Diaporthe (anamorph = Phomopsis) species are plant pathogens and endophytes on a wide range of hosts including economically important crops. At least four Diaporthe taxa occur on soybean and they are responsible for serious diseases and significant yield losses. Although several studies have extensively described the culture and morphological characters of these pathogens, their taxonomy has not been fully resolved. Diaporthe and Phomopsis isolates were obtained from soybean and other plant hosts throughout Croatia. Phylogenetic relationships were determined through analyses of partial translation elongation factor 1-alpha (EF1-α) gene and ITS nrDNA sequence data. By combining morphological and molecular data, four species could be distinguished on soybeans in Croatia. Diaporthe phaseolorum is described in this study and its synonyms are discussed. Diaporthe phaseolorum var. caulivora is raised to species status and the name Diaporthe caulivora is introduced to accommodate it. A species previously known as Phomopsis sp. 9 from earlier studies on sunflower, grapevine, rooibos and hydrangea is reported for the first time on soybean, and is formally described as Diaporthe novem. The well-known soybean pathogen Phomopsis longicolla was also collected in the present study and was transferred to Diaporthe longicolla comb. nov. The presence of these species on herbaceous hosts raises once more the relevance of weeds as reservoirs for pathogens of economically important plants.

The usage and value of soybean (Glycine max (L.) Merr.) seed oil are mainly determined by its fatty acid composition, which affects physical, chemical and nutritional properties. In order to assess genotypes' suitability for edible oil production and determine the variability in phenotypic expression of the amount of oil and fatty acid composition in the seed, three-year (2010-2012) trials were set up with eight early maturing advanced soybean lines. As a result, we determined the amount of seed oil and composition of seed fatty acids (palmitic, stearic, oleic, linoleic and linolenic). After analysis of variance (ANOVA), we calculated the saturated fatty acid (SFA) amount, monounsaturated fatty acid (MUFA) and polyunsaturated fatty acid (PUFA) ratio (MUFA:PUFA) as an indicator of the oxidative stability of the oil, and linoleic and linolenic acids ratio as an indicator of nutritional quality. To give further insight into divergence of given set of genotypes, cluster analysis was performed, while correlation analysis was used to better understand the relationships between all the traits investigated in this research, which play an important role in breeding procedures. The experimental and biometric results indicate the existence of variability in phenotypic expression of investigated traits with significant year and genotype effects, while cluster analysis divided genotypes into two main groups confirming the results of ANOVA. The amount of oil was higher than that obtained in earlier researches conducted in the same geographical region and all averages of five fatty acids coincided with the average values for commercial soybean varieties. MUFA:PUFA was lower than recommended for all tested genotypes, and linoleic and linolenic acids ratio values were higher than the recommended limits for vegetable oils. The results of the correlation study showed the significant and positive relationship between oil and oleic acid, while the significant and negative correlation between oil and both polyunsaturated fatty acids. According to the overall conclusions, the most suitable as a parental component in breeding programs aimed at creating genotypes for the production of edible oil was genotype OS-L-774, while genotypes OS-L-806 and OS-L-805 were the least suitable for the same purpose.

Characterizing concentrations of several beneficiary and toxic metals in maize leaves is of importance for ionomic studies and for silage production. The intermated B73 × Mo17 maize population (IBM) was evaluated for concentrations of eight metals (cadmium - Cd, copper - Cu, iron - Fe, potassium - K, magnesium - Mg, manganese - Mn, strontium - Sr and zinc - Zn) in ear-leaf to map quantitative trait loci (QTL) with 2161 molecular markers across the genome. QTL analysis revealed nine significant QTLs for concentrations of Cd, Cu, Fe, K, Mg and Sr combined over two environments. Median resolution for the QTL interval was less than 1 cM on a regular F2 map, which is a big improvement compared with the prior mapping (8 cM). The highest LOD scores of 15.52 and 15.31 were detected for K and Cd concentrations, respectively, explaining more than 20 percent of the phenotypic variance. No QTLs were found to be colocalized. QTL mapping in the IBM population did not confirm our earlier QTL results demonstrating considerable QTL ×genetic background interaction. The only exception is confirmation of the major QTL for Cd accumulation on chromosome 2. Our results could facilitate further genetic and physical mapping of genes for metal accumulation in maize.

No abstract

No abstract

No abstract

Sunflower (Helianthus annuus) stem canker caused by Diaporthe helianthi is one of the most important sunflower diseases in Croatia. Until recently, sunflower was the only known host for D. helianthi. In our research carried out in the area of Eastern Croatia, isolates of Diaporthe/Phomospis were collected from Xanthium italicum, X. strumarium and Arctium lappa. Using morphological, cultural and molecular ITS rDNA data, isolates from these weeds were identified as D. helianthi. The following isolates were used in the pathogenicity test: one isolate originated from sunflower (Su5/04), three from X. italicum (Xa2, Xa3 and Xa5), two from X. strumarium (Xa9 and Xa12), one from Xanthium sp. (Xa13) and one from A. lappa (Ar3). According to the results, it was determined that isolate Xa5 (originated from X. italicum) was the most pathogenic to sunflower stems. The average length of the lesion was 11.3 cm. The lowest level of pathogenicity was found in Xa9 (isolated from X. strumarium). The length of the lesion was 0.1 cm.

The potential of soybean for food, feed, and pharmaceutical industry arises from the composition of its seed. Since European countries import 95% of the annual demand for soybean grains, meal, and oil, causing an enormous trade deficit, the governments in Europe had started to introduce additional incentives to stimulate soybean cropping. To rebalance the sources of soybean supply in the future, production must be followed by continuous research to create varieties that would make European soybean more appealing to the processing industry and profitable enough to satisfy European farmers. This chapter is giving an overview of the European soybean seed quality research and an insight into soybean seed quality progress made at the Agricultural Institute Osijek, Croatia. The studies presented are mainly considering maturity groups suitable for growing in almost all European regions. The most important traits of soybean seed quality discussed are protein content and amino acid composition, oil content and fatty acid composition, soluble sugars, and isoflavones. Defining quality traits facilitates the parental selection in breeding programs aiming to improve the added value properties of final soybean products and enables the exchange of materials between different breeding and research institutions to introduce diversity, which is a prerequisite for genetic advance.