Pumpkin Accessions Research Articles

Examination of the diversity in pumpkin (Cucurbita maxima L.) growth accessions in south-eastern Nigeria

The aim of the study was to compare the growth rates of various pumpkin (Cucurbita maxima L.) accessions. Pumpkins from Aku I, Aku II, Awka, Ifite-Ogwari Nsukka I, and Nsukka II were the various accessions. A field study was conducted at the Ifite-Ogwari Campus of Nnamdi Azikiwe University in Anambra State. The experiment was laid out using a completely randomized design (CRD) with three replications. As experimental sample units, two (2) of the middle-most plants in each polybag were cut off and tagged. Analysis of Variance (ANOVA) was used to analyze data on vegetative growth factors at a 5% probability level and the treatment means were divided using the least significant difference (LSD 0.05). The result of the experiment revealed that all of the pumpkin accessions performed similarly in terms of the amount of time it took for them to emerge after sowing, their percentage of emergence, and their overall vegetative growth. None of the accessions were statistically different with respect to their emergence and growth parameters. However, the growth parameter evaluations were dominated, on average, by pumpkin accession from Nsukka (I and II) pumpkins. In addition, the Aku II pumpkin had the shortest days-to-emergence (3.33 days) and the greatest mean percentage of emergence (100%). Conversely, Aku I pumpkin consistently performed the lowest when it came to the factors that were looked at. For a comprehensive characterization of C. maxima, additional research at the molecular and genomic levels is advised including a greater number of accessions.

Characterization of cultivated pumpkin (Cucurbita moschata Duchesne) landraces for genotypic variance, heritability and agro-morphological traits

Cucurbita moschata (Pumpkin) is a multipurpose species whose fruits and sometimes oil seeds are used for various purposes. It is low in calories and is a significant source of income. Despite the great potential of the pumpkin production and usage, there is no attention to establish the varieties grown in Benin for proper documentation. Therefore, the present study was carried out to (i) evaluate the agro-morphological variability of pumpkin accessions collected in Benin and (ii) investigate heritability, genetic gain, phenotypic and genotypic variances of the agronomic traits. Six landraces from one hundred and twenty accessions collected in Benin were sown and characterized. The agronomic experiment was laid out in a complete randomized block design with three replicates. Out of the twenty-seven quantitative descriptors measured, fifteen were found to be significant. The 50% emergence time (p = 0.03), the number of female flowers (p = 0.02), the seed width (p = 0.05) and the ratio seed width and length (p = 0.01) were significant. A highly significant difference was observed with the days to 50% flowering and the length of male flower stalks (p = 0.002), the average weight of one hundred seeds (p = 0.009). Fruit set at 50%, length of female flower peduncle, number of male flowers, mean fruit weight, fruit length, fruit diameter, average number of seeds per fruit and seed length were very highly significant (p < 0.001). Fruit color and shape, seed color and leaf color showed phenotypic variability. A positive correlation (r = 0.76; p < 0.05) was observed between average fruit weight and average number of seeds per fruit. Principal component analysis and Hierarchical Ascending Classification revealed three classes. Estimates of the phenotypic coefficient of variation were higher than estimates of the genotypic coefficient of variation for most characters. High heritability was observed for fruit diameter (96.73%), average fruit weight (96.46%) and fruit length (94.64%). High heritability associated with high genetic advance was observed for these traits. In sum, the genetic diversity observed within the landraces of pumpkin shows that there is possibility for further selection.

Genetic divergence between pumpkin accessions for morphoagronomic characters

The objective of this work was to evaluate the diversity between accessions of Cucurbita moschata from the Northeast of Brazil and preserved at the Universidade Federal Rural do Semi-Árido (UFERSA) in Mossoró-RN. The experiment was carried out in complete randomized blocks, with two replications and three plants per plot. The treatments consisted of 51 accessions of C. moschata Duch and a commercial cultivar of Cucurbita maximum Duch. After ripening, the fruits were harvested (one fruit per plant) and evaluated for morpho-agronomic descriptors. Univariate and multivariate variance analyzes were performed. From the dissimilarity matrices, accessions were hierarchically grouped by the UPGMA method. The relative contribution of quantitative characters to the divergence was also estimated. There was an effect of accessions (p &lt;0.01 or p &lt;0.05) for all characters in univariate analyzes, indicating that there is heterogeneity between the accessions evaluated. Considering the quantitative descriptors, the accessions formed eight groups and for the qualitative six groups. When considering the two sets of descriptors, the accessions were distributed in eight groups but presenting a greater distribution of accessions. The descriptors that most contributed to the discrimination of accessions were the firmness of the pulp and the length of the fruit.

Principal component analysis (PCA) of physio-chemical components in different pumpkin (Cucurbita moschata Duch.) accessions

Pumpkin (Cucurbita moschata Duch.) is an immense fruit with varied chemical composition and nutritional value. The aim of the study was to decide the major contributing physiochemical properties that explain the variations in different pumpkin accessions by applying principal component analysis. Thus the study revealed that starch, moisture, total solids, reducing sugar, total carbohydrate and TSS were the principal component of pumpkin accessions followed by flesh thickness, fruit weight and fruit equatorial diameter.

Genome-wide SNP discovery and core marker sets for assessment of genetic variations in cultivated pumpkin (Cucurbita spp.)

Three pumpkin species Cucurbita maxima, C. moschata, and C. pepo are commonly cultivated worldwide. To identify genome-wide SNPs in these cultivated pumpkin species, we collected 48 F1 cultivars consisting of 40 intraspecific hybrids (15 C. maxima, 18 C. moschata, and 7 C. pepo) and 8 interspecific hybrids (C. maxima x C. moschata). Genotyping by sequencing identified a total of 37,869 confident SNPs in this collection. These SNPs were filtered to generate a subset of 400 SNPs based on polymorphism and genome distribution. Of the 400 SNPs, 288 were used to genotype an additional 188 accessions (94 F1 cultivars, 50 breeding lines, and 44 landraces) with a SNP array-based platform. Reliable polymorphisms were observed in 224 SNPs (78.0%) and were used to assess genetic variations between and within the four predefined populations in 223 cultivated pumpkin accessions. Both principal component analysis and UPGMA clustering found four major clusters representing three pumpkin species and interspecific hybrids. This genetic differentiation was supported by pairwise Fst and Nei’s genetic distance. The interspecific hybrids showed a higher level of genetic diversity relative to the other three populations. Of the 224 SNPs, five subsets of 192, 96, 48, 24, and 12 markers were evaluated for variety identification. The 192, 96, and 48 marker sets identified 204 (91.5%), 190 (85.2%), and 141 (63.2%) of the 223 accessions, respectively, while other subsets showed <25% of variety identification rates. These SNP markers provide a molecular tool with many applications for genetics and breeding in cultivated pumpkin.

DIVERSITY OF THE PUMPKIN COLLECTION AND ITS HEREDITARY POTENTIAL. RESULTS AND PROSPECTS OF BREEDING PRACTICE

Background. Pumpkin is an important food, feed and medicinal crop. It is widely used by national cuisines in many countries and utilized as raw material for canning industry and in pharmacy to prepare drugs. The Kuban Experiment Station of VIR, where the collection of pumpkin genetic resources is maintained and regenerated for long-term storage in the genebank, conducts comprehensive research work to analyze the genetic diversity of pumpkin accessions and disclose the potential of its hereditary variation.Objective. The aim of this study was to screen various species from the global pumpkin collection and identify sources of traits valuable for breeders in order to develop promising cultivars and hybrids.Materials and methods. The pumpkin collection was studied and the breeding work was performed using the guidelines worked out by VIR’s scientists. The work included botanical description, study of variability and inheritance of traits, hybridization, inbreeding, mutagenesis, and different selection techniques (individual, group, individual/ family, and mass selection). In the first stages of the study, inbreeding was employed to select best plants from the collection in order to set up a trait-specific collection and incorporate its accessions into the hybridization process. Self-pollination was usedfor several years to obtain self-pollinated lines, sufficiently uniform in the selected trait. The hybrid progenies from crosses between parental forms were analyzed to throw light on the inheritance of major traits and their genetic control. The accessions were assessed for their earliness, productivity and quality. Evaluation of disease resistance was carried out in the field under natural infection pressure.Results and discussion. Targeted breeding efforts resulted in releasing cultivars of Cucurbita pepo L., C. maxima Duch. and C. moschata Duch. ex. Poir. having different maturation schedules and approved for cultivation in various regions of Russia: ‘Kustovaya oranzhevaya’, ‘Lechebnaya’, ‘Kustovaya zolotaya’, ‘Malyshka’, ‘Matreshka’, ‘Krasavitsa’, Zimnyaya sladkaya’, ‘Zhemchuzhina’, ‘Yantarnaya’ and ‘Mariya’. These cultivars are in demand among both agricultural producers and individual growers. New sources of valuable morphobiological and agronomic characters have been identified as useful for modern plant breeding trends: KL 625, ZhZM 692, L-180, L-193, KPL 168, KL 568 and KL 570. New bushy lines of C. maxima and C. moschata selected from cultivar and hybrid populations are now tested in an elite test nursery in order to submit the best of them to the State Variety Trials.

Genetic Variation among &amp;lt;i&amp;gt;Cucurbita pepo&amp;lt;/i&amp;gt; Accessions Varying in Seed Nutrition and Seed Size

Pumpkin seed (Cucurbita pepo L.) is a nutritionally valuable food and a significant source of income globally. Pumpkin seeds are rich in oil, protein, unsaturated fatty acids and tocopherols, which are associated with improved human health. Understanding the genetic diversity among pumpkin accessions varying in seed nutrition traits is necessary for designing sound breeding strategies for developing superior cultivars. In the current study, 26 simple sequence repeats (SSR) markers were used to assess genetic relatedness among 29 C. pepo accessions varying in seed oil, seed protein, seed-coat phenotype, seed size and fatty acid composition. The SSR markers revealed 102 alleles averaging 3.92 alleles per loci and mean polymorphic information content (PIC) of 0.44. Eleven of the markers had a PIC of ≥0.5. Ward dendrogram and principle component analysis based on seed traits grouped the genotypes into two major clusters corresponding to subspecies pepo and texana, with all the reduced-hull accessions grouping within the former. Collectively, this data suggests wide phenotypic (seed traits) and genotypic variation within C. pepo that may be exploited to develop superior reduced-hull cultivars.

Genetic Diversity between Pumpkin Accessions Growing in the Northern Border Region in Saudi Arabia Based on Biochemical and Molecular Parameters

THE GENETIC variation and relationships among 16 pumpkin accessions of Cucurbita moschata & Cucurbita maxima were assessed based on variation in fruit shape, skin color, flesh and size of fruits. Polyacrylamide gel electrophoresis of seed protein and molecular markers revealed by SCoT and ISSR techniques. The SDS-PAGE electropherogram showed 12 bands; two (75 and 145 kDa) were found in accessions (1-8) and one (85 kDa) was found in accessions 9-16. Other three bands were unique to accessions 1, 2 & 11. Five ISSR primers produced 79 markers ranging in molecular size from 130 to 2140 bp. Six SCoT primers produced 173 markers ranging from 135 to 2660 bp. The ISSR polymorphism among the examined accessions was 100% in the case of primers 49A, 44 B and HB-12, and was 92% for primer HB-15. Similarly, 100% polymorphism was scored for the primers SCoT8, SCoT11, SCoT12 and SCoT14. The lowest polymorphism was 93.94% in case of primer SCoT1. Our data based on protein, RAPD and ISSR data using the SYSTAT version 7.0 program clearly distinguished accessions from each other.

Health Benefits of Pumpkin Seed and Nutrition Profile of 35 Pumpkin Accessions

This article aims to summise production and nutrition aspects of pumpkin seed. Specifically, it focuses on health benefits of the seeds, production practices and provides data on the oil, protein and fatty acid composition of 35 pumpkin accessions.

Characterization and preliminary evaluation of local germplasm of &lt;i&gt;Telfairia occidentalis&lt;/i&gt; Hook F. accessions in Enugu, Nigeria

The variability among 18 accessions of Telfairia occidentalis were studied by examining their yield and yield component traits. The 18 accessions were collected from four local government areas in Enugu State, Nigeria. The experiment was performed in a randomized complete block design replicated three times. Ih-M accession gave the highest fruit circumference and average fruit weight that was significantly higher than Ih-L accession. Ib-S accession gave the highest total fruit weight and number of fruits per hectare. The PCA result showed that the first three principal components explained 86.91% of the total variation. The dendrogram grouped the fluted pumpkin accessions into three major clusters at similarity coefficient of 0.80. The cluster means showed that cluster I gave the highest number of days to first male anthesis and number of leaves per vine length of 40 cm. Cluster II gave the shortest number of days to male and female anthesis. It gave the highest total marketable leaf yield, number and length of the vine, width and length of the terminal leaflet. Cluster III gave the highest total and average fruit weights, number of fruits, fruit length and circumference, vine diameter, number of leaves per plant, fresh and dry leaf:vine ratio. The results indicated that the reproductive and yield traits assessed had significant contributions towards fluted pumpkin diversity. This information is vital for conservation of different genetic materials and initiation of improvement programme for T. occidentalis in Nigeria.Keywords: accession, germplasm, principal component, Telfairia, yield

Sources of resistance in accessions of Cucurbita spp. to virus species from the genus Potyvirus

ABSTRACT The identification of source of resistance in cultivated cucurbits species is very important for the development of resistant cultivars to control diseases caused by virus from the genus Potyvirus. The present research had the objective to evaluate the phenotypic reactions and the behavior of pumpkin (Cucurbita spp.) accessions to the virus species from the genus Potyvirus: Papaya ringspot virus type Watermelon (PRSV-W), Zucchini yellow mosaic virus (ZYMV) and Watermelon mosaic virus (WMV). Twenty-eight accessions of pumpkin from the Cucurbit Germplasm Bank from Embrapa Semiarido, Petrolina, PE, Brazil were evaluated. Twelve young plants from each pumpkin accession were inoculated with each one of the virus species and were maintained at greenhouse for their symptom reaction evaluations. All possible virus infections or absence of infection were confirmed by plate-trapped antigen enzyme linked immunosorbent assay (PTA-ELISA) against antisera specific to PRSV-W, ZYMV and WMV at the Plant Virus Laboratory, Universidade Federal do Ceara. Three pumpkin accessions showed extreme resistant to WMV and eight accessions presented mild mosaic when inoculated with PRSV-W. The most severe symptoms were observed on those accessions inoculated with ZYMV and 50% of the accessions showed to be highly susceptible. On the other hand, the pumpkin accessions inoculated with WMV presented the mildest symptoms, indicating that 39% of them were resistant, and 39% were tolerant. The Cucurbita spp. accessions BGC 518, BGC 530, BGC 567, and BGC 683 that showed resistance to one or more than one virus species constitute promising sources of resistance for developing virus resistant pumpkin cultivars or hybrids.

Composition and variability of precursors of vitamin A in pumpkin accessions for biofortification breeding

Composition and variability of precursors of vitamin A in pumpkin accessions for biofortification breeding

Genetic divergence among pumpkin landraces

Estimating the genetic variability in germplasm collections is important not only for conserving genetic resources, but also for plant breeding purposes. However, generating a large number of different categories data (qualitative and quantitative) often complicate the analysis and results interpretation, resulting in an incomplete distinction of accessions. This study reports the characterization and evaluation of 14 pumpkin (Cucurbita moschata) accessions collected from farms in the northern region of Rio de Janeiro state. Genetic diversity among accessions was also estimated using qualitative and quantitative variables considering joint analysis. The plants were grown under field conditions in a randomized block design with three replications and six plants per plot. Eight qualitative traits (leaf size; seed shape; seed color; color of the fruit pulp; hollow; fruit shape; skin color, and fruit skin texture) and eight quantitative traits (fruit weight; fruit length; fruit diameter; soluble solids, 100 seed weight, and wall thickness measured in the middle and in the lower stem) were evaluated. The data were analyzed considering the Gower distance, and cluster analysis was performed using unweighted pair group method with arithmetic mean (UPGMA). Variability among accessions was observed considering morphoagronomic data. The Gower distance together with UPGMA cluster allowed for good discrimination between accessions in the groups, demonstrating that the simultaneous analysis of qualitative and quantitative data is feasible and may increase the understanding of the variation among accessions.

Estimation of Genetic Diversity in Cucurbita Species Using Morphological and Phytochemical Analysis

ABSTRACTClimate and planting system can affect crop responses and morphological and physiological characters. Evaluation of genetic variation in crops provides useful information about trait affinity and helps to conserve and protect germplasm. Genetic and phytochemical diversity of pumpkin accessions were evaluated to identify characters in the selection of parents for future breeding. Comparison was made to three accessions of naked seed and 11 accessions of true seed involved C. pepo, C. moschata and C. maxima Duch were planted in May 2012. At ripening stage fruit were harvested and analyzed for fruit and seed morphological characters. Cluster analysis divided accessions into six main groups mainly on fruit and seed characters. The seed oil contains the unsaturated fatty acids oleic acid and linoleic acid. The maxima accessions were placed in a separate group. For those with naked seed, the Khomein accession had higher seed weight than other naked seed types. The Chaloos C. moschata accession was best based on fruit and seed characters and amounts of saturated and unsaturated fatty acids, and an accession from Isfahan had the highest content of oleic acid, a valuable nutritional component of seed. Seed width, fruit width, seed cavity diameter, and fruit weight and length were appropriate for improvement through breeding to enhance seed quality.

Slow mildewing in Pumpkins: an opportunity to reduce Pumpkin yield losses caused by Erysiphe cichoracearum

&lt;p class="Normal1"&gt;&lt;span&gt;Pumpkin powdery mildews, a disease caused by fungus &lt;em&gt;Erysiphe cichoracearum&lt;/em&gt;, is one of the major diseases that reduce yield and quality of pumpkins. A field screening study involving fifty two pumpkin accessions was carried out at three powdery mildew hot spot sites in Malawi. The main objective was to assess the reactions of pumpkin accessions to &lt;em&gt;E. cichoracearum&lt;/em&gt;. The experiment was laid out in a randomized complete block design replicated three times. Plot size was 3m x 3. 7m. There were statistically significant differences in apparent infection rates (P&amp;lt;0.001), area under disease progress curve, AUDPC (P&amp;lt;0.001), percent disease index, PDI (P&amp;lt;0.001) among the accessions across all sites. Pumpkin accessions 6 and 42 consistently showed slow rate of powdery mildew development at 4&lt;sup&gt;th&lt;/sup&gt;, 6&lt;sup&gt;th&lt;/sup&gt;, and 8&lt;sup&gt;th&lt;/sup&gt; week after germination. A strong positive correlation (R= 0.7 at 8&lt;sup&gt;th&lt;/sup&gt; week, and 0.97 at 12&lt;sup&gt;th&lt;/sup&gt; week after germination) was observed between the number of rotten fruits and AUDPC. This study showed that out of the fifty two pumpkin accessions tested, none was immune to &lt;em&gt;Erysiphe cichoracearum&lt;/em&gt;. However the accessions that recorded very slow rate of powdery mildew development showed high potential to maintain viable vines and support their fruits up to physiological maturity. We concluded that promoting slow mildewing pumpkin genotypes is appropriate solution to fruit yield and quality losses caused by&lt;em&gt; E. cichoracearum&lt;/em&gt;.&lt;/span&gt;&lt;/p&gt;

Phenotypic and Genetic Diversity in Pumpkin Accessions with Mutated Seed Coats

The increasing importance of pumpkin (Cucurbita pepo L.) cultivars for seed production has led to considerable breeding efforts for novel high-yielding and disease-resistant cultivars lacking seedcoats. Because it is very important to use genetically diverse genotypes for the development of cultivars with a broad genetic and phenotypic base, this study focused on phenotypic and genetic diversity within and among available pumpkin accessions with mutated seedcoat phenotypes. Fifty-one accessions were collected from various sources and countries, which showed a wide variety of seedcoat types. Genetic analysis with 18 simple sequence repeat (SSR) markers revealed that 37.59% of the total genetic diversity was attributable to interpopulation differentiation and 62.41% to individual differentiation within populations. The average genetic differentiation between accessions (FST) was from 0.030 to 0.760, whereas expected heterozygosity (He) was between 0.048 and 0.491 and observed heterozygosity (Ho) between 0.056 and 0.522. Based on unweighted pair group method with arithmetic mean (UPGMA) analysis, the genetic relationship among accessions reflects the primary geographical origin of accessions. Marker amplification yielded a total of 109 alleles with an average number of alleles per locus of 6.06. Gene diversity per locus varied between 0.027 and 0.879, whereas the polymorphism information content (PIC) varied between 0.027 and 0.867. This is the first report about intra-accession phenotypic and genotypic variability of pumpkins with mutated seedcoats cultivated for their seeds, which are today used in the baking industry, seed oil production, and in traditional and modern medicine.

Interspecific Transferability of Watermelon EST-SSRs Assessed by Genetic Relationship Analysis of Cucurbitaceous Crops

본 연구는 수박의 EST-SSR 마커를 이용하여, 네 개의 주요 박과(Cucurbitaceae) 작물인 수박, 호박, 오이, 멜론의 유연 관계를 분석하고 마커의 타 박과 작물에 활용 가능성을 알아보기 위해 수행되었다. Cucurbit Genomics Initiative(ICuGI) database로부터 선발된 120 EST-SSR 프라이머 중 51(49.17%)가 PCR이 성공하였고, 49(40.8%)가 8개 박과 유전자원에서 다형성을 보였다. 총 24개 박과 유전자원을 24개 EST-SSR 프라이머로 분석한 결과 총 382개 대립유전자 특이적 PCR 밴드를 얻었으며, 이를 토대로 짝유사행렬과 계통도를 작성하였다. 짝유사행렬의 범위는 0.01-0.85였으며, 작성된 계통도에서 24개 유전자원이 두 개의 주요그룹(Clade I, II)으로 분류되었다. Clade I은 다시 수박으로 구성된 하위집단 I-1[I-1a, I-1b-2: 각 1개와 2수박 야생종(Citrullus lanatus var. citroides Mats. & Nakai)으로 구성, I-1b-1: 6개수박 재배종(Citrullus lanatus var. vulgaris Schrad.)로 구성]과 멜론과 오이로 구성된 하위집단I-2[I-2a-1: 4개 멜론 재배종(Cucumis melo var. cantalupensis Naudin.), I-2a-2: 2개 참외 재배종(Cucumis melo var. conomon Makino.), I-2b: 5개 오이 재배종(Cucumis sativus L.)]로 분류되었다. 호박으로 구성된 Clade II는 다시 Cucurbita moschata(Duch. ex Lam.) Duch. & Poir와 Cucurbita maxima Duch.로 구성된 하위집단 II-1과 Cucurbita pepo L.과 Cucurbita ficifolia Bouche로 구성된 하위집단 II-2로 나누어졌다. 이러한 결과는 기존의 종명법에 따른 분류와 일치하며, 따라서 수박 EST-SSR 마커를 이용한 타 박과 작물의 비교 유전체 등 연구분야에 적용 가능성을 확인하였다. This study was performed to analyze genetic relationships of the four major cucurbitaceous crops including watermelon, melon, cucumber, and squash/pumpkin. Among 120 EST-SSR primer sets selected from the International Cucurbit Genomics Initiative (ICuGI) database, PCR was successful for 51 (49.17%) primer sets and 49 (40.8%) primer sets showed polymorphisms among eight Cucurbitaceae accessions. A total of 382 allele-specific PCR bands were produced by 49 EST-SSR primers from 24 Cucurbitaceae accessions and used for analysis of pairwise similarity and dendrogram construction. Assessment of the genetic relationships resulted in similarity indexes ranging from 0.01 to 0.85. In the dendrogram, 24 Cucurbitaceae accessions were classified into two major groups (Clade I and II) and 8 subgroups. Clade I comprised two subgroups, Clade I-1 for watermelon accessions [I-1a and I-1b-2: three wild-type watermelons (Citrullus lanatus var. citroides Mats. & Nakai), I-1b-1: six watermelon cultivars (Citrullus lanatus var. vulgaris S chrad.)] a nd C lade I -2 for melon and cucumber accessions [I-2a-1 : 4 melon cultivars(Cucumis melo var. cantalupensis Naudin.), I-2a-2: oriental melon cultivars (Cucumis melo var. conomon Makino.), and I-2b: five cucumber cultivars (Cucumis sativus L.)]. Squash and pumpkin accessions composed Clade II {II-1: two squash/ pumpkin cultivars [Cucurbita moschata (Duch. ex Lam.)/Duch. & Poir. and Cucurbita maxima Duch.] and II-2: two squash/pumpkin cultivars, Cucurbita pepo L./Cucurbita ficifolia Bouche.}. These results were in accordance with previously reported classification of Cucurbitaceae species, indicating that watermelon EST-SSRs show a high level of marker transferability and should be useful for genetic study in other cucurbit crops.

Produtividade da cultura da abóbora em diferentes densidades de plantio no Vale do São Francisco

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.

Phenotypic variability among pumpkin accessions in the Brazilian semiarid

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.

Reação de acessos de Cucurbita sp. ao Zucchini yellow mosaic virus (ZYMV)

Cucurbita moschata pode ser infectada por várias espécies de vírus, dentre os quais se destacam os pertencentes à família Potyviridae. No presente estudo avaliou-se os acessos de abóbora pertencentes às coleções dos Banco de Germoplasma de Hortaliças da UFV e Banco Ativo de Germoplasma de Cucurbitáceas da Embrapa Semi-Árido, visando identificar fontes de resistência ao potyvírus Zucchini yellow mosaic virus (ZYMV). Dos 100 acessos de abóbora avaliados, 61 pertencem ao BAG-Embrapa Semi-Árido, 37 ao BGH-UFV e dois à empresa de sementes Sakata Seed Sudamerica. Quatro plantas de cada acesso foram inoculadas com o ZYMV, em telado, na fase cotiledonar, antes do aparecimento da primeira folha verdadeira, e reinoculadas dois dias depois. As plantas que persistiram sem sintomas, por até 30 dias após a primeira inoculação, foram avaliadas para a presença do ZYMV por ELISA indireto. Dentre os acessos avaliados, três (BGH-1934, BGH-1937 e BGH-1943) foram imunes ao ZYMV quando inoculados na época mais quente do ano. Os acessos suscetíveis apresentaram sintomas 10 a 15 dias após a primeira inoculação, nas duas épocas estudadas (janeiro e julho). Os genótipos resistentes permaneceram sem sintomas até o final da avaliação e a concentração viral foi baixa. Os acessos BGH-1934, BGH-1937 e BGH-1943 poderão ser utilizados em programas de melhoramento que visem incorporar resistência ao ZYMV em cultivares comerciais.