Pablo Aleza - Academia.edu (original) (raw)

Papers by Pablo Aleza

Este estudio utiliza por primera vez el método de las preguntas CATA (Check-all-that-apply) inclu... more Este estudio utiliza por primera vez el método de las preguntas CATA (Check-all-that-apply) incluyendo la descripción del Producto Ideal (PI) para la selección de nuevas variedades de mandarina. Tres nuevas variedades preseleccionadas en el programa de mejora del IVIA ('Tri-707/'Pri-88' y 'Pri-89') fueron evaluadas por 134 consumidores y comparadas con las variedades 'Clemules' y 'Oronules' con las que comparten periodo de recolección. Todos los consumidores describieron su mandarina ideal de forma similar: olor intenso al separar el gajo, muy aromática, muy dulce, jugosa, poco fibrosa, con sabor intenso y refrescante, y acidez media. Sin embargo, se identificaron dos grupos de consumidores diferentes en base a su descripción de las nuevas variedades. Las preguntas-CATA incluyendo el PI resultaron muy útiles para identificar las variedades más prometedoras ('Tri-707' y Pri-89') por compartir más características con la mandarina Ideal q...

Este proyecto final de carrera se ha realizado en el IVIA con la colaboración del Departamento de... more Este proyecto final de carrera se ha realizado en el IVIA con la colaboración del Departamento de Citricultura. Las especies estudiadas pertenecen al Banco de Germoplasma del IVIA. En el trabajo se ha realizado una caracterización de los frutos, semillas, hojas y flores de 42 especies incluidas en la subfamilia de las Aurantioideas, seleccionadas por su valor ornamental. Las plantas descritas pertenecen a los géneros

Citrus breeding programs focused to produce seedless varieties need to increase the knowledge abo... more Citrus breeding programs focused to produce seedless varieties need to increase the knowledge about the parthenocarpic ability (PA) of the different citrus genotypes used as parents in sexual hybridizations. Current information is insufficient and in some cases contradictory. In this context, ten citrus genotypes were assessed for their PA including Campeona, Imperial, Saltenita, Fortune and Moncada mandarins, Clemenules and Monreal clementines, Tardia Picana satsuma, Ellendale tangor and Pink pummelo. We used terminal flowers at balloon stage and performed the following treatments: 1) hand-cross-pollination with FOrtune and bagged (Clemenules was used for Fortune due the self-incompatibility of Fortune, 2) hand-self-pollination and bagged, 3) emasculated and bagged, 4) bagged and 5) open pollination. About 100 flowers were used for each treatment and were repeated in two consecutive seasons. Fruits were collected when ripe and data of fruit set, number of seeds per fruit and fruit ...

HortScience, 2010

Citrus is the most extensively produced fruit tree crop in the world (FAO, Food and Agriculture O... more Citrus is the most extensively produced fruit tree crop in the world (FAO, Food and Agriculture Organization, 2009). There are two clearly differentiated markets: fresh fruit and processed juice. In 2007, the main citrus fruit-producing countries were China (17.9%), Brazil (17.8%), the Mediterranean countries (17.1%), and the United States (8.5%) (FAO, Food and Agriculture Organization, 2009).

Acta Horticulturae, 2018

In many crops, anther culture is the most used method to induce gametic embryogenesis, aimed to r... more In many crops, anther culture is the most used method to induce gametic embryogenesis, aimed to regenerate homozygous plants. However, also somatic embryogenesis can be obtained by this method, when somatic tissue is involved in the regeneration process. Many factors can affect this procedure, such as genotype, temperature pre-treatment applied to floral buds, pollen developmental stage, donor plant state, culture media composition and culture conditions. Anthers of Citrus sinensis L. Osbeck 'Moro', were collected at the vacuolate stage, and after a chilling (4°C) pre-treatment of 7 days, were placed on the same medium, evaluating different temperature stresses applied after placing them in culture. In this study, the effect of three thermal treatments, compared with direct in vitro culture of the anthers (after the pre-treatment of the floral buds at 4°C for 7 days), was observed in cultivar 'Moro'. Embryo regeneration has been obtained and their characterization, through ploidy and molecular analyses, showed that they were heterozygous tetraploids.

Journal of Plant Physiology, 2016

Tetraploid citrus seedlings are more tolerant to salt stress than diploid genotypes. To provide i... more Tetraploid citrus seedlings are more tolerant to salt stress than diploid genotypes. To provide insight into the causes of differences in salt tolerance due to ploidy and thus to better understand Clexclusion mechanisms in citrus, diploid and tetraploid seedlings of Carrizo citrange (CC) were grown at 0 (control) and 40 mM NaCl (salt-treated) medium for 20 days. Chloride uptake and root-to-shoot translocation rates were on average 1.4-fold higher in diploid than in tetraploid salt-treated plants, which resulted in a greater (1.6-fold) Clbuild up in the leaves of the former. Root hydraulic conductance and leaf transpiration rate were 58 % and 17 % lower, respectively, in tetraploid than in diploid control plants. Differences remained after salt treatment which reduced these parameters by 30-40 % in both genotypes. Morphology of the root system was significantly influenced by ploidy. Tetraploid roots were less branched and with lower number of root tips than those of diploid plants. The cross-section diameter and area were lower in the diploid, and consequently specific root length was higher (1.7-fold) than in tetraploid plants. The exodermis in sections close to the root apex was broader and with higher deposition of suberin in cell walls in the tetraploid than in the diploid genotype. Net CO2 assimilation rate in tetraploid salt-treated seedlings was 1.5-fold higher than in diploid salt-treated plants, likely due to the loss of photosynthetic capacity of diploid plants induced by Cltoxicity. Leaf damage was much higher, in terms of burnt area and defoliation, in diploid than in tetraploid salt-treated plants (8-and 6fold, respectively). Salt treatment significantly reduced (37 %) the dry weight of the diploid plants, but did not affect the tetraploids. In conclusion, tetraploid CC plants appear more tolerant to salinization and this effect seems mainly due to differences in morphological and histological traits of roots affecting hydraulic conductance and transpiration rate. These results may suggest that tetraploid CC used as rootstock could improve salt tolerance in citrus trees.

Plant biotechnology journal, Oct 26, 2016

The long juvenile period of citrus trees (often more than six years) has hindered genetic improve... more The long juvenile period of citrus trees (often more than six years) has hindered genetic improvement by traditional breeding methods and genetic studies. In this work we have developed a biotechnology tool to promote transition from the vegetative to the reproductive phase in juvenile citrus plants by expression of the Arabidopsis thaliana or citrus FLOWERING LOCUS T (FT) genes using a Citrus leaf blotch virus-based vector (clbvINpr-AtFT and clbvINpr-CiFT, respectively). Citrus plants of different genotypes graft inoculated with either of these vectors started flowering within four to six months, with no alteration of the plant architecture, leaf, flower or fruit morphology in comparison with non-inoculated adult plants. The vector did not integrate in or recombine with the plant genome nor was it pollen or vector transmissible, albeit seed transmission at low rate was detected. The clbvINpr-AtFT is very stable and flowering was observed over a period of at least five years. Precoc...

XII International Citrus Congress - International Society of Citriculture, 2015

Very active programs to produce new mandarin varieties are being carried out in several countries... more Very active programs to produce new mandarin varieties are being carried out in several countries using different approaches and technologies (diploid and triploid breeding, irradiation, somatic hybridization, genetic transformation, etc.). The objective of this workshop was to discuss about the most important breeding methods, the main limitations of the different approaches and methodologies, which is the challenge of new mandarin varieties in the next future and also their relationship with the legislation related to essentially derived varieties that in some cases may preclude the protection of breeder's rights of new varieties.

XII International Citrus Congress - International Society of Citriculture, 2015

The availability of a saturated genetic map of Clementine was identified by the International Cit... more The availability of a saturated genetic map of Clementine was identified by the International Citrus Genome Consortium as an essential prerequisite to assist the assembly of the reference whole genome sequence based on a Clementine derived haploid. The primary goals of the present study were to establish a Clementine reference map, and to perform comparative mapping with pummelo and sweet orange. Five parental genetic maps were established with SNPs, SSRs and InDels. A medium density reference map (961 markers for 1084.1 cM) of Clementine was established and used by the ICGC to facilitate the chromosome assembly of the haploid genome sequence. Comparative mapping with pummelo and sweet orange revealed that the linear order of markers was highly conserved. Reasonable inferences of most citrus genomes should be obtained by mapping next-generation sequencing data against the haploid reference genome sequence. Skewed segregations were frequent and higher in the male than female Clementine potentially leading to false interpretation of the genetic determinism of phenotypic traits. The mapping data confirmed that Clementine arose from hybridization between 'Mediterranean' mandarin and sweet orange and identified nine recombination break points for the sweet orange gamete that contributed to the Clementine genome. Introgression of pummelo genome fragments were identified in heterozygosity in each chromosome. Moreover, it appeared that the genome of the haploid Clementine used to establish the citrus reference genome sequence was inherited primarily from the 'Mediterranean' mandarin. The usefulness of this genetic map, anchored in the reference whole genome sequence, is discussed.

Acta Horticulturae, 2015

In the Mediterranean area, citrus fruits are primarily produced for the fresh fruit market and Sp... more In the Mediterranean area, citrus fruits are primarily produced for the fresh fruit market and Spain is the principal producer of the area. Seedlessness is one of the most important characteristics for mandarin fresh fruits. Triploid hybrids allow implementing this trait in commercial cultivars. In this work we described 'Alborea' and 'Albir', two new triploid hybrids originated from the IVIA triploid breeding program, which will be soon released to growers. 'Alborea' was obtained from an open pollinated 'Fortune' mandarin. Fruits reach optimum maturity at the beginning of January, although they can be harvested from December until the end of January. Fruits are easy-to-peel, with a diameter of 50-60 mm, and rind is deep orange red in color. 'Albir' was obtained from a cross between 'Fortune' and 'Kara' mandarins. Fruits reach optimum maturity at the beginning of February, although they can be harvested from January until second half of February. Fruits are easyto-peel with a diameter of 60-70 mm and fruit rind is orange red in color. This variety has the same origin as 'Safor', a previously released triploid hybrid. The fruits of the two varieties are somewhat similar, but 'Albir' matures one month earlier. With these cultivars, 'Albir' and 'Safor', it will be possible to supply similar fruits to the market from January to the end of March.

A haploid C. clementina was chosen by the International Citrus Genomic Consortium (ICGC) to estab... more A haploid C. clementina was chosen by the International Citrus Genomic Consortium (ICGC) to establish the reference whole genome sequence for Citrus. Development of a dense clementine linkage map was part of the objectives of this global

Frontiers in plant science, 2016

Alternaria brown spot (ABS) is a serious disease affecting susceptible citrus genotypes, which is... more Alternaria brown spot (ABS) is a serious disease affecting susceptible citrus genotypes, which is a strong concern regarding citrus breeding programs. Resistance is conferred by a recessive locus (ABSr) previously located by our group within a 3.3 Mb genome region near the centromere in chromosome III. This work addresses fine-linkage mapping of this region for identifying candidate resistance genes and develops new molecular markers for ABS-resistance effective marker-assisted selection (MAS). Markers closely linked to ABSr locus were used for fine mapping using a 268-segregating diploid progeny derived from a heterozygous susceptible × resistant cross. Fine mapping limited the genomic region containing the ABSr resistance gene to 366 kb, flanked by markers at 0.4 and 0.7 cM. This region contains nine genes related to pathogen resistance. Among them, eight are resistance (R) gene homologs, with two of them harboring a serine/threonine protein kinase domain. These two genes along wi...


Este estudio utiliza por primera vez el método de las preguntas CATA (Check-all-that-apply) inclu... more Este estudio utiliza por primera vez el método de las preguntas CATA (Check-all-that-apply) incluyendo la descripción del Producto Ideal (PI) para la selección de nuevas variedades de mandarina. Tres nuevas variedades preseleccionadas en el programa de mejora del IVIA ('Tri-707/'Pri-88' y 'Pri-89') fueron evaluadas por 134 consumidores y comparadas con las variedades 'Clemules' y 'Oronules' con las que comparten periodo de recolección. Todos los consumidores describieron su mandarina ideal de forma similar: olor intenso al separar el gajo, muy aromática, muy dulce, jugosa, poco fibrosa, con sabor intenso y refrescante, y acidez media. Sin embargo, se identificaron dos grupos de consumidores diferentes en base a su descripción de las nuevas variedades. Las preguntas-CATA incluyendo el PI resultaron muy útiles para identificar las variedades más prometedoras ('Tri-707' y Pri-89') por compartir más características con la mandarina Ideal q...

Este proyecto final de carrera se ha realizado en el IVIA con la colaboración del Departamento de... more Este proyecto final de carrera se ha realizado en el IVIA con la colaboración del Departamento de Citricultura. Las especies estudiadas pertenecen al Banco de Germoplasma del IVIA. En el trabajo se ha realizado una caracterización de los frutos, semillas, hojas y flores de 42 especies incluidas en la subfamilia de las Aurantioideas, seleccionadas por su valor ornamental. Las plantas descritas pertenecen a los géneros

Citrus breeding programs focused to produce seedless varieties need to increase the knowledge abo... more Citrus breeding programs focused to produce seedless varieties need to increase the knowledge about the parthenocarpic ability (PA) of the different citrus genotypes used as parents in sexual hybridizations. Current information is insufficient and in some cases contradictory. In this context, ten citrus genotypes were assessed for their PA including Campeona, Imperial, Saltenita, Fortune and Moncada mandarins, Clemenules and Monreal clementines, Tardia Picana satsuma, Ellendale tangor and Pink pummelo. We used terminal flowers at balloon stage and performed the following treatments: 1) hand-cross-pollination with FOrtune and bagged (Clemenules was used for Fortune due the self-incompatibility of Fortune, 2) hand-self-pollination and bagged, 3) emasculated and bagged, 4) bagged and 5) open pollination. About 100 flowers were used for each treatment and were repeated in two consecutive seasons. Fruits were collected when ripe and data of fruit set, number of seeds per fruit and fruit ...

HortScience, 2010

Citrus is the most extensively produced fruit tree crop in the world (FAO, Food and Agriculture O... more Citrus is the most extensively produced fruit tree crop in the world (FAO, Food and Agriculture Organization, 2009). There are two clearly differentiated markets: fresh fruit and processed juice. In 2007, the main citrus fruit-producing countries were China (17.9%), Brazil (17.8%), the Mediterranean countries (17.1%), and the United States (8.5%) (FAO, Food and Agriculture Organization, 2009).

Acta Horticulturae, 2018

In many crops, anther culture is the most used method to induce gametic embryogenesis, aimed to r... more In many crops, anther culture is the most used method to induce gametic embryogenesis, aimed to regenerate homozygous plants. However, also somatic embryogenesis can be obtained by this method, when somatic tissue is involved in the regeneration process. Many factors can affect this procedure, such as genotype, temperature pre-treatment applied to floral buds, pollen developmental stage, donor plant state, culture media composition and culture conditions. Anthers of Citrus sinensis L. Osbeck 'Moro', were collected at the vacuolate stage, and after a chilling (4°C) pre-treatment of 7 days, were placed on the same medium, evaluating different temperature stresses applied after placing them in culture. In this study, the effect of three thermal treatments, compared with direct in vitro culture of the anthers (after the pre-treatment of the floral buds at 4°C for 7 days), was observed in cultivar 'Moro'. Embryo regeneration has been obtained and their characterization, through ploidy and molecular analyses, showed that they were heterozygous tetraploids.

Journal of Plant Physiology, 2016

Tetraploid citrus seedlings are more tolerant to salt stress than diploid genotypes. To provide i... more Tetraploid citrus seedlings are more tolerant to salt stress than diploid genotypes. To provide insight into the causes of differences in salt tolerance due to ploidy and thus to better understand Clexclusion mechanisms in citrus, diploid and tetraploid seedlings of Carrizo citrange (CC) were grown at 0 (control) and 40 mM NaCl (salt-treated) medium for 20 days. Chloride uptake and root-to-shoot translocation rates were on average 1.4-fold higher in diploid than in tetraploid salt-treated plants, which resulted in a greater (1.6-fold) Clbuild up in the leaves of the former. Root hydraulic conductance and leaf transpiration rate were 58 % and 17 % lower, respectively, in tetraploid than in diploid control plants. Differences remained after salt treatment which reduced these parameters by 30-40 % in both genotypes. Morphology of the root system was significantly influenced by ploidy. Tetraploid roots were less branched and with lower number of root tips than those of diploid plants. The cross-section diameter and area were lower in the diploid, and consequently specific root length was higher (1.7-fold) than in tetraploid plants. The exodermis in sections close to the root apex was broader and with higher deposition of suberin in cell walls in the tetraploid than in the diploid genotype. Net CO2 assimilation rate in tetraploid salt-treated seedlings was 1.5-fold higher than in diploid salt-treated plants, likely due to the loss of photosynthetic capacity of diploid plants induced by Cltoxicity. Leaf damage was much higher, in terms of burnt area and defoliation, in diploid than in tetraploid salt-treated plants (8-and 6fold, respectively). Salt treatment significantly reduced (37 %) the dry weight of the diploid plants, but did not affect the tetraploids. In conclusion, tetraploid CC plants appear more tolerant to salinization and this effect seems mainly due to differences in morphological and histological traits of roots affecting hydraulic conductance and transpiration rate. These results may suggest that tetraploid CC used as rootstock could improve salt tolerance in citrus trees.

Plant biotechnology journal, Oct 26, 2016

The long juvenile period of citrus trees (often more than six years) has hindered genetic improve... more The long juvenile period of citrus trees (often more than six years) has hindered genetic improvement by traditional breeding methods and genetic studies. In this work we have developed a biotechnology tool to promote transition from the vegetative to the reproductive phase in juvenile citrus plants by expression of the Arabidopsis thaliana or citrus FLOWERING LOCUS T (FT) genes using a Citrus leaf blotch virus-based vector (clbvINpr-AtFT and clbvINpr-CiFT, respectively). Citrus plants of different genotypes graft inoculated with either of these vectors started flowering within four to six months, with no alteration of the plant architecture, leaf, flower or fruit morphology in comparison with non-inoculated adult plants. The vector did not integrate in or recombine with the plant genome nor was it pollen or vector transmissible, albeit seed transmission at low rate was detected. The clbvINpr-AtFT is very stable and flowering was observed over a period of at least five years. Precoc...

XII International Citrus Congress - International Society of Citriculture, 2015

Very active programs to produce new mandarin varieties are being carried out in several countries... more Very active programs to produce new mandarin varieties are being carried out in several countries using different approaches and technologies (diploid and triploid breeding, irradiation, somatic hybridization, genetic transformation, etc.). The objective of this workshop was to discuss about the most important breeding methods, the main limitations of the different approaches and methodologies, which is the challenge of new mandarin varieties in the next future and also their relationship with the legislation related to essentially derived varieties that in some cases may preclude the protection of breeder's rights of new varieties.

XII International Citrus Congress - International Society of Citriculture, 2015

The availability of a saturated genetic map of Clementine was identified by the International Cit... more The availability of a saturated genetic map of Clementine was identified by the International Citrus Genome Consortium as an essential prerequisite to assist the assembly of the reference whole genome sequence based on a Clementine derived haploid. The primary goals of the present study were to establish a Clementine reference map, and to perform comparative mapping with pummelo and sweet orange. Five parental genetic maps were established with SNPs, SSRs and InDels. A medium density reference map (961 markers for 1084.1 cM) of Clementine was established and used by the ICGC to facilitate the chromosome assembly of the haploid genome sequence. Comparative mapping with pummelo and sweet orange revealed that the linear order of markers was highly conserved. Reasonable inferences of most citrus genomes should be obtained by mapping next-generation sequencing data against the haploid reference genome sequence. Skewed segregations were frequent and higher in the male than female Clementine potentially leading to false interpretation of the genetic determinism of phenotypic traits. The mapping data confirmed that Clementine arose from hybridization between 'Mediterranean' mandarin and sweet orange and identified nine recombination break points for the sweet orange gamete that contributed to the Clementine genome. Introgression of pummelo genome fragments were identified in heterozygosity in each chromosome. Moreover, it appeared that the genome of the haploid Clementine used to establish the citrus reference genome sequence was inherited primarily from the 'Mediterranean' mandarin. The usefulness of this genetic map, anchored in the reference whole genome sequence, is discussed.

Acta Horticulturae, 2015

In the Mediterranean area, citrus fruits are primarily produced for the fresh fruit market and Sp... more In the Mediterranean area, citrus fruits are primarily produced for the fresh fruit market and Spain is the principal producer of the area. Seedlessness is one of the most important characteristics for mandarin fresh fruits. Triploid hybrids allow implementing this trait in commercial cultivars. In this work we described 'Alborea' and 'Albir', two new triploid hybrids originated from the IVIA triploid breeding program, which will be soon released to growers. 'Alborea' was obtained from an open pollinated 'Fortune' mandarin. Fruits reach optimum maturity at the beginning of January, although they can be harvested from December until the end of January. Fruits are easy-to-peel, with a diameter of 50-60 mm, and rind is deep orange red in color. 'Albir' was obtained from a cross between 'Fortune' and 'Kara' mandarins. Fruits reach optimum maturity at the beginning of February, although they can be harvested from January until second half of February. Fruits are easyto-peel with a diameter of 60-70 mm and fruit rind is orange red in color. This variety has the same origin as 'Safor', a previously released triploid hybrid. The fruits of the two varieties are somewhat similar, but 'Albir' matures one month earlier. With these cultivars, 'Albir' and 'Safor', it will be possible to supply similar fruits to the market from January to the end of March.

A haploid C. clementina was chosen by the International Citrus Genomic Consortium (ICGC) to estab... more A haploid C. clementina was chosen by the International Citrus Genomic Consortium (ICGC) to establish the reference whole genome sequence for Citrus. Development of a dense clementine linkage map was part of the objectives of this global

Frontiers in plant science, 2016

Alternaria brown spot (ABS) is a serious disease affecting susceptible citrus genotypes, which is... more Alternaria brown spot (ABS) is a serious disease affecting susceptible citrus genotypes, which is a strong concern regarding citrus breeding programs. Resistance is conferred by a recessive locus (ABSr) previously located by our group within a 3.3 Mb genome region near the centromere in chromosome III. This work addresses fine-linkage mapping of this region for identifying candidate resistance genes and develops new molecular markers for ABS-resistance effective marker-assisted selection (MAS). Markers closely linked to ABSr locus were used for fine mapping using a 268-segregating diploid progeny derived from a heterozygous susceptible × resistant cross. Fine mapping limited the genomic region containing the ABSr resistance gene to 366 kb, flanked by markers at 0.4 and 0.7 cM. This region contains nine genes related to pathogen resistance. Among them, eight are resistance (R) gene homologs, with two of them harboring a serine/threonine protein kinase domain. These two genes along wi...