ABSTRACT Buriti (Mauritia flexuosa L.f), a palm tree native to South America and widely distributed in Brazil, displays significant ecological, economic and biotechnological importance. However, the disorderly extractivism and environmental degradation of its endemic areas are leading to reductions in, and/or extinction of the buriti palm tree, causing ecological imbalance with significant economic losses for rural communities and genetic diversity. Consequently, populational genetic diversity studies have become relevant as a strategy for conserving the species. Therefore, this study evaluated the genetic structure of 10 populations from the Lençóis Maranhenses region, in the state of Maranhão, Brazil, using microsatellite markers. Results indicated that eight pairs displayed a high level of polymorphism in the populations evaluated (98.5 %). The genetic diversity estimations allowed for identifying 220 alleles (average of 9.5 alleles/loci), and the heterozygosity averages observed (Ho) were lower than the heterozygosity expected (He) in the population (0.16 and 0.64) and loci levels (0.15 and 0.65), respectively. The Shannon Index (I) mean value of 1.36 indicated high diversity and genotypic richness in the populations evaluated, while the population index (FST) indicated a low value (0.05) and the fixation index pertaining to individuals indicated a high value (FIS = 0.79) exhibiting a moderate population distribution structure, and pointing to greater diversity between individuals. Based on these results, populations denominated as PA and PB presented a high genetic similarity (0.219), while populations denominated as PF and PJ exhibited more distant genetic characteristics (0.519). These results can be correlated based on prioritization of conservation of this non–domesticated species, influenced by environmental characteristics, suggesting that the genetic diversity found should be conserved in a germplasm bank, and subsequently exploited in breeding programs.

ABSTRACT Selection indexes represent the real efforts of a breeding program to obtain genetic gains for various significant traits simultaneously. As such, this study selected superior F5 lines by combined selection for fruit quality using an index based on predicted genotypic values via residual or restricted maximum likelihood/best linear unbiased prediction (REML/BLUP) methodology weighted by agronomic weights. To do so, 97 F5 papaya lines obtained by the single seed descent method, resulting from the biparental cross between the genotypes JS-12 and Sekati, were evaluated for the main traits related to fruit quality. Results of the analysis of deviance and the genetic parameters indicated that there was genetic variability, indicating possible success in the selection process. Based on the selection index, 29 lines were selected as superior for fruit quality with ‘Formosa’ pattern. The strategy of the selection index combining BLUPs of multiple traits of interest associated with agronomic weights allows maximizing genetic progress while discarding less-promising genotypes.

ABSTRACT: The growing demand for quality of papaya by the domestic and international markets requires the development of genotypes that are capable of incorporating traits, such as high yield and fruit quality. This study estimated the genetic parameters and the specific combining ability of F4 papaya lines crossed to the SS-72/12 tester to identify genotypes with higher genetic value for hybrid production. We evaluated 169 treatments consisting of 62 topcross hybrid combinations, 97 F5 lines, and 10 controls in a 13 × 13 lattice design with five replicates and two plants per plot. The following traits were evaluated: plant height (PH), stem diameter (SD), first-fruit insertion height (FFIH), number of marketable fruits (NMF), number of deformed fruits (NDF), number of fruitless nodes (NFN), average fruit weight (FW), and yield (YLD). Differences p < 0.05 were found in most traits evaluated. The specific combining ability estimates indicate that hybrids formed by the cross between SS-72/12 tester and the following lines are promising, considering the multiple traits: UCLA08-088, UCLA08-101, UCLA08-071, UCLA08-014, UCLA08-025, UCLA08-028, UCLA08-122, UCLA08-055, UCLA08-026, and UCLA08-092. These hybrids meet the demands for domestic and international markets and may be available to producers as new papaya cultivars.

ABSTRACT Developing superior lines based on a simultaneous response from many traits of agronomic importance is a fundamental strategy to expand papaya cultivar supply, mainly the much-needed cultivars belonging to group Formosa. Our goal was to associate the pedigree method with REML/Blup procedure to select plants of progenies F2:3 with superior agronomic performance. The variance components and genetic parameters were estimated using REML approach, and the genetic values were predicted using Blup methodology. The combined selection was performed using the IG2 selection index based on weights associated with agronomic values to indicate the best progenies and lines. The heritability estimates of progeny mean were high in most traits and evidenced significant genetic variability between progenies. The narrow-sense individual heritability was moderate in traits such as commercial fruits and soluble solid contents, which indicates a favorable condition for selections within progenies. The index was consistent in the selection of six superior progenies according to the assessed traits. This index also enabled promising genetic gains in traits of great interest such as yield and pulp thickness. Although the progenies are derived from self generations, they proved to be superior in traits of significant importance such as yield, commercial fruits, and pulp thickness when compared to the Tainung-01 hybrid, which is a worldwide-planted cultivar used as a reference to Formosa representatives. Six lines were selected within the superior progenies to continue the Formosa group-lines development program. The association of the pedigree method with REML/Blup procedure can be useful to assist breeders in an autogamous breeding program.

Abstract The papaya cultivar UC14, recommended for the Southeast and Northeast regions of Brazil, was developed by UENF/CALIMAN breeding program. ‘UC14’ produces smaller fruit than those of Formosa hybrid, with a mean weight of 0.8 kg and a mean fruit yield of 199.45 t ha-1.

ABSTRACT The aim of this study was to estimate the percentage of deformed fruits (carpelloid, pentandric, and bananoid), summer sterility, repeatability coefficients, and correlations among the variables for floral abnormalities; and select genotypes withthe lowest incidence of deformed fruits and summer sterility. In theexperiment, which involved 254 plants, traits were evaluated using the digital-phenotypic method and the obtained images were processed and analysed using ImageJ v1.48 software with the Cell Counter plugin. Summer sterility had the highest percentage of occurrence in the evaluated periods. Based on the quantificationof total abnormalities, the 30 genotypes with the lowest incidence offloral abnormalities were selected. Summer sterility is the main problem of the papaya crop in terms of floral abnormalities. The non-significant correlations between the traits: NDF/TNF+NFN (number of deformed fruits/number of fruits + number of fruitless nodes) and NFS/TNF+NFN (number of fruitless nodes/number of fruits + number of fruitless nodes); NDF/TNF+NFN and NFN/SUM(number of fruitless nodes/sum of abnormalities); andNFS/TNF+NFN and NDF/SUM (number of deformed fruits/sum of abnormalities) indicate that the variables are independent of each other. Of the 254 evaluated progenies, at least 30 were identified as having potential for selection, with lower occurrence of total floral abnormalities.

Abstract UC10 is a new papaya cultivar, recommended to the southeast and northern regions of Brazil. It has a very good agronomic performance in and adaptation to these regions, with Formosa fruits of approximately 1.9 kg and yield of 260 t ha-1. The cultivar has early fruit production, and fruits have excellent flavor.

Abstract Due to the great economic importance of coconut palm in Brazil and the development of a coconut breeding program intended to produce intravarietal hybrids, the present work aimed to ease the production of hybrids with the same morphological heritage. DNA was extracted from leaf samples of 13 dwarf coconut populations from Brazil, and PCR amplification was performed using 21 previously selected microsatellites. Furthermore, this study selected nine microsatellite markers with the potential to identify Green Dwarf x Yellow Dwarf hybrids and 16 microsatellites with the potential to identify Red Dwarf x Yellow Dwarf hybrids. In conclusion, SSR marker based on DNA Fingerprinting allowed the accurate identification of legitimate intravarietal hybrids since, for those crosses, the methodology of identification based on seedling color is not a viable alternative.

RESUMO Neste trabalho, objetivou-se verificar se a divergência genética entre as linhagens de mamoeiro, obtida por marcadores moleculares, é correlacionada com a heterose dos híbridos para características relacionadas à produção, qualidade de frutos e resistência a doenças. Oito genitores e 56 híbridos obtidos dos cruzamentos em esquema dialélico, foram avaliados em blocos casualizados, com quatro repetições. Quantificaram-se o número de frutos comerciais (NCF), o peso médio do fruto (AFW), a produtividade (PROD), a firmeza do fruto (FIRM), o sólido solúvel total (TSS) e as severidades de pinta-preta em folha (BSS) e fruto (BSSFr), mancha-de-phoma (PSS) e oídio em folha (PMS) em folha. Estimaram-se as correlações entre a divergência genética obtida por SSR e a heterose estimada para cada característica em quatro possibilidades de cruzamentos dentro do dialelo: i) todos os cruzamentos; ii) entre genitores do grupo Solo; iii) entre genitores do grupo Formosa; e, iv) entre os genitores do grupo Solo com Formosa e Formosa com Solo. Os resultados indicam a possibilidade de se explorar a heterose tanto em cruzamentos entre grupo quanto em cruzamentos dentro de grupo. A baixa magnitude das estimativas de correlação entre heterose e características morfológicas dos híbridos com a distância genética obtida por SSR nos genitores, indica que não é possível fazer inferências sobre o comportamento dos híbridos a partir da divergência genética entre genitores.

ABSTRACT This study aimed to verify if the genetic divergence between papaya lines, obtained by means of molecular markers, is correlated with heterosis in the hybrids for characteristics related to production, fruit quality and disease resistance. Eight parents and 56 hybrids obtained from diallel crosses were evaluated in randomized blocks, with four replicates. The number of commercial fruits (NCF), the average fruit weight (AFW), the productivity (PROD), the fruit firmness (FIRM) and the total soluble solids (TSS) were evaluated, as well as the severity of black spot on leaves (BSS) and fruits (BSSFr), phoma spot (PSS) and powdery mildew on leaves (PMS). Correlations were estimated between genetic divergence, obtained based on SSR, and heterosis, estimated for each characteristic in four possibilities of crossings within the diallel: i) all crossings; ii) between parents of the ‘Solo’ group; iii) between parents of the ‘Formosa’ group; and iv) between parents of ‘Solo’ with ‘Formosa’ group and ‘Formosa’ with ‘Solo’ group. Results indicate the possibility of exploring heterosis both in crossings between groups and in crossings within groups. The low magnitude of the estimates of correlation between heterosis and morphological characteristics of the hybrids with genetic distance obtained by SSR in the parents indicates that the behavior of hybrids cannot be inferred based on the genetic divergence between parents.

ABSTRACT: The selection of superior Carica papaya (L) genotypes depends on the availability of genetic variability and on the favorable and simultaneous response of the genotypes to those traits of most interest. However, manual phenotyping (MP) demands intensive labor, is time-consuming and expensive. The aim of the current study is to access the efficiency of image-based phenotyping (IBP) in estimating genetic parameters and in selecting F4 recombinant inbred lines. The genetic parameters and values were estimated in accordance with the REML/BLUB procedure and combined selection using the selection index based on standardized genetic values. The majority of traits accessed through IBP showed experimental coefficients of variation similar to those found through MP. Both methodologies showed genetic parameters of similar magnitude, indicating expressive genetic variability between lines in the traits accessed in this study. The same superior lines were indicated in both methodologies and expressive genetic gains obtained through the lines were selected for all traits. IBP performance was similar to that of MP with respect to the estimates of breeding-relevant traits such as commercial fruits and yield. Thus, IBP showed efficient phenotypic assessment, as well as selective accuracy in accessing genetic variability and genetic gains, when it was compared to MP. Since IBP is far less dependent on labor, it is expected to be incorporated into the routine of papaya breeding programs as a way of increasing the number of accessed lines and, consequently, increasing genetic gains.

ABSTRACT Manual phenotyping for papaya Carica papaya (L) breeding purposes limits the evaluation of a great number of plants and hampers selection of superior genotypes. This study aimed to validate two methodologies for the phenotyping of morpho-agronomic plant traits using image analysis and fruit traits through image processing. In plants of the ‘THB’ variety and ‘UENF/Caliman-01’ hybrid two images (A and B) were analyzed to estimate commercial and irregularly shaped fruits. Image A was also used in the estimation of plant height, stem diameter and the first fruit insertion height. In ‘THB’ fruits, largest and smallest diameters, length, and volume were estimated by using a caliper and image processing (IP). Volume was obtained by water column displacement (WCD) and by the expression of ellipsoid approximation (EA). Correlations above 0.85 between manual and image measurements were obtained for all traits. The averages of the morpho-agronomic traits, estimated by using images, were similar when compared to the averages measured manually. In addition, the errors of the proposed methodologies were low compared to manual phenotyping. Bland-Altman's approach indicated agreement between the volume estimated by WCD and EA using caliper and IP. The strong association obtained between volume and fruit weight suggests the use of regression to estimate this trait. Thus, the expectation is that image-based phenotyping can be used to expand the experiments, thereby maintaining accuracy and providing greater genetic gains in the selection of superior genotypes.

RESUMO Os objetivos deste trabalho foram gerar estimativas de capacidade combinatória de 22 linhagens de mamoeiro com testadores do grupo 'Solo' e 'Formosa' em esquema de top cross e identificar híbridos agronomicamente superiores. As linhagens foram selecionadas em gerações de retrocruzamentos para conversão sexual, tendo como genitor recorrente, o genótipo dióico 'Cariflora' e como doador a linhagem elite ginóico-andromonóica, 'SS 783'. As linhagens per se, os híbridos top crosses (híbridos T1 e híbridos T2) e duas testemunhas comercias foram avaliados em um delineamento em látice 8x8 quanto ao número de nós sem fruto (NNSF-un), número de frutos deformados (NFD-un), número de frutos comerciais (NFC-un), peso médio de fruto (PMF-g), comprimento do fruto (CF-mm), diâmetro do fruto (DF-mm), espessura média da polpa (EP-cm), firmeza do fruto (FF-N), firmeza da polpa (FP-N), teor de sólidos solúveis (TSS-°brix) e Produtividade (PROD-t ha-1). Obtiveram-se as estimativas de capacidade especifica de combinação pela diferença entre a média de cada híbrido obtido de um testador, com a média geral dos cruzamentos com o mesmo testador. A análise de variância realizada com as médias ajustadas revelou variabilidade genética entre grupos de tratamentos para todas as características avaliadas, bem como dentro de cada grupo de tratamento. Considerando os híbridos T1, as combinações que melhor conciliaram as estimativas de CEC para as características produtivas e de qualidade de frutos foram: L3xT1, L8xT1, L10xT1, L11xT1, L16xT1, L17xT1 e L20xT1. Para os híbridos T2 foram: L12xT2, L13xT2, L17xT2, L21xT2 e L22xT2.

ABSTRACT The aim of this study were to generate estimates of combining ability in 22 lines of papaya using testers from the 'Solo' and 'Taiwan' group in a top-cross scheme, and identify those hybrids which are superior agronomically. The strains were selected from generations backcrossed for sexual conversion, with the dioecious genotype Cariflora as recurrent parent, and the elite ginoic -andromonoic line, SS 783, as donor. The lines themselves, the top cross hybrids (T1 hybrids and T2 hybrids), and two commercial controls were evaluated in an 8 x 8 lattice design for number of nodes with no fruit (NNSF-un), number of deformed fruit (NFD-un), number of commercial fruit (NFC-un), average fruit weight (PMF-g), fruit length (CF-mm), fruit diameter (DF-mm), average pulp thickness (EP-cm), fruit firmness (FF-N), pulp firmness (PF-N), level of soluble solids (TSS-°brix) and productivity (PROD-t ha-1). Estimates of specific combining capacity were obtained from the difference between the average for each hybrid obtained from the tester and the overall average of crossings with the same tester. The analysis of variance carried out with the adjusted average values revealed genetic variability between treatment groups for all the evaluated characteristics, as well as within each treatment group. Considering the T1 hybrid, the combinations that best reconciled the CEC estimates for the characteristics of production and fruit quality were L3xT1, L8xT1, L10xT1, L11xT1, L16xT1, L17xT1 and L20xT1; for the T2 hybrids the combinations were L12xT2, L13xT2, L17xT2, L21xT2 e L22xT2..

Ao longo das três últimas décadas os estudos sobre os marcadores moleculares alcançaram avanços extraordinários, em especial nas técnicas de sequenciamento e bioinformática. A seleção assistida por marcadores tornou-se parte da rotina dos programas de melhoramento de importantes empresas de sementes, com o objetivo de acelerar e otimizar o processo de desenvolvimento de novas cultivares. Empresas privadas de sementes crescentemente adotam a seleção assistida por marcadores, especialmente para as espécies de grande importância para o mercado de sementes, como milho, soja e girassol. Nas instituições públicas brasileiras poucos programas de melhoramento a adotam eficientemente. As possíveis razões são: falta de "know-how", falta de laboratório adequado, poucos marcadores validados, alto custo e falta de urgência na obtenção de cultivares. Neste artigo são analisados o uso e as limitações da seleção assistida por marcadores nos programas de melhoramento de plantas dos institutos públicos brasileiros.

Over the past three decades, molecular marker studies reached extraordinary advances, especially for sequencing and bioinformatics techniques. Marker-assisted selection became part of the breeding program routines of important seed companies, in order to accelerate and optimize the cultivar developing processes. Private seed companies increasingly use marker-assisted selection, especially for the species of great importance to the seed market, e.g. corn, soybean, cotton, and sunflower. In the Brazilian public institutions few breeding programs use it efficiently. The possible reasons are: lack of know-how, lack of appropriate laboratories, few validated markers, high cost, and lack of urgency in obtaining cultivars. In this article we analyze the use and the constraints of marker-assisted selection in plant breeding programs of Brazilian public institutes.

O mamoeiro é uma das fruteiras tropicais de grande impacto na fruticultura brasileira. Os principais entraves à expansão da cultura são a baixa variabilidade genética e a ocorrência de doenças que encarecem a produção. Neste contexto, realizou-se um cruzamento entre os genótipos 'JS12' e 'Golden' na expectativa de se transferir a característica coloração verde-clara da casca dos frutos (característica Golden), associada à tolerância da mancha fisiológica do mamoeiro, do genitor 'Golden' para o genitor 'JS12'. A variação genética entre e dentro das progênies segregantes obtidas foi avaliada na população RC1S1. Três indivíduos possuidores da característica Golden (38RC1S1-11, 30RC1S1-10 e 31RC1S1-10) foram selecionados pela análise de agrupamento. Estas progênies aliam maior proporção genômica do genitor recorrente (JS12) e bons atributos morfoagronômicos, sendo os mais indicados para o avanço das autofecundações e retrocruzamentos em mamoeiro.

Papaya is a tropical fruit of high impact in Brazilian fruit crop. The main barriers to the expansion of the crop are reduced genetic variability and disease occurrence that results in the more expensive production. In this context it was made a cross between the genotypes ' JS12' and 'Golden' in the expectation of transferring the trait pale green peel of the fruit (Golden trait), associated as tolerant papaya skin freckles from the 'Golden' genitor to the 'JS12' genitor. The population BC1S1 was evaluated for its genetic variation between and within segregating progenies. Three individuals possessing the Golden characteristics (38BC1S1-11, 31BC1S1-10 and 30BC1S1-10-10) were selected. These progenies combine greater genomic proportion of the recurrent parent and good morphoagronomic attributes being the most suitable for the advancement of self pollination and backcrossing in papaya.

Este estudo objetivou avaliar o comportamento genético e sazonal da expressão do sexo em gerações segregantes de mamoeiro oriundas de retrocruzamento e em genótipos elite. Avaliou-se 200 plantas hermafroditas nas quatro estações, nos anos 2005/2006. Das oito características avaliadas, quatro foram ligadas à floração e quatro referentes à frutificação, a citar, proporção de flores normais, deformadas, estéreis e totais, além da proporção de frutos totais, carpelóides, pentândricos e comerciais. Os resultados possibilitaram verificar a existência de diferença significativa para a interação genótipo versus estação do ano. Com base no coeficiente de determinação genotípica, bem como no índice de variação conclui-se que o inverno e a primavera são as épocas mais propícias para a seleção de genótipos superiores. Assim, maior sucesso pode ser alcançado com a seleção em estágios iniciais do desenvolvimento da planta, indicando que a idade fisiológica pode ser mais um fator envolvido na expressão das características avaliadas.

This study aimed to evaluate the genetic and seasonal influence on sex expression in segregating generations of papaya elite and backcrossed genotypes. In the four seasons of the 2005/2006 growing season, 200 hermaphrodite plants were evaluated. Of the eight studied traits, four were related to flowering and four to fruiting, i.e., to the percentage of normal, deformed, sterile, and total number of flowers, as well as the percentage of total, carpelloid, pentandric, and marketable fruits. Significant differences due to the genotype x season interaction were verified. Based on the genotypic determination coefficient and the variation index it was concluded that winter and spring are most appropriate for the selection of superior genotypes. Thus, selection in early stages of plant development is more successful, indicating that the physiological age may also be a factor involved in the expression of the above traits.