Sugar beet is a significant industrial crop, often grown in the areas where summer drought can severely limit root yield and sugar content. In order to improve development of sugar beet cultivars with increased drought tolerance it is necessary to understand plant response to water stress at the genomic level. Since recent research efforts have focused on the molecular response of the plant in order to identify water deficit inducible genes, the aim of this investigation was to develop qRT-PCR methodology for the quantification of gene expression in sugar beet under conditions of water deficiency in vitro. Sugar beet genotypes, selected for different response to water deficit, were grown and multiplied in vitro. Axilary shoots were placed on micropropagation media with 0%, 3% and 5% PEG, for 28 days. To determine reaction of sugar beet genotypes to in vitro induced water deficit changes in number of axillary shoots, shoot fresh weight and dry matter content were measured. Total RNA was extracted from leaves and reverse transcribed into cDNA, which served as matrix in real-time PCR reaction using TaqMan technology. The housekeeping gene for glutamine synthetase was used as endogenous control, while the genes for alpha amylase and osmotin-like protein were target genes. The relative quantification values for each target gene were calculated by the 2−ΔΔCt method. Selected candidate genes differed in relative gene expression among genotypes and applied PEG treatments. The obtained results indicated that qRT-PCR protocol was efficient and accurate, showing the potential to be used in further expression analysis of candidate genes involved in sugar beet reaction to water stress.

O objetivo deste trabalho foi avaliar a interação genótipo x ambiente para rendimento de grãos por planta em cultivares de canola cultivadas no norte da Sérvia, pelo modelo AMMI (modelo de efeitos principais aditivos e interação multiplicativa). O estudo foi composto por 19 genótipos de canola, analisados em sete anos por meio de ensaios de campo em delineamento de blocos ao acaso, com três repetições. O rendimento de grãos por planta das cultivares testadas variou de 1,82 a 19,47 g ao longo das sete estações, com média de 7,41 g. Na análise de variância, 72,49% da variação do rendimento total foi explicada pelo ambiente, 7,71% por diferenças entre os genótipos e 19,09% pela interação genótipo x ambiente. No biplot, as cultivares com alto potencial de rendimento genético tiveram correlação positiva com as estações do ano com condições favoráveis de crescimento, enquanto as cultivares com menor potencial de rendimento foram correlacionadas aos anos com condições desfavoráveis. A produção de grãos por planta é altamente influenciada por fatores ambientais, o que indica adaptabilidade de genótipos a estações de cultivo específicas.

The objective of this study was to assess genotype by environment interaction for seed yield per plant in rapeseed cultivars grown in Northern Serbia by the AMMI (additive main effects and multiplicative interaction) model. The study comprised 19 rapeseed genotypes, analyzed in seven years through field trials arranged in a randomized complete block design, with three replicates. Seed yield per plant of the tested cultivars varied from 1.82 to 19.47 g throughout the seven seasons, with an average of 7.41 g. In the variance analysis, 72.49% of the total yield variation was explained by environment, 7.71% by differences between genotypes, and 19.09% by genotype by environment interaction. On the biplot, cultivars with high yield genetic potential had positive correlation with the seasons with optimal growing conditions, while the cultivars with lower yield potential were correlated to the years with unfavorable conditions. Seed yield per plant is highly influenced by environmental factors, which indicates the adaptability of specific genotypes to specific seasons.