ReDivia - Repositorio Digital de l'Instit Valencià d'Investigacions Agràries
Not a member yet
2747 research outputs found
Sort by
El cultivo del caqui
No full textEn este capítulo se abordan los aspectos más importantes relacionados con el manejo poscosecha de los frutos de caqui, desde la recolección hasta su comercialización. Se describen los resultados más destacables obtenidos en las investigaciones realizadas durante los últimos años en el IVIA y que se han centrado principalmente en la variedad ‘Rojo Brillante’ para consumo como caqui duro. Se detallarán brevemente los cambios fisiológicos que tienen lugar durante la maduración del caqui, así como los parámetros a tener en cuenta en el momento de su recolección. Como ya se ha comentado en capítulos anteriores, una característica particular de las variedades cultivadas mayoritariamente en España es la astringencia del fruto en recolección. Este aspecto se ha resuelto satisfactoriamente con la aplicación de determinados tratamientos poscosecha, que se describen con detalle en este capítulo conjuntamente con los factores que influyen en su efectividad, tanto desde el punto de vista fisiológico como tecnológico
Detection and absolute quantitation of Tomato torrado virus (ToTV) by real time RT-PCR
No full textTomato torrado virus (ToTV) causes serious damage to the tomato industry and significant economic losses. A quantitative real-time reverse-transcription polymerase chain reaction (RT-qPCR) method using primers and a specific TaqMan (R) MGB probe for ToTV was developed for sensitive detection and quantitation of different ToTV isolates. A standard curve using RNA transcripts enabled absolute quantitation, with a dynamic range from 10(4) to 10(10) ToTV RNA copies/ng of total RNA. The specificity of the RT-qPCR was tested with twenty-three ToTV isolates from tomato (Solanum lycopersicum L), and black nightshade (Solanum nigrum L) collected in Spain, Australia, Hungary and France, which covered the genetic variation range of this virus. This new RT-qPCR assay enables a reproducible, sensitive and specific detection and quantitation of ToTV, which can be a valuable tool in disease management programs and epidemiological studies
Acta Horticulturae
No full textPolyploidy has long been recognized as an important force in the evolution of flowering plants and often results in novel phenotypes having advantages in adaptation and major interest for agriculture. Many crops, including citrus, are bred to a higher level of ploidy in search of desirable traits. In previous works of our group synthetic clementines with different levels of ploidy, specifically haploid, dihaploid and autotetraploid, were generated. This plant material represents a valuable tool for studying the effects of polyploidization at the molecular level since important traits are expressed in different manners. By using a microarray approach, we have accomplished a comprehensive analysis of transcriptome divergence among the newly created clementine lineages with different genome dosage. Differences in expression in the bark tissue of the four lineages were found significant for 89 (haploid-dihaploid comparison) or 93 genes (diploid-tetrapolid comparison). These genes were classified on the basis of their structure in different families
Acta Horticulturae
No full textMany adult parasitoids depend on sugar-rich foods such as nectar and honeydew to meet their energy requirements. Here, we first use HPLC (high performance liquid chromatograph) analyses to assess whether Aphytis melinus DeBach (Hymenoptera: Aphelinidae), the most successful biological control agent of California red scale Aonidiella aurantii Maskell (Hemiptera: Diaspididadae), feeds on honeydew in the field. Our data showed that A. melinus, whose host does not produce honeydew, fed commonly on honeydew from other abundant hemipterans in spring and summer. In a second assay, we studied the longevity of A. melinus when it had access to honeydew excreted by five common hemipterans in citrus: Aleurothrixus floccosus (Maskell) (Aleyrodidae), Aphis spiraecola Patch (Aphididae), Coccus hesperidum L. (Coccidae), Icerya purchasi Maskell (Monphlebidae) and Planococcus citri (Risso) (Pseudococcidae). A. melinus longevity entirely depended on the honeydew source. The longevity of females with access to honeydew excreted by A. spiraecola was similar to unfed females. Contrarily, C. hesperidum and I. purchasi excreted the honeydew with highest nutritional value
Genetic dissection of tomato rootstock effects on scion traits under moderate salinity
Get PDFThe present study approaches the QTL dissection of rootstock effects on a commercial hybrid variety grafted on a population of RILs derived from Solanum pimpinellifolium, genotyped for 4370 segregating SNPs from the SolCAP tomato panel and grown under moderate salinity. Results are compared to those previously obtained under high salinity. The most likely functional candidate genes controlling the scion [Na+] were rootstock HKT1;1 and HKT1;2 as it was previously reported for non-grafted genotypes. The higher fruit [Na+] found when rootstock genotype was homozygote for SpHKT1 supports the thesis that scion HKT1 is loading Na+ into the phloem sap in leaves and unloading it in sink organs. A significant increment of small, mostly seedless, fruits was found associated with SlHKT1 homozygous rootstocks. Just grafting increased the incidence of blossom end rot and delayed fruit maturation but there were rootstock RILs that increased commercial fruit yield under moderate salinity. The heritability and number of QTLs involved were lower and different than those found under high salinity. Four large contributing (>17 %) rootstock QTLs, controlling the leaf concentrations of B, K, Mg and Mo were detected whose 2 Mbp physical intervals contained B, K, Mg and Mo transporter-coding genes, respectively. Since a minimum of 3 QTLs (two of them coincident with leaf K and Ca QTLs) were also found governing rootstock-mediated soluble-solids content of the fruit under moderate salinity, grafting desirable crop varieties on stress-tolerant rootstocks tenders an opportunity to increase both salt tolerance and quality
Acta Horticulturae
No full textCitrus psorosis virus (CPsV), genus Ophiovirus, causes an important disease in many countries. In growing regions where natural disease spread occurs, damage caused by the virus can be controlled using resistant or tolerant cultivars, but sensitivity of many species and hybrids of Citrus and related genera is presently unknown. To find potential sources of CPsV resistance, we first propagated 61 species (or cultivars) and hybrids of Citrus and related genera [Citrus (37), Microcitrus (5), Fortunella (6), Eremocitrus (1), Pleiospermium (1), Atalantia (1), Severinia (1), Clausena (1), Poncirus (1) and hybrids (7)] on Rough lemon seedlings inoculated with the CPsV isolate PB 143. Out of the 61 accessions tested 54 showed symptoms and reacted by ELISA with a CPsV-specific antibody, 2 (M. inodora and F. hindsii) were symptomless but gave high ELISA values, suggesting tolerance to CPsV, 5 (C. depresa, Cleopatra mandarin, C. excavata, Carrizo citrange and CPB 4475 citrumelo) showed symptoms in the first flush but gave a negative ELISA reaction, and 1 (Poncirus trifoliata) was ELISA negative and symptomless. We then examined CPsV infection by ELISA and RT-PCR in Cleopatra mandarin, P. trifoliata and Citrumelo seedlings inoculated with CPsV isolates P 121, PB 108 and PB 143. While P 121 was detected in all Cleopatra and citrumelo plants, the other isolates were detected in only 50% of the inoculated plants, with all plants indexed as CPsV positive displaying symptoms. All P. trifoliata plants inoculated with either isolate indexed negative for CPsV and remained symptomless. Our results suggest CPsV resistance in P. trifoliata and partial isolate-specific resistance in some accessions
Acta Horticulturae
No full textTetranychus urticae Koch (Acari: Tetranychidae) is a key pest of clementine mandarins, Citrus clementina Tanaka (Rutaceae), in Spain. This mite is highly polyphagous and can be easily found in clementine orchards, both in the trees and in the associated flora. In a previous study we found that the use of a cover of Festuca arundinacea Schreber (Poaceae) offered a better regulation of T. urticae populations than either bare soil or the traditional wild cover, which included a mix of weed species. We hypothesized that the selection of two host races of T. urticae, specialized in F. arundinacea and C. clementina, could partly explain the results obtained in field studies (bottom-up regulation). Reciprocal transplant experiments show that sympatric deme x host combinations had higher mean fitness values for most of the parameters evaluated than the allopatric combinations in clementine, but not in F. arundinacea. Because local adaptation implies mean deme fitness to be systematically higher for the sympatric deme x habitat combinations than for the allopatric ones, these results can be taken as indicative of occurrence of local adaptation in T. urticae. Molecular genetic analyses with microsatellite markers support this conclusion and indicate that host adaptation of T. urticae found in our system may indeed contribute to a better natural regulation of this mite
Acta Horticulturae
No full textEstimation of allele copy numbers for molecular markers has long been considered a challenge for polyploid species, while this process is essential for most genetic research. With the increasing availability and whole genome coverage of SNP markers, it is important to implement a versatile SNP genotyping method to efficiently assign allelic configuration in polyploids. This work demonstrates the usefulness of the KASPar method, based on competitive allele-specific PCR, for the assignment of SNP allelic configuration in an efficient, accurate, simple, and cost effective way and it has been successfully applied in genotyping citrus triploids
Annual Review of Phytopathology
No full textVirus diseases of perennial trees and vines have characteristics not amenable to study using small model annual plants. Unique disease symptoms such as graft incompatibilities and stem pitting cause considerable crop losses. Also, viruses in these long-living plants tend to accumulate complex populations of viruses and strains. Considerable progress has been made in understanding the biology and genetics of Citrus tristeza virus (CTV) and in developing it into a tool for crop protection and improvement. The diseases in tree and vine crops have commonalities for which CTV can be used to develop a baseline. The purpose of this review is to provide a necessary background of systems and reagents developed for CTV that can be used for continued progress in this area and to point out the value of the CTV-citrus system in answering important questions on plant-virus interactions and developing new methods for controlling plant diseases
Rapid detection and discrimination of fabaviruses by flow-through hybridisation with genus- and species-specific riboprobes
No full textViruses cause significant damage in agricultural crops worldwide. Disease management requires sensitive and specific tools for virus detection and identification. Also, detection techniques need to be rapid to keep pace with the continuous emergence of new viral diseases. The genus Fabavirus is composed of five viruses infecting many economically important crops worldwide. This research describes the development of a procedure based on flow-through hybridisation (FTH), which is faster than and as sensitive as conventional hybridisation for virus detection in tissue-prints from infected plants. Six digoxigenin-labelled RNA probes were synthesised with two levels of specificity: (a) five specific for each viral species within this genus, and (b) a genus-specific probe that hybridises with a nucleotide sequence signature only found in the 5-untranslated region of the genus Fabavirus, which is the first of this type reported for plant viruses. The new procedure developed is useful for rapid detection and discrimination of the five fabaviruses identified so far and opens the possibility of discovering new species of this genus