Varijabilnost patogenih svojstava Fusarium spp. poreklom iz zrna kukuruza i pšenice

Differences in the pathogenicity of 93 isolates of seven species belonging to the genus Fusarium (F. graminearum, F. verticillioides, F. proliferatum, F. subglutinans, F. sporotrichioides, F. semitectum and F. equiseti), originating from maize kernels (61) and wheat grains (32), were examined based on the germination percentage of inoculated seeds. The studied species demonstrated inter- and intraspecies variability regarding the effects on maize seed germination. On the average, the greatest germination reduction was found in seeds inoculated with the spore suspensions of F. sporotrichioides and F. graminearum. A similar reduction was detected in seeds inoculated with F. proliferatum and F. subglutinans. The effect of F. subglutinans on seed germination reduction was higher compared to the two latter species, while the effects of F. semitectum and F. equiseti were smallest. The majority of isolates were of moderate pathogenicity, while the lowest number of isolates was either very pathogenic (7) or apathogenic (10). Pathogenicity of the isolates originating from wheat grains was generally lower than the pathogenicity of isolates originating from maize kernels, with the exception of F. sporotrichioides.Razlike u patogenost 93 izolata sedam vrsta roda Fusarium (F. graminearum, F. verticillioides, F. proliferatum, F. subglutinans, F. sporotrichioides, F. semitectum i F. equiseti), poreklom iz zrna kukuruza (61) i pšenice (32), proučavane su na osnovu procenta klijavosti inokulisanog semena. Ispitivane vrste ispoljile su inter- i intraspecijsku varijabilnost u pogledu uticaja na klijavost semena kukuruza. U proseku, najveće smanjenje klijavosti je utvrđeno kod inokulacije semena suspenzijom spora F. sporotrichioides i F. graminearum, a zatim, približno isto, kod inokulacija semena pomoću F. proliferatum i F. subglutinans. F. verticillioides je, u poređenju sa ove dve poslednje vrste, značajnije uticala na smanjenje klijavosti semena, dok su najmanje uticale vrste F. semitectum i F. equiseti. Većina izolata je bila srednje patogenosti, a najmanji broj je bio jako patogen (7) ili apatogen (10). Izolati poreklom iz zrna pšenice bili su slabije patogenosti od izolata poreklom iz zrna kukuruza, sa izuzetkom F. sporotrichioides

Otpornost novosadskih hibrida suncokreta prema prouzrokovaču mrko-sive pegavosti stabla u uslovima prirodne zaraze

Sunflower diseases have a major impact on sunflower yield and quality of seed. When conditions during vegetation are favorable, the intensity of damage can be very high. Therefore, surveys of economically important diseases are necessary. A survey of incidences and severity of phomopsis stem canker was performed on 9 locations during 2007 and 2008. A total of 8 hybrids per location was examined. Lodging of plants as a symptom of stem canker disease was not detected. The mean disease incidence was less than 5%, depending on hybrid, location and year. Generally, higher deasease incidence was recorded in the first year of survey than in the second. The hybrids Velja, NS-H-111 and Baæa demonstrated an elevated level of resistance. Despite significant differences in disease severity that was found among the hybrids tested, all of them were highly resistant to phomopsis stem canker.Suncokret predstavlja našu najvažniju biljnu vrstu za dobijanje kvalitetnih biljnih ulja. Napada ga više od 40 raznih prouzrokovača bolesti od kojih samo određeni broj predstavlja problem u proizvodnji. Praćenje njihove pojave je značajno sa aspekta suzbijanja jer doprinosi stabilnosti proizvodnje. Pojava mrko-sive pegavosti stabla praćena je 2007. i 2008. godine u mreži demonstracionih ogleda. U prvoj godini posmatranja zabeležena je veća pojava bolesti na svim lokalitetima u odnosu na drugu godinu. Među hibridima u obe godine posmatranja najveća otpornost prema Phomopsis heliathi zabeležena je kod hibrida NS-H-111, Velja i Baća. Uprkos značajnim razlikama u intenzitetu pojave mrko-sive pegavosti stabla između hibrida, nije zabeležena jača pojava bolesti iz čega proizilazi da posmatrani hibridi poseduju visok stepen otpornosti prema Ph. helianthi u agroekološkim uslovima Vojvodine

Sadržaj polifenola i antioksidativni kapacitet ekstrakata listova paradajza zaraženih plamenjačom

Late bligth is one of the main causes of the tomato yeild losses. In this paper, the biochemical response of tomato variety Plovdivski kasni in leaves infected with Phytopththora infestans was analyzed. It was found that there is a correlation between the degree of disease severity and the content of total polyphenols and flavonoids in the leaves. The different content of phenolic compounds also affected the antioxidant capacity of leaf extracts. By increasing the degree of infection, the content of the soluble polyphenolic compounds and the antioxidant capacity of the leaves decreased.Plamenjača je jedan od glavnih uzroka smanjenja prinosa paradajza što može dovesti do velikih ekonomskih gubitaka. U ovom radu je ispitan biohemijski odgovor listova paradajza sorte ‘Plovdivski kasni’ na infekciju prouzrokovačem plamenjače Phytopththora infestans. Utvrđeno je da postoji korelacija između stepena zaraženosti biljke i sadržaja ukupnih polifenola i flavonoida u listovima. Različit sadržaj fenolnih jedinjenja je uticao i na antioksidativni kapacitet ekstrakata listova. Povećanjem stepena infekcije sadržaj rastvorljivih polifenolnih jedinjenja i antioksidativni kapacitet listova se smanjivao

Korelacija sinteze deoksinivalenola i zearalenola od strane Fusarium izolata poreklom sa zrna pšenice i kukuruza

A total of 39 Fusarium graminearum, F. sporotrichioides, F. semitectum and F. equiseti isolates, originating from wheat and maize samples collected at 10 locations in Serbia, were analyzed by ELISA method for their potential of deoxynivalenol (DON) and zearalenone (ZEA) production under optimal laboratory conditions. Fusarium graminearum isolates with the highest intraspecies variability were the best producers of both deoxynivalenol and zearalenone. In contrast, F. equiseti isolates were the weakest producers of these two toxins. Considering the plant origin of the isolates, wheat-originating F. sporotrichioides isolates were better deoxynivalenol producers, while the maize-originating isolates produced more zearalenone. There was no clear difference in ZEA production between wheat- and maizeoriginating isolates of F. graminearum, while higher average DON concentrations were produced by F. graminearum wheat-originating isolates. Negative correlation was detected between the production of deoxynivalenol and zearalenone by various Fusarium spp.Potencijal za stvaranje deoksinivalenola (DON) i zearalenona (ZEA) ukupno 39 izolata vrsta Fusarium graminearum, F. sporotrichioides, F. semitectum i F. Equiseti, poreklom iz zrna pšenice i kukuruza sa 10 različitih lokaliteta u Srbiji, analiziran je u optimalnim laboratorijskim uslovima ELISA testom. Izolati vrste F. graminearum su imali najvišu intraspecijsku varijabilnost i ujedno su bili najveći proizvođači i deoksinivalenola i zearalenona. Nasuprot njima, izolati F. equiseti su bili najslabiji proizvođači ova dva mikotoksina. S obzirom na poreklo izolata, F. sporotrichioides izolati poreklom sa pšenice su bili bolji proizvođači deoksinivalenola, dok su izolati ove vrste poreklom sa kukuruza stvarali više koncentracije zearalenona. Među F. graminearum izolatima nije bilo jasne razlike u sintetisanim koncentracijama ZEA zavisno od porekla izolata, dok je pri sintezi DON-a uočena viša prosečna koncentracija sintetisana od strane F. graminearum izolata poreklom sa pšenice. Negativna korelacija je registrovana između sinteze deoksinivalenola i zearalenona od strane Fusarium spp

Uticaj Trichoderma spp. na klijavost semena soje i potencijalni antagonistički efekat na Sclerotinia sclerotiorum

Trichoderma species have been registered as species with important plant growth promoting potential and antagonistic effect against various phytopathogens. Trichoderma isolates originating from different soil types from the Vojvodina region (Serbia) were screened using dual culture test for their antagonistic effect against the pathogen Sclerotinia sclerotiorum. All tested isolates had high radial growth inhibition (RGI) factors of the pathogen and high colonization percentage. Growth promoting activity of Trichoderma isolates on soybean seeds was tested under glasshouse conditions. Soybean seeds were coated with suspensions of different Trichoderma isolates and seed germination percentage, root and shoot length were measured. According to data analysed in Statistica 10, using Duncan’s test, there were no significant effects on shoot length among the tested isolates, compared to the control. The four tested Trichoderma isolates showed significant positive effects on germination, root length and vigour index, while two isolates exhibited no significant effect on any of the measured parameters.Vrste roda Trichoderma su poznate po svom antagonističkom efektu na veliki broj fitopatogenih organizama kao i po stimulativnom efektu za rast biljke. Izolati Trichoderma spp. testirani u ovom istraživanju su izolovani iz različitih tipova zemljišta u Vojvodini (Srbija). Test dvojnih kultura je korišćen za testiranje antagonističkog dejstva izolata na patogena Sclerotinia sclerotiorum. Svi testirani izolati su imali visok RGI (faktor inhibicije porasta micelije patogena) i visok procenat kolonizacije patogena. Stimulativni efekat rasta Trichoderma izolata na seme soje je testiran u uslovima staklenika, i sedmog dana su mereni dužina korena, izdanka i klijavost semena tretiranih suspenzijom različitih izolata Trichoderma spp. Svi podaci su analizirani primenom Duncan testa u programu Statistica 10, i ukazuju da nije bilo statistički značajne razlike u dužini izdanaka tretiranih semena i kontrole. Četiri izolata su statistički značajno uticala na povećanje dužine korena, klijavosti i vigor indeksa u odnosu na kontrolu, dok dva izolata nisu statistički značajno uticala ni na jedan od merenih parametara

Smanjenje bolesti ozimog stočnog graška u združenoj setvi u polju

A field experiment was conducted at the experimental field of the Institute of Field and Vegetable Crops in Novi Sad to investigate the effect of forage winter pea and winter oat intercropping on ascochyta blight and powdery mildew infections. Seeding rations of pea and oat in Treatment 1 (50:50%) and Treatment 2 (75:25%, respectively) reduced ascochyta leaf infection by 32.5% and 12.8%, and powdery mildew infection by 12.3% and 17.5%, respectively, compared to pea monoculture used as a control (Treatment 3). The same seeding rations in Treatment 1 and 2 reduced ascochyta blight on pea plants by 37.2% and 18.3%, respectively. However, there were no significant differences between the treatments in reducing powdery mildew on plants. The effects of different treatments on the average number of pods per plant, seed per pod, shriveled pods and seed weight were analyzed using Spearman’s correlation coefficient. Negative but not statistically significant effects on those measured parameters were registered in Treatments 2 and 3, while Treatment 1 showed positive effects on all parameters except shriveled pods. According to all data obtained in this research, the intercropping mixture of pea and oat at 50:50% seeding ratio had the best effect on the measured parameters while the intercropping mixture of pea and oat at 75:25% seeding ratio had low to moderate effect in comparison with pea monocrop.Poljski ogled je postavljen na oglednom polju Instituta za ratarstvo i povrtarstvo u Novom Sadu kako bi se istražio uticaj smeše ozimog stočnog graška i ozimog ovsa na pojavu antraknoze i pepelnice. Smeše graška i ovsa u Tretmanu 1 (50:50%) i Tretmanu 2 (75:25%) smanjile su antraknozu lista za 32.5% i 12.8%, a pepelnicu za 12.3% i 17.5% u odnosu na monokulturu graška, koja je uzeta za kontrolu (Tretman 3). Navedene smeše u Tretmanima 1 i 2 su smanjile pojavu antraknoze celih biljaka za 37.2% i 18.3%. Međutim, između tretmana nije uočena značajnija razlika u pojavi pepelnice na celoj biljci graška. Uticaj tretmana na prosečan broj mahuna po biljci, šturih mahuna po biljci, zrna po mahuni i mase semena analizirani su Spearman-ovim koeficijentom korelacije. Negativne ali ne statistički značajne korelacije sa merenim parametrima su registrovane u Tretmanima 2 i 3, dok je Tretman 1 imao pozitivan efekat na merene parametre sa izuzetkom šturih mahuna. Prema dobijenim rezultatima u sprovedenom istraživanju, združena setva ozimog stočnog graška i ozimog ovsa u smeši 50:50% je imala najbolji efekat na istraživane parametre dok je združeni usev graška i ovsa u smeši 75:25% imao slab do srednji uticaj u poređenju sa kontrolom, odnosno monokulturom graška