Giovani O Silva

Correlações entre caracteres de aparência e rendimento e análise de trilha para aparência de batata

The objective of this work was to verify correlations between characters of tuber appearance and yield; as well as the influence of tuber appearance components characters on their expression and selection implications. A potato hybrid population of 15 families each one with 60 genotypes. The experiments were conducted in the experimental field of Embrapa Clima Temperado, Pelotas, Rio Grande do Sul State, Brazil, in Fall of 2004 and 2005. Tuber appearance was closer correlated with tuber shape, tuber curvature, tuber pointing and tuber eyebrow, in the seedling generation, and with tuber shape and tuber size uniformity, in the first clonal generation. Yield was strongly associated with tuber size, tuber number and average tuber weight, in the seedling stage, and with tuber size, tuber number, average tuber weight, tuber flatness and plant vigor, in the first clonal generation. Tuber curvature showed to be the most effective trait for indirect selection to improve tuber appearance in both generations. The results suggest that in the seedling stage, tuber pointing should also be considered along with tuber curvature the selection of tuber appearance.

Desempenho agronômico de clones elite de batata

The aim of this work was to verify the growth cycle, yield components and specific gravity of advanced potato clones as compared to the main varieties grown in Brazil. The experiment was carried on at the Embrapa Clima Temperado experimental field, in Pelotas, Rio Grande do Sul state, Brazil. Eight advanced potato clones developed by the Embrapa Potato Breeding Program, and two commercial cultivars were evaluated in the autumn season of 2011. A randomized complete block design with four replications was used, the plots being constituted by a line of 20 plants. Growth cycle was assessed 95 days after planting. Plants of each plot were harvested at 110 days, followed by evaluation of yield components and specific gravity. After checking for normality of error distribution, the data were submitted to analysis of variance and to means grouping by the Scott & Knott test. CL02-05, CL69-05, CL27-05 and 2197-15 clones showed higher commercial tuber number, percentage of commercial tubers and average tuber weight than the check varieties. CL02-05 clone showed, besides, the highest yield potential of commercial tubers of all four clones. CL69-05 and 2197-15 presented specific gravity and growth cycle similar to Asterix, but had higher yield potential and larger tuber size than it.

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%.

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.

Caracterização e dissimilaridade entre populações de cenoura

The effectiveness of phenotypic characters for characterization and evaluation of dissimilarity, and the genetic distance among improved carrot populations and cultivars were observed. The essays were carried out in Brasilia, Brazil. Three improved carrot populations (712467, 712473 and 712464), and three cultivars (Brasilia, BRS Esplanada and BRS Planalto) belonging to the Brasilia group, were evaluated in the summers of 2008, 2009, 2010, in a complete randomized block design with two replications and plots of 1 m2. At 100 days after sowing, in each plot, 25 roots were harvested and evaluated individually for diameter of root xylem, and some characters that are part of the standard descriptors and protection of carrot cultivars. We performed estimates of repeatability and the necessary number of evaluations to characterize the populations, the phenotypic and genotypic dissimilarity, and the coefficients of determination (R2) according to different numbers of evaluations. Except for the character root tip format, the other characters studied which are part of the standard descriptors of carrot, are not effective to both processes of characterization and distinction of carrot populations belonging to Brasilia group. It is not expect to occur great heterotic effects when crossing the processing populations BRS Esplanada and 712464. For the in natura cultivars evaluated, it may be possible to obtain heterotic effects only when the Brasilia cultivar is used in the crosses.

Repetibilidade e importância de caracteres para avaliação de coleção ativa de germoplasma de batata

As the genetic base of the cultivated potato (Solanum tuberosum L.) is narrow, it is important to use the existing germplasm in the breeding programs, associated with an efficient characterization method. We verified the repeatability, the necessary number of evaluations and the relative importance of phenotypic characters in the characterization of an active potato germplasm bank. A group of 77 potato cultivars and elite clones was cultivated in the experimental field of Embrapa Clima Temperado, on spring seasons of the years 1999, 2000, 2001, 2002 and 2003. The plots consisted of a single row of 15 plants, spaced 0.30 x 0.80 m, within and between rows, respectively. Thirty-three plant and tuber descriptors characters were evaluated. The data were submitted to the analysis of variance, repeatability and importance of characters. Stem pigmentation and color intensity of the sprout base are the more important characters to characterize the potato germplasm, either by the percentage of contribution or by the repeatability of the expression in the various growing years, reflecting in a reduced number of necessary evaluations. The characters leaf coalescence and vein pigmentation, presence of wings, foliage type, leaf insertion, leaflet width, leaflet size, skin color, flower frequency, pubescence of sprout base, peduncle and external corolla pigmentation, apex aspect, and skin roughness showed reduced repeatability and/or small contribution for the dissimilarity. Therefore they should receive less emphasis in the evaluations.

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.

Relações entre caracteres de raiz e ganhos genéticos diretos e indiretos em populações de cenoura

Informacoes sobre efeitos multiplos da selecao para caracteristicas especificas de raiz ainda sao limitadas em cenoura. Neste contexto, os objetivos do trabalho foram: (1) verificar a possibilidade da utilizacao do efeito direto da analise de trilha em substituicao a correlacao genetica nas estimativas de ganhos correlacionados; (2) identificar estrategias de selecao para a obtencao de ganhos correlacionados em massa de raiz, a selecao de raizes mais grossas ou mais compridas; (3) determinar quais tecidos da raiz possibilitam maiores ganhos para o aumento do diâmetro da raiz; e (4) verificar a possibilidade de obter ganhos positivos concomitantemente, para coloracao da raiz e para os demais caracteres avaliados. Tres populacoes de cenoura (derivadas da cv. Brasilia) foram cultivadas durante o periodo do verao no Distrito Federal. Aos 90 dias apos a semeadura foram colhidas 25 raizes por parcela e avaliados individualmente os caracteres massa da raiz; comprimento de raiz; diâmetro da raiz e do xilema da raiz; espessura do floema e o valor do componente de cromaticidade a* do xilema e floema. Foi realizada analise de variância e calculadas as correlacoes geneticas entre os caracteres. Posteriormente foi realizada a analise de trilha, calculadas as respostas correlacionadas (baseadas na correlacao genetica e no efeito direto da analise de trilha), e estimacao dos ganhos diretos com a selecao. Observou-se que a substituicao das correlacoes geneticas pelos efeitos diretos da analise de trilha para o calculo dos ganhos correlacionados proporcionou melhor estimacao do efeito que a selecao para determinado carater traria nos demais, apos a retirada dos efeitos indiretos. Para massa de raiz nao sao esperados ganhos correlacionados pela selecao nos demais caracteres avaliados. Para diâmetro da raiz os maiores ganhos correlacionados foram observados pela selecao no carater espessura do floema da raiz. A selecao exercida exclusivamente para o componente de cromaticidade a* do xilema provoca a reducao principalmente no diâmetro do xilema. No entanto, a selecao direta nestes dois caracteres provoca ganhos positivos para ambos.