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Diego Rubiales - One of the best experts on this subject based on the ideXlab platform.
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A diversity of resistance sources to Fusarium oxysporum f. sp. pisi found within Grass Pea germplasm
Plant and Soil, 2021Co-Authors: Ana Margarida Sampaio, Stefania Vitale, David Turrà, Antonio Di Pietro, Diego Rubiales, Fred Van Eeuwijk, Maria Carlota Vaz PattoAbstract:Purpose Grass Pea is a legume species with recognized resistance to several diseases and thus important for the improvement of related major legume crops. It is infected by the soil-borne fungus Fusarium oxysporum f. sp. pisi ( Fop ), known as causal agent of Pea fusarium wilt. We aim to identify, among Grass Pea, new sources of resistance against Fop and characterize the detected resistance mechanisms. Methods A Grass Pea worldwide collection of accessions was characterized under controlled conditions for response to Fop race 2. Fungal colonization dynamics and potential resistance mechanisms were studied through confocal laser scanning microscopy (CLSM) using Fop race 2 expressing green fluorescent protein (GFP). Results A quantitative nature of resistance to Fop , ranging from highly to partially resistant and susceptible accessions was detected, with resistance being the most frequent phenotype. Diverse colonization patterns were observed, suggesting the existence of different resistance mechanisms. In the highly resistant accessions, absence of fungal colonization in the vascular tissue was detected, while fungal progression was arrested at the level of roots both in highly resistant and partially resistant accessions. Conclusions The resistant accessions identified here can be exploited in Grass Pea breeding for fusarium wilt resistance, and due to the phylogenetic relatedness to Pea, potentially contribute to Pea improvement.
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the effect of orobanche crenata infection severity in faba bean field Pea and Grass Pea productivity
Frontiers in Plant Science, 2016Co-Authors: Monica Fernandezaparicio, Fernando Flores, Diego RubialesAbstract:Broomrape weeds (Orobanche and Phelipanche spp.) are root holoparasites that feed off a wide range of important crops. Among them, Orobanche crenata attacks legumes complicating their inclusion in cropping systems along the Mediterranean area and West Asia. The detrimental effect of broomrape parasitism in crop yield can reach up to 100% depending on infection severity and the broomrape-crop association. This work provides field data of the consequences of O. crenata infection severity in three legume crops i.e. faba bean, field Pea and Grass Pea. Regression functions modelled productivity losses and revealed trends in dry matter allocation in relation to infection severity. The host species differentially limits parasitic sink strength indicating different levels of broomrape tolerance at equivalent infection severities. Reductions in host aboveground biomass were observed starting at low infection severity and half maximal inhibitory performance was predicted as 4.5, 8.2 and 1.5 parasites per faba bean, field Pea and Grass Pea plant, respectively. Reductions in host biomass occurred in both vegetative and reproductive organs, the latter resulting more affected. The proportion of resources allocated within the parasite was concomitant to reduction of host seed yield indicating that parasite growth and host reproduction compete directly for resources within a host plant. However, the parasitic sink activity does not fully explain the total host biomass reduction because combined biomass of host-parasite complex was lower than the biomass of uninfected plants. In Grass Pea, the seed yield was negligible at severities higher than 4 parasites per plant. In contrast, faba bean and field Pea sustained low but significant seed production at the highest infection severity. Data on seed yield and seed number indicated that the sensitivity of field Pea to O. crenata limited the production of grain yield by reducing seed number but maintaining seed size. In contrast, the size of individual parasites was not genetically determined but dependent on the host species and resource availability as a consequence of parasite competition at increasing infection severities.
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escape and true resistance to crenate broomrape orobanche crenata forsk in Grass Pea lathyrus sativus l germplasm
Field Crops Research, 2012Co-Authors: Fernando Flores, Monica Fernandezaparicio, Diego RubialesAbstract:Abstract Grass Pea (Lathyrus sativus L.) is an annual cool season legume widely grown as a pulse crop for human food and animal feed and as forage. Infection by the parasitic weed crenate broomrape (Orobanche crenata Forsk.) has been identified as major constraint for Grass Pea cultivation. We studied the response to O. crenata of a germplasm collection of Grass Pea in field trials over two seasons showing that the level of infection was highly influenced by environmental factors and plant growth cycle. Earlier or very late accessions were less infected. O. crenata infection increased with host plant vigour. O. crenata infection strongly reduced host biomass and grain yield. Even when resistance is scarce and masked by confounding environmental and plant growth cycle factors, calculation of the deviations from the polynomic nonlinear regression provided an improved approximation of the true genetic resistance levels present in the germplasm, here defined as resistance that do not depend on precocity.
Monica Fernandezaparicio - One of the best experts on this subject based on the ideXlab platform.
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the effect of orobanche crenata infection severity in faba bean field Pea and Grass Pea productivity
Frontiers in Plant Science, 2016Co-Authors: Monica Fernandezaparicio, Fernando Flores, Diego RubialesAbstract:Broomrape weeds (Orobanche and Phelipanche spp.) are root holoparasites that feed off a wide range of important crops. Among them, Orobanche crenata attacks legumes complicating their inclusion in cropping systems along the Mediterranean area and West Asia. The detrimental effect of broomrape parasitism in crop yield can reach up to 100% depending on infection severity and the broomrape-crop association. This work provides field data of the consequences of O. crenata infection severity in three legume crops i.e. faba bean, field Pea and Grass Pea. Regression functions modelled productivity losses and revealed trends in dry matter allocation in relation to infection severity. The host species differentially limits parasitic sink strength indicating different levels of broomrape tolerance at equivalent infection severities. Reductions in host aboveground biomass were observed starting at low infection severity and half maximal inhibitory performance was predicted as 4.5, 8.2 and 1.5 parasites per faba bean, field Pea and Grass Pea plant, respectively. Reductions in host biomass occurred in both vegetative and reproductive organs, the latter resulting more affected. The proportion of resources allocated within the parasite was concomitant to reduction of host seed yield indicating that parasite growth and host reproduction compete directly for resources within a host plant. However, the parasitic sink activity does not fully explain the total host biomass reduction because combined biomass of host-parasite complex was lower than the biomass of uninfected plants. In Grass Pea, the seed yield was negligible at severities higher than 4 parasites per plant. In contrast, faba bean and field Pea sustained low but significant seed production at the highest infection severity. Data on seed yield and seed number indicated that the sensitivity of field Pea to O. crenata limited the production of grain yield by reducing seed number but maintaining seed size. In contrast, the size of individual parasites was not genetically determined but dependent on the host species and resource availability as a consequence of parasite competition at increasing infection severities.
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escape and true resistance to crenate broomrape orobanche crenata forsk in Grass Pea lathyrus sativus l germplasm
Field Crops Research, 2012Co-Authors: Fernando Flores, Monica Fernandezaparicio, Diego RubialesAbstract:Abstract Grass Pea (Lathyrus sativus L.) is an annual cool season legume widely grown as a pulse crop for human food and animal feed and as forage. Infection by the parasitic weed crenate broomrape (Orobanche crenata Forsk.) has been identified as major constraint for Grass Pea cultivation. We studied the response to O. crenata of a germplasm collection of Grass Pea in field trials over two seasons showing that the level of infection was highly influenced by environmental factors and plant growth cycle. Earlier or very late accessions were less infected. O. crenata infection increased with host plant vigour. O. crenata infection strongly reduced host biomass and grain yield. Even when resistance is scarce and masked by confounding environmental and plant growth cycle factors, calculation of the deviations from the polynomic nonlinear regression provided an improved approximation of the true genetic resistance levels present in the germplasm, here defined as resistance that do not depend on precocity.
Rubiales Diego - One of the best experts on this subject based on the ideXlab platform.
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Grass Pea and Pea phylogenetic relatedness reflected at Fusarium oxysporum host range
'Elsevier BV', 2021Co-Authors: Sampaio A. M., Rubiales Diego, Vaz Patto, María CarlotaAbstract:Vascular wilt, caused by the infection of the soil-borne pathogen Fusarium oxysporum (Fo), is one of the most destructive diseases of many crops, including legumes such as Grass Pea (Lathyrus sativus), with several formae speciales (ff. spp.) defined according to their hosts. Commonly described as host-specific, Fo could, in some cases, show a broader host range comprising related plant species, making its host range characterization an important aspect of epidemiology and crop protection. No information on identification and host range status of strains able to infect Grass Pea is available, nor whether Grass Pea could act as host to different Fo ff. spp.. In this study, the host range of two Fo strains isolated from Grass Pea (Fo ex. L. sativus 1 and 2) was evaluated using related legume species: Pea (Pisum sativum), lentil (Lens culinaris), chickPea (Cicer arietinum), common bean (Phaseolus vulgaris), and barrel medic (Medicago truncatula). In addition, the responses of Grass Pea to the causal agents of fusarium wilt in these legume species, Fo f. sp. pisi, lentis, ciceris, phaseoli, and medicaginis, were also investigated. Disease symptom evaluation by disease rating over time, its related area under disease progress curve (AUDPC) and disease progress rate (DIr), revealed that Fo ex. L. sativus 1 and 2 are host-specific, infecting only Grass Pea although with low aggressiveness. Grass Pea could also be infected by Fo f. sp. pisi races, with race 2 being the most virulent strain in Grass Pea, even more virulent than the Fo strains retrieved originally from Grass Pea. The phylogenetic relatedness between Grass Pea and Pea may in part explain this observation, indicating that Fo f. sp. pisi can also infect legume-related species such as Grass Pea. Additionally, specialization might be occurring, with particular Fo isolates being only virulent to Grass Pea, although with lower virulence than Fo f. sp. pisi race 2 itself. These cross-inoculation results reinforce the importance of performing host-range studies, even on specialist pathogens, to identify potential closely related alternative hosts and consequently improve or adapt disease control management.Financial support by Fundação para a Ciência e Tecnologia (FCT), Portugal, is acknowledge through grant PD/BD/114418/2016 (A.M.S.), the IF/01337/2014 FCT Investigator contract (M.C.V.P.), the research unit GREEN-IT (UID/04551/2020), the QuaLaty project (PTDC/AGR-TEC/0992/2014) and the Spanish Research Agency (AEI) project AGL2017-82907-R
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Adaptation of Grass Pea (Lathyrus sativus) to Mediterranean Environments
'MDPI AG', 2020Co-Authors: Rubiales Diego, Emeran, Amero A., Flores FernandoAbstract:Grass Pea (Lathyrus sativus) is an annual legume crop widely cultivated in South Asia and Sub-Saharan Africa, but in regression in Mediterranean region. Its rusticity and nutritious value is calling back attention for its reintroduction into Mediterranean rain-fed farming systems. We studied the adaptation of a range of breeding lines in multi-environment field testing in Spain and Egypt, showing wide variation for grain yield. Broomrape (Orobanche crenata) infection apPeared as the major limiting factor in both countries. Level of broomrape infection was highly influenced by environmental conditions, being favored by moderate temperatures at crop flowering and rain and humidity after flowering. The additive main effects and multiplicative interaction (AMMI) analysis was applied to understand the interaction between genotype (G) and environment (E) on grain yield and on broomrape infection. AMMI analyses revealed significant G and E effects as well as G*E interaction with respect to both traits. The AMMI analysis of variance (ANOVA) revealed that both, yield and broomrape infection were dominated by the environment main effect. AMMI1 biplot for grain yield revealed Ls10 and Ls11 as the accession with highest yields, closely followed by Ls16, Ls18 and Ls19. However, these accessions showed also lower stability, being particularly adapted to Delta Nile conditions. On the contrary, accessions Ls12 and Ls14 were more adapted to rain fed Spanish conditions. Accessions Ls7, Ls1 and Ls3 were the most stable over environments for grain yield
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Broomrape as a Major Constraint for Grass Pea (Lathyrus sativus) Production in Mediterranean Rain-Fed Environments
'MDPI AG', 2020Co-Authors: Rubiales Diego, Barilli Eleonora, Flores FernandoAbstract:Grass Pea (Lathyrus sativus) is an annual legume crop that is currently underutilized but has the potential for reintroduction into Mediterranean rain-fed farming systems. In this study, we compared the adaptation of breeding lines in multi-environment field testing, which had wide variation for precocity, grain yield and broomrape infection. Heritability-adjusted genotype plus genotype-by-environment interaction (HA-GGE) biplot and non-metric multidimensional scaling (NMDS) were performed to determine the effect on genotype (G), environment (E) and G × E interaction on grain yield, precocity and broomrape infection. Precocity was associated with reduced broomrape infection, and this with increased grain yield. Step-wise regression analysis revealed that the broomrape infection had the highest influence on grain yield, whereas precocity had a lower effect. Rain and humidity and mild temperatures before and during flowering were the climatic factors most influential on broomrape. Accessions with a shorter growth cycle suffered lower broomrape infection and were more productive in the environments with a high broomrape incidence. Accessions with longer growth cycle suffered overall higher broomrape infection and were therefore more productive in the environments with low or moderate broomrape incidence
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How can Grass Pea overcome Fusarium wilt? Insights from a natural variation study
'Japanese Society of Applied Entomology & Zoology', 2019Co-Authors: Sampaio A. M., Rubiales Diego, Alves, Mara Lisa, Pereira P. M., Santos C., Vaz Patto, María CarlotaAbstract:Trabajo presentado en la Third International Legume Society Conference ILS3 2019 (Legumes for human and planet health), celebrada en Poznan (Polonia) del 21 al 24 de mayo de 2019.Grass Pea (Lathyrus sativus L.) is an annual grain legume with high adaptability to unfavorable environments, which cultivation spread over three continents. Beyond its rec-ognized potential as a feed and food crop, is remarkably re-sistant to several important legume diseases, which may be useful in the breeding of related major legume crops.We are thankful to Fundação para a Ciência e Tecnologia, Portugal PD/BD/114418/2016, IF/01337/2014 FCT Investigator contract, Research Unit GREEN-it “Bioresources for Sustainability” (UID/Multi/04551/2013), QuaLaty project (PTDC/AGR-TEC/0992/2014)) and to the EuroPean Community’s Seventh Framework Programme (FP7/2007-2013) through the LEGATO project (grant agreement nº 613551).Peer reviewe
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The effect of Orobanche crenata infection severity in faba bean, field Pea, and Grass Pea productivity
'Frontiers Media SA', 2018Co-Authors: Fernandez-aparicio Ruiz Monica, Flores Fernando, Rubiales DiegoAbstract:Prod 2018-285b équipe SPE ésuipe EA GESTAD INRAInternational audienceBroomrape weeds (Orobanche and Phelipanche spp.) are root holoparasites that feed off a wide range of important crops. Among them, Orobanche orenata attacks legumes complicating their inclusion in cropping systems along the Mediterranean area and West Asia. The detrimental effect of broomrape parasitism in crop yield can reach up to 100% depending on infection severity and the broomrape-crop association. This work provides field data of the consequences of O. crenate infection severity in three legume crops, i.e., faba bean, field Pea, and Grass Pea. Regression functions modeled productivity losses and revealed trends in dry matter allocation in relation to infection severity. The host species differentially limits parasitic sink strength indicating different levels of broomrape tolerance at equivalent infection severities. Reductions in host aboveground biomass were observed starting at low infection severity and half maximal inhibitory performance was predicted as 4.5, 8.2, and 1.5 parasites per faba bean, field Pea, and Grass Pea plant, respectively. Reductions in host biomass occurred in both vegetative and reproductive organs, the latter resulting more affected. The increase of resources allocated within the parasite was concomitant to reduction of host seed yield indicating that parasite growth and host reproduction compete directly for resources within a host plant. However, the parasitic sink activity does not fully explain the total host biomass reduction because combined biomass of host-parasite complex was lower than the biomass of uninfected plants. In Grass Pea, the seed yield was negligible at severities higher than four parasites per plant. In contrast, faba bean and field Pea sustained low but significant seed production at the highest infection severity. Data on seed yield and seed number indicated that the sensitivity of field Pea to O. crenata limited the production of grain yield by reducing seed number but maintaining seed size. In contrast, the size of individual parasites was not genetically determined but dependent on the host species and resource availability as a consequence of competition between parasites at increasing infection severities
Hari B Krishnan - One of the best experts on this subject based on the ideXlab platform.
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identification and characterization of β lathyrin an abundant glycoprotein of Grass Pea lathyrus sativus l as a potential allergen
Journal of Agricultural and Food Chemistry, 2018Co-Authors: Fengjuan Liu, Peng Chen, Hari B Krishnan, Bo Song, Yaoyao Song, Shanshan LiuAbstract:Grass Pea, a protein-rich, high-yielding, and drought-tolerant legume, is used as food and livestock feed in several tropical and subtropical regions of the world. The abundant seed proteins of Grass Pea are salt-soluble globulins, which can be separated into vicilins and legumins. In many other legumes, the members of vicilin seed proteins have been identified as major allergens. However, very little information is available on the allergens of Grass Pea. In this study, we have identified an abundant 47 kDa protein from Grass Pea, which was recognized by immunoglobulin E (IgE) antibodies from sera drawn from several Peanut-allergic patients. The IgE-binding 47 kDa protein was partially purified by affinity chromatography on a Con-A sepharose column. Matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry analysis of the 47 kDa Grass Pea protein revealed sequence homology to 47 kDa vicilin from Pea and Len c 1 from lentil. Interestingly the Grass Pea vicilin was found to be susceptible to pepsin digestion in vitro. We have also isolated a cDNA encoding the Grass Pea 47 kDa vicilin (β-lathyrin), and the deduced amino acid sequence revealed extensive homology to several known allergens, including those from Peanut and soybean. A homology model structure of the Grass Pea β-lathyrin, generated using the X-ray crystal structure of the soybean β-conglycinin β subunit as a template, revealed potential IgE-binding epitopes located on the surface of the molecule. The similarity in the three-dimensional structure and the conservation of the antigenic epitopes on the molecular surface of vicilin allergens explains the IgE-binding cross-reactivity.
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Identification and Characterization of β‑Lathyrin, an Abundant Glycoprotein of Grass Pea (Lathyrus sativus L.), as a Potential Allergen
2018Co-Authors: Bo Song, Fengjuan Liu, Peng Chen, Yaoyao Song, Shanshan Liu, Hari B KrishnanAbstract:Grass Pea, a protein-rich, high-yielding, and drought-tolerant legume, is used as food and livestock feed in several tropical and subtropical regions of the world. The abundant seed proteins of Grass Pea are salt-soluble globulins, which can be separated into vicilins and legumins. In many other legumes, the members of vicilin seed proteins have been identified as major allergens. However, very little information is available on the allergens of Grass Pea. In this study, we have identified an abundant 47 kDa protein from Grass Pea, which was recognized by immunoglobulin E (IgE) antibodies from sera drawn from several Peanut-allergic patients. The IgE-binding 47 kDa protein was partially purified by affinity chromatography on a Con-A sepharose column. Matrix-assisted laser desorption/ionization–time-of-flight mass spectrometry analysis of the 47 kDa Grass Pea protein revealed sequence homology to 47 kDa vicilin from Pea and Len c 1 from lentil. Interestingly the Grass Pea vicilin was found to be susceptible to pepsin digestion in vitro. We have also isolated a cDNA encoding the Grass Pea 47 kDa vicilin (β-lathyrin), and the deduced amino acid sequence revealed extensive homology to several known allergens, including those from Peanut and soybean. A homology model structure of the Grass Pea β-lathyrin, generated using the X-ray crystal structure of the soybean β-conglycinin β subunit as a template, revealed potential IgE-binding epitopes located on the surface of the molecule. The similarity in the three-dimensional structure and the conservation of the antigenic epitopes on the molecular surface of vicilin allergens explains the IgE-binding cross-reactivity
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metabolomics approach to understand mechanisms of β n oxalyl l α β diaminopropionic acid β odap biosynthesis in Grass Pea lathyrus sativus l
Journal of Agricultural and Food Chemistry, 2017Co-Authors: Fengjuan Liu, Chengjin Jiao, Peng Chen, Adam L Heuberger, Hari B KrishnanAbstract:A study was performed to identify metabolic processes associated with β-ODAP synthesis in Grass Pea using a metabolomics approach. GC–MS metabolomics was performed on seedlings at 2, 6, and 25 days after sowing. A total of 141 metabolites were detected among the three time points representing much of Grass Pea primary metabolism, including amino acids, carbohydrates, purines, and others. Principal component analysis revealed unique metabolite profiles of Grass Pea tissues among the three time points. Fold change, hierarchical clustering, and orthogonal projections to latent structures-discriminant analyses, and biochemical pathway ontologies were used to characterize covariance of metabolites with β-ODAP content. The data indicates that alanine and nitrogen metabolism, cysteine and sulfur metabolism, and purine, pyrimidine, and pyridine metabolism were associated with β-ODAP metabolism. Our results reveal the metabolite profiles in Grass Pea development and provide insights into mechanisms of β-ODAP accum...
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Metabolomics Approach To Understand Mechanisms of β‑N‑Oxalyl‑l‑α,β-diaminopropionic Acid (β-ODAP) Biosynthesis in Grass Pea (Lathyrus sativus L.)
2017Co-Authors: Fengjuan Liu, Chengjin Jiao, Peng Chen, Adam L Heuberger, Hari B KrishnanAbstract:A study was performed to identify metabolic processes associated with β-ODAP synthesis in Grass Pea using a metabolomics approach. GC–MS metabolomics was performed on seedlings at 2, 6, and 25 days after sowing. A total of 141 metabolites were detected among the three time points representing much of Grass Pea primary metabolism, including amino acids, carbohydrates, purines, and others. Principal component analysis revealed unique metabolite profiles of Grass Pea tissues among the three time points. Fold change, hierarchical clustering, and orthogonal projections to latent structures-discriminant analyses, and biochemical pathway ontologies were used to characterize covariance of metabolites with β-ODAP content. The data indicates that alanine and nitrogen metabolism, cysteine and sulfur metabolism, and purine, pyrimidine, and pyridine metabolism were associated with β-ODAP metabolism. Our results reveal the metabolite profiles in Grass Pea development and provide insights into mechanisms of β-ODAP accumulation and degradation
Fernando Flores - One of the best experts on this subject based on the ideXlab platform.
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the effect of orobanche crenata infection severity in faba bean field Pea and Grass Pea productivity
Frontiers in Plant Science, 2016Co-Authors: Monica Fernandezaparicio, Fernando Flores, Diego RubialesAbstract:Broomrape weeds (Orobanche and Phelipanche spp.) are root holoparasites that feed off a wide range of important crops. Among them, Orobanche crenata attacks legumes complicating their inclusion in cropping systems along the Mediterranean area and West Asia. The detrimental effect of broomrape parasitism in crop yield can reach up to 100% depending on infection severity and the broomrape-crop association. This work provides field data of the consequences of O. crenata infection severity in three legume crops i.e. faba bean, field Pea and Grass Pea. Regression functions modelled productivity losses and revealed trends in dry matter allocation in relation to infection severity. The host species differentially limits parasitic sink strength indicating different levels of broomrape tolerance at equivalent infection severities. Reductions in host aboveground biomass were observed starting at low infection severity and half maximal inhibitory performance was predicted as 4.5, 8.2 and 1.5 parasites per faba bean, field Pea and Grass Pea plant, respectively. Reductions in host biomass occurred in both vegetative and reproductive organs, the latter resulting more affected. The proportion of resources allocated within the parasite was concomitant to reduction of host seed yield indicating that parasite growth and host reproduction compete directly for resources within a host plant. However, the parasitic sink activity does not fully explain the total host biomass reduction because combined biomass of host-parasite complex was lower than the biomass of uninfected plants. In Grass Pea, the seed yield was negligible at severities higher than 4 parasites per plant. In contrast, faba bean and field Pea sustained low but significant seed production at the highest infection severity. Data on seed yield and seed number indicated that the sensitivity of field Pea to O. crenata limited the production of grain yield by reducing seed number but maintaining seed size. In contrast, the size of individual parasites was not genetically determined but dependent on the host species and resource availability as a consequence of parasite competition at increasing infection severities.
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escape and true resistance to crenate broomrape orobanche crenata forsk in Grass Pea lathyrus sativus l germplasm
Field Crops Research, 2012Co-Authors: Fernando Flores, Monica Fernandezaparicio, Diego RubialesAbstract:Abstract Grass Pea (Lathyrus sativus L.) is an annual cool season legume widely grown as a pulse crop for human food and animal feed and as forage. Infection by the parasitic weed crenate broomrape (Orobanche crenata Forsk.) has been identified as major constraint for Grass Pea cultivation. We studied the response to O. crenata of a germplasm collection of Grass Pea in field trials over two seasons showing that the level of infection was highly influenced by environmental factors and plant growth cycle. Earlier or very late accessions were less infected. O. crenata infection increased with host plant vigour. O. crenata infection strongly reduced host biomass and grain yield. Even when resistance is scarce and masked by confounding environmental and plant growth cycle factors, calculation of the deviations from the polynomic nonlinear regression provided an improved approximation of the true genetic resistance levels present in the germplasm, here defined as resistance that do not depend on precocity.
