Morphological and molecular characterization of Ascochyta species

Poslednjih godina u različitim delovima Srbije zapažena je manja ili veća pojava patogena iz Ascochyta spp. kompleksa, kako na stočnom, tako i na konzumnom grašku. Navedeni kompleks čine tri fitopatogene gljive: Didymella pinodes, Didymella pinodella i Ascochyta pisi. Kompleksno oboljenje prouzrokovano gljivama iz Ascochyta spp. kompleksa se naziva Crna pegavost graška. Cilj istraživanja je bio da se prouče morfološke, molekularne i odgajivačke odlike gljiva D. pinodes, D. pinodella i A. pisi, kao i njihova patogenost i rasprostranjenost na teritoriji Republike Srbije, kao i da se ispita tolerantnost domaćeg sortimenta stočnog graška prema navedenim patogenima. U periodu od 2013. do 2015. godine, utvrđeno je prisustvo Ascochyta spp. na 27 različitih lokaliteta u Srbiji, kao i na po jednom lokalitetu u Bosni i Hercegovini, Turskoj i Francuskoj. Morfološko - molekularnim analizama sakupljenih izolata, prvi put je potvrđeno prisustvo D. pinodes i D. pinodella na teritoriji Srbije, kao i prisustvo A. pisi na teritoriji BiH. Od ukupnog broja izolata poreklom iz Srbije, 48 izolata (62%) pripada vrsti D. pinodes, 26 izolata (34%) vrsti A. pisi i 3 izolata (4%) vrsti D. pinodella. Molekularna identifikacija svih 89 izolata sprovedena je na osnovu ITS i TEF1-α sekvenci, kao i na osnovu dužine amplikona IGS1 prajmera. IGS1 prajmeri su omogućili pouzdanu i nedvosmislenu identifikaciju pojedinačnih vrsta D. pinodes, D. pinodella i A. pisi. Navedeni prajmerski par je po prvi put uspešno primenjen na vrsti A. pisi. Sagledavanjem interakcija između različitih uslova gajenja i testiranih izolata Ascochyta spp., uočene su statistički značajne intraspecijske varijacije u pogledu porasta kolonija. Kod ispitivanih izolata D. pinodes, D. pinodella i A. pisi, u zavisnosti od svetlosno-temperaturnog režima i hranljive podloge uočena je velika varijabilnost u boji supstratne i vazdušne micelije. Kod pojedinih izolata vrste D. pinodella registrovano je formiranje belih kristala lepezastog, pahuljastog i paperjastog oblika na PDA hranljivoj podlozi pri temperaturi od 20ºC. Peritecije gljive D. pinodes su se formirale samo na Conn’s hranljivoj podlozi na 15ºC u tami, kao i na 20ºC pri oba svetlosna režima. Izolati D. pinodes, D. pinodella i A. pisi ispoljili su veliku varijabilnost u dužini i širini obrazovanih askospora i piknospora kao i hlamidospora u različitim uslovima gajenja. U ovom radu je po prvi put zabeleženo formiranje sklerocija kod izolata vrsta D. pinodes i D. pinodella u ispitivanim laboratorijskim uslovima. Veštačkom inokulacijom uočena je i velika varijabilnost u patogenosti između izolata D. pinodes, D. pinodella i A. pisi, prema domaćim sortama stočnog graška. Sorta Dukat je bila najosetljivija na ispitivane patogene Ascochyta spp. kompleksa, dok je sorta Kosmaj bila najtolerantnija.The presence of pathogens from the complex Ascochyta spp., either in low or high levels, has been confirmed on both forage pea and field pea in different regions of Serbia in the previous several years. This complex consists of three phytopathogenic fungi: Didymella pinodes, Didymella pinodella and Ascochyta pisi. Ascochyta blight (blackspot) of field pea is a composite disease caused by the fungi belonging to Ascochyta spp. complex. The aim of this dissertation was to study the morphological, molecular and selection characteristics of the fungi D. pinodes, D. pinodella and A. pisi, and their pathogenicity and distribution on the territory of the Republic of Serbia, as well as to test the tolerance of domestic forage pea cultivars to the given pathogens. In the period 2013-2015, the presence of Ascochyta spp. was confirmed on 27 different sites in Serbia, as well as on one site in Bosnia and Herzegovina, one in Turkey, and one in France. Morphological and molecular analyses of the collected isolates confirmed the first appearance of D. pinodes and D. pinodella in Serbia, and A. pisi in Bosnia and Herzegovina. Out of the total number of isolates that originated from Serbia, 48 isolates (62%) belong to the species D. pinodes, 26 isolates (34%) belong to A. pisi and 3 isolates (4%) belong to D. pinodella. Molecular identification of all 89 isolates was based on ITS and TEF1-α sequences and amplicon length of IGS1 primer. IGS1 primers enabled reliable and unambiguous identification of individual species of D. pinodes, D. pinodella and A. pisi. The mentioned primer pair was successfully applied to A. pisi for the first time. The interactions between different growing conditions and the tested isolates of Ascochyta spp. were studied, and statistically significant intraspecies variations in colony growth were found. Depending on the light-temperature regime and growth medium, the tested isolates of D. pinodes, D. pinodella and A. pisi showed high variability in the colour of substrate and aerial mycelia. Certain isolates of D. pinodella formed white fan-shaped, dendritic and plumose crystals on PDA growth medium at 20ºC. Perithecia of D. pinodes formed only on Conn’s medium at 15ºC in the dark, and at 20ºC in both lights regimes. Isolates of D. pinodes, D. pinodella and A. pisi showed high variability in length and width of the formed ascospores and picnospores, as well as chlamydospores under different growing conditions. This study is the first report on the formation of sclerotia in isolates of D. pinodes and D. pinodella under the tested laboratory conditions. Artificial inoculation also showed a high variability in pathogenicity among the isolates of D. pinodes, D. pinodella and A. pisi to domestic cultivars of forage pea. The cultivar Dukat was the most susceptible to the tested pathogens of Ascochyta spp. complex, and the cultivar Kosmaj was the most tolerant

Morfološko - molekularna karakterizacija patogena iz Ascochyta spp. kompleksa

The presence of pathogens from the complex Ascochyta spp., either in low or high levels, has been confirmed on both forage pea and field pea in different regions of Serbia in the previous several years. This complex consists of three phytopathogenic fungi: Didymella pinodes, Didymella pinodella and Ascochyta pisi. Ascochyta blight (blackspot) of field pea is a composite disease caused by the fungi belonging to Ascochyta spp. complex. The aim of this dissertation was to study the morphological, molecular and selection characteristics of the fungi D. pinodes, D. pinodella and A. pisi, and their pathogenicity and distribution on the territory of the Republic of Serbia, as well as to test the tolerance of domestic forage pea cultivars to the given pathogens. In the period 2013-2015, the presence of Ascochyta spp. was confirmed on 27 different sites in Serbia, as well as on one site in Bosnia and Herzegovina, one in Turkey, and one in France. Morphological and molecular analyses of the collected isolates confirmed the first appearance of D. pinodes and D. pinodella in Serbia, and A. pisi in Bosnia and Herzegovina. Out of the total number of isolates that originated from Serbia, 48 isolates (62%) belong to the species D. pinodes, 26 isolates (34%) belong to A. pisi and 3 isolates (4%) belong to D. pinodella. Molecular identification of all 89 isolates was based on ITS and TEF1-α sequences and amplicon length of IGS1 primer. IGS1 primers enabled reliable and unambiguous identification of individual species of D. pinodes, D. pinodella and A. pisi. The mentioned primer pair was successfully applied to A. pisi for the first time. The interactions between different growing conditions and the tested isolates of Ascochyta spp. were studied, and statistically significant intraspecies variations in colony growth were found. Depending on the light-temperature regime and growth medium, the tested isolates of D. pinodes, D. pinodella and A. pisi showed high variability in the colour of substrate and aerial mycelia. Certain isolates of D. pinodella formed white fan-shaped, dendritic and plumose crystals on PDA growth medium at 20ºC. Perithecia of D. pinodes formed only on Conn’s medium at 15ºC in the dark, and at 20ºC in both lights regimes. Isolates of D. pinodes, D. pinodella and A. pisi showed high variability in length and width of the formed ascospores and picnospores, as well as chlamydospores under different growing conditions. This study is the first report on the formation of sclerotia in isolates of D. pinodes and D. pinodella under the tested laboratory conditions. Artificial inoculation also showed a high variability in pathogenicity among the isolates of D. pinodes, D. pinodella and A. pisi to domestic cultivars of forage pea. The cultivar Dukat was the most susceptible to the tested pathogens of Ascochyta spp. complex, and the cultivar Kosmaj was the most tolerant.Poslednjih godina u različitim delovima Srbije zapažena je manja ili veća pojava patogena iz Ascochyta spp. kompleksa, kako na stočnom, tako i na konzumnom grašku. Navedeni kompleks čine tri fitopatogene gljive: Didymella pinodes, Didymella pinodella i Ascochyta pisi. Kompleksno oboljenje prouzrokovano gljivama iz Ascochyta spp. kompleksa se naziva Crna pegavost graška. Cilj istraživanja je bio da se prouče morfološke, molekularne i odgajivačke odlike gljiva D. pinodes, D. pinodella i A. pisi, kao i njihova patogenost i rasprostranjenost na teritoriji Republike Srbije, kao i da se ispita tolerantnost domaćeg sortimenta stočnog graška prema navedenim patogenima. U periodu od 2013. do 2015. godine, utvrđeno je prisustvo Ascochyta spp. na 27 različitih lokaliteta u Srbiji, kao i na po jednom lokalitetu u Bosni i Hercegovini, Turskoj i Francuskoj. Morfološko - molekularnim analizama sakupljenih izolata, prvi put je potvrđeno prisustvo D. pinodes i D. pinodella na teritoriji Srbije, kao i prisustvo A. pisi na teritoriji BiH. Od ukupnog broja izolata poreklom iz Srbije, 48 izolata (62%) pripada vrsti D. pinodes, 26 izolata (34%) vrsti A. pisi i 3 izolata (4%) vrsti D. pinodella. Molekularna identifikacija svih 89 izolata sprovedena je na osnovu ITS i TEF1-α sekvenci, kao i na osnovu dužine amplikona IGS1 prajmera. IGS1 prajmeri su omogućili pouzdanu i nedvosmislenu identifikaciju pojedinačnih vrsta D. pinodes, D. pinodella i A. pisi. Navedeni prajmerski par je po prvi put uspešno primenjen na vrsti A. pisi. Sagledavanjem interakcija između različitih uslova gajenja i testiranih izolata Ascochyta spp., uočene su statistički značajne intraspecijske varijacije u pogledu porasta kolonija. Kod ispitivanih izolata D. pinodes, D. pinodella i A. pisi, u zavisnosti od svetlosno-temperaturnog režima i hranljive podloge uočena je velika varijabilnost u boji supstratne i vazdušne micelije. Kod pojedinih izolata vrste D. pinodella registrovano je formiranje belih kristala lepezastog, pahuljastog i paperjastog oblika na PDA hranljivoj podlozi pri temperaturi od 20ºC. Peritecije gljive D. pinodes su se formirale samo na Conn’s hranljivoj podlozi na 15ºC u tami, kao i na 20ºC pri oba svetlosna režima. Izolati D. pinodes, D. pinodella i A. pisi ispoljili su veliku varijabilnost u dužini i širini obrazovanih askospora i piknospora kao i hlamidospora u različitim uslovima gajenja. U ovom radu je po prvi put zabeleženo formiranje sklerocija kod izolata vrsta D. pinodes i D. pinodella u ispitivanim laboratorijskim uslovima. Veštačkom inokulacijom uočena je i velika varijabilnost u patogenosti između izolata D. pinodes, D. pinodella i A. pisi, prema domaćim sortama stočnog graška. Sorta Dukat je bila najosetljivija na ispitivane patogene Ascochyta spp. kompleksa, dok je sorta Kosmaj bila najtolerantnija

Efikasnost Trichoderma spp. izolata protiv najčešćih gljivičnih patogena

Nowadays, organic food production demands more environmental friendly control of plant diseases. Biocontrol based on Trichoderma spp. usage is a promising due to Trichoderma is aggressive to broad range of phytopathogenic fungi. Given that, the aim of this study was to test in vitro antagonistic ability of ten native Serbian Trichoderma strains to ten common fungal pathogens. Study confirmed that Trichoderma spp. inhibits radial growth of Ascochyta pinodella (76.9%), A. pinodes (60.0%), A. pisi (68.5%), Fusarium graminearum (71.1%), F. proliferatum (63.9%), F. verticillioides (62.6%), F. oxysporum (63.9%), Macrophomina phaseolina (63.8%), and Pyrenophora teres (83.9%). These are first reports of Trichoderma spp. in vitro efficacy against A. pisi, A. pinodes, A. pinodella and P. teres. The lowest inhibitory effect was registered in dual cultures with Sclerotinia sclerotiorum - 52.2%.U današnje vreme, organska proizvodnja sve više zahteva primenu ekoloških metoda u suzbijanju biljnih bolesti. Biološka kontrola bazirana na upotrebi Trichoderma vrsta obećava jer su Trichoderma vrste izuzetno agresivne prema velikom broju fitopatogenih gljiva. Stoga je cilj ovih istraživanja bio da se in vitro testira antagonističko dejstvo deset Trichoderma spp. izolata poreklom iz Srbije na deset ekonomski značajnih fitopatogenih gljiva. Istraživanja su potvrdila da su testirani izolati Trichoderma spp. inhibirali radijalni porast vrsta do: Ascochyta pinodella (76,9%), A. pinodes (60,0%), A. pisi (68,5%), Fusarium graminearum (71,1%), F. proliferatum (63,9%), F. verticillioides (62,6%), F. oxysporum (63,9%), Macrophomina phaseolina (63,8%) i Pyrenophora teres (83,9%). Najniža inhibicija porasta patogena je registrovana u dvojnim kulturama sa vrstom S. sclerotiorum – do 52,2% inhibicije

Značaj izbora sorte u intenzivnoj proizvodnji lucerke

Alfalfa is an autotetraploid, perennial forage crop adapted to different environments and management systems. Trial with 12 alfalfa populations was established in spring of 2014. The research involved 9 commercial alfalfa varieties from IFVCNS, Serbia, and included 3 experimental populations in the final phase of breeding program. The main objectives of this paper were to examine the impact of variety selection on alfalfa yield and plant height in intensive cutting management in order to define harvesting strategies (using 6 and 5 cuts per season), with main goal to maximize profit on alfalfa farms in Serbia and Southeast Europe. Our study clearly demonstrates that there is genetic potential in some Serbian varieties (NS Sila, Nera, NS Jelena, and Banat VS) for use in intensive cutting systems with 6 cuts per year that can meet farmers' needs in conventional or organic type of alfalfa hay production.This research represents an initial guideline for the alfalfa variety selection in intensive cutting management systems in Serbia and Southeast Europe.Lucerka (Medicago sativa L.) je najznačajnija višegodišnja krmna biljka visokih prinosa krme, sena, senaže, odlične hranljive vrednosti. Sistem kosidbe predstavlja odlučujući faktor u determinaciji prinosa i kvaliteta lucerke. U cilju provere reakcije populacija lucerke stvorenih u Institutu za ratarstvo i povrtarstvo na intenzivan sistem kosidbe (sa primenjenih 6 otkosa u II i III godini života i 5 otkosa u IV godini trajanja useva) postavljen je ogled u Novom Sadu u 2014. godini, a rezultati su praćeni tokom 2015-2017. godine. U ispitivanje je uključeno 9 priznatih sorti i 3 eksperimentalne populacije lucerke stvorene u različitom vremenskom periodu, primenom različitih metoda oplemenjivanja i germplazme različitog porekla. Dobijeni rezultati pokazuju da režim kosidbe lucerke treba prilagoditi tipu/grupi sorti, načinu proizvodnje i rejonu gajenja. Najveći prinosi suve materije tokom perioda ispitivanja registrovani su kod sorti NS Sila (18,4 t/ha), Nera (18,2 t/ha), Banat VS (17,9 t/ha) i NS Jelena (17,7 t/ha) u intenzivnom sistemu kosidbe. Režim kosidbe sa 6 otkosa u Srbiji predstavlja realan način proizvodnje, ali prilagođavanje ovom sistemu kosidbe zavisi od cilja proizvodnje, sorte, rejona gajenja, starosti useva. Genetički potencijal NS sorti lucerke koji odgovara maksimalnom intenzitetu kosidbe sa 6 otkosa u godini ostvaren je sa sortama NS Sila, Nera, Banat VS i NS Jelena, a za sistem kosidbe sa 5 otkosa u godinama pune eksploatacije, a koji najviše odgovara farmerima u umereno-kontinentalnom klimatu Srbije, mogu se preporučiti i sorte NS Banat ZMS II, NS Mediana ZSM V. Ostvareni rezultati predstavljaju značajan doprinos razumevanju značaja primene intezivnog sistema kosidbe tokom godina iskorišćavanja a posebno kritičnoj fazi vezanoj za izbor sorte i različite rejone gajenja, načine iskorišćavanja, kao i potrebe različitih tržišta za senom lucerke

Resistance of some sunflower genotypes to broomrape (Orobanche cumana Warll.) and its influence on seed yield and quality

Broomrape (Orobanche cumana Wallr.) is a flowering parasitic plant which is one of the major sunflower parasites. Different sunflower hybrids have different reaction to the broomrape. The aim of this paper is to evaluate influence of broomrape attack to seed yield and quality in different experimental sunflower genotypes. In this trial we evaluated 13 experimental hybrids to broomrape which belong to 3 different groups: resistant to broomrape, high-oleic and resistant to imidazolinone herbicides and 4 standard hybrids. Out of 13 inoculated sunflower hybrids broomrape was noticed on 8. Obtained seed yield and oil content were higher in non-infected plants in comparison to the plants infected with broomrape in five hybrids. The negative correlations between number of broomrape plants per sunflower plant and seed yield (-0.419717) and oil yield (-0.409165) were obtained

Analysis of storage proteins in a worldwide collection of pea seeds

Peas (Pisum sativum L.) are an important source of vegetable protein for both humans and animals. However, pea seed proteins are limited in sulfur-containing amino acids (SCAA) and thus considered to be an insufficient source. The main seed proteins in pea are 7S (vicilins, convicilins) and 11S (legumins) globulins. Because 11S globulins contain more SCAA than 7S globulins, variations in the 7S/11S ratio affects the nutritional quality of pea seeds. Sodium Dodecyl Sulphate Polyacrylamide Gel Electrophoresis (SDS-PAGE) was used to separate seed proteins from 260 pea genotypes from around the world (the EUCLEG collection). Based on the electropherogram, 18 protein bands were densitometrically measured. Protein compositional data are intrinsically multivariate. The protein concentration of each genotype is presented in closed form i.e., sum up to 100%. Therefore, for multivariate data analysis specific statistical methodology was used. All methods used in the study were carried out in classical and robust manner that was resistant to outlier observations. The storage protein composition of the genotypes studied varied greatly; in some cases, only traces of the main components were found. The results suggest that some of the genotypes tested could be useful in various breeding programs aimed at producing agronomically viable plants, yielding high-protein seed with specific composition of storage proteins for specific food applications

Uticaj faze košenja i setvene norme na prinos i kvalitet lucerke

Cultivated alfalfa (Medicago sativa L.) is a highly productive forage crop with great economic potential. Our objectives were to investigate the effects and interactions of environment, harvest maturity stage, seeding rate and cultivars on alfalfa dry matter yield and quality. The field experiment was carried out over 2010-2012 at the Experimental Field of Institute of Field and Vegetable Crops in Novi Sad, at two locations: (I) Cenej, and (II) Rimski Šančevi, which were characterized by a contrasting soil condition. The experimental treatments included two seeding rates of 8 and 16 kg ha-1, three different harvest maturity stages of alfalfa, and four alfalfa cultivars included as a subplot in every treatment. Harvesting alfalfa five times within a year (cutting in the beginning of flowering) in the second and third year of stand life is the most efficient harvest regime that allows full exploitation of cultivar genetic potential and environmental conditions. There was no difference in yields between harvests at early and full flowering stage (15.9 t ha-1). Data related to forage quality components show increase of nutritive value when harvesting alfalfa in earlier maturity stage. Maturity stage in the moment of harvesting significantly affected all quality parameters. The results obtained suggest that in a temperate climate of Southeast Europe there is little justification for planting higher seeding rates of alfalfa varieties under good establishment practices. Increasing seeding rates above 16 kg ha-1 does not provide a long-term boon in alfalfa production.Lucerka (Medicago sativa L.) je visokoproduktivna krmna biljka velikog ekonomskog potencijala. Cilj rada je bio da se ispita uticaj uslova spoljne sredine, faze košenja, setvene norme i sorte, kao i njihove interakcije, na prinos i kvalitet suve materije lucerke. Poljski ogled je zasnovan na oglednim poljima Instituta za ratarstvo i povrtarstvo u Novom Sadu, na dva lokaliteta: (I) Čenej, i (II) Rimski Šančevi, različitih zemljišnih karakteristika. Tretmani su uključivali dve setvene norme, od 8 i 16 kg ha-1, tri sistema kosidbe i četiri sorte lucerke, tretirane kao podparcele u svakom tretmanu. Kao najbolji sistem kosidbe, u kojem je ostvarena puna eksploatacija i potencijal sorte, bilo je košenje lucerke pet puta godišnje (kosidba u početku cvetanja) u drugoj i trećoj godini života lucerišta. Prinosi ostvareni košenjem na početku i u punom cvetanju se nisu razlikovali (15,9 t ha-1). Podaci o komponentama kvaliteta krme ukazuju na značajno povećanje nutritivne vrednosti pri kosidbi u ranim razvojnim fazama biljaka lucerke. Fenološka faza biljaka u momentu košenja značajno je uticala na sve parametre kvaliteta. Dobijeni rezultati govore da u umerenom klimatu jugoistočne Evrope postoji opravdanje za setvu manje količine semena. Povećanje setvene norme preko 16 kg ha-1 ne obezbeđuje dugoročnu dobit u proizvodnji lucerke

Prvi nalaz Fusarium tricinctum na poljskom jasenu (Fraxinus angustifolia Vahl.) u Srbiji

Monitoring the health status of narrow-leaved ash tree seedlings (forest office Morović, locality Vinična) in the early spring of 2015, after the catastrophic floods in May 2014, revealed presence of large dark necrotic areas on 1–2 year old sprouts. The isolation of the fungal pathogen was done by standard phytopathological protocols. Three representative isolates (K41, K42 and K78) were preliminary detected and purified by a single-spore technique for further morphological, molecular analyses and pathogenicity testing. Morphological characteristics classified the isolates as Fusarium tricinctum. Tested isolates on narrow leaved ash sprouts caused reddish brown elongated necrotic lesions averaged 20.1 mm. Two marker genes, translation elongation factor 1-alpha (TEF1-α) and internal transcribed spacer (ITS1), were used in this study. Using the Basic Local Alignment Search Tool (BLAST) searching engine, nucleotide sequences were compared to all related sequences. Alignement score resulted in 98.9% identities with F. tricinctum for isolate K78, while isolates K41 and K42 showed 94.1% and 94.3% identities with F. tricinctum complex respectively. To the best of our knowledge, this is the first report of F. tricinctum pathogen infection on flood stressed narrow-leaved ash trees in Serbia.Poljski jasen (Fraxinus angustifolia Vahl.) je drvenasta vrsta rasprostranjena u nizijskim šumama u Evropi. Region jugozapadnog Srema gde se nalaze najvrednije šume ove vrste u Srbiji, bio je izložen katastrofalnim poplavama u maju 2014. Praćenjem zdravstvenog stanja sadnica jasena (šuma Morović, lokalitet „Vinična”) u rano proleće 2015. godine otkriveno je prisustvo velikih tamnih nekrotičnih područja na izbojcima starim 1–2 godine. Sa obolelih izbojaka, standardnim fitopatološkim postupkom, urađena je izolacija patogena. Prema morfološkim karakteristikama dobijeni izolati su determinisani kao Fusarium tricinctum. Za dalje analize su uzeta tri reprezentativna monosporna izolata (K41, K42 i K78). BLAST pretragom NCBI nukleotidne baze utvrđeno je 98,9% sličnosti TEF1-α sekvence izolata K78 (MN822227.1) sa Fusarium tricinctum i 100% poklapanja ITS sekvence ovog izolata (GenBank MK928426.1) sa izolatom F. tricinctum ZMXR6 (MT446111.1). IGS sekvence izo lata K41 i K42 (MZ749901 i MZ749902) imale su 94,1% i 94,3% sličnosti sa F. tricinctum kompleksom, na osnovu BLAST pretrage FUSARIUM-ID nukleotidne baze. Testovi patogenosti na izbojcima jasena starim godinu dana pokazali su crvenkasto smeđe izdužene nekrotične lezije prosečne dužine 20,1 mm. Patogen je reizolovan iz izbojaka sa simptomima. Prema našim saznanjima, ovo je prvi nalaz F. tricinctum na stablima poljskog jasena u Srbiji

Poređenje biplot analize i Kangove statistike stabilnosti (YSi) u proceni stabilnosti hibrida kukuruza

Integration of mean yield and stability evaluation into a single analysis is practical for maize hybrids recommendation and approval in multi-environment trials. The objective of this study was (i) to investigate grain yield performance and stability of 21 experimental maize hybrids via the use of the Kang's yield-stability statistics (YSi) and via the sites regression biplot (GGL) from multi-location trial conducted in Serbia; and (ii) to determine if hybrids yield stability was influenced by the linear effect of an environmental index. Hybrid main effect was highly significant and captured 9% of total sum of squares. Hybrid × location interaction was highly significant and accounted for 8.1% of the total sum of squares. Heterogeneity caused by environmental index was statistically non-significant. The same genotypes were recognized as stable by YSi and GGL biplot, but we recommend the sites regression biplot as more informative and precise tool for simultaneous hybrids mean performance and stability estimation.Istovremena procena prinosa i stabilnosti prinosa na osnovu rezultata iz multi-lokacijskih ogleda ima veliki značaj u preporuci hibrida kukuruza. Cilj ovog istraživanja bio je da se ispita (i) prinos i stabilnost prinosa eksperimentalnih hibrida kukuruza pomoću Kangove statistike stabilnosti (YSi) i metodom SREG GGL biplot analize, na osnovu podataka iz multi-lokacijskih ogleda u Srbiji, i (ii) da li su linearni efekti indeksa spoljašnjih sredina uticali na stabilnost hibrida. Glavni efekti genotipa (hibrida) bili su visoko značajni i obuhvatali su 9% od ukupne sume kvadrata. Interakcija hibrid × lokalitet je takođe bila visoko značajna i obuhvatala je 8,1% od ukupne sume kvadrata. Heterogenost uslovljena razlikom između spoljašnjih sredina bila je statistički neznačajna. Na osnovu rezultata obe analize isti genotipovi su izdvojeni kao stabilni ali je prednost na strani SREG modela kao preciznijeg i informativnijeg