepljene na divlju maslinu i 'Oblice' na vlastitu korijenu. Kod 'Oblice' na vlastitom korijenu i nacijepljene utvrđena je usklađenost u fenofazi cvatnje. Prema fenofazi cvatnje genotipovi divljih maslina grupirali su se u tri grupe: 1) G1, G2, G3 ; 2) G4 i G5, 3) G6, G7 i G8. Visok postotak klijavosti (>30%) utvrđen je kod divljih maslina, dok je postotak klijavosti kod 'Oblice' na vlastitom korijenu kao i nacijepljene bio niži (

Soybean (Glycine max L. Merr.) is one of the major sources of protein for human and animal nutrition as well as a source for vegetable oil. Drought is a major limiting factor that can drastically reduce soybean yield. Due to climatic changes, periods of severe drought can occur at germination and early vegetative stage. The objective of this study was to screen 32 soybean genotypes for drought tolerance in early vegetative stage in controlled conditions. Seeds were germinated in moist silica sand and seedlings transplanted in tubes filled with vermiculite. The tubes were placed in a containers filled with a half strength Hoagland solution (control) or the same solution with 6% of diluted polyethylene glycol (PEG) 8000 (drought). Plants were grown in growth chamber at 22°C, 60% air humidity under cool-white light and 16/8 day/night photoperiod for 26 days. The following traits were measured: root and shoot length, fresh weight and dry weight. PEG-treated plants showed decrease in all measured traits with significant difference among genotypes. Drought tolerant genotype no. 3, 8, 11, 15, 22 and 25 with the highest drought tolerance efficiency (DTE) and the lowest decrease of shoot and root fresh and dry weight in drought were identified. These traits were highly positively correlated while root length negatively correlated with them. In conclusion, soybean genotypes that attained high root biomass without compromising shoot biomass are considered as drought tolerant.

Cilj ovog rada bio je utvrditi utjecaj tretmana zagrijanim zrakom i mehaničke skarifikacije na dormantnost sjemena odabranih dormantnih sorata ječma (Bc Vedran i Favorit) proizvedenog u dvije vegetacijske sezone (2015. i 2016. godina). U prvom pokusu sjeme dormantnih sorata tretirano je zagrijanim zrakom temperature 45°C tijekom 15 minuta i 30 minuta. Prvo utvrđivanje klijavosti u navedenim tretmanima započelo je 2. tjedna nakon žetve te se kasnije provodilo svakih 7 dana narednih 9 tjedana. U drugom pokusu sjeme dormantnih sorata ječma je tretirano mehaničkom skarifikacijom (ukolonjene su pljevice) te je utvrđivana klijavost u 2. tjednu nakon žetve. Rezultati istraživanja pokazuju kako su obje sorte bile dormantne 9 tjedana u prvoj godini istraživanja (2015.), i 8 tjedana u drugoj godini istraživanja (2016.). Tretman dormantnog sjemena ječma (Bc Vedran i Favorit) zagrijanim zrakom nije utjecao na skraćivanje dormantnosti. Prekidanje dormantnosti postignuto je mehaničkom skarifikacijom u obje godine i kod obje sorte (2015. i 2016. ; Bc Vedran 100%, te 2015. i 2016. ; Favorit 99%). Energija klijanja mehanički skarificiranog sjemena bila je veća nego energija klijanja kontrolnog sjemena u obje godine i kod obje sorte.

Amelanchier alnifolia je listopadni grm ili nisko stablo s jestivim bobicama. Pripada porodici Ružovki, a porijeklom je s područja Kanade gdje se i komercijalno uzgaja. Najučinkovitiji način razmnožavanja ove vrste je in vitro razmnožavanje. Cilj ovog rada je bio istražiti utjecaj tri tipa citokinina: tidiazurona (TDZ), 6-benzilaminopurina (BAP) i meta-topolina (mT) na in vitro propagaciju izdanaka A. alnifolia. Kao kontrola korišten je hranidbeni medij bez dodatka regulatora rasta. Tretmani su bili izloženi LED ili fluorescentnoj rasvjeti. Na tretmanu s 0.1 mg/l TDZ-a postignut je najveći stupanj multiplikacije neovisno o izvoru osvjetljenja. Izdanci s hranidbenog medija s dodatkom 0.6 mg/l mT-a pod fluorescentnim svjetlom su bili najduži. Određena je i ukupna koncentracija klorofila (a+b) na izdancima razvijenim iz svakog tretmana, s oba izvora osvjetljenja. Najveća ukupna koncentracija klorofila izmjerena je kod izdanaka dobivenih na tretmanu s 0.6 mg/l BAP-a pod fluorescentnim svjetlom. Iako hranidbeni medij s dodatkom TDZ-a osigurava najveću stopu multiplikacije, izdanci dobiveni na hranidbenom mediju s dodatkom BAP-a kao i s dodatkom mT-a bili su bolje kvalitete. Ti su izdanci bili duži i imali su veću koncentraciju ukupnog klorofila.

Na hrvatskom tržištu postoji velika potražnja za domaćim češnjakom, a sadašnja proizvodnja nije dostatna zbog nedostatka kvalitetnog sadnog materijala i neodgovarajućeg skladištenja. U cilju očuvanja domaće autohtone sorte češnjaka od nestajanja i unaprjeđenja proizvodnje, pokrenut je projekt revitalizacije proizvodnje češnjaka u Zadarskoj županiji poznatoj po povoljnim ekološkim uvjetima za njegov uzgoj. Sadni materijal je prikupljen s 4 lokacije iz okolice Benkovca: Bruška (E1), Lisičić (E2), Rodaljice (E3) i Gornji Karin (E4). Poljski pokus postavljen je u jesen 2012. godine u Zadarskoj županiji (Buković) i Zagrebu (Maksimir). Tijekom vegetacije jednom mjesečno su utvrđivani broj listova i visina biljke, dok su pri berbi analizirana morfološka svojstva lukovice (masa, visina, promjer i broj češnjeva). Ekotip E4 je na obje lokacije razvio najviše biljke s najvećim brojem listova. Najveću masu lukovice ostvario je ekotip E2 (25, 2 g) na lokaciji Buković, odnosno, ekotip E4 na lokaciji Maksimir (44 g). Na lokaciji Buković lukovice češnjaka razvile su manji broj češnjeva (2, 9 do 4, 8) u odnosu na lokaciju Maksimir (5, 2 do 7, 6). Na obje lokacije najvećim brojem češnjeva u lukovici isticali su se ekotipovi E1 i E2. Testirani ekotipovi prema morfološkim svojstvima uz potrošnju u svježem stanju imaju potencijal različite primjene u prerađivačkoj i farmaceutskoj industriji.

Stres suše u pojedinim godinama ograničava proizvodnju pšenice u Hrvatskoj smanjujući urod i do 50%. Cilj ovog rada je bio utvrditi reakciju na sušu u nalijevanju zrna za šest genotipova ozime pšenice, 12 morfoloških i agronomskih svojstva, te utvrditi utjecaj svojstava na formiranje uroda. Najveće smanjenje u suši utvrđeno je za urod zrna po klasu i masu 1000 zrna, a značajno su se smanjili i urod, broj klasova po m2, broj zrna u klasu, hektolitarska masa i žetveni indeks. Genotipovi kod kojih je utvrđen najveći urod u suši su Kaja i ZGM3. Na formiranje većeg uroda u suši utjecali su broj klasova po m2, broj zrna u klasu i masa 1000 zrna.

Topaz belongs to a group of apple varieties with high sugar content and high acidity, developed in Czech Republic. Besides its fruit quality preferred by consumers, ´Topaz´ is also scab-resistant. This fact is the most important characteristic which is providing another reason for significant spread of this cultivar in European orchards, especially in the organic fruit production industry. Considering the sparse information about the potential of this apple tree to be propagated in vitro, the role of several factors on micropropagation of apple cv. Topaz was evaluated. The results showed that 1 mg/L thidiazuron (TDZ) gave the highest number of shoots (3.6) per inoculated shoot, but the shoots obtained on this medium were fasciated. Media with 0.5 or 1 mg/L 6-benzylaminopurine (BA) or BA (0.5) + 1.5 mg/L kinetin (Kin) produced in average of 1.9-2.5 microshoots with no significant differences among them. Considering different explants types the best results gave decapitated microshoots placed vertically although not significantly different from those obtained from intact microshoots placed vertically and one-nodal segments placed horizontally. Shoots treated with 2 mg/L of indole-3-butyric acid (IBA) showed the highest average root number (6.6) and the highest percentage of rooting (68.7%).

Drought is one of the most important abiotic stresses in agricultural productions. In areas exposed to drought yield losses of winter wheat could be more than 50%. Wheat plant is not equally sensitive to drought stress at all stages of growth and development. Therefore, the aims of this study were to examine responses of winter wheat genotypes and agronomic traits to drought stress induced in two different growth stages and to determine the relationship of these traits to yield. The field experiment was conducted with six Croatian winter wheat genotypes under three water regimes: control, drought stress applied at tilling stage and grain filling period. Results showed significant difference between genotypes for the most of observed agronomic traits. Drought stress induced in both growth stages resulted with reduction of yield. Decline in yield when drought was induced at tilling stage was caused by reduction of number of spikes per square meter, increased number of sterile spikelets per spike and reduction of grain number per square meter, while decline in yield when drought was induced at grain filling period was result of reduction in grain number per spikelet, grain weight, 1000 grain weight and harvest index.

Gisela 5 is one of the most successful dwarfing cherry rootstocks despite its difficulty in clonal propagation by conventional methods. Micropropagation and rooting of shoots in vitro could thus improve production of ‘Gisela 5’. The in vitro proliferation efficacy of Gisela 5 cherry rootstock was investigated depending on the type and concentration of different cytokinins added to Quoirin and Lepoivre (QL) nutrient media, explant type and orientation. A protocol for successful in vitro rooting was also developed. Axillary shoot proliferation was induced by varying concentrations of cytokinins 6-benzylaminopurine (BA), thidiazuron (TDZ) and kinetin (KIN) at a constant concentration (0.1 mg L-1) of the auxin indole-3-butyric acid (IBA) and gibberelic acid (GA3 0.5 mg L-1). The highest multiplication coefficients (4.1 and 3.7 shootlets per plant) were achieved on a medium with 1 mg L-1 BA or 0.5 mg L-1 TDZ, respectively. Explant orientation also had a significant influence on the multiplication rate. Microshoots with an excised apex and removed leaves placed horizontally showed significantly higher multiplication rates (8.9) compared to microshoots placed vertically (4.1). In an additional experiment, the rooting efficiency of six different rooting treatments was assessed. Rooting treatments varied in auxin concentrations – indole-3-acetic acid (IAA) or IBA coupled with incubation in the dark. The best rooting was achieved in treatments in which shoots were kept in a solution of 80 mg L-1 IBA for 20 h and then transferred to hormone-free rooting medium.

The present study was undertaken to establish a protocol for plant regeneration of I. adriatica, I. illyrica and I. rotschildii. Leaf base segments were used as explants. For callus induction leaf base explants were incubated in the dark on three media with MS mineral solution containing different content of growth regulators: dichlorophenoxyacetic acid (2, 4-D), 1- naphthaleneacetic acid (NAA) and kinetine (KIN). Logistic model with genotypes and treatments as explanatory variables was used to analyse callus response data. Transfer of embryogenic calli on hormone free medium enabled the development of mature somatic embryos. When plant tissue has passed through in vitro culture, many regenerants appear to be no longer clonal copies of their donor genotypes. For this reason phenotypic variability among regenerants was evaluated. Several morphological characteristics were measured and subjected to a principal-component analysis (PCA). The DNA ploidy level was analysed by flow cytometry analysis. Analysis was conducted among 105 regenerants and showed that the DNA ploidy level remained stable in 104 regenerants.

The level of seed dormancy at harvest maturity is the main component of resistance to pre-harvest sprouting in wheat. Wheat genotypes with enhanced dormancy show increased embryo sensitivity to exogenously applied abscisic acid (ABA), a phytohormone considered to be involved in acquisition of dormancy. The aim of this study was to determine genotype differences in embryo sensitivity to ABA during the period of seed after-ripening. Twenty four winter wheat genotypes together with a highly dormant check RL4137, were grown in the field at two locations in Croatia during 2008/2009 growing season in a randomized complete block design with two replicates. From each plot 40 spikes were harvested at harvest maturity (approximately 14% moisture content on a wet weight basis). Spikes were hand-threshed and the seeds were stored at 20°C to allow after-ripening. Germination tests were conducted at 20°C in darkness with treatments: whole seeds in water (T1), embryos in water (T2) and embryos in 20 M ABA (T3). Four germination tests were carried out at intervals of 10 days starting from the harvest maturity until 30 days after harvest maturity. Germinated seeds were counted after three and six days and germination rate, expressed as weighted (by day) germination index (WGI), was calculated for each genotype by treatment combination. Combined analysis of variance across locations revealed a significant effect of genotype (G) and location (L) for WGI for all treatments in all germination tests, whereas G x L interaction was significant for WGI for all treatment by germination test combinations except for T2 and T3 at harvest maturity. Generally, at harvest maturity as well as during the course of after-ripening, dormant genotypes showed higher embryo sensitivity to ABA compared to less dormant genotypes. However, large variation in embryo sensitivity to ABA was found within groups of genotypes with high, moderate as well as low level of seed dormancy in all four germination tests at both locations. Furthermore, differences in embryo sensitivity to ABA between dormant and non dormant genotypes disappeared when the two groups were compared to each other at the same level of embryo or seed dormancy attained through genotype dependent time of after-ripening. In summary, results of the present study indicate that at least part of the differences in wheat embryo sensitivity to ABA during the period of seed after-ripening is the consequence of dormancy status of a seed sample regardless of its genotype (dormancy per se).

Efficient plant regeneration of intended genotypes is a prerequisite for the genetic modifications, mutation breeding and in vitro somaclones production. Petiole and leaf segments of two begonia genotypes, Begonia semperflorens cv. “Eureka” and Begonia spp. were used for in vitro adventitious bud induction and plant regeneration. Begonia spp. is 6th selfing generation after crossing B. semperflorens and Begonia x hybrida cv. “Dragon Wings”. Excised explants were placed on agar-solidified Murashige and Skoog (MS) media supplemented with 0.2 mg l-1 naphthalene-acetic acid (NAA) + 0.5 mg l-1 6-benzylaminopurine (BA) (MS1-treatment 1) or thidiazuron (TDZ) (MS2-treatment 2), or were soaked in liquid ½ MS medium supplemented with 9.0 mg l-1 BA (MSBA) or TDZ (MSTDZ) and then transferred to hormone-free MS medium (MSHF) (treatment 3 and 4, respectively). Initial necrosis of explants was a considerable problem in this study. The highest percentage of necrosis occurred when explants, especially leaf explants, were exposed to a high concentration of BA or TDZ (treatments 3 and 4) and then transferred to MSHF medium. Explants that survived formed adventitious buds with different rates of efficiency depending on genotype and treatment. B. semperflorens cv. Eureka formed, in average, adventitious buds on 47.3% and Begonia spp. on 13% of explants. The mean percentages of adventitious bud formation recorded in treatment 3 (55.0%) and 4 (53.7%) were significantly higher than in treatments 1 (32.1%) and 2 (16.8%). Petiole and leaf explants responded to bud induction with similar efficiency (31% and 29.3%, respectively). The final regeneration efficiency expressed as a number of shoots per responding explant significantly differed only according to explant type. Petiole explants produced in average 5.3 and leaf explants only 1.7 shoots per responding explant. Efficient plant regeneration of Begonia spp. genotype indicates that homozygous parental lines of wax begonias could be amenable to efficient in vitro regeneration. Different treatments resulted with similar mean number of shoots per responding explant (2.9 - 4.1), but the treatments with BA could be recommended for plant regeneration as it induced normal shoots, while TDZ caused stunted growth.

Somaklonska varijabilnost biljaka regeneriranih u kulturi biljnog tkiva može biti vrijedan izvor varijabilnosti u oplemenjivanju novih kultivara. Izolirani nezreli embriji pšenice sorte Karla nakon kalusiranja supkultivirani su na MS medij s različitim koncentracijama (tretmanima) polietilen glikola (PEG) u svrhu selekcije stanica kalusa tolerantnih na vodni deficit. Nakon višemjesečne selekcije utvrđena je efikasnost regeneracije biljaka pšenice iz pojedinih tretmana. U zriobi, regenerantima i biljkama polaznog genotipa (kontrola) analizirana su svojstva: (1) broj klasova po biljci, (2) dužina primarnog klasa, (3) broj klasića primarnog klasa, (4) broj zrna primarnog klasa, (5) masa zrna primarnog klasa. Kod regeneranata je utvrđena varijabilnost za sva analizirana svojstva, a visoke maksimalne vrijednosti svojstava nekih regeneranata ukazuju na potencijalno obećavajuće somaklonove.

Drought is one of the major environmental factors that inhibits many metabolic processes and constrains plant growth and crop productivity. Croatia is part of Mediterranean Drought Group with late season drought stress during the grain filling in wheat. In order to evaluate water deficit on relative water content (RWC), chlorophyll content (Chl) and grain yield of six Croatian winter wheat genotypes, a factorial experiment based on randomized complete block design with three replications was conducted in 2009-2010. Factors were six winter wheat genotypes (Kaja, Divana, Karla, Kuna, Banica and ZGM 13) and two water regimes (control and water deficit occurred from anthesis to maturity). Physiological responses (RWC and Chl) were measured in late milk maturity (LMM) and in early waxy maturity (EWM). Grain yield, yield per spike and 1000 grain weight were measured after harvesting the plots at maturity. Results showed that genotypes Kuna and Banica had the highest Chl in LMM, and the genotype Karla had the highest Chl in EWM in both environments. The highest RWC was observed in the genotype Karla in LMM, and in the genotype Kuna in EWM in both environments. Genotypes Karla, Kuna and Banica are all high yielding genotypes, but Kuna and Banica had the biggest loss in yield in stress condition (17%, 15.9%). For this reason Karla, that is high yielding genotype, with high RWC, and high Chl, could be recommended for planting in regions with Mediterranean type of drought.

Pre-harvest sprouting resistance in wheat depends on the level of grain dormancy at harvest time as well as on certain spike characteristics including the level of water soluble germination inhibitors found in wheat bracts. The objectives of the present study were: (i) to evaluate the influence of germination temperature on inhibitory effect of water bract extracts on wheat germination and (ii) to compare different germination criteria for measuring germination inhibition. Samples of bracts were taken at harvest ripeness from 30 wheat cultivars grown in the field. Germination tests were performed at 20C or 30C using nondormant seeds of the cultivar Banica and 5 ml of bract extracts of 30 genotypes or 5 ml distilled water as a control. Three criteria were used to characterise a seed as germinated: 1) rupture of the pericarp over the embryo (P), 2) at least one rootlet >3mm in length (1R) and 3) three rootlets 3mm in length (3R). Mean germination percentage (GP) and germination index (GI) in bract extracts were significantly lower compared to GP and GI in water for both germination temperatures but the inhibition was stronger at the higher germination temperature. Comparing the three germination criteria the highest inhibition of germination was observed using 3R and 1R for GP and GI, respectively. Significant differences among cultivars for germination inhibition were observed for both germination temperatures.

Chrysanthemum (Dendrathema grandiflora Tzvelev) is globally the second economically most important floricultural crop. It is propagated vegetatively by cuttings. Because the cuttings are obtained repeatedly from mother plants, they may be subjected to a virus infection. Production of the new mother stock plants by micropropagation every year could be cost- effective and would guarantee production of healthy cuttings. Alternative way of defence against pathogens is breeding of resistant genotypes. One method of doing this is a genetic transformation with suitable genes, in which case an effective regeneration protocol should be made available, one that is usually genotype depended. Objectives of this study were finding out: (1) which medium constitution is optimal for in vitro propagation of the chrysanthemum cv. Palisade by axillary branching and (2) is it possible to obtain the somatic embryogenesis of this cultivar as a method of in vitro regeneration. Among the three different, slightly modified MS media the highest multiplication rate of 3.8 new micro- shoots per one inoculated was obtained when BA and GA3 were used in concentration of 0.1 and 0.5 mg/l, respectively. Rooting medium supplemented with IBA (0.5 mg/l) gave higher number of roots (5.3) per plantlet then the same medium supplemented with IAA (1 mg/l). Leaf, petiole and stem explants were used for somatic embryogenesis and the highest number of somatic embryos was obtained on leaf explants. We can conclude that chrysanthemum cv. Palisade could be in vitro efficiently propagated by axillary branching and it is amenable for somatic embryogenesis.