ABSTRACT The molecular diversity studies of alfalfa (Medicago sativa L.) germplasm could contribute to a more precise selection of parental populations in many breeding programs. Sequence-related amplified polymorphism (SRAP) markers were used to assess the genetic diversity of 110 individual plants from 13 selected alfalfa cultivars, landraces, and natural populations from Tunisia, Australia, Serbia, and Kazakhstan. Ten polymorphic SRAP primer combinations generated 137 alleles with 0.90 polymorphism information content. The percentage of polymorphic bands per genotype ranged from 57.66% to 70.07% with a mean of 64.29% and overall value of 100%. The genotype Sardi 10 had the highest value for the effective number of alleles; Nei’s gene diversity and Shannon information index, exhibited the highest variability level (Ne = 1.453, He = 0.259, I = 0.381, respectively), whereas the genotype Nera exhibited the lowest variability level (Ne = 1.359, He = 0.211, I = 0.317, respectively). The AMOVA analysis showed that 68% of the variance was within the genotypes; this was in line with the coefficient of genetic differentiation (Gst = 0.370). The genetic relatedness of alfalfa individuals analyzed by the neighbor-joining dendrogram was consistent with the Bayesian model-based clustering approach. The exceptions were individuals from genotypes Slavija and Nera, which were grouped separately by STRUCTURE analyses. These results provide useful information for the management of alfalfa genetic resources and the rational use of local and foreign alfalfa populations in breeding programs focused on the development of new, high-yielding cultivars more adapted to drought conditions in North Africa.

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 quantificar o acúmulo das principais subunidades de proteínas de reserva da soja, β-conglicinina e glicinina, e como elas influenciam a produtividade e os conteúdos de proteína e de óleo em genótipos de soja com alto conteúdo de proteína. A acumulação relativa de subunidades foi calculada por escaneamento em géis SDS-PAGE, com uso de densitometria. O conteúdo de proteínas dos genótipos testados foi maior que o da cultivar controle dentro do mesmo grupo de maturação. Vários genótipos com conteúdo de proteína aumentado, mas com produtividade ou conteúdo de óleo inalterados, foram desenvolvidos como resultados de novas iniciativas de melhoramento. Esta pesquisa confirmou que as cultivares com alto conteúdo de proteína acumulam maior quantidade de glicinina e β-conglicinina. Os genótipos KO5427, KO5428, e KO5429, que acumularam menor quantidade de todas as subunidades de glicinina e β-conglicinina, foram as únicas exceções. Deve-se atentar para os genótipos KO5314 e KO5317, que acumularam quantidades significativamente maiores das duas subunidades da glicinina, e para os genótipos KO5425, KO539 e KO536, que acumularam quantidades significativamente maiores das subunidades de β-conglicinina. Estes resultados indicam que alguns dos genótipos testados poderiam ser benéficos em programas de melhoramento que visem à produção de plantas agronomicamente viáveis, com sementes com alto conteúdo de proteínas e composição específica de proteínas de reserva para fins alimentícios definidos.

The objective of this work was to quantify the accumulation of the major seed storage protein subunits, β-conglycinin and glycinin, and how they influence yield and protein and oil contents in high-protein soybean genotypes. The relative accumulation of subunits was calculated by scanning SDS-PAGE gels using densitometry. The protein content of the tested genotypes was higher than control cultivar in the same maturity group. Several genotypes with improved protein content and with unchanged yield or oil content were developed as a result of new breeding initiatives. This research confirmed that high-protein cultivars accumulate higher amounts of glycinin and β-conglycinin. Genotypes KO5427, KO5428, and KO5429, which accumulated lower quantities of all subunits of glycinin and β-conglycinin, were the only exceptions. Attention should be given to genotypes KO5314 and KO5317, which accumulated significantly higher amounts of both subunits of glycinin, and to genotypes KO5425, KO5319, KO539 and KO536, which accumulated significantly higher amounts of β-conglycinin subunits. These findings suggest that some of the tested genotypes could be beneficial in different breeding programs aimed at the production of agronomically viable plants, yielding high-protein seed with specific composition of storage proteins for specific food applications.