RESUMO
Vigna unguiculata (L.) Walp (cowpea) is a food crop with high nutritional value that is cultivated throughout tropical and subtropical regions of the world. The main constraint on high productivity of cowpea is water deficit, caused by the long periods of drought that occur in these regions. The aim of the present study was to select elite cowpea genotypes with enhanced drought tolerance, by applying principal component analysis to 219 first-cycle progenies obtained in a recurrent selection program. The experimental design comprised a simple 15 x 15 lattice with 450 plots, each of two rows of 10 plants. Plants were grown under water-deficit conditions by applying a water depth of 205 mm representing one-half of that required by cowpea. Variables assessed were flowering, maturation, pod length, number and mass of beans/pod, mass of 100 beans, and productivity/plot. Ten elite cowpea genotypes were selected, in which principal components 1 and 2 encompassed variables related to yield (pod length, beans/pod, and productivity/plot) and life precocity (flowering and maturation), respectively.
Assuntos
Adaptação Biológica , Secas , Fabaceae/genética , Fabaceae/metabolismo , Estudos de Associação Genética , Característica Quantitativa Herdável , Seleção Genética , Genótipo , Fenótipo , Análise de Componente PrincipalRESUMO
Molecular markers are important for characterizing the genetic diversity of plants and can provide the basis for strategies to protect and conserve endangered populations. However, numerous molecular techniques are used, requiring an evaluation of fast and efficient methods to extract DNA. Since molecular studies of Caesalpinia ferrea are rare, it is important to develop and/or adapt a DNA extraction protocol that produces quality DNA samples to enable the design of strategies for the conservation of this threatened species. This study aimed to compare five methods for DNA extraction and to determine the most efficient protocol for C. ferrea. Sufficient genomic DNA was obtained from the leaves of C. ferrea using all the tested protocols to perform techniques involving molecular markers. Two protocols based on the detergent cetyl trimethyl ammonium bromide, as well as a commercial kit, yielded high concentrations of pure DNA. However, when polymerase chain reaction amplifications were performed, DNA was only successfully amplified from extractions performed with the commercial kit, which produced sufficient genomic DNA of good quality from the leaves of C. ferrea to perform techniques involving molecular markers.