Identifikacija Alternaria spp. na zrnu spelte i uticaj zaraze na komponente prinosa, sadržaj mikotoksina i tehnološki kvalitet / Identification of Alternaria spp. on spelt kerenels and impact of infection on yield parameters, mycotoxins content and techno

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 6 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. 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. 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.