A abóbora é amplamente cultivada e consumida no Brasil, em especial na região Nordeste. O espaçamento entre e dentro da linha são cruciais para o desenvolvimento e produção da cultura. Com o objetivo de avaliar diferentes espaçamentos de plantio na produtividade de acessos e cultivar de abóbora, instalou-se um experimento no período de maio a setembro de 2010, no campo experimental da Embrapa Semiárido em Petrolina-PE. O delineamento experimental utilizado foi de blocos ao acaso, em esquema fatorial 5x3, compreendendo quatro acessos selecionados do Banco Ativo de Germoplasma de Abóbora (Acessos: A422, A612, A620 e A627) e a cultivar Jacarezinho como testemunha, e três espaçamentos entre plantas (4x1; 4x2 e 4x3 m), com quatro repetições. Maior produtividade foi obtida pelo acesso A612 (17,3 t ha-1), seguido pelo acesso A422 (15,2 t ha-1) e, o pior desempenho foi obtido pela cultivar Jacarezinho (12,2 t ha-1), sem diferenciar dos demais acessos. Para espaçamento entre plantas observou-se que as maiores produtividades foram verificadas no menor espaçamento (4x1 m) com 18,2 t ha-1, e menores produtividades no espaçamento de 4x3 m (11,9 t ha-1). O acesso A612 sobressaiu-se com maior massa fresca (3,5 kg fruto-1), não se diferenciando estatisticamente do acesso A422, que alcançou 3,2 kg fruto-1. A cultivar Jacarezinho e o acesso A620, com respectivos 1,9 e 2,0 kg fruto-1 obtiveram os menores valores para massa fresca do fruto, assim como maior número de frutos por planta com 4,7 e 4,6 frutos plantas-1, respectivamente.

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The aim of this study was to estimate the phenotypic divergence among fourteen pumpkins accessions of the cucurbits Germplasm Active Bank of Embrapa Semiárido, in order to support breeding program to these species. Nine morphoagronomic descriptors were analyzed by the principal components and by UPGMA techniques. In the analysis of principal components, the formation of three contrasting clusters was observed, each one composed of two accessions. There occurred also the formation of one core group composed of five accessions, being the accessions called 683 and 684 collected in Bahia and the other in Maranhão. The most divergent accessions were 620, 624 and 748. The variables of the greatest contribution to the genetic divergence were diameter, weight and average length of the fruit. In the UPGMA analysis, obtained from the symmetric matrices generated by the Mahalanobis distance for the nine descriptors, there was the formation of one core group, composed of ten accessions, whose similarity was 45.71%, with geographically divergent accessions presenting the greatest similarity. Three accessions were not clustered with others. The study identified phenotypic variability for the analyzed characters and the absence of relationship between place of collection and phenotypic diversity.

The estimation of genetic parameters allows for the selection of superior individuals for important traits in plant breeding. The objectives of the present study were to estimate and predict the gains in genetic parameters, as well as to select superior individuals for morphoagronomic and pulp quality characteristics in C. moschata. Ten progenies derived from accessions collected in the northeast of Brazil were evaluated for 17 morphoagronomic characteristics and chemical quality of the pulp, including total carotenoids and β-carotene. The low values of additive genetic variance denote the need for additional selection cycles for the evaluated characteristics. Heritability greater than 30% was observed for 13 of the 17 variables analysed, indicating success in selection. Likewise, accuracy values between 74 and 93% were obtained for 15 of the evaluated variables, demonstrating the existence of high genetic variance. Individual ranking was conducted for the variables fruit weight (FRW), soluble solid content (SSC), titratable acidity (TA), total carotenoid content (TCC) and β-carotene (β-Car), identifying five individuals of progeny 10 that were promising for advancement in selection for SSC, TCC and β-car. In ranking the simultaneous evaluations for all the characteristics and taking into account the formats piriform and 'moranga', two individuals of progeny 10, which coincided with the top ranking for SSC, CBT and β-car, were identified. This identification of more than one promising individual enhances the potential of the progenies evaluated for the development of commercial and productive lines in semi-arid conditions.

This study had the following objectives: to investigate the sexual expression in seven watermelon populations; to evaluate some population parameters and the genetic potential of a population (PCS) obtained by crossing and segregating for sexual expression and other traits. For verifying the sexual expression, populations were evaluated with respect to type of flower, under controlled conditions. Maternal and selfed progenies were obtained from the PCS population for field evaluation, considering: fruit yield per plant, fruit weight, number of fruits per plant, flesh colour and sugar content. On the basis of molecular marker data (RAPD), the outcrossing rate (t m and t s ), allelic frequencies (p i ) and the coefficient of inbreeding (F) were estimated for the PCS population. Results indicated that populations B9 and P14 are andromonoecious in which natural selfing occurs, giving rise to normal fruits. The remaining populations are monoecious. Population PCS practices a mixed mating system (t m = 0.765) and, having shown sufficient genetic variation and relatively low inbreeding depression, has high potential for breeding purposes. The importance of obtaining accurate estimates of the outcrossing rate is pointed out, specially because sexual expression and the mating system are genetically conditioned in watermelon populations.

Resumo -O objetivo deste trabalho foi avaliar a divergência fenotípica em uvas da Coleção da Embrapa Semi-Árido, com base em oito variáveis morfoagronômicas avaliadas nos anos 2005 e 2006. Nas uvas com sementes, a análise por componentes principais identifi cou oito grupos contrastantes. As variáveis mais relevantes, quanto à divergência genética, foram peso e comprimento de bagas. Em uvas sem sementes, formouse apenas um grupo, e as variáveis mais relevantes foram peso de bagas e produção. A distância euclidiana média padronizada no grupo com sementes mostrou que 41% dos acessos apresentaram estimativas acima da média geral. No grupo sem sementes, o percentual foi de 47%. Foi observada concordância de resultados com os componentes principais. Pelo UPGMA, formaram-se três grandes grupos das uvas com sementes: o primeiro, com 14 acessos; o segundo, com seis acessos e similaridade de 56%; e o terceiro, com 19 acessos e similaridade de 73%. Das uvas sem sementes, formaram-se três grupos: um, com 11 acessos e similaridade de 59%; outro, com sete acessos e similaridade de 58%; e o terceiro com apenas um acesso. Sugere-se que os acessos com maior divergência quanto aos caracteres estudados sejam utilizados para a obtenção de híbridos de videira.Termos para indexação: Vitis vinifera, descritores de videira, divergência genética, melhoramento genético. Phenotypic divergence among table grapes accesses in the Brazilian Semi-AridAbstract -The aim of this work was to evaluate the phenotypic divergence in grapes from the Collection of Embrapa Semi-Árido, in 2005/2006, based on eight morphoagronomic variables. In seeded grapes, the analysis by main components identifi ed eight contrasting groups. The most important variables for genetic divergence were weight and length of berries. In seedless grapes, only one group was found, with berry weight and yield as the most important variables. The standardized mean Euclidean distance in the seeded grapes showed that 41% accesses had estimative higher than the general mean; in the seedless grapes, it was 47%. Agreement with the principal components was observed. Through UPGMA, three big groups with seeds were formed: the fi rst with 14 accesses; the second with six accesses and 56% similarity; the third with 19 accesses and 73% similarity. In the seedless group, two groups were formed: one with 11 accesses and 59% similarity; another with seven accesses and 58% similarity; and the third with one access. It is suggested that accesses with higher divergence for the studied characters be used to obtain grape hybrids.

The objective of this work was to characterize 119 accessions of guava and 40 accessions of "araçá" sampled in 35 Brazilian ecoregions, according to the International Union for the Protection of New Varieties of Plants (UPOV) descriptors. The majority of "araçá" accessions presented wide spacing of leaf veins, while guava accessions presented medium to close spacing. Most fruits of "araçá" accessions were classified as small, contrasting with medium to large fruits of guava accessions. Most of "araçá" accessions (91%) presented white flesh fruit color, while 58% of guava accessions presented pale pink, pink and dark pink colors. Fruit differences among wild and cultivated Psidium species indicate fruit as the most altered trait under artificial selection.

Traits related to fruit yield and physical and chemical fruit quality are being evaluated by Embrapa pumpkin breeding program. Path and Pearson's correlation analysis are necessary to allow the knowledge of the relation between the variables of interest for this program. The objective of the present study was to determine the genetic correlations between yield- and sensorial and nutritional quality attributes-associated variables in pumpkin progenies to support the selection process. Twelve genotypes were evaluated for 10 yield-related traits, and 8 sensory and nutritional quality traits of fruit, including the commercial cultivar Jacarezinho. A path analysis considered the fruit weight (FrW) was as basic variable and the others as explanatory. The FrW had 98% of its total variation available in a function of the explanatory variables. The highest variations were observed in the fruit-shape related traits. In addition, the variables internal median cavity diameter (IDmed), equatorial pulp thickness (EPT), apical pulp thickness (APT), and smallest fruit diameter (Dsm) are indicated for a direct selection of progenies targeting a higher FrW. The correlation analysis highlighted that color-related variables have the possibility of indirect selection aiming to increase total carotenoid content (TCC) and β-carotene content (β-car). The evaluated progenies showed notable soluble solids content (SSC), TCC and β-car contents compared to the commercial cultivar. Furthermore, the contribution of β-car to TCC is at least 50% higher in these progenies than in 'Jacarezinho' pumpkin.