<p>Savremeni trendovi na tržištu utiču na sve veću potražnju za speltom (Triticum aestivum ssp. spelta), alternativnom, plevičastom formom pšenice visoke nutritivne vrednosti, koja doprinosi održavanju agroekoloških sistema gajenja. Smatra se da prisustvo plevičastih omotača pruža zaštitu zrna od različitih bolesti i štetočina, što je od naročitog značaja za organsku proizvodnju gde upotreba hemijske zaštite nije dozvoljena. Rod Alternaria obuhvata veliki broj izrazito varijabilnih i široko rasprostranjenih saprofitnih i fitopatogenih vrsta. Značaj Alternaria spp. se ogleda ne samo u smanjenju prinosa i narušavanju kvaliteta zrna pšenice, već i u tome što mnoge vrste ovog roda produkuju toksične metabolite, koji su štetni za zdravlje ljudi i životinja. U cilju preduzimanja blagovremenih i efikasnih mera suzbijanja fitopatogenih vrsta roda Alternaria i monitoringa dominantnih toksigenih vrsta, veoma je značajna njihova pouzdana i prezicna identifikacija.<br />Istraživanja su obuhvatila identifikaciju i molekularnu karakterizaciju Alternaria spp. na zrnu spelte u Republici Srbiji uz analizu intenziteta zaraze posebno plevičastih i oljuštenih zrna spelte kako bi se ispitala efikasnost plavičastih omotača u zaštiti zrna spelte. Istovremeno je određen sadržaj najznačajnijih Alternaria toksina (alternariol-AOH i alternariol monometil-etar-AME), kao i sveobuhvatni uticaj ovih gljiva na komponente prinosa, zdravstvenu bezbednost i tehnološki kvalitet spelte. Izolovano je ukupno 25 Alternaria spp. sa zrna spelte roda 2011. god. iz različitih regiona Vojvodine i na osnovu morfoloških, patogenih i molekularnih karakteristika utvrđeno je prisustvo dve vrste: A. tenuissima (22 izolata) i A. infectoria (3 izolata). Dobijeni rezultati predstavljaju ujedno i prvo naučno saopštenje od vrstama roda Alternaria na spelti u Srbiji. Veštačkom inokulacijom tri različita genotipa spelte (Nirvana, Austria i Ostro) odabranim Alternaria izolatima u 2011. i 2012. god. uočena je značajna razlika u intenzitetu zaraze Alternaria spp. na zrnima sa plevičastim omotačima gde se intenzitet infekcije kretao od 87-100% dok je na oljuštenim zrnima iznosio od 16-72% u 2011. god., odnosno od 95-100% na plevičastim zrnima i 42-68% na oljuštenim zrnima u 2012. god. Efekat hemijske zaštite fungicidom se pokazao značajan za redukciju Alternaria spp. u obe istraživačke godine kako na plevičastim tako i na oljuštenim zrnima spelte. Kolorimetrijskim merenjima intenziteta zaraze plevičastih omotača i oljuštenih zrna inokulisanih biljaka u 2011. i 2012. god. potvrđena su standardna vizuelna fitopatološka ispitivanja, što ukazuje na to da se metoda instrumentale ocene zaraze može koristiti kao efikasna i brza metoda detekcije tamnokličnih zrna, gde uz dodatne verifikacije postoji mogućnost primene i u praksi. AOH i AME detektovani su u proseku četiri puta većoj koncentraciji u plevičastim omotačima nego u oljuštenim zrnima, što potvđuje efikasnost plevičastih omotača u zaštiti zrna spelte, ne samo od prodiranja Alternaria spp. već i od njihovih toksičnih metabolita. Najmanja koncentracija Alternaria toksina zabeležena je na oljuštenim zrnima bijaka tretiranih fungcidom (AOH - 84 μg/kg i AME - 153 μg/kg). Ispitivanja prometnog i tehnološkog kvaliteta spelte zaražene Alternaria spp. su pokazala da tamnoklična zrna značajno narušavaju parametre prometnog i tehnološkog kvaliteta spelte, negativno utičući na nalivanje i sazrevanje zrna kao i sintezu skroba i proteina.<br />Prikazani rezultati ukazuju na to da plevičasti omotači predstavljaju efikasnu barijeru u zaštiti zrna od infekcije vrstama roda Alternaria, što ima izuzetan značaj za otpornost spelte naročito u uslovima gajenja u sistemu organske proizvodnje gde upotreba hemijske zaštite nije dozvoljena. Međutim, uprkos prirodnoj otpornosti i genetskoj predodređenosti spelte za organsku proizvodnju, rezultati efikasne primene fungicida u suzbijanju Alternaria spp. opravdavaju adekvatan hemijski tretman u dobroj poljoprivrednoj praksi i proizvodnji zdravstveno bezbedne hrane. Multidisciplinarni pristup ove doktorske disertacije, ukazuje na neophodnost komplementarnog sagledavanja agronomskih i tehnoloških aspekata u poljoprivrednoj i prehrambenoj industriji, kao jedinstvenog modela koji omogućava praćenje savremenih tendencija u proizvodnji zdravstveno bezbedne hrane visokog nutritivnog kvaliteta.</p> / <p>There is an increasing market demand for alternative crops such as spelt wheat (Triticum aestivum ssp. spelta), an ancient, hulled with high nutritional values which<br />6<br />encourages agroecogical production systems. Accodrding to literture overview, it is considered that hulls protect kernels aginst different pests and pathogens, which is of great importance in organic production where chemical treatment is forbidden. Alternaria is a ubiquitous fungal genus that includes saprobic, and pathogenic species associated with yield losses and reduction of technological quality of small grains. Moreover, some of Alternaria spp. has high toxigenic potential and can be harmful for human and animal health. In order to conduct efficient disease control and monitoring of toxigenic Alternaria species, precise and reliable identification is highly important issue.<br />This study include identification and molecular characterisation of Alternaria spp. isolated from spelt kernels in the Republic of Serbia, followed by assessing of level of infection of hulled and dehulled kernels, separately. Additionally, the content of the most important Alternaria toxins (alternariol-AOH and alternariol monomethyl-etar-AME) is analysed, as well as the overall impact of infection on yield parameneters, food safety and technological quality of spelt wheat. Out of 25 Alternaria strains isolated from spelte kernels harvested in 2011. from different regions of Vojvodina and according to morphological, pathogenic and molecular characteristics, the most dominant species was A. tenuissima (22 isolates) followed by A. infectoria (3 isolates). This is the first report of Alternaria spp. detected on species level on spelt wheat in Serbia. After artificial inoculation of three different spelt genotypes (Nirvana, Austria i Ostro) with Alternaria isolates in 2011. and 2012., the sighnificant difference in the level of infection on hulled and dehulled kernels is noted. On the hulled kernels infection was in the range of 87-100%, while on the dehulled kernels was from 16 to 72% in 2011., and from 95 to 100% on hulled kernels and from 42 to 68% on dehulled kernels in 2012., respectivelly. Chemical treatment showed positive effect in the reduction of Alternaria disease in both years, on hulled and dehuled kernels as well. Colorimetric measurements of the level of infection proved conventional phytopatholoical analyses, which indicates that such instrumental method can be efficiently used in rapid detection of black point kernels and with additional verifications might be use in practise. AOH and AME were detected in four time higher concetrations in hulls compared to dehulled kernels, which confirms that hulls act as barriers against fungal infection and their toxic metabolities. The minimum concetration was detected on dehulled kernels treated with fungicide (AOH - 84 μg/kg i AME - 153 μg/kg). In the technological quality analysis of infected kernels, it was found that black point disease reduced tecnhnological quality, due to negeative impact of infection on maturation of grains and sinthesis of proteins and starch.<br />Presented results indicate that hulls on spelt kernels act as efficient barrires in the protection of kernels against Alternaria spp. and their toxic metabolities, which is of great importance for the resistance of spelt wheat particulary in the organic farming where chemical treatment is forbidden. Inspite of the fact that spelt is suitable for organic production, adequate fungicide application against Alternaria spp. is justified from the aspect of the good agriculture practise and food safety. Multidisciplinary approach of this doctoral dissertation points to necessity of complementary perception of agronomic and technological aspects in agriculture and food industry, as the unique model that supports contemporary trends in the production of food safety products with high nutritional value.</p>
| Identifer | oai:union.ndltd.org:uns.ac.rs/oai:CRISUNS:(BISIS)94881 |
| Date | 11 December 2015 |
| Creators | Đisalov Jovana |
| Contributors | Bagi Ferenc, Lazić Sanja, Bodroža-Solarov Marija |
| Publisher | Univerzitet u Novom Sadu, Poljoprivredni fakultet u Novom Sadu, University of Novi Sad, Faculty of Agriculture at Novi Sad |
| Source Sets | University of Novi Sad |
| Language | Serbian |
| Detected Language | English |
| Type | PhD thesis |
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