Genetic variability of indigenous cowpea genotypes as determined using inter-simple sequence repeats markers

Cowpea [Vigna unguiculata (L.) Walp.] is cultivated widely by small farmers in the semiarid region of Northeastern Brazil for subsistence purposes, especially to complement the family income. However, owing to the limited availability of water in this region, there is an urgent need for novel highly productive drought-tolerant cultivars. The aim of the present study was to establish the genetic variability of 14 cowpea populations (60 indigenous genotypes from 13 microregions of Rio Grande do Norte and 4 domesticated cultivars produced by Embrapa) using inter-simple sequence repeats (ISSR) markers. The set of 13 selected primers generated a total of 257 loci, 247 (96.11%) of which were polymorphic, with sizes ranging between 200 and 2000 bp. Genetic similarities between accessions were estimated from Jaccard coefficients and genetic relationships were determined from the dendrogram constructed using the unweighted pair group method with arithmetic average (UPGMA) technique. Bayesian statistics  coupled with the Markov chain Monte Carlo technique was applied to determine population structure, while the genetic variability was established by analysis of molecular variance. UPGMA analysis allowed the separation of the genotypes into three groups, but no relationship between the genetic and  geographical distances was observed. The fixation index was considered intermediary (FST = 0.0818), the average heterozygosity was low (HS = 0.39) and the coefficient of endogamy was high (f = 92.6%). The results show the presence of genetic diversity among the studied populations and revealed that such variability could be attributed mainly to intra-population variability (91.82%).Key words: Vigna unguiculata, genetic diversity, plant improvement, drought stress

Análise de parâmetros perceptivo-auditivos e acústicos em indivíduos gagos Analysis of acoustic and auditory-perceptual parameters in stutterers

OBJETIVO: Analisar parâmetros perceptivo-auditivos e acústicos da voz em indivíduos adultos gagos. MÉTODOS: Foram analisados 15 indivíduos gagos do gênero masculino na faixa etária de 21 a 41 anos (média 26,6 anos), atendidos no Centro Clínico de Fonoaudiologia da instituição no período de fevereiro de 2005 a julho de 2007. Os parâmetros perceptivo-auditivos analisados envolveram a qualidade vocal, tipo de voz, ressonância, tensão vocal, velocidade de fala, coordenação pneumofônica, ataque vocal e gama tonal; quanto aos parâmetros acústicos, foram analisadas a frequência fundamental e sua variabilidade durante a fala espontânea. RESULTADOS: A análise perceptivo-auditiva mostrou que as características mais frequentes nos indivíduos gagos foram: qualidade vocal normal (60%), ressonância alterada (66%), tensão vocal (86%), ataque vocal alterado (73%), velocidade de fala normal (54%), gama tonal alterada (80%) e coordenação pneumofônica alterada (100%). No entanto, a análise estatística revelou que apenas a presença de tensão vocal, coordenação pneumofônica e a gama tonal alteradas apresentaram-se estatisticamente significativas nos indivíduos gagos estudados. Na análise acústica, a frequência fundamental variou de 125,54 a 149,59 Hz e a variabilidade da frequência fundamental foi de 16 a 21 semitons ou 112,50 a 172,40 Hz. CONCLUSÃO: Os parâmetros perceptivo-auditivos analisados que tiveram frequência significativa nos indivíduos gagos estudados foram: presença de tensão vocal, alteração da gama tonal e na coordenação pneumofônica. Desta forma, é importante avaliar os aspectos vocais nesses pacientes, pois a desordem da fluência pode comprometer alguns parâmetros vocais podendo ocasionar disfonia.<br>PURPOSE: To analyze auditory-perceptual and acoustic parameters of the voices of adult stutterers. METHODS: Fifteen male stutterers in the age range from 21 to 41 years (mean 26.6 years), attended at the institution's Speech-Language Pathology Clinical Center in the period from February 2005 to July 2007, were analyzed. The auditory-perceptual parameters analyzed were vocal quality, type of voice, resonance, vocal tension, speech rate, pneumo-phonic coordination, vocal attack and pitch range; the acoustic parameters analyzed were fundamental frequency and its variability during spontaneous speech. RESULTS: The auditory-perceptual analysis showed that the most frequent characteristics among the subjects were normal vocal quality (60%), altered resonance (66%), vocal tension (86%), altered vocal attack (73%), normal speech rate (54%), altered pitch range (80%) and altered pneumo-phonic coordination (100%). However, only the presence of vocal tension and the altered pneumo-phonic coordination and pitch range were statistically significant in the stutterers studied. In the acoustic analysis, fundamental frequency varied from 125,54 to 149,59 Hz, and the variability of the fundamental frequency ranged from 16 to 21 halftones, or from 112,50 to 172,40 Hz. CONCLUSION: The auditory-perceptual parameters that were significantly frequent among stutterers were: presence of vocal tension, altered pneumo-phonic coordination, and altered pitch range. Therefore, it is important to evaluate the vocal aspects of these patients, for the fluency disorders might undermine some vocals parameters, causing dysphonia