Ângela Celis de Almeida Lopes

Controle genético do comprimento do pedúnculo em feijão-caupi

The objective of this work was to investigate the genetic control of peduncle length in cowpea (Vigna unguiculata L.). A short peduncle cowpea line (TVx-5058-09C) was crossed with a long peduncle line (TE 96-282-22G). The parents and the F1, F2, RC1 (P1xF1), and RC2 (P2xF1) generations were evaluated in randomized block design with four replications. Genotypic, phenotypic, environmental, additive, and dominance variances for peduncle length were determined. Narrow and broad sense heritability, the degree of dominance, and the minimum number of genes determining peduncle length were estimated. The additive-dominant model was adequate to explain the observed variation. The additive gene effect was the most important in controlling peduncle length, which appeared to be controlled by five genes.

Variabilidade e correlações entre caracteres em cruzamentos de soja

A estimacao de parâmetros em geracoes iniciais de endogamia tem importância para direcionar o programa de melhoramento, principalmente em relacao ao processo de selecao dos genotipos mais promissores. Este trabalho avaliou 21 genotipos de soja (seis parentais e 15 combinacoes dialelicas em F2), em dois locais (ESALQ e Anhembi) de Piracicaba, SP. O delineamento usado foi em blocos ao acaso, com seis repeticoes por local. A parcela experimental foi de 12 covas de plantas individuais espacadas de 0,80 m x 0,80 m. Os caracteres avaliados foram numero de dias e altura da planta no florescimento e maturidade; valor agronomico; produtividade de graos; teor de oleo na semente e produtividade de oleo. Todas as estimativas de parâmetros basearam-se nos componentes das analises de variância e covariância individuais e conjuntas. Parentais e F2 apresentaram variabilidade para todos os caracteres. Em termos de qualidade ambiental favoravel, os dois locais foram bons para a expressao do potencial genetico dos genotipos, no entanto, o local Anhembi foi mais favoravel para produtividade de graos. A interacao genotipos x locais mostrou-se um importante componente da variacao fenotipica, com excecao do carater teor de oleo. As correlacoes genotipicas foram geralmente maiores que as fenotipicas e de ambiente nos dois locais. A magnitude das correlacoes fenotipicas e genotipicas mostrou que o fenotipo refletiu satisfatoriamente o genotipo. Os caracteres relacionados ao florescimento e a maturidade mostraram-se importantes para o melhoramento da produtividade, com destaque para o valor agronomico. Existe evidencia de dificuldades em obter novos genotipos produtivos e precoces.

Heterosis in soybeans for seed yield components and associated traits

The objective of this research was to quantify heterosis of agronomic traits and evaluate direct and indirect correlations among seed yield and other traits. A diallel involving six parents was grown in two localities. Seed yield (PG), one-hundred seed weight (PCS), number of pods per plant (NV), weight of aerial part of the plant (PPA), harvest index (IC) and number of seeds per pod (NGV) were evaluated. Positive values of heterosis were detected for all traits. Estimates of heterosis components were significative for most traits, showing effects of aditivity and dominance. The specific heterosis was more important than the variety heterosis, mainly in the locality Anhembi. MTBR-95-123800 presented the best potential per se and as parent in crosses, but it was excelled by some of the hybrids in the two localities. Number of pods per plant demonstrated to be suitable for indirect selection for PG.

Repetibilidade e correlações entre caracteres morfo-agronômicos de cajazeira

Objetivou-se estimar os coeficientes de repetibilidade em quatorze cajazeiras (Spondias mombin L.), no municipio de Teresina, PI, utilizando-se o metodo de analise de variância; determinar o numero de medicoes necessarias para predicao do valor real dos individuos e os coeficientes de correlacao fenotipica entre os caracteres: comprimento e largura da folha, numero de foliolos por folha, peso da panicula, numero de frutos por panicula, comprimento, diâmetro e peso do fruto, peso da semente, rendimento de polpa, teor de solidos soluveis, acidez titulavel, relacao solidos soluveis/acidez. Os genotipos diferiram com relacao a todos os caracteres avaliados, indicando a presenca de variabilidade genetica. As estimativas dos coeficientes de repetibilidade expressaram maior estabilidade para peso do fruto, diâmetro do fruto, peso da semente, acidez titulavel e relacao solidos soluveis/acidez titulavel, indicando maior precisao na predicao do valor real desses caracteres, nas cajazeiras. A avaliacao de onze frutos e suficiente para predizer o valor real de todos os caracteres, com 90% de confiabilidade. A selecao para maior produtividade de frutos pode ser alcancada atraves da selecao indireta para caracteres relacionados a folha. Panicula mais pesada pode ser obtida pela selecao indireta de genotipos com sementes de menor peso.

Diversidade genética entre acessos de espécies cultivadas de pimentas

The knowledge of the genetic diversity among the accessions in germplasm banks it is important for the conservation of genetic resources and the use in breeding programs. This study aimed to evaluate the genetic divergence of 23 accessions of the genus Capsicum, and was based in seven quantitative and nineteen qualitative multicategorical descriptors and using multivariate techniques. The analyses of variance revealed significant difference (P<0.05) among the accessions of peppers for all quantitative descriptors. The coefficient variation ranged from 8,97% (LF) to 30,91% (NFA). The Tocher optimization method detected eight clusters for quantitative descriptors and also in as well as qualitative multicategoric descriptors. The UPGMA method detected three clusters for quantitative descriptors and four clusters within qualitative multicategoricdescriptors. There is genetic diversity inter and intraspecific in germplasm bank of Capsicum coming from The Federal University of Piaui, and these results indicate that there are not duplicated accessions.

Reação de genótipos de feijão-caupi revela resistência às coinfecções pelo Cucumber mosaic virus, Cowpea aphid-borne mosaic virus e Cowpea severe mosaic virus

Many factors can affect the yield of cowpea, especially viruses. The main species of viruses infecting cowpea in Brazil are Cucumber mosaic virus (CMV), Cowpea aphid-borne mosaic virus (CABMV), Cowpea severe mosaic virus (CPSMV) and Cowpea golden mosaic virus (CPGMV). This study aimed to evaluate the reaction of cowpea genotypes for resistance to CMV in single or in co-infections (CMV+CABMV, CMV+CPSMV-I and CMV+CABMV+CPSMV-I), which was accomplished in two steps. Firstly, 57 genotypes were evaluated in four evaluations: three in aphid proof cages with infection under controlled conditions, and one in field-grown plants under natural infection. To perform the second step, we selected 18 genotypes to be conducted in nine trials, with eight under aphid proof cages control infection, and one under natural infection. The qualitative and quantitative effects resulting from infections were evaluated. In the field trial, we assessed the number of asymptomatic plants, pod length, number of grains per pod, 100-grain mass and yield. Mixed infections reduced the plant height and dry weight, and premature death of some genotypes was observed in infections involving the three viruses. The genotypes BR17-Gurgueia, Epace V-96, TE97-309G-9, TE97-309G-22, TE97-309G-24 and Patativa showed the best behavior in relation to the mixed viral infections, presenting seeds with appropriate commercial standard and with potential for using in breeding programs.

Distinct bacterial communities across a gradient of vegetation from a preserved Brazilian Cerrado

The Cerrado biome in the Sete Cidades National Park, an Ecological Reserve in Northeastern Brazil, has conserved its native biodiversity and presents a variety of plants found in other savannas in Brazil. Despite this finding the soil microbial diversity and community structure are poorly understood. Therefore, we described soil bacterial diversity and distribution along a savanna vegetation gradient taking into account the prevailing environmental factors. The bacterial composition was retrieved by sequencing a fragment of the 16S ribosomal RNA gene. The bacterial operational taxonomic units (OTUs) were assigned to 37 different phyla, 96 classes, and 83 genera. At the phylum level, a core comprised by Proteobacteria, Acidobacteria, Actinobacteria, Firmicutes, Verrucomicrobia and Planctomycetes, was detected in all areas of Cerrado. ‘Cerrado stricto sensu’ and ‘Cerradao’ share more similarities between edaphic properties and vegetation and also present more similar bacterial communities, while ‘Floresta decidual’ and ‘Campo graminoide’ show the largest environmental differences and also more distinct bacterial communities. Proteobacteria (26%), Acidobacteria (21%) and Actinobacteria (21%) were the most abundant phyla within the four areas. All the samples present similar bacteria richness (alpha diversity) and the observed differences among them (beta diversity) were more related to the abundance of specific taxon OTUs compared to their presence or absence. Total organic C, N and P are the main abiotic factors structuring the bacterial communities. In summary, our findings show the bacterial community structure was clearly different across the Cerrado gradient, but that these environments share a bacterial phylum-core comprising Proteobacteria, Acidobacteria, Actinobacteria, Verrucomicrobia and Planctomycetes with other Brazilian savannas.

Correlações entre parâmetros de adaptabilidade e estabilidade da produtividade de óleo em soja

O objetivo deste trabalho foi determinar o grau de correlacao entre parâmetros que avaliam a adaptabilidade e a estabilidade da produtividade de oleo em soja. Os parâmetros foram estimados a partir da analise de dados resultantes da avaliacao de 93 linhagens de soja, divididas em tres ciclos de maturacao (28 precoces, 38 semiprecoces e 27 intermediarias). Os ensaios foram conduzidos em doze ambientes do municipio de Piracicaba, SP, Brasil. Os seguintes parâmetros foram correlacionados: media geral (mi), coeficiente de regressao (bi), ecovalencia de Wricke (wWi), ecovalencia AMMI (wAi), variância dos desvios da regressao (s2di) e coeficiente de determinacao (R2i). Utilizou-se a correlacao (r) de Sperman do ordenamento das linhagens, segundo cada parâmetro. As correlacoes entre mi e bi e entre os parâmetros de estabilidade entre si (wWi, wAi, s2di e R2i) foram positivas e significativas (0,53 < r < 0,93) . As correlacoes entre os parâmetros de adaptabilidade e estabilidade foram baixas ou negativas e nao significativas (-0,39 < r < 0,38), exceto entre bi e R2i (r = 0,49 e 0,89 para as linhagens precoces e intermediarias, respectivamente). Os parâmetros de estabilidade classificam a ordem das linhagens de forma similar e, provavelmente, pertencem ao mesmo conceito de estabilidade. Os resultados indicam que e dificil a selecao simultânea para adaptabilidade e estabilidade da produtividade de oleo em soja.

Stratified mass selection of promising Spondias mombin clones in a commercial crop

This study aimed to estimate genetic parameters and identify promising clones of Spondias mombin in ungrafted commercial crop by stratified mass selection, based on the average of two harvests, using mixed models. The base population growing on a private farm in Teresina/PI comprised 82 plants, which were evaluated in the growing seasons 2008 and 2009. Total titratable acidity (TTA), total soluble solids (Brix), Brix/TTA, fruit weight (FW), seed weight (SW), pulp yield (PuY), and processing yield (PrY) were measured. Significant genetic variation among plants was detected for all traits. The coefficients of repeatability were 0.97 (TTA), 0.39 (Brix), 0.86 (Brix/TTA), 0.84 (FW), 0.82 (SW), 0.35 (PuY), and 0.39 (PrY). The chemical were generally not correlated with the physical fruit traits. Ranking by predicted phenotypic values associated with PrY and Brix/TTA identified nine promising plants (PrY>6.9% and Brix/TTA>10).

Genetic variability in subsamples of determinate growth lima bean

Abstract – Lima bean, a highly important legume, serves as a source of protein, reducing nutritional dependency on meat and other beans, especially for needy populations. This crop, with production concentrated in the Northeast of Brazil, has been the subject of very few studies, considering the evaluation of varieties predominantly with indeterminate growth habit. The characterization of ma -terial presenting determinate growth, an agronomically important characteristic, may subsidize breeding programs. We characterize subsamples of determinate growth lima bean in morpho-agronomic terms and estimate genetic divergence. We identified pairs of divergent and complementary genotypes for crosses. The genotypes were grouped in six and five groups in regard to the Tocher and UPGMA methods, respectively, for the quantitative traits. For the qualitative traits, three groups were formed. Analyses of canonical variables identified traits related to production of importance for variability. The study shows the importance of characterization of