Nikola Hristov

Genotype by environment interactions in wheat quality breeding programs in southeast Europe

The objective of this study was to determine genotypexa0×xa0environment interactions (GEI) obtained in wheat production in southeast Europe for protein content, sedimentation value, and loaf volume. Twenty wheat genotypes divided in two groups with different combinations of high molecular weight glutenin subunits (HMW-GS) were analyzed in 15 environments (E). In a combined analysis of variance, effects of genotype, environment, and their interaction (GEI) were highly significant for almost all the analyzed traits. All the three traits were influenced more by location than by year, with protein content and sedimentation value being more responsive to changes in environmental conditions than loaf volume. The genotypes with high protein content had the regression coefficient value (b) close to 1, indicating that they did not react to extreme environmental conditions as was the case with genotypes with high sedimentation and loaf volume values. There were no significant differences in average values for the analyzed traits and adaptability parameters between the two groups of genotypes. It means that, concerning wheat quality improvement, genotypes with different HMW-GSs on the Glu-1D locus could be recommended for growing in southeast Europe. It is necessary to take into account the differences in adaptability of protein content to either positive or negative environmental changes that were observed between the groups.

Interação genótipo x ambiente para a produção de sementes por planta em canola pelo modelo AMMI

O objetivo deste trabalho foi avaliar a interacao genotipo x ambiente para rendimento de graos por planta em cultivares de canola cultivadas no norte da Servia, pelo modelo AMMI (modelo de efeitos principais aditivos e interacao multiplicativa). O estudo foi composto por 19 genotipos de canola, analisados em sete anos por meio de ensaios de campo em delineamento de blocos ao acaso, com tres repeticoes. O rendimento de graos por planta das cultivares testadas variou de 1,82 a 19,47 g ao longo das sete estacoes, com media de 7,41 g. Na analise de variância, 72,49% da variacao do rendimento total foi explicada pelo ambiente, 7,71% por diferencas entre os genotipos e 19,09% pela interacao genotipo x ambiente. No biplot, as cultivares com alto potencial de rendimento genetico tiveram correlacao positiva com as estacoes do ano com condicoes favoraveis de crescimento, enquanto as cultivares com menor potencial de rendimento foram correlacionadas aos anos com condicoes desfavoraveis. A producao de graos por planta e altamente influenciada por fatores ambientais, o que indica adaptabilidade de genotipos a estacoes de cultivo especificas.

Whole grain phenolics and antioxidant activity of Triticum cultivars and wild accessions

Total phenolics (TP), total tannins (TT), total flavonoids (TF) and proanthocyanidins (PA) content, as well as the DPPH-radical scavenging capability of the whole grain of 17 different Triticum spp. accessions were analyzed. The content of TP ranged from 976 to 2927 μg catechin/g, while TT ranged from 335 to 1412 μg catechin/g and TF from 0.16 to 1.12 µg/rutin gof dry whole grain. The presence of PA in the whole grains has not been established. The values for DPPH-radical scavenging activity were rather moderate, under 40 % of neutralized radicals. A positive correlation between DPPH-activity and analyzed phenolics was recorded in twelve of seventeen genotypes ( r =0.73-0.99). Trans -cinnamic acid was a major compound among phenolic acids and quercetin among flavonoids found in wheat varieties. The data obtained should enable the selection of the accessions rich in biologically active compounds that could further be processed into functional food with higher nutritive and antioxidant properties.

Associação genética na detecção de QTLs relacionados a características da espiga de trigo

The objective of this work was to assess the genetic diversity and population structure of wheat genotypes, to detect significant and stable genetic associations, as well as to evaluate the efficiency of statistical models to identify chromosome regions responsible for the expression of spike‑related traits. Eight important spike characteristics were measured during five growing seasons in Serbia. Axa0set of 30 microsatellite markers positioned near important agronomic loci was used to evaluate genetic diversity, resulting in a total of 349 alleles. The marker‑trait associations were analyzed using the general linear and mixed linear models. The results obtained for number of allelic variants per locus (11.5), average polymorphic information content value (0.68), and average gene diversity (0.722) showed that the exceptional level of polymorphism in the genotypes is the main requirement for association studies. The population structure estimated by model‑based clustering distributed the genotypes into six subpopulations according to log probability of data. Significant and stable associations were detected on chromosomes 1B, 2A, 2B, 2D, and 6D, which explained from 4.7 to 40.7% of total phenotypic variations. The general linear model identified a significantly larger number of marker‑trait associations (192) than the mixed linear model (76). The mixed linear model identified nine markers associated to six traits.

Polymorphism of microsatellite loci in bread wheat (Triticum aestivum L.) and related species

This study analysed polymorphism of 15 microsatellite loci in the collection comprising of 40 genotypes of bread wheat (Triticum aestivum L.), 32 genotypes belonging to other species within Triticum genus and 3 genotypes from Aegilops genus. The results showed significant differences in the variability of the tested loci in bread wheat and related species. In the collection of bread wheat genotypes, 119 alleles were detected with the average number of 7.9 alleles per locus. In wild and cultivated related species 157 alleles were identified, with the average of 10.5 alleles per locus. All analysed parameters of microsatellite loci variability (PIC value, gene diversity, heterozygosity, etc.) indicated higher level of polymorphism in wild relatives than in the cultivated bread wheat. Analyses of individual genomes indicated that in the bread wheat genetic diversity of the B and D genomes was significantly reduced in relation to the A genome, while the differences in polymorphism between genomes in the wild relatives were significantly lower. The results showed that wild related species can be used as sources for new variability in wheat breeding.