Armando Martins dos Santos

Caracterização de espécies diploides de Lotus em resposta à toxidez por alumínio

The objective of this work was to characterize diploid species, including Lotus japonicus model species and recombinant inbred lines of the Lotus genus for resistance to aluminum (Al) toxicity by using acid soil and nutrient solution. The experiments were conducted in greenhouse, being tested three diploid species (L. japonicus MG-20 and GIFU, L. filicaulis and L. burtii), and 180 recombinant inbred lines. In the experiments with diploid species, alfalfa was used as a check, and in the experiments with recombinant inbreed lines, GIFU model species was used. In the soil experiments, the morphological characteristics of the aerial part and the root were evaluated, and in the nutrient solution experiment, only the root length and growth were evaluated. MG-20 and GIF model species were the most productive in general. The results in nutrient solution followed the response pattern similar to the one observed in acid soil evaluations. The MG-20 genotype was superior to the others in all Al concentrations tested. Of the 180 recombinant inbred lines tested, 24 were superior and 39 inferior to the GIFU species. The great diversity observed in the model species and in the recombinant inbred lines can help in future selection of cultivated genotypes (tetraploids) inasmuch as they have a group of developed molecular markers which can be used at identification of regions responsible for higher or lower tolerance to aluminum toxicity.

Análise da diversidade genética de cornichão com o uso de marcadores microssatélites

The aim of this work was to analyze the genetic diversity of 14 Lotus corniculatus L. materials through microsatellite markers. Four cultivars and one population of L. corniculatus and their respective genotypes selected were analyzed aiming aluminium tolerance and sensibility. The 17 markers used detected a total of 36 alleles, with an average of 2.25 alleles per locus. The result of the similarity analyses showed the formation of three groups: one enclosing germplasm and selected genotypes for aluminium sensibility, while the other two groups were formed by selected genotypes for aluminium tolerance. The molecular analysis was efficient in detecting and quantifying the variability among the genotypes, adding useful information to the breeding program. The utilization of microsatellite markers permitted the distinction of genotypes originated from a selection program aiming aluminium tolerance. The performed selections originate polymorphic genotypes in relation to the original populations.

Seleção de populações de Lotus corniculatus L. com maior tolerância ao alumínio em solução nutritiva

The experiment was carried out to select genotypes of Lotus corniculatus L. (Draco, Sao Gabriel and UFRGS) more tolerant to aluminum, using the technique of selection in nutrient solution. The solution contained 200 µmol/L calcium (CaCl2) and 100 µmol/L aluminum (AlCl3) and a pH controlled in the range from 4.1 to 4.3. It was performed two cycles of selection, in which the seedlings were selected by the root final length. Subsequently, the genetic gain achieved in the cycles of selection was tested, in original and improved populations in an experiment in nutrient solution with four concentrations of aluminum (0, 50, 100 and 150 µmol/L) (AlCl3), by liquid root growth. Use of nutritional solution was efficient in the selection of seedlings of birdsfoot trefoil tolerant to aluminum. The materials analyzed differ for this characteristic, with the genotype UFRGS F2, being the most tolerant.

Heliotropism and water availability effects on flowering dynamics and seed production in Macroptilium lathyroides

The experiment was carried out in pots in a glasshouse, with one plant per pot and nine repetitions per treatment. The treatments consisted of free or restricted leaves, submited to 90-100% or 60-70% soil field capacity (FC). Only independent effects of water availability or leaf movement were observed on yield components. Plants under well-watered conditions and with freely orienting leaves were taller, and had a larger number of ramifications. The greater development favored the setting of a higher number of inflorescences per plant in these treatments. This behavior resulted in a high number of flowers, green and mature legumes per plant, thus resulting in high seed production which was the most evident response to water availability. Although individual seed weight was higher in the water stress treatment, total seed production was higher for well- watered plants, with no statistically significant effect of leaf movements. RESUMO - O experimento foi conduzido em casa de vegetacao, em vasos, com uma planta por vaso e nove repeticoes por tratamento. Os tratamentos constituiram: plantas com folhas livremente orientadas ou restritas, submetidas as condicoes hidricas de 90-100% e 60-70% da capacidade de campo. Foram observados efeitos independentes da disponibilidade hidrica e da movimentacao foliar para os componentes do rendimento de sementes ao longo do periodo experimental. Plantas submetidas a alta disponibilidade hidrica e com folhas livremente orientadas apresentaram maior numero de ramificacoes por planta. Este melhor desenvolvimento favoreceu a emissao de maior numero de inflorescencias por planta, proporcionando maior numero de flores, legumes verdes e legumes maduros por planta que, por sua vez, gerou maior producao diaria de sementes. Esta resposta foi evidenciada ao se avaliar o efeito da disponibilidade hidrica. Apesar da massa individual da semente ter apresentado valores superiores para o tratamento com restricao hidrica, a producao total de sementes foi superior no tratamento com alta disponibilidade hidrica, nao se observando efeito significativo para a movimentacao foliar.

Construção e avaliação agronômica de genótipos de cornichão com respostas contrastantes à toxidez por alumínio

The objective of this study was to select and characterize Lotus corniculatus genotypes with contrasting responses to toxicity by aluminum. Four cultivars (Sao Gabriel, San Gabriel, Draco, Estanzuela) and one population (UFRGS) were submitted to two consecutive selections in soils that presented 30-35% aluminum saturation. Selections consisted of separating 1% of the most and less vigorous individuals in order to obtain tolerant and sensitive genotypes, respectively. The individuals chosen were compared with the original germplasm by agronomical evaluation. Genotypes selected by tolerance to toxic aluminum were overall superior to the original populations. However, the materials chosen by sensitivity were inferior to the original populations even in situations where toxic aluminum was absent. Among the selected genotypes, the UFRGS selected for tolerance stood out, presenting an elevated dry matter production level - superior to all other genotypes. Field testing and seed multiplication of these genotypes for further use in areas that present this limitation is necessary, especially for the UFRGS population selected for tolerance to aluminum.