COEFICIENTES DE SIMILARIDADE PARA AVALIAÇÃO DA DIVERSIDADE GENÉTICA EM PINHÃO-MANSO POR MARCADORES ISSR

Objetivou-se com este trabalho, avaliar a eficiência da utilização de diferentes coeficientes de similaridade na estimação da diversidade genética de Jatropha curcas L. utilizando marcadores moleculares ISSR. O DNA genômico foi extraído a partir de folhas jovens de 43 acessos de pinhão-manso. Matrizes de dissimilaridade genética foram obtidas a partir dos coeficientes Baroni, Coincidência Simples, Hamann, Índice II, Índice III, Jaccard, Nei e Li, Ochiai I, Ochiai II, Rogers e Tanimoto e Sokal e Sneath. Os dendrogramas foram construídos utilizando o método UPGMA e comparados mediante os parâmetros de coeficiente de correlação cofenético, estresse e distorção. Foram estimadas as correlações entre os pares de matrizes pelo teste de Mantel. Houve concordância entre as matrizes originais e as matrizes resultantes do processo de agrupamento para todos os coeficientes estudados. Os índices de Jaccard e Nei e Li não diferiram quanto ao ordenamento dos acessos avaliados e permitiram maior discriminação destes, sendo os mais adequados para avaliar a diversidade genética em pinhão-manso baseada em marcadores moleculares ISSR.Palavras-chave: dissimilaridade genética; análise de agrupamento; Jatropha curcas L. SIMILARITY COEFFICIENTS FOR EVALUATION OF GENETIC DIVERSITY IN JATROPHA BY ISSR MARKERS ABSTRACT:The aim of this work was to evaluate the efficiency of using different similarity coefficients in the estimation of Jatropha curcas L. genetic diversity using ISSR molecular markers. Genomic DNA was extracted from young leaves of the 43 jatropha accessions. Genetic dissimilarity matrices were obtained from the Baroni, Simple Matching, Hamann, Index II, Index III, Jaccard, Nei and Li, Ochiai I, Ochiai II, Rogers and Tanimoto and Sokal and Sneath coefficients. The dendrograms were constructed using the UPGMA method and compared using the co-phenetic correlation coefficient, stress and distortion parameters. Correlations between pairs of matrices were estimated by the Mantel test. There was agreement between the original matrices and the matrices resulting from the grouping process for all the studied coefficients. The Jaccard and Nei and Li indices did not differ in terms of the order of the evaluated accessions and allowed for greater discrimination of these, being the most suitable for assessing genetic diversity in physic nut based on ISSR molecular markers.Keywords: genetic dissimilarity; cluster analysis; Jatropha curcas L

Herança do teor de betacaroteno em melão

The objective of this work was to determine the inheritance of beta‑carotene content in melon (Cucumis melo). The AC-16 accession (Cucumis melo subsp. melo var. acidulus) – with a low beta-carotene content and white mesocarp – was crossed with the Vedrantais cultivar (C. melo subsp. melo var. cantalupensis) – with a high beta-carotene content and salmon colored mesocarp –, to obtain the F1, F2, BC1 and BC2 generations. The AC‑16 and 'Vedrantais' parents, the F1 and F2 generations, and the BC1 and BC2 backcrosses of each parent were evaluated. The quantification of beta‑carotene was carried out in a high-performance liquid chromatography system. Mean components related to the additive and dominance effects, additive and dominance variances, and heritability were estimated. The beta‑carotene content was high in 'Vedrantais' (17.78 µg g-1) and low in AC-16 (0.34 µg g-1). The following results were observed: additive and dominance effects on the genetic control of the character, incomplete character dominance, estimated number of loci close to two, greater variance for segregating populations (F2 and backcrosses), and heritability values in the broad (87.75%) and narrow (64.19%) senses. The beta-carotene content in melon is controlled by a major effect gene, with additive and dominance effects associated with polygenes with additive effects.O objetivo deste trabalho foi determinar a herança do teor de betacaroteno em melão (Cucumis melo). O acesso AC-16 (Cucumis melo subsp. melo var. acidulus) – com baixo teor de betacaroteno e mesocarpo branco – foi cruzado com a cultivar Vedrantais (C. melo subsp. melo var. cantalupensis) – com alto teor de betacaroteno e mesocarpo de cor salmão –, para obtenção das gerações F1, F2, RC1 e RC2. Avaliaram-se os genitores AC‑16 e 'Vedrantais', as gerações F1 e F2, e os retrocruzamentos de cada genitor RC1 e  RC2. A quantificação do betacaroteno foi realizada em sistema de cromatografia líquida de alto desempenho. Foram estimados os componentes de média relacionados aos efeitos aditivos e de dominância, as variâncias aditiva e de dominância e a herdabilidade. O teor de betacaroteno foi alto (17,78 µg g-1) em 'Vedrantais' e baixo em AC-16 (0,34 µg g-1). Observaram-se os seguintes resultados: efeito aditivo e de dominância no controle genético do caráter, dominância de caráter incompleta, número estimado de loci próximo de dois, maior variância para populações segregantes (F2 e retrocruzamentos), e valores de herdabilidade nos sentidos amplo (87,75%) e restrito (64,19%). O teor de betacaroteno em melão é controlado por um gene de efeito maior, com efeitos aditivos e de dominância associados a poligenes com efeitos aditivos

COEFICIENTES DE SIMILARIDADE PARA AVALIAÇÃO DA DIVERSIDADE GENÉTICA EM PINHÃO-MANSO POR MARCADORES ISSR

Objetivou-se com este trabalho, avaliar a eficiência da utilização de diferentes coeficientes de similaridade na estimação da diversidade genética de Jatropha curcas L. utilizando marcadores moleculares ISSR. O DNA genômico foi extraído a partir de folhas jovens de 43 acessos de pinhão-manso. Matrizes de dissimilaridade genética foram obtidas a partir dos coeficientes Baroni, Coincidência Simples, Hamann, Índice II, Índice III, Jaccard, Nei e Li, Ochiai I, Ochiai II, Rogers e Tanimoto e Sokal e Sneath. Os dendrogramas foram construídos utilizando o método UPGMA e comparados mediante os parâmetros de coeficiente de correlação cofenético, estresse e distorção. Foram estimadas as correlações entre os pares de matrizes pelo teste de Mantel. Houve concordância entre as matrizes originais e as matrizes resultantes do processo de agrupamento para todos os coeficientes estudados. Os índices de Jaccard e Nei e Li não diferiram quanto ao ordenamento dos acessos avaliados e permitiram maior discriminação destes, sendo os mais adequados para avaliar a diversidade genética em pinhão-manso baseada em marcadores moleculares ISSR.Palavras-chave: dissimilaridade genética; análise de agrupamento; Jatropha curcas L. SIMILARITY COEFFICIENTS FOR EVALUATION OF GENETIC DIVERSITY IN JATROPHA BY ISSR MARKERS ABSTRACT:The aim of this work was to evaluate the efficiency of using different similarity coefficients in the estimation of Jatropha curcas L. genetic diversity using ISSR molecular markers. Genomic DNA was extracted from young leaves of the 43 jatropha accessions. Genetic dissimilarity matrices were obtained from the Baroni, Simple Matching, Hamann, Index II, Index III, Jaccard, Nei and Li, Ochiai I, Ochiai II, Rogers and Tanimoto and Sokal and Sneath coefficients. The dendrograms were constructed using the UPGMA method and compared using the co-phenetic correlation coefficient, stress and distortion parameters. Correlations between pairs of matrices were estimated by the Mantel test. There was agreement between the original matrices and the matrices resulting from the grouping process for all the studied coefficients. The Jaccard and Nei and Li indices did not differ in terms of the order of the evaluated accessions and allowed for greater discrimination of these, being the most suitable for assessing genetic diversity in physic nut based on ISSR molecular markers.Keywords: genetic dissimilarity; cluster analysis; Jatropha curcas L

Effects of ground cover from branches of arboreal species on weed growth and maize yield

ABSTRACTCultivating maize under systems of alley cropping results in improvements to the soil, a reduction in weeds and an increase in yield. Studies using ground cover from tree shoots produce similar results. The aim of this study was to evaluate the effects on weed growth and maize yield of ground cover made up of 30 t ha-1 (fresh matter) of branches from the tree species: neem (Azadirachta indica A. Juss), gliricidia [Gliricidia sepium(Jacq.) Kunth ex Walp.], leucaena [Leucaena leucocephala (Lam.) de Wit.] and sabiá (Mimosa caesalpiniifolia Benth.). Two treatment groups (cultivars and weed control) were evaluated. The cultivars AG 1041 and AL Bandeirantes were subjected to the following treatments: no hoeing, double hoeing, and ground a cover of branches of the above species when sowing the maize. A randomised block design was used with split lots (cultivars in the lots) and ten replications. The cultivars did not differ for green ear or grain yield. Double hoeing was more effective than ground cover at reducing the growth of weeds. However, both weeding and ground cover resulted in similar yields for green ears and grain, which were greater than those obtained with the unweeded maize

Yield loss in sunflower cultivars due to bird attack

ABSTRACT Bird attacks on the sunflower may hinder its exploitation in the Brazilian semi-arid region. The aim of this study was to evaluate the effects of different levels of protection (0, 33, 66 and 100%) of the capitula of eight sunflower cultivars, evaluated in randomized blocks with sub-divided plots and four replications. The cultivars were allocated in the plots and the levels of protection in the sub-plots, by covering the capitula with caps of non-woven fabric after physiological maturity. The most frequent bird species was the Paroaria dominicana. The Aguará 06 cultivar was the most productive and most tolerant to bird attack, followed by the Helio 250, CF 101 and Charrua cultivars. There was a positive correlation between yield loss (YL) due to birds and the flowering period, YL and the period for physiological maturity, YL and capitulum diameter, YL and stem diameter, YL and plant height, YL and the angle of the capitulum with the stem, and between YL and the distance of the capitulum from the ground. A negative correlation and the absence of correlation were seen between YL and the number of leaves, and between YL and distance of the capitulum to the stem respectively. The effects of protecting the capitula were similar for grain yield in the cultivars under test. Use of the caps was efficient, since an increase in the proportion of protected capitula determined an increase in grain yield, number of grains per capitulum and 1000-grain weight. These increases continued up to a certain proportion, after which there was a decrease in the three characteristics