Uticaj izvora inokuluma Tilletia spp. i uslova sredine na učestalost zaraženih klasova

The influence of inoculum source on the incidence of common bunt, caused by fungi from the genus Tilletia, was estimated based on the frequency of bunt infected wheat spikes in our agroecological conditions. The cultivar Novosadska rana 5 was sown in a random split plot design with four replicates at Rimski Šančevi on three sawing dates in 1999/2000 and 2000/2001. The following variables were evaluated: I - control, II - soilborne inoculum (4 g teliospores/1 l soil), III - seedborne inoculum (2 g teliospores/1 kg seeds), IV - seedborne inoculum + soilborne inoculum (4 g teliospores/1 l soil + 2 g teliospores/1 kg seeds). Correlation and regression analysis were used to evaluate the effect of temperature and precipitation on the frequency of infected spikes. The frequency of bunt infected spikes depended on the source of Tilletia spp. inoculum, and difference in infection frequencies between variables II and III, as well as III and IV, were determined for the assessed infection parameters. When teliospores are the only source of inoculum in soil, 60 days after sawing (r>+0.52) is a critical period in which temperature influences the development of infection. The highest number of plants was infected in the first, while less were infected in the second ten days (decade) after sawing (r>0.41), when temperature was the optimal 5.0-6.0ºC. The initial 60 days after sawing were also critical for disease development when teliospores on seeds were the only source of inoculum (r>+0.50). The highest number of plants was infected in the third and fewer in the fifth decade after sawing (r>0.41), when temperature was the optimal 5.0-6.0ºC. When infection was caused by teliospores on seeds and in soil, the critical period lasted 120 days after sawing (r>0.42), with a maximum frequency of infection found at the optimal temperatures for the period of 4.0- 5.0ºC.Uticaj izvora inokuluma na pojavu glavnice pšenice koju prouzrokuju gljive roda Tilletia u našim agroekološkim uslovima praćen je, između ostalih, ispitivanjem parametra infekcije: stepen zaraženosti klasova. Sorta Novosadska rana 5 je sejana po split plot metodu u tri roka setve sa 4 ponavljanja na lokalitetu Rimski Šančevi tokom 1999/2000. i 2000/2001. godine. Ispitivane su sledeće varijante: I - apsolutna kontrola, II - zemlja infestirana teleutosporama (4 g teleutospora/1 l zemlje), III - seme infestirano teleutosporama (2 g teleutospora/1 kg semena) i IV - zemlja infestirana teleutosporama + seme infestirano teleutosporama (4 g teleutospora/1 l zemlje + 2 g teleutospora/1 kg semena). Izvršena je korelaciona i regresiona analiza ispitivanog parametara infekcije u odnosu na temperaturu i padavine. Stepen zaraženosti klasova je zavisio od izvora inokuluma Tilletia spp., a uočene su razlike u nivou infekcije između varijanti II i III, kao i III i IV. Kasniji rokovi setve (drugi i treći) su uticali značajno na ispitivani parametar infekcije, ali između njih nisu utvrđene značajne razlike. Kritični period u kom temperature utiču na ostvarivanje infekcije u uslovima kad su teleutospore u zemlji jedini izvor inokuluma traje 60 dana nakon setve (r>+0,52). Najveći broj biljaka je zaražen u prvoj i nešto manje u drugoj dekadi posle setve (r>0,41), pri čemu je optimalna temperatura u tom periodu iznosila 5,0-6,0ºC. Prvih 60 dana nakon setve je, takođe, kritičan period za ostvarivanje infekcije u uslovima kad su teleutospore na semenu jedini izvor inokuluma (r>+0,50). Najveći broj biljaka je zaražen u trećoj i nešto manje u petoj dekadi posle setve (r lt -0,45), pri čemu je optimalna temperatura u tim dekadama iznosila 6,0-7,0ºC. U uslovima kad infekciju pšenice ostvaruju teleutospore prisutne na semenu i u zemlji kritičan period traje 120 dana posle setve (r>+0,42), pri čemu je maksimalna infekcija ostvarena pri optimalnoj temperaturi 4,0-5,0ºC

Otpornost novosadskih sorti pšenice prema fuzariozi klasa u prirodnim uslovima zaraze

Fusarium head blight caused by Fusarium graminearum is a very destructive pathogen and can cause significant losses in yield by total or partial destruction of grain. One of the main ways of control this pathogen is growing resistant varieties. Resistance to F. graminearum was examined on 26 NS wheat varieties in natural conditions of infection, determining the percentage of Fusarium damaged kernels. The loss in weight of wheat kernels due to infection by F. graminearum was determined on the basis of the difference in 1000 kernel weight of healthy kernels and 1000 kernel weight in which were located Fusarium damaged kernels. The percentage of Fusarium damaged kernels was ranged from 1-18.3%. The largest percentage of infected kernels in field conditions had durum wheat varieties Dušan (18.3%) and Durumko (17%). The facultative variety Nevesinjka had 17% Fusarium damaged kernels. The lowest percentage of Fusarium damaged kernels had varieties Zlatka and Sofija (1.3%). Reducing in the 1000 kernel weight was noticed in all the studied varieties and was ranged from 1.6 to 15.1%. Between the percentage of Fusarium damaged kernels and loss in weight of wheat kernels was found a significant correlation (0,59). .Prouzrokovač fuzarioze klasa (Fusarium graminearum) je veoma destruktivan patogen i može prouzrokovati značajne gubitke u prinosu, potpunom ili delimičnom destrukcijom zrna. Jedan od osnovnih načina njegovog suzbijanja je gajenje otpornih genotipova. Otpornost prema fuzariozi klasa ispitivana je na 26 novosadskih sorti pšenice u uslovima prirodne zaraze, na osnovu procenta zaraženih zrna. Gubitak u masi zrna izračunat je na osnovu razlike između mase 1000 zdravih i mase 1000 zrna među kojima su bila i fuzariozna. U uslovima prirodne zaraze, procenat fuzarioznih zrna kretao se od 1-18.3%. Najveći procenat zaraženih zrna bio je kod sorti durum pšenice Dušan (18.3%) i Durumko (17%). Fakultativna sorta Nevesinjka imala je 17% zaraženih zrna. Najniži procenat fuzarioznih zrna imale su sorte Zlatka i Sofija (1.3%). Smanjenje mase 1000 zrna uočeno je kod svih ispitivanih sorti i kretalo se od 1.6 do 15.1%. Između procenta fuzarioznih zrna i gubitaka u masi 1000 zrna utvrđena je značajna korelacija (0,59).

The challenge of managing yellow rust (Puccinia striiformis f.sp. tritici) in winter wheat: how combined climate and pathogen stressors impact variability in genotype reactions

Despite the ongoing evolution of wheat pathogens due to the selection pressures of agro-ecological conditions, many studies have often overlooked the combined impact of both biotic and abiotic factors on disease occurrence. From 2016 to 2023, a comprehensive screening of obligate pathogens, including B. graminis f. sp. tritici, P. graminis f. sp. tritici, P. triticina, and P. striiformis f. sp. tritici, was carried out. This screening was conducted on a phenotyping platform encompassing 2715 winter wheat genotypes and their wild relatives, both with and without resistant genes (Lr, Yr, and Sr) for rust diseases. The data were analyzed using PCAmix, best subsets regression, and linear regression modeling. The findings from this study reveal that the plant reactions to leaf and yellow rust infections is far from straightforward. It is heavily influenced not only by prevalent rust races and climatic factors that impact pathogen life cycles but also by variations in the susceptibility reactions of wheat genotypes to the broader agro-ecological conditions. We also observed a tendency for leaf rust and yellow rust to coexist within the same host plant, even though yellow rust is typically considered more aggressive. We reported for the first time genes related to yellow rust resistance breakdown in Serbia in 2023. Lastly, we underscored the importance of investigating resistance responses to rust diseases not exclusively through the interrelation between resistance genes and pathogen virulence, but also by considering how plants respond to the combined stresses of abiotic and biotic factors. Consequently, our study sets the groundwork for further research into how plants respond to multiple stressors and contributes for further investigations related with effective integrated rust management

Occurrence of grass bunt in Vojvodina and its influence on wheat seed quality control

Causal agents of grass bunt, which infect wild grass hosts in Bromus, Festuca, Ventenata and Vulpia, are Tilletia species whose teliospores could be found in wheat seed samples too. Among them, T. bromi is morphologically similar to those of quarantined T. contraversa, and misidentification of this species could lead to commodity rejection. As a result, monitoring the presence of teliospores of quarantined species in seed samples, and identification of Tilletia species on the basis of morphological characteristics is difficult and in some cases impossible. In order to investigate the presence of grass bunt in seed samples of wheat in Vojvodina, teliospore extraction was carried out by using the size-selective sieving wash method and the OEPP/EPPO diagnostic protocol for Tilletia indica (2007). The analysis of 151 samples of basic, certified and commercial non-processed seed of wheat revealed that 127 samples were contaminated with T. caries, while 12 samples were contaminated with teliospores of Tilletia species which had morphological characteristics that correspond to T. bromi complex or quarantined T. contraversa. These teliospores displayed prominent gelatinous sheath with conspicuous depth of reticulations. Molecular identification of grass bunt teliospores was not possible in this study, because contamination level was too low (1 teliospore per 10 seeds). However, knowing that teliospores of T. bromi often occur in wheat seed samples in very low numbers there is a need for standardization of molecular techniques for the identification of a single teliospore of Tillletia species in order to make plant protection more efficient and reliabl

Interaction of Two Neonicotinoid Insecticides and Lr Genes Focusing Wheat Growth and Residues

Seedlings of ten Lr near-isogenic lines (NIL) and four wheat lines with enhanced resistance to Puccinia triticina were treated with overdosed neonicotinoid insecticides. The enzyme of Lr 20 gene accelerated thiacloprid degradation while Lr 29 gene accelerated thiamethoxam degradation according to NILs upper plant parts lengths reduction by 6% or 10% six days after the last of three daily treatments. Lr 27 and Lr 33 effects were intermediate on thiamethoxam but only in the driest conditions. Among other NILs the growth was increased 1-5% by N faster release of S or Cl. The accumulation of Lr 20 and Lr 9 facilitated treatment in the late grain filling period when the amount of their circled residues in seed was permissible. In semiarid regions, when thiamethoxam was applied before June, respecting the adequate leaf area duration of prevalent varieties, interaction with Lr 29 could be also practical through simultaneous release of fungi reducing elements

Jari ječam Lav i Branko

In 2000, the Federal Variety Commission registered two new cultivars of spring barley Lav and Branko. Botanically, both are classified as two-rowed spring barley (Hordeum sativum, ssp. distichum var. nutans). The cultivar Lav was developed by crossing the cultivars Novosadski 294, Alva, and Novosadski 313, while the cultivar Branko is a result of a cross between the cultivars Kaskada and Novosadski 310. Both of the cultivars have an elastic stem resistant to lodging that is shorter than that of the standard cultivar Novosadski 294 (on average, Lav is shorter by 11.8 cm and Branko by 3.9 cm). Looking at an average of all three study years (1996-1998) and all three trial locations, both Lav (5,748 kg/ha) and Branko (5,432 kg/ha) significantly outyielded the standard (4,230 kg/ha). Both cultivars also have better technological characteristics of the grain and malt than Novosadski 294. Lav has a low protein content (11.2%), whereas Branko sprotein content is somewhat higher (13.5%) than that of the standard.Savezna sortna komisija. 2000. godine priznala je dve nove sorte jarog ječma Lav i Branko. Obe sorte po botaničkoj klasifikaciji pripadaju jarom dvoredom ječmu Hordeum sativum, ssp. distichum var. nutans. Sorta Lav nastala je ukrštanjem sorti Novosadski 294, Alva i Novosadski 316, a sorta Branko ukrštanjem sorti Kaskade i Novosadski 310. Sorte imaju elastičnu stabljiku otpornu na poleganje i nižu u odnosu na standardnu sortu Novosadski 294, sorta Lav je u proseku niža za 11,8 cm a sorta Branko za 3,9 cm. U proseku za sva tri lokaliteta i sve tri godine (1996-1998) sorta Lav (5748 kg ha-1) i sorta Branko (5432 kg ha-1) su dale visoko značajno veće prinose u odnosu na standardnu sortu (4230 kg ha-1). Obe sorte su po tehnološkim osobinama zrna i slada bolje od standardne sorte Novosadski 294. Sorta Lav ima nizak sadržaj proteina 11,2% a sorta Branko ima nešto viši sadržaj proteina 13,5% u odnosu na standard

Metode za detekciju Phytophthora fragariae var. rubi na malini

Phytophthora fragariae var. rubi (Wilcox & Duncan), a causal agent of raspberry root rot, is a serious soil-borne pathogen listed by EPPO as an A2 quarantine pest. Root samples were collected from badly diseased raspberry plants showing a variety of characteristic and often dramatic symptoms during surveys carried out in western Serbia in 2002. Identification of the causal agent was performed in collaboration work with the Scottish Crop Research Institute (S.C.R.I.), Dundee, UK. Necrotic roots were plated on selective French bean agar (incorporating ampicilin, ryfamicin, bavistin and hymexasol). Detection of isolates was based on cultural and morphological features compared with referent cultures. DNA was extracted directly from the sampled roots using extraction buffer (200 mM Tris-HCl pH 8.5, 250 mM NaCl, 25 mM EDTA, 0.5% SDS), purified by multi spin separation columns [Thistle Scientific (Axygen)] or in 24:1 mixture of chlorophorm-isoamyl alcohol and amplified by nested PCR (ITS 4 and DC 6 for first round, DC 1 and DC 5 for second round). Diluted DNA extracts were also amplified by conventional PCR with modified 'universal' Phytophthora primers (ITS 6, ITS 7 and ITS 8, Cooke et al., 2000) and digested with Msp1. Digestion patterns of the universal primers PCR product from infected roots matched those of Scottish strains. P. fragariae var. rubi occurred on 8 out of 14 sites. Our results indicate that nested PCR (ITS 4 and DC 6 for first round, DC 1 and DC 5 for second round) or digestion of the 'universal' Phytophthora primers PCR product for detection of P. fragariae var. rubi are more sensitive and less time-consuming and therefore recommended for use.Phytophthora fragariae var. rubi (Wilcox & Duncan), prouzrokovač truleži korena maline, je veoma značajan zemljišni patogen A2 karantinskog statusa u EPPO. Uzorci korena su sakupljeni sa jako zaraženih biljaka maline koje su ispoljavale čitav niz karakterističnih i često dramatičnih simptoma tokom pregleda koji su vršeni u zapadnoj Srbiji 2002. godine. Identifikacija prouzrokovača je izvršena u saradnji sa Scottish Crop Research Institute (S.C.R.I.), Dundee, UK. Nekrotični korenčići su unošeni u selektivnu French bean podlogu, koja je sadržala ampicilin, rifamicin, bavistin i himeksazol. Detekcija dobijenih izolata je vršena posmatranjem kulture i morfoloških karakteristika i poređenjem sa autentičnim kulturama. DNK je ekstrahovana direktno iz uzorkovanih korenova pomoću ekstrakcionog pufera (200 mM Tris-HCl pH 8,5, 250 mM NaCl, 25 mM EDTA, 0,5% SDS), prečišćena Multi spin separacionim kolonama (Thistle Scientific (Axygen) ili 24:1 mešavinom hloroforma i izoamil alkohola i amplifikovana nested PCR (ITS 4 i DC 6 za prvi krug, DC 1 i DC 5 za drugi krug). Rastvoreni DNK ekstrakti su takođe amplifikovani putem konvencionalnog PCR sa modifikovanim 'univerzalnim' Phytophthora prajmerima (ITS 6, ITS 7 i ITS 8, Cooke i sar., 2000) i di gestirani sa Msp1. Digestioni paterni proizvoda univerzalnih prajmera iz zaraženih korenova su se poklapali sa škotskim izolatima. P. fragariae var. rubi se javila na 8 od 14 lokaliteta. Naši rezultati ukazuju da su nested PCR (ITS 4 i DC 6 za prvi krug, DC 1 i DC 5 za drugi krug) i digestija produkta univerzalnih Phytophthora prajmera u cilju detekcije P. fragariae var. rubi senzitivnije i zahtevaju manje vremena, pa ih stoga preporučujemo za korišćenje

Variability of Stem-Base Infestation and Coexistence of Fusarium spp. Causing Crown Rot of Winter Wheat in Serbia

Investigations related with factors influencing root and crown rot are rare and mainly related to farming practice and soil management. The main objective of this study was to examine broader range of factors influencing stem-base infestation of winter wheat in the field conditions. The effect of spatial distribution of infected plants on disease index (DIs) assessments was also investigated. Analysis of factors influencing DIs of crown rot of wheat demonstrated significant influence of the growing seasons (P lt 0.001) and extreme fluctuations in winter temperatures (P lt 0.001). In addition to that, localities together with their interaction with the growing season also significantly influenced DIs (P lt 0.001). Aggregation of infected plants influenced variability of DI estimations, and it was pointed out that more extensive investigation should be conducted on broad range of DI in order to establish sampling method giving uniform sampling precision. Fusarium graminearum was shown to be predominant Fusarium species in Serbia (72.6%) using sequence-characterized amplified region analysis. Interestingly F. oxysporum was isolated in higher frequencies (27.4%) than it was reported in the literature. Given that there were no reports on the diversity of Fusarium species causing crown rot of wheat in Serbia, this study presents first report on this important subject. It also indicated that more attention should be focused on combined effects of abiotic and biotic factors influencing stem-base infestation of winter wheat. This knowledge will contribute to better understanding of factors influencing root and crown rot of wheat which would ensure sustainable disease management in the future

Tolerantnost sejanaca sorti pšenice preko ubrzane degradacije glifosata

Lengths of seedlings aboveground parts of nine wheat varieties grown in greenhouse were reduced by 4-20%. They were tested during April at around 20oC after twice daily treatments with glyphosate based herbicide (0.5 ml in 1l water solution, 0.5 dl on 0.5 m2). When results of permanent artificially and daily lighted trials were compared, four groups of varieties were recognized same as was when near isogenic lines containing different leaf rust resistance genes (Lr NILs) were focused in winter. Growth of variety Pobeda decreased more when seedlings were not permanent lighted which confirmed the common herbicide effect. Tolerance of other varieties was again explained by enzymatic degradation of glyphosate and chlorophyll inhibition by consequential phosphorus acids. Varieties Simonida, Tavita and Rapsodia were similar by reaction to glyphosate as Lr 1 and Lr 21 NILs. NS 40S contained Lr 3a with increased hydrolytic stability compared to Lr 24 but able to cleave external single phosphorus for the difference of Lr 19 or Lr 29. Their final effect was similar to previous stated of Lr 15 NIL during the winter. Varieties Gora and Metka had gene Lr 19, Enigma Lr 29 while Ilina Lr 24. Focusing herbicide residua transfer in seed probability, accounting optimal time for recovering ability of chlorophyll and temporary higher temperatures necessary for Lr genes even parasite free activity the varieties Gora, Metka and Enigma appeared to be possible solution for glyphosate apply near wheat heading in semiarid regions.Dužine nadzemnih delova sejanaca devet sorti pšenice gajenih u staklari bile su redukovane 4-20%. Testirane su pri temperaturama oko 20oC tokom proleća posle dva dnevno uzastopna tretmana herbicidom na bazi glifosata (0,5 ml u 1l vodenog rastvora, 0,5 dl na 0,5 m2). Na osnovu razlika između stalno veštački i dnevno osvetljenog ponavljanja prepoznate su četiri grupe sorti, što je potvrdilo rezultate dobijene kod izogenih linije različitih gena otpornosti prema prouzrokovaču lisne rđe (NIL) testiranih tokom zime. Rast sorte Pobeda bio je usporeniji kada nije bila permanentno osvetljena te je prepoznat uobičajen efekat herbicida. Tolerantnost drugih sorti je bila povezana sa ubrzanom degradacijom glifosata te uticajem posledične fosforne kiseline na inhibiciju hlorofila. Sorte Rapsodija, Simonida i Tavita su po reakciji prema herbicidu bile slične Lr 1 i Lr 21 liniji. Ubrzano žućenje lista NS 40S bilo je zavisno od gena Lr 3a neuticajnog na poslednje fosforne residue nakon otpuštanja kiseonika, dok je sličan efekat hidrolitički najstabilnijeg Lr 15 u NIL isključen na osnovu analiza uticaja na degradaciju glutena. Na osnovu pomenutih kriterijuma, sorte Gora i Metka su sadržale Lr 19, Enigma Lr 29 a Ilina Lr 24. Poštujući pre svega više vremena za eliminaciju originalnih rezidua herbicida blizu klasanja, česte temperature uslove povoljne za aktivnost Lr gena, posledice na rast te brži oporavak hlorofila, za tretman u to doba u semiaridnim regionima, sorte s Lr genima kao Gora, Metka i Enigma su prepoznate kao moguće praktično rešenje. Tretman sorte Ilina je rizičan usled očekivanog izostanka efekta a ostalih usled rezidua