Agnaldo Df Carvalho

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.

Effect of plant density and genotype on root size and recovery of Cenourete ® raw-material

Cenourete® is a cut and peeled mini carrot, produced by the abrasion of 55-60 mm cylindrical carrot root segments. The longer and the thinner the carrot root, the higher is the recovery of Cenourete®. Two new carrot genotypes obtained at Embrapa Hortalicas, Brasilia, Brazil, populations 1012568 (P68) and 1012575 (P75), and the cultivar Esplanada were evaluated in relation to the production of roots for mini carrot manufacture. Two crops were cultivated in the summer of 2010-2011 under the densities 8, 10 and 12 lines/meter in order to obtain respectively 1.06, 1.33 and 1.60 million plants/ha and harvested approximately 3 months after sowing. We evaluated the total root production (kg/ha), the diameter, the length and the weight of individual roots and the production of root pieces 60 mm long with diameter in the ranges <15 mm, 15-25 mm, 25-30 mm. Total yield of 60 mm root pieces varied from 19,000 to 34,000 kg/ha depending on treatment. Total yield from cv. Esplanada was significantly higher than yield from genotypes P68 and P75 which did not differ from each other. The new genotypes produced longer and thinner roots compared to cv. Esplanada, what resulted in higher production of smaller root pieces (diameter <15 mm) and a corresponding lower proportion of larger pieces (diameter of 25-30 mm). Plant density had no influence on the total production of root pieces but affected the recovery of particular size ranges, with the proportion of smaller pieces increasing at higher density. The amount of cut waste varied from about 3,000 to 7,000 kg/ha depending on treatment. Cv. Esplanada produced a higher mass of cut waste than P68 and P75 due to a larger amount of pieces with diameter higher than 30 mm. Although increased plant density reduced root size of all genotypes, the variation in root length and root diameter was mainly due to genotype effect.

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.