Vanderlei da Silva Santos

Germinação e crescimento de espécies de maracujá

This work aimed to verify the germination and speed of emergence index of passion fruit species to obtain plants suitable for grafting. The experiment was carried out in a greenhouse at Embrapa Cassava and Tropical Fruits, in Cruz das Almas, BA from January to June, 2002. It was used a completely randomized design and the treatments were constituted of five passion fruit species: Passiflora edulis Sims f. flavicarpa Deg., Passiflora edulis Sims, Passiflora giberti N.E. Brown, Passiflora laurifolia L. and Passiflora alata Curtis, with four replications. The species constitute five different groups for the variable, speed of emergence index and, concerning to the germination, two different groups, one formed by the species P. giberti and P. laurifolia and the other by the species P. edulis Sims f. flavicarpa, P. edulis Sims and P. alata. Regarding to plant height, the species P. giberti had the highest average, 40,40 cm, constituting a group that is different from the others. The species P. edulis and P. edulis f. flavicarpa presented better speed of emergence index and germination, consequently the plants obtained were ready for grafting in a shorter period of time.

Potential of SNP markers for the characterization of Brazilian cassava germplasm

Key messageHigh-throughput markers, such as SNPs, along with different methodologies were used to evaluate the applicability of the Bayesian approach and the multivariate analysis in structuring the genetic diversity in cassavas.AbstractThe objective of the present work was to evaluate the diversity and genetic structure of the largest cassava germplasm bank in Brazil. Complementary methodological approaches such as discriminant analysis of principal components (DAPC), Bayesian analysis and molecular analysis of variance (AMOVA) were used to understand the structure and diversity of 1,280 accessions genotyped using 402 single nucleotide polymorphism markers. The genetic diversity (0.327) and the average observed heterozygosity (0.322) were high considering the bi-allelic markers. In terms of population, the presence of a complex genetic structure was observed indicating the formation of 30 clusters by DAPC and 34 clusters by Bayesian analysis. Both methodologies presented difficulties and controversies in terms of the allocation of some accessions to specific clusters. However, the clusters suggested by the DAPC analysis seemed to be more consistent for presenting higher probability of allocation of the accessions within the clusters. Prior information related to breeding patterns and geographic origins of the accessions were not sufficient for providing clear differentiation between the clusters according to the AMOVA analysis. In contrast, the FST was maximized when considering the clusters suggested by the Bayesian and DAPC analyses. The high frequency of germplasm exchange between producers and the subsequent alteration of the name of the same material may be one of the causes of the low association between genetic diversity and geographic origin. The results of this study may benefit cassava germplasm conservation programs, and contribute to the maximization of genetic gains in breeding programs.

Resistance to Fusarium dry root rot disease in cassava accessions

The objective of this work was to identify sources of resistance to dry root rot induced by Fusarium sp. in cassava accessions. A macroconidial suspension (20 µL) of 11 Fusarium sp. isolates was inoculated in cassava roots, from 353 acessions plus seven commercial varieties. Ten days after inoculation, the total area colonized by the pathogen on the root pulp was evaluated by digital image analysis. Cluster analysis revealed the presence of five groups regarding resistance. The root lesion areas ranged from 18.28 to 1,096.07 mm2 for the accessions BGM 1518 and BGM 556, respectively. The genotypes BGM 1042, BGM 1552, BGM 1586, BGM 1598, and BGM 1692 present the best agronomical traits.

Estimativas de correlações genotípicas e fenotípicas em germoplasma de maracujazeiro

Abstract The objective of this study was to estimate the genotypic and phenotypic correlations among 25 morphological and agro-nomic characteristics of leaves, flowers and fruits of passion plants. Seventeen germplasm accessions were evaluated in a randomized block design with two replications and ten plants per plot. The data were standardized and phenotypic ( r p ) and genotypic ( r g ) correlation coefficients were estimated. Ninety phenotypic correlations (30%) were significant by t-test and 83% of correlations were above 0.60. The results showed a high genotypic correlation among the following characteristics: a) androgynophore length vs. leaf width ( r g = -0.61); b) peel thickness vs . petiole length ( r g = 0.98); c) pulp yield without seed vs . petiole length and petal width, both with r g -0.88; d) total soluble solids vs . fruit width ( r g = -0.72), and e) weight of fruit vs . fruit width and peel weight ( r g = -0.88 and 0.91, respectively). Although the genotypes are not originated from a single population, indirect selection to aforementioned characteristics is easily, because the genotypic correlation was higher than the phenotypic.Key words: Passiflora edulis Sims, plant breeding, germplasm, indirect seletion.

Seleção de híbridos diplóides (AA) de bananeira com base em três índices não paramétricos

The objective of the present study was to select diploids (AA) hybrids of banana based on three non-parametric indices as to guide the selection and increase the use of the variability present in the Banana Germplasm Bank of Embrapa Cassava and Tropical Fruits. Eleven hybrids were evaluated in random blocks with four replicates. The plots consisted of six plants spaced 2.5 m x 2.5 m whereas the border rows were from the Pacovan cultivar. The following characteristics were evaluated: plant height, pseudostem diameter, number of suckers, number of leaves during flowering, plant cycle from planting to bunch emission, presence of pollen, number of hands, number of fruits, fruit length and yellow-Sigatoka resistance. The average of these ten characteristics was used for calculating the multiplicative indices of sum of classification and genotype-ideotype distance. The two hybrids presenting best global performance SH3263 and 1318-01 ranked respectively, first and second by the multiplicative indices and sum of classification whereas the genotype-ideotype distance index ranked them first and fourth . Although in general, all three indexes presented good coherence between general performance of the hybrids and their classification, the multiplicative and sum of classification indexes provided a more adequate classification of these hybrids.

Crop losses in Brazilian cassava varieties induced by the Cassava common mosaic virus

Despite the widespread distribution of the Cassava common mosaic virus (CsCMV) in Brazil, little is known about the losses it causes in yield. The effect of CsCMV on different varieties was evaluated by reference to several agronomic traits. Four field trials were established in 2012/2013 and 2013/2014 using six varieties of cassava. Following mechanical inoculation with CsCMV, the presence of the virus was confirmed using the ELISA assay. The evaluated traits were plant height (PH), dry matter content (DMC), harvest index (HI), aerial part yield (APY), root yield (RoY), and starch yield (StY) in both inoculated and non-inoculated plants. Overall, the presence of the virus contributed little to the reduction in PH, HI, and DMC across the varieties, with PH being significantly reduced by 9.2 and 7.0 % in the BGM0212 and BRS Kiriris varieties, respectively. In contrast, APY, RoY, and StY were reduced by 30.2, 29.3, and 30.0 %, in the virus-infected plants respectively. While the BRS Kiriris and BRS Jari varieties suffered the highest reductions overall and were considered highly susceptible to CsCMV, none of the traits suffered reductions in the inoculated BRS Formosa plants. Although RoY and StY were reduced in inoculated plants of BRS Tapioqueira, crop yield for this variety was the highest. Thus, BRS Formosa and BRS Tapioqueira exhibited tolerance against CsCMV, which warrants further investigation.

Avaliação de progênies f2:4 e f4:6 de soja e perspectivas do uso de teste precoce para a produção de grãos

The objective of this work was to evaluate the perspectives of using early generation testing for grain yield in soybeans. The base material comprises a population derived from a two-way cross between lines 14 and 38, divergent for grain yield. One hundred progenies F2:4 and one hundred progenies F4:6 were derived from this population and evaluated in the 2006/07 growing season, using a lattice design with 4 replications, in two locations, at Piracicaba, SP. Plots consisted of 2 meter long rows spaced 0,5 meter apart, with 35 plants after thinning. The components of variance, coefficients of heritability on a plot mean basis and expected response to selection were estimated for grain yield from the joint analysis of variance, for F2:4 and F4:6 generations. Estimates of expected response to selection were about 60% higher in the F4:6 generation; however this superiority would probably be offset by the larger time to complete a cycle. General results indicate that early generation testing for grain yield in soybeans can be effective for moderate selection intensities.

Classification of cassava genotypes based on qualitative and quantitative data

We evaluated the genetic variation of cassava accessions based on qualitative (binomial and multicategorical) and quantitative traits (continuous). We characterized 95 accessions obtained from the Cassava Germplasm Bank of Embrapa Mandioca e Fruticultura; we evaluated these accessions for 13 continuous, 10 binary, and 25 multicategorical traits. First, we analyzed the accessions based only on quantitative traits; next, we conducted joint analysis (qualitative and quantitative traits) based on the Ward-MLM method, which performs clustering in two stages. According to the pseudo-F, pseudo-t2, and maximum likelihood criteria, we identified five and four groups based on quantitative trait and joint analysis, respectively. The smaller number of groups identified based on joint analysis may be related to the nature of the data. On the other hand, quantitative data are more subject to environmental effects in the phenotype expression; this results in the absence of genetic differences, thereby contributing to greater differentiation among accessions. For most of the accessions, the maximum probability of classification was >0.90, independent of the trait analyzed, indicating a good fit of the clustering method. Differences in clustering according to the type of data implied that analysis of quantitative and qualitative traits in cassava germplasm might explore different genomic regions. On the other hand, when joint analysis was used, the means and ranges of genetic distances were high, indicating that the Ward-MLM method is very useful for clustering genotypes when there are several phenotypic traits, such as in the case of genetic resources and breeding programs.

Obtenção de híbridos de cultivares e de subespécies silvestres de mandioca

The objective of this work was to evaluate the crossability between cassava (Manihot esculenta subsp. esculenta) cultivars and the subspecies M. esculenta subsp. flabellifolia and M. esculenta subsp. peruviana. Plants from the BRS Jari, BRS Formosa, BRS Verdinha, and BGM 2050 (Equador 72) cultivars were crossed with the two subspecies. During flowering, at pre-anthesis, pistillate flowers were covered with a nylon bag and staminate flowers on the same inflorescence were emasculated. The staminate flowers were collected and placed in flasks previously labeled and sterilized with alcohol; some fresh flowers were stored at room temperature due to asynchronous flowering. The crosses were made between 10 a.m. and 2 p.m. After pollination, the flowers were covered again. Evaluations were made from the moment of pollination to the dehiscence of the fruit. Of the total flowers pollinated, 38% were fertilized, and 504 developed fruits and 816 produced seeds were observed. As a male parent, M. esculenta subsp. flabellifolia is more efficient in crosses with M. esculenta subsp. esculenta and may be recommend for controlled crosses. The crosses between the cassava cultivars and M. esculenta subsp. flabellifolia and M. esculenta subsp. peruviana produce viable seeds.

Genetic parameters and selection gains in early clonal evaluation trials: implications for cassava breeding

The objective of this study was to estimate and compare genetic parameters in early cassava breeding phases (clonal evaluation trials—CET and preliminary yield trials—PYT) in full-sib (F1) and self-pollinated (S1) families, besides estimating the genetic gains. Twenty-three F1 and six S1 families were evaluated using the augmented block design in CET and the randomized complete block design in PYT for fresh root yield (FRY), root dry matter content (DMC) and starch yield (STY). In CET, most of the variance was due to environmental (