José Jaime Vasconcelos Cavalcanti

Repetibilidade de caracteres de produção e porte da planta em clones de cajueiro-anão precoce

This work was carried out to estimate the repeatability coefficient, to compare the efficiency of methodologies used in the estimation process, as well as to determine the number of evaluations for selecting dwarf cashew (Anacardium occidentale L.) clones. The methodologies used to estimate the coefficient of repeatability were: analysis of variance in which the temporary effect is removed from the error (ANOVA); analysis of the principal components obtained from both the correlation matrix (PCCOR) and the covariance and phenotypic variance matrix (PCCOV); and the structural analysis based on the theoretic eigenvalue of the correlation matrix or mean correlation (EVCOR). Characters such as plant height (PH), canopy diameter (CD) and nut yield (NY) from 30 clones were evaluated during five years. The r value for PH and CD varied from 0.85 (ANOVA) to 0.96 (PCCOV). The yield r values varied from 0.51 (ANOVA) to 0.88 (PCCOV). Therefore, it was admitted that the principal components method employing the covariance and phenotypic variance matrix is the most efficient to dwarf cashew clonal selection, mainly in relation to yield. It was also concluded that two evaluations of both characters PH and CD, and three evaluations of NY are sufficient in the selective process.

Interação enxerto e porta-enxerto na incidência da resinose do cajueiro

A expansao do cajueiro-anao-precoce no Brasil vem promovendo baixa diversidade genetica dos genotipos usados como enxerto e porta-enxerto, ensejando vulnerabilidade da cultura as vicissitudes bioticas como a resinose (Lasiodiplodia theobromae), principal doenca do cajueiro no semiarido nordestino. Estima-se que cerca de meio milhao de mudas de cajueiro-anao-precoce sejam produzidas anualmente, sendo a grande maioria delas produzida de propagulos enxertados sobre plântulas oriundas de sementes do clone CCP 06. A principal estrategia de manejo da resinose e o plantio de clones resistentes. Entretanto, entre os aspectos que contribuem para sucessivas epidemias da resinose, destaca-se a falta de estudos de interacoes genotipicas entre enxerto e porta-enxerto. Este estudo objetivou avaliar o efeito de combinacoes de clones de cajueiro-anao-precoce usados como enxerto e porta-enxerto na incidencia da resinose. Sementes de plantas de polinizacao aberta de seis clones selecionados foram usadas para producao de porta-enxerto. Os clones comerciais CCP 76 (suscetivel) e BRS 226 (resistente) foram usados como enxertos. O experimento foi realizado obedecendo ao delineamento de blocos ao acaso, no esquema fatorial 2 x 6, com quatro repeticoes e nove plantas por parcela do tipo quadrada, sob condicoes de elevada pressao da doenca, em Pio IX-PI. Tres anos apos o plantio definitivo, a incidencia (I) e a severidade (S) (escala de 0 a 4) da resinose foram superiores no clone CCP 76 (I = 97% e S=2,10) em relacao ao BRS 226 (I = 33% e S=0,36), independentemente do porta-enxerto. O clone CP 06 como porta-enxerto foi o unico que reduziu a incidencia e a severidade da resinose, independentemente do genotipo do enxerto. Este clone foi capaz de reduzir a severidade da resinose do clone CCP 76 (S=2,10) como enxerto em quase 30%.

Heterose em cajueiro anão precoce

Esse trabalho foi conduzido com o objetivo de avaliar a heterose no cajueiro (Anacardium occidentale L.) anao precoce. O experimento foi composto por seis clones parentais (CCP 06, CCP 09, CCP 76, CCP 1001, C1P3 e P399E) e 18 combinacoes hibridas. Utilizou-se delineamento de blocos casualizados, com duas repeticoes e cinco plantas por parcela. A heterose media foi de 12,09%, 19,38%, 98,01%, 96,97% e -2,11%, respectivamente, para altura da planta, diâmetro da copa, numero de castanha por planta, produtividade de castanha e peso medio de castanha, indicando presenca de vigor hibrido nos cruzamentos, para todos os caracteres, exceto para peso medio de castanha, demonstrando a importância de sua exploracao, com perspectivas de avancos geneticos sobre caracteres da cultura do caju. A consequencia seria a obtencao de clones comerciais com caracteristicas de producao desejaveis e a formacao de populacoes-base para o programa de melhoramento populacional. Os hibridos CCP 06 x C1P3, CCP 09 x P399E e CCP 09 x CCP 06 sao os mais promissores.

Variabilidade genética de feijão-caupi de porte ereto e ciclo precoce analisada por marcadores RAPD e ISSR

O conhecimento da variabilidade genetica e de fundamental importância para a identificacao de genotipos superiores no inicio de um programa de melhoramento genetico das culturas em geral. Objetivou-se avaliar a variabilidade genetica em 38 genotipos de feijao-caupi de porte ereto e ciclo precoce por meio de marcadores RAPD e ISSR. O material foi proveniente do Banco de Germoplasma da Universidade Federal do Ceara e do programa de melhoramento genetico de feijao-caupi da Embrapa Meio Norte. As extracoes de DNA foram realizadas de acordo com o protocolo de Doyle e Doyle. Dez iniciadores RAPD geraram 71 bandas polimorficas (88,75%) com 7,1 marcadores por iniciador, ja nove iniciadores ISSR produziram 47 bandas polimorficas (75,81%) com 5,22 marcadores por iniciador. Pela analise de agrupamento, o genotipo CE-748 apresentou-se distinto dos demais e os genotipos AU 94-MOB-816 e UCR 95-701 apresentaram o maior grau de similaridade entre os avaliados. Os marcadores RAPD e ISSR foram eficientes em detectar o polimorfismo entre os genotipos de feijao-caupi de porte ereto e ciclo precoce.

Predição simultânea dos efeitos de marcadores moleculares e seleção genômica ampla em cajueiro

A selecao genomica ampla (genome wide selection - GWS) foi proposta como uma forma de aumentar a eficiencia e acelerar o melhoramento genetico, enfatizando a predicao simultânea dos efeitos geneticos de grande numero de marcadores geneticos de DNA dispersos em todo o genoma de um organismo, de forma a capturar os efeitos de todos os locos e explicar a variacao genetica de um carater quantitativo. Objetivou-se com o presente trabalho aplicar o principio da GWS no melhoramento do cajueiro, estimando simultaneamente os efeitos de 238 marcadores avaliados em 74 individuos de uma familia de irmaos completos, visando a explicar grande porcentagem da variacao genotipica total do carater peso da amendoa e a aumentar a eficiencia do melhoramento do cajueiro. Verificou-se que a capacidade preditiva e a acuracia sao praticamente maximizadas na analise com 70 marcadores de maiores efeitos. O aumento do numero de marcadores nao aumenta linearmente a acuracia da GWS pelo metodo RR-BLUP. Os 70 marcadores de maiores efeitos capturam 74% da variacao genotipica total e propiciam alta acuracia seletiva (86%) da selecao para o peso de amendoas, enquanto os cinco marcadores de maiores efeitos capturam apenas 19% da variacao genotipica total e propiciam acuracia seletiva de apenas 44%. Assim, a selecao assistida (MAS), baseada em poucos (cinco) marcadores de efeitos significativos, propicia eficiencia muito inferior a GWS. Os valores geneticos genomicos preditos na populacao de validacao cruzada aproximam-se bem dos valores fenotipicos observados, com correlacao de 0,79. A estimacao simultânea dos efeitos dos marcadores, segundo o conceito da GWS, e uma alternativa interessante, visando a aumentar a eficiencia do melhoramento do cajueiro.

QTL detection of yield-related traits of cashew

The identification of quantitative trait loci (QTL) and marker-assisted selection with a view to breeding programs have aroused great interest, including for cashew improvement. This study identified QTL for yield-related traits: nut weight, male and hermaphrodite flowers. The traits were evaluated in 71 F1 genotypes of the cross CCP 1001 x CP 96. The methods of interval mapping and multiple QTL mapping were applied to identify QTL. Eleven QTL were detected: three for nut weight, four for male flowers and four for hermaphrodite flowers. The QTL accounted for 3.79 to 12.98 % of the total phenotypic variance and had phenotypic effects of -31.81 to 34.25 %. The potential for marker-assisted selection of the QTL hf-2f and hf-3m is great and the phenotypic effects and percentage of phenotypic variation higher than of the others.

Cashew (Anacardium occidentale L.) Breeding: A Global Perspective

The cashew tree (Anacardium occidentale L.), which first originated from Brazil, is now found throughout the tropical world and in some subtropical areas with favourable climatic conditions: rainfall not so heavy and a dry period between rainy seasons. Its economic importance lies in the commercial value of the kernel extracted from the fruit, one of the tastiest and much appreciated by the nut consumers. The cashew nut producing chain provides employment and income for thousands of people and a significant turnover for agri-business dependent countries (Barros and Crisostomo 1995). The Cashew was introduced from Brazil into India by the Portuguese during the sixteenth century. Following its introduction into southwestern India, the cashew probably diffused throughout the Indian subcontinent. Cochin served as a dispersal point for Southeast Asia as well (Johnson 1973). A look at the evolution of the world production of cashew nut gives an understanding on how the geography of the production is changing fast. From the early 1990s, a number of Asian countries have become important producers that did not appear in the statistics previously (Table 9.1). This is a clear indication that unless the traditional producers change the systems of production in utilisation through adding technologies capable of increasing production and productivity, very little will actually be achieved to improve its capability to compete with Asiatic producers in the international market. The most important nut producers are Vietnam, India, Brazil, Nigeria and Tanzania. Collectively, these countries account for 78% of the world production, according to FAO’ statistical data from 2004. Vietnam has seen dramatic increases in production over the last 10 years, rising from 202,000 mt in 1995 to approximately 675,000 mt in 2004. This represents 31% of the world production

VARIABILIDADE GENÉTICA EM CARACTERES MORFOLÓGICOS DE POPULAÇÕES DE PLANTAS JOVENS DE ACEROLA

Aiming to estimate and to interpret the role of genetic variability occuring in sexually propagated young populations of acerola, originated from selected populations, an experiment was set up with three different populations. The experiment was conducted at the Experimental Station of the Embrapa Agroindustria Tropical, in Pacajus county, state of Ceara (Brazil). The experimental design was a randomized blocks, with 45 progenies, 3 replicates and 4 to 6 plants per plot. Results revealed that the evaluation of genetic variability in young acerola populations is not an adequate tool for the improvement of this species. Besides, it was not possible to interpret the genetic variability occurring in these populations due to the absence of a clear pattern capable of establish correlation between the populations studied. Additional test are recommended with bigger samples of progenies per population and higher number of plants per progeny in order to confirm these results.

Validating a probe from GhSERK1 gene for selection of cotton genotypes with somatic embryogenic capacity

Substantial progress is being reported in the techniques for plant transformation, but successful regeneration of some genotypes remains a challenging step in the attempts to transform some recalcitrant species. GhSERK1 gene is involved on embryo formation, and its overexpression enhances the embryogenic competence. In this study we validate a short GhSERK1 probe in order to identify embryogenic cotton genotypes using RT-qPCR and blotting assays. Cotton genotypes with contrasting somatic embryogenic capacity were tested using in vitro procedures. High expression of transcripts was found in embryogenic genotypes, and the results were confirmed by the RT-PCR-blotting using a non-radioactive probe. The regeneration ability was confirmed in embryogenic genotypes. We confirmed that GhSERK1 can be used as marker for estimating the somatic embryogenesis ability of cotton plants.

Desempenho de híbridos de cajueiro-anão-precoce no litoral do estado do Ceará

The selection of cashew genotypes in segregating progenies obtained via artificial hybridization consists of a chance to associate favorable genes inherited from known parents. Additionally, knowing the dynamics of the main characters of interest can help define effective strategies to obtain genetic gains. So, the objective of this study was to evaluate the performance of cashew full-sib progenies in relation to production and morphological characters, cultivated in the municipality of Pacajus-CE in three growing seasons, and to estimate the correlations among traits of interest. In the seasons of 2010, 2011 and 2012 were evaluated seven progenies of cashew in relation to morphological and productive characters. The crosses CCP 76 x BRS 226, CCP 76 x Embrapa 51 and BRS 226 x Embrapa 51 shown to be promising in generating superior genotypes for agronomic interest characters. The size of the plant showed positive associations with productivity of nuts, and the number of nuts per plant showed strong correlation with yield. So, it is important to emphasize the necessity to perform the selection seeking balance in relation to the performance on morphological and productive characters in order to obtain genotypes that combine high productivity of nuts and appropriate size of plant.