Jadir B Pinheiro

Severidade da ferrugem da soja em função do suprimento de potássio e cálcio em solução nutritiva

Entre as estrategias para o controle da ferrugem da soja cita-se a nutricao mineral equilibrada. Objetivou-se, neste trabalho, verificar o efeito do calcio e do potassio na severidade da ferrugem (Phakopsora pachyrhizi), na fotossintese potencial e na nutricao de plantas de soja. O delineamento experimental foi em blocos casualizados, com 25 tratamentos, 4 repeticoes e 2 plantas por repeticao. Utilizou-se esquema fatorial 5 x 5, com 5 doses de K (4, 5, 6, 7, 8 mmol L-1), combinadas com 5 doses de Ca (3, 5, 7, 9, 11 mmol L-1). As plantas foram inoculadas no estadio V4 e, apos nove dias, iniciaram-se avaliacoes da severidade da ferrugem pelas porcentagens de tecido lesionado, as quais foram transformadas em area abaixo da curva de progresso da doenca (AACPS).Tambem foram avaliados a fotossintese potencial e o teor de nutrientes na materia seca de raiz, caule e folhas. O suprimento de Ca reduziu a AACPS em todas as doses de K. O suprimento de K tambem reduziu a AACPS nas doses 5, 7 e 11 mmol L-1 de Ca. A menor AACPS foi observada na combinacao das doses de 8 e 11 mmol L-1 de K e Ca, enquanto a maior AACPS foi observada nas doses de 4 e 5 mmol L-1 de K e Ca. As plantas tratadas com as doses 6 e 5 mmol L-1 de K e Ca e 5 e 5 mmol L-1 de K e Ca apresentaram melhor resposta fotossintetica. Com o incremento das doses de K na solucao, houve aumento dos teores foliares de K e reducao linear dos teores foliares de Ca. Com o incremento das doses de Ca em solucao nutritiva verificaram-se aumentos nos teores desse elemento e reducao linear dos teores de K nas folhas.

Resistência de populações de cenoura à queima-das-folhas com diferentes níveis de germoplasma tropical

A queima-das-folhas e responsavel por perdas significativas na producao de cenoura e a resistencia genetica e uma das formas mais eficientes de controle da doenca. Objetivou-se com este trabalho avaliar a resistencia de progenies de populacoes de cenoura a queima-das-folhas com diferentes niveis de germoplasma tropical. Foram avaliadas as populacoes 561, 586 e 587 e como testemunhas as cultivares comerciais, Juliana e BRS Planalto. Foi utilizado o delineamento de blocos casualizados, com duas repeticoes e parcela de 1,2 m2. A doenca ocorreu de forma natural no campo e foi avaliada a cada cinco dias, a partir dos 72 dias apos a semeadura. As populacoes 561, 586 e 587 e a cultivar BRS Planalto apresentaram severidades semelhantes e inferiores as cultivares Brasilia e Juliana, as quais nao diferiram entre si. Nao foram observadas diferencas significativas na producao comercial e total de raizes. Nas analises realizadas entre as progenies dentro de cada populacao e as testemunhas nao foram observadas diferencas na producao comercial e total de raizes. Com relacao a severidade, as progenies da populacao 561 e 586 e BRS Planalto nao diferiram entre si e apresentaram maiores niveis de resistencia que Brasilia e Juliana. Contudo, uma progenie da populacao 586 apresentou resistencia intermediaria. Dez de 15 progenies da populacao 587 apresentaram niveis de resistencia semelhantes a BRS Planalto, enquanto cinco apresentaram resistencia semelhante a Brasilia e Juliana. Esta maior variabilidade fenotipica indica seu potencial para a obtencao de ganho genetico para resistencia a queima-das-folhas. A producao de raizes comerciais e totais das populacoes 561 e 586 apresentaram correlacao negativa com a severidade da doenca. Tais resultados indicam que a resistencia a queima-das-folhas atribui-se, majoritariamente, ao germoplasma tropical, observado em maior quantidade na populacao 561, cerca de 87,5%.

Análise de fatores e regressão bissegmentada no estudo da adaptabilidade e estabilidade de cenoura

Analysis of factors and bissegmented regression in the study of adaptability and stability in carrots The objective of this study was to evaluate the stability and adaptability of eight genotypes of carrots (three cultivars and five populations) in 17 environments in the Northeast, Midwest, Southeast and Southof Brazil in the crop years 2009/10, 2010/11 and 2011/12. The experiments were grown from November to January of each year according to the farmers’ crop calendar. The plot was composed of an area with 1.0 m 2 in a randomized block design with three replications. The cultural practices were the same used by the farmers. At harvest, the marketable roots were quantified and the values converted to tha -1 . Analysis of variance was performed and after that, the factor analysis and bissegmented regression analysis to study the stability and adaptability . None of the genotypes showed wide adaptability. Factor analysis was able to cluster less than 50% of the evaluated environments. The ideal genotype was not found by regression analysis. The ‘BRS Planalto’ cultivar was the most adaptedby the bissegmented regression method while ‘Brasilia’ CNPH-589 and CNPH-600 were the most adapted by factor analysis. The results obtained by these methods demonstrate the difficulty of recommending a cultivar for all producing regions and regionalized programs should be initiated. The use of the two associated methods allows safer decisions concerning the behavior of genotypes of carrot.

Capacidade combinatória em cenoura para componentes de produção e tolerância à queima-das-folhas

The use of hybrid carrots is a growing demand in the Brazilian market of seeds because they combine earliness and uniformity, as well as yield. We evaluated the effects of combining ability between carrot lineages for production components and tolerance to leaf blight. The crosses were carried out in a partial diallel 5x2, using five male-sterile lines of temperate and two male-fertile parents of tropical origin of the breeding program of Embrapa Hortalicas. The experiment was conducted at the experimental field of Embrapa Vegetables in the season 2011/12. The experimental designed was randomized blocks with three replications. The experimental plot consisted of a bed 1.0 m wide by 3.0 m in length. The ten hybrids and their male parents were evaluated for tolerance to leaf blight at 90 days after sowing. At 100 days plants were harvested and measured total and marketable roots yield, the ratio between them, weight, length and diameter of marketable roots. The analysis of variance was performed and the effects of general combining ability (GCA) and specific combining ability (SCA) were estimated. There were significant differences among hybrids for most traits. We detected predominant effects of GCA over SCA for most of yield components characters: weight of marketable roots (WMR, t ha-1) , total weight of roots (TWR, t ha-1), the relationship between WMR and TWR (PROP), mean weight of marketable roots (MWM), mean marketable root length (MRL) and mean marketable root diameter (MRD). SCA effects were significant for the tolerance to leaf blight. From these results we concluded that the male sterile lineages CNPH-11 and CNPH-72 and the male lineage CNPH-36 are the most promising for use in breeding programs aiming to produce hybrids.

Reação de genótipos de Capsicum ao nematoide-das-galhas

Reaction of Capsicum genotypes to root-knot nematode The objective of this research was to evaluate the response of experimental hybrids of Capsicum annuum [‘Experimental Hybrid (EH)’ and its Reciprocal (EHR)] and Embrapa Hortalicas elite genotypes of C. chinense, C. frutescens and C. baccatum to Meloidogyne incognita race 1, M. javanica and M. enterolobii. The hybrid pepper ‘Magali R’ was used as susceptible control to M. incognita race 1 and resistant to M. javanica, and as resistant controls to M. incognita race 1 and M. javanica ‘Silver’ and ‘Snooker’ rootstocks were used. ‘Rutgers’ tomato was used to confirm the viability of the inoculum. Two experiments were carried out in a greenhouse in a completely randomized design with six replications. Thirty-day old seedlings were transplanted to 2.0 L pots containing a mixture of soil, sand, cattle manure and carbonized rice husk (1:1:1:1). Plants were inoculated after transplanting with deposition of 5.0 mL of suspension containing 5,000 eggs and J2 of each species alone. After seventy days, plants were assessed by measuring the index of egg mass and galls, the number of eggs per gram of roots and the reproduction factor. The C. annuum experimental rootstock hybrids were resistant to M. incognita and M. javanica and susceptible to M. enterolobii, similar to ‘Silver’ and ‘Snooker’. The hybrid ‘Magali R’ only showed resistance to M. javanica. Elite genotypes of C. chinense and C. baccatum were susceptible to all three species, while genotypes of C. frutescens were susceptible only to M. enterolobii. The experimental hybrids of Capsicum annuum and most genotypes of C. frutescens may be used in protected cultivation areas infested with M. incognita race 1 and M. javanica. However the search for resistant genotypes to M. enterolobii, as well as the development and adoption of control strategies is of crucial importance.

Produtividade e tolerância à queima-das-folhas de diferentes genótipos de cenoura de verão

The replacement of open-pollinated carrot cultivars by hybrids is a reality in the seed market. We aimed to evaluate the productive potential of experimental carrot hybrids, tolerance to leaf blight as well as the uniformity of roots, compared to open-pollinated cultivars. Eighteen carrot genotypes, 15 experimental hybrids, one commercial hybrid (Juliana) and two open-pollinated cultivars (OPs) (Brasilia and BRS Planalto) were evaluated in the 2011/12 crop in Brasilia, Brazil, in randomized blocks design with three replications in plots of 2 m2. At 90 days the incidence of leaf blight was evaluated and at 100 days we measured production component characters, in addition to taking at random 50 roots per plot for individual measures. Difference was observed for all traits among the genotypes, hybrid being better or worse than OPs. For total root yield, no contrast was found between hybrids and OPs. However, hybrids showed higher amount of marketable roots compared to OPs. Regarding uniformity of root lenght, OPs were similar to hybrids, but more irregular in relation to diameter and individual weight. The results demonstrate superiority of hybrids in relation to OPs for marketable production and uniformity of roots.

Evaluation of carrot experimental hybrids in the Federal District, Brazil

O plantio de hibridos de cenoura traz algumas vantagens em comparacao com cultivares de polinizacao livre, pois associam produtividade, qualidade e uniformidade de raizes. O objetivo deste trabalho foi avaliar o potencial agronomico de 24 hibridos de cenoura, sendo nove obtidos pelo cruzamento entre linhagens de origem tropical (grupo Brasilia - CNPH-520 e CNPH-536) e temperada (macho-estereis - CNPH-610, CNPH-664, CNPH-633, CNPH-612 e CNPH-671) e 15 obtidos do cruzamento entre linhagens de origem tropical (CNPH-1 a CNPH-15) e a linhagem macho-esteril CNPH-612. A semeadura foi realizada no campo da Embrapa Hortalicas em novembro de 2011. A parcela experimental consistiu de tres fileiras duplas espacadas 20 centimetros de distância, com 10 cm entre linhas. Utilizou-se o delineamento experimental de blocos casualizados com tres repeticoes. A queima-das-folhas ocorreu de forma natural no campo e foi avaliada 90 dias apos a semeadura. Os rendimentos agronomicos foram avaliados 10 dias apos. No primeiro experimento os hibridos CNPH-610×CNPH-536, CNPH-612×CNPH-536 e CNPH-610×CNPH-520 apresentaram menores severidades da doenca, enquanto CNPH-610×CNPH-520 e os hibridos CNPH-664×CNPH-520 e CNPH-671×CNPH-520 apresentaram as maiores producoes de raizes comerciais e menores producoes de raizes refugos. Os hibridos nao diferiram entre si em relacao ao peso e comprimento medio de raizes. No segundo experimento, os hibridos CNPH-612×CNPH-2, CNPH-612×CNPH-6, CNPH-612×CNPH-10 e CNPH-612×CNPH-11 apresentaram resultados superiores para todas as caracteristicas avaliadas (resistencia a queima-das-folhas, producao de raizes comerciais e refugos, peso, comprimento e diâmetro medio de raizes), seguidos de CNPH-612×CNPH-3, que apresentou comprimento medio de raizes inferior.