Herramientas moleculares para la caracterización de Rhizoctonia spp. causales de patologías en tabaco Tipo Virginia en Salta y Jujuy (Argentina)

Desde fines de los años noventa la actividad tabacalera se encuentra afectada por una sintomatología que se visualiza con distintas manifestaciones externas como: marchitamiento de la parte aérea de la planta, amarillamiento y posterior necrosis de los tejidos que puede terminar con la muerte de la planta. Coincidente con aquella manifestación aérea, el sistema radicular se presenta con escaso desarrollo y en su mayoría con presencia de raíces con podredumbre, visualizándose muchas veces en el cuello necrosis total o parcial. En las campañas 2008/09/10 se relevaron 80 lotes comerciales de tabaco por campaña en las provincias de Salta y Jujuy, diagnosticándose Rhizoctonia solani agente causal de la podredumbre radicular, como la enfermedad con mayor prevalencia e incidencia, siendo este patógeno uno de los responsables del complejo del amarillamiento en tabaco. En sus comienzos esta sintomatología se manifestaba en forma aislada, pero en los últimos años se expandió por toda la zona tabacalera transformándose en uno de los problemas fitosanitarios más importantes de este sector productivo, por lo cual surge la necesidad de implementar medidas de manejo para mitigar esta dolencia. Uno de los pilares más importantes para el manejo de una enfermedad, es el diagnóstico certero del agente causal. El sistema de clasificación para los aislamientos de R. solani está basado en la capacidad de anastomosis o fusión de las hifas, siendo el criterio más usado para separarlo en grupos relativamente homogéneos. Se ha clasificado a este hongo en 14 grupos de anastomosis y varios subgrupos. En tabaco los grupos de anastomosis AG1, AG2.2, AG4 y AG5 causan damping off en plantines bajo almácigo y en plantas jóvenes posterior al transplante al campo y podredumbre radicular en planta adulta. Mientras que AG2.2 y AG3 producen la mancha foliar o target spot. Recientemente los marcadores moleculares y estudios de secuenciación de ADN demostraron ser herramientas de gran utilidad para la caracterización de aislamientos en AG permitiendo una caracterización más rápida y precisa que los tests de anastomosis convencionales ya que estos últimos pueden dar falsos positivos. Entre los métodos moleculares más utilizados para la clasificación de Rhizoctonia spp. se destaca el análisis de secuencias ITS o espaciadores internos transcritos (internal transcribed spacers). Los ITS son regiones de ADN no codificantes que separan las regiones que codifican las unidades de ADN ribosómico. Estas regiones muestran mayor polimorfismo de secuencia que las regiones codificantes y por lo tanto son útiles como fuente de marcadores genéticos y se utilizaron para estudios filogenético en Rhizoctonia spp. En el presente trabajo se caracterizaron 49 aislamientos de Rhizoctonia spp. colectados en diferentes lotes comerciales de tabaco en las provincias de Salta y Jujuy empleando marcadores ITS-rDNA.Fil: Mercado Cárdenas, Guadalupe. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Salta-Jujuy. Estación Experimental Agropecuaria Salta; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Salta; ArgentinaFil: Galván, Marta Zulema. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Salta-Jujuy. Estación Experimental Agropecuaria Salta; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Salta; ArgentinaFil: Rodriguero, Marcela Silvina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Ecología, Genética y Evolución; Argentin

Common Bean Germplasm Molecular Analysis: A Biotechnological Approach for Breeding

Argentina, which is a major producer of common bean (Phaseolus vulgaris L.), represents the southern most limit of the Andean diversification center of the species. The diverse environmental conditions of these places and human selection favored the development of a great variability of wild beans and landraces, which is endangered due to the destruction of habitats by forest exploitation and agriculture. Information on the variability of these resources is essential to set conservation strategies and design breeding programs aimed at enlarging the genetic base of commercial beans. This work is an overview of the marker-based studies on landraces and wild bean genetic diversity, with special emphasis on Argentinean beans, as a first step for the optimal exploitation of the naturally available bean genetic resources, to generate new traits and improve crop performance. The identification of diversity and hybridization between populations is enhanced by the application of the new tools and the information generated by bean genomic research. Gene flow, which appears to occur fairly frequently in bean, has to be studied in more detail in this region in order to facilitate the transfer of useful alleles from the unexploited germplasm to improved lines, broadening the genetic diversity available for breeding. Some resistance gene analogs (RGAs) have been described within the Andean gene pool and only a few have been functionally characterized or linked to a phenotype. Therefore, a strategy for the exploitation of bean germplasm variability based on the detection of RGAs is also mentioned, though more work should be devoted at identifying these sequences in Andean landraces and wild beans.Facultad de Ciencias Agrarias y Forestale

Inter simple sequence repeat (ISSR) markers as a tool for the assessment of both genetic diversity and gene pool origin in common bean (Phaseolus vulgaris L.)

In this study, we report the use of ISSR to assess genetic diversity and to determine the relationships among ten cultivars of common bean developed in Argentina and three materials from France. ISSR markers resolved two major groups corresponding to the Andean and Mesoamerican gene pools of common bean. We compared the results of previous analysis, performed with RAPD markers (Galvan et al., 2001), with the results generated by means of ISSR. It appears that ISSR are better tools than RAPDs to identify beans by gene pool of origin though they did not revealed as many differences between individuals as RAPDs.Instituto de Fisiología Vegeta

Evaluación de la tolerancia a Fusarium oxysporum and Fusarium solani en variedades de tabaco (Nicotiana tabacum L.) tipo Virginia bajo condiciones controladas en el noroeste de Argentina

La producción de Tabaco (Nicotiana tabacum L.) en Argentina se concentra en la Región Noroeste (NOA), donde la incidencia de las enfermedades radiculares y de tallo causadas por Fusarium spp. han aumentado en los últimos años. Este estudio, tuvo como objetivo evaluar los niveles de patogenicidad de aislamientos de los complejos F. oxysporum y F. solani en diferentes variedades de tabaco tipo Virginia. Las variedades evaluadas fueron: MB47, PVH229, NC71, K346, K326 y K394 que se inocularon con seis aislamientos de ambos complejos. Las variables evaluadas fueron incidencia (I) y severidad (S). Se calculó el área bajo las curvas de progreso de la enfermedad (ABCPE) y se sometió a análisis de varianza (ANOVA). Además, se ajustaron los datos experimentales a modelos epidemiológicos del proceso de enfermedad. La variedad MB47 resultó significativamente menos infectada y las variedades K346, K326, K394 presentaron los valores de ABCPE más altos, mostrando un comportamiento susceptible. Las curvas de intensidad de la enfermedad se describieron adecuadamente mediante los modelos monomolecular y logístico. Los resultados generados en el presente estudio proporcionan por primera vez información sobre los niveles de tolerancia al marchitamiento vascular y podredumbre radicular en condiciones controladas para las principales variedades de tabaco cultivadas en NOA.The production of tobacco (Nicotiana tabacum L.) in Argentina is centered in the northwestern region (NWA), where the incidence of root rots and stem diseases caused by Fusarium spp. has increased considerably in recent years. This study aimed to evaluate the pathogenicity levels of isolates of the F. oxysporum and F. solani complexes in different varieties of Virginia Type tobacco. The commercial varieties MB47, PVH229, NC71, K346, K326, and K394 were inoculated with six isolates of both complexes. The variables evaluated were the incidence and severity of the symptoms. The area under the disease progress curves (AUDPC) was calculated and subjected to analysis of variance (ANOVA). Also, disease epidemiological models were fitted to the experimental data. The MB47 variety was significantly less infected and the varieties K346, K326, and K394 had the highest AUDPC means, showing susceptibility to the isolates. The disease intensity curves were adequately described by the monomolecular and logistic models. The results provide, for the first time, information about the levels of tolerance to vascular wilt and root rot under controlled conditions for the main varieties of Virginia-type tobacco grown in NWA.Fil: Berruezo, Lorena Andrea. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Salta. Estación Experimental Agropecuaria Salta; ArgentinaFil: Harries, Eleonora del Milagro. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Salta-Jujuy. Estación Experimental Agropecuaria Salta; ArgentinaFil: Galván, Marta Zulema. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Salta-Jujuy. Estación Experimental Agropecuaria Salta; ArgentinaFil: Stenglein, Sebastian Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Cientifico Tecnolológico Mar del Plata. Instituto de Investigaciones en Biodiversidad y Biotecnología. Laboratorio de Biología Funcional y Biotecnología; ArgentinaFil: Mercado Cárdenas, Guadalupe Eugenia. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Salta. Estación Experimental Agropecuaria Salta; Argentin

Caracterização da raça 65 de Colletotrichum lindemuthianum utilizando sequenciamento das regiões ITS

The present work aimed characterize isolates of C. lindemuthianum race 65 from different regions in Brazil by ITS sequencing. A total of 17 isolates of race 65, collected in the states of Mato Grosso, Minas Gerais, Paraná, Santa Catarina and São Paulo, were studied. Analysis of the sequences of isolates 8, 9, 12, 14 and 15 revealed the presence of two single nucleotide polymorphisms (SNPs) in the ITS1 region at the same positions. These isolates, when analyzed together with the sequence of isolate 17, revealed a SNP in the ITS2 region. The highest genetic dissimilarity, observed between isolates 11 and 3 and between isolates 11 and 10, was 0.772. In turn, isolates 7 and 2 were the most similar, with a value of 0.002 for genetic distance. The phylogenetic tree obtained based on the sequences of the ITS1 and ITS2 regions revealed the formation of two groups, one with a subgroup. The results reveal high molecular variability among isolates of race 65 of C. lindemuthianum.O presente trabalho teve como objetivo caracterizar isolados de C. lindemuthianum da raça 65 provenientes de diversas regiões do Brasil, por meio de sequenciamento de regiões ITS. Um total de 17 isolados da raça 65, coletados nos estados do Mato Grosso, Minas Gerais, Paraná, Santa Catarina e São Paulo, foram estudados. As análises das sequências dos isolados 8, 9, 12, 14 e 15 revelaram a presença de dois SNPs na região ITS1 nas mesmas posições. Estes mesmos isolados quando analisados juntamente com a sequência do isolado 17 apresentaram um SNP na região ITS2. A maior dissimilaridade genética foi de 0,772 observada entre os isolados 11 e 3 e entre os isolados 11 e 10. Por sua vez, os isolados 7 e 2 foram os mais similares, com valor de distância genética de 0,002. A árvore filogenética obtida com base nas sequências das regiões ITS1 e ITS2 revelou a formação de dois grupos, sendo um com a divisão de um subgrupo. Estes resultados revelam uma elevada variabilidade molecular entre isolados da raça 65 de C. lindemuthianum.Fil: Coelho, Marcela. Universidade Estadual de Maringá; BrasilFil: Gonçalves Vidigal, María Celeste. Universidade Estadual de Maringá; BrasilFil: Souza, Lorenna Lopes de. Universidade Federal de Goiás; BrasilFil: Nunes, María Paula Barion Alvez. Universidade Estadual de Londrina; BrasilFil: Azevedo, Rafhael Felipin. Universidade Estadual de Maringá; BrasilFil: Galván, Marta Zulema. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Salta. Estación Experimental Agropecuaria Salta; Argentin

Genetic diversity and population structure of sweet cassava using simple sequence repeat (SSR) molecular markers

The objective of this study was to evaluate the population structure and genetic diversity among 66 sweet cassava (Manihot esculenta Crantz) traditional accessions collected in Maringa, Parana, Brazil, using microsatellite molecular markers. Population structure was analyzed by means of genetic distances and probabilistic models; allelic frequencies were used in order to assess the genetic diversity indexes (Ht , Ho, PIC, % polymorphism and number of alleles) for each locus studied. All evaluated loci were polymorphic and the average was highly heterozygote. The number of alleles per locus was low, suggesting that restrict genetic base is a consequence of accession exchange and a reduced number of ancestors in the population. The polymorphic information content (PIC) values showed considerable genetic diversity with a mean value of 0.5076 and peak of 0.5707 for locus GA140. The microsatellites markers revealed a wide genetic variability among the traditional accessions evaluated. Moreover, the sweet cassava populations were separated in two groups using two analytical methods (probabilistic and genetic distances). The most divergent accessions were BGM 17, BGM 20, BGM 51 and BGM 95. On the other hand, the most similar accessions were BGM 25, BGM 33, BGM 37, BGM 59 and BGM 214. Hybrid combinations formed by the most divergent combinations, especially between BGM 51 × BGM 296, BGM 95 × BGM 222 and BGM 20 × BGM 12, are the most promising ones for future sweet cassava breeding programsFil: Costa, Tiago Ribeiro Da. Universidade Estadual de Maringá. Departamento de Agronomia; BrasilFil: Vidigal Filho, Pedro Soares. Universidade Estadual de Maringá. Departamento de Agronomia; BrasilFil: Gonçalves Vidigal, Maria Celeste. Universidade Estadual de Maringá. Departamento de Agronomia; BrasilFil: Galván, Marta Zulema. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Salta-Jujuy. Estación Experimental Agropecuaria Salta; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico La Plata. Instituto de Fisiología Vegetal; ArgentinaFil: Lacanallo, Giselly Figueiredo. Universidade Estadual de Maringá. Departamento de Agronomia; BrasilFil: Silva, Luciano Ivano Da . Universidade Estadual de Maringá. Departamento de Agronomia; BrasilFil: Kvitschal, Marcus Vinicius. Empresa de Pesquisa Agropecuária e Extensão Rural de Santa Catarina; Brasi

Inheritance and allelic relationships of anthracnose resistance in common bean paloma cultivar

Anthracnose, caused by Colletotrichum lindemuthianum L., is one of the most important fungal diseases of common bean (Phaseolus vulgaris, L). Genetic resistance is the most effective method for this disease control. So far, twenty one resistance genes have been already characterized, and among them, only eight are Andean and due to it, the search for Andean resistance sources is really necessary. This way, the work aimed to characterize the genetic resistance of an Andean common bean cultivar.Fil: Castro, S. A. L.. Universidade Estadual de Maringá; BrasilFil: Gonçalves Vidigal, M. C.. Universidade Estadual de Maringá; BrasilFil: Nanami, D. S. Y.. Universidade Estadual de Maringá; BrasilFil: Frias, A. A. T.. Universidade Estadual de Maringá; BrasilFil: Franzon, R. C.. Universidade Estadual de Maringá; BrasilFil: Poletine, J. P.. Universidade Estadual de Maringá; BrasilFil: Lacanallo, G. F.. Universidade Estadual de Maringá; BrasilFil: Galván, Marta Zulema. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Salta-Jujuy. Estación Experimental Agropecuaria Salta; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Salta; Argentin

Screening common bean germplasm for resistance to genetically diverse Sclerotinia sclerotiorum isolates from Argentina

White mold caused by Sclerotinia sclerotiorum (Lib.) de Bary is a devastating disease that affects the common bean (Phaseolus vulgaris. L) crop worldwide. In Argentina, white mold has been detected in all bean production areas, reaching seed yield and quality losses up to 100% on susceptible common bean cultivars under favorable weather conditions. The aim of this study was to screen the physiological resistance of 20 common bean accessions to five genetically distinct isolates of S. sclerotiorum collected from the main common bean growing area of Argentina, using the greenhouse straw test. The white mold reaction was scored at 7, 14, and 21 days post-inoculation using a 1 (no disease symptoms) to 9 (severely diseased or dead plants) scale and the area under the disease progress curve (AUDPC) was determined. Highly significant differences (p < 0.001) were observed between isolates, accessions and genotype x isolate interaction at the three evaluations dates. All cultivars and lines were susceptible at the end of the assessment, except line A 195 which was resistant to white mold against the five isolates tested and was significantly different from all accessions. This work represents a valuable contribution to regional breeding programmes aimed to obtain cultivars with durable resistance.Fil: Aban, Carla Luciana. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Salta. Estación Experimental Agropecuaria Salta; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta; ArgentinaFil: Taboada, Gisel María. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Salta. Estación Experimental Agropecuaria Salta; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta; ArgentinaFil: Casalderrey, Norma Beatriz. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Salta. Estación Experimental Agropecuaria Salta; ArgentinaFil: Maggio, María Elisa. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Salta. Estación Experimental Agropecuaria Salta; ArgentinaFil: Chocobar, Mario Osvaldo. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Salta. Estación Experimental Agropecuaria Salta; ArgentinaFil: Spedaletti, Yamila Andrea. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Salta. Estación Experimental Agropecuaria Salta; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta; ArgentinaFil: Aparicio González, Mónica Alicia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Investigaciones para la Industria Química. Universidad Nacional de Salta. Facultad de Ingeniería. Instituto de Investigaciones para la Industria Química; ArgentinaFil: Vizgarra, Oscar Vicéforo. Gobierno de Tucumán. Ministerio de Desarrollo Productivo. Estación Experimental Agroindustrial Obispo Colombres; ArgentinaFil: Galván, Marta Zulema. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Salta. Estación Experimental Agropecuaria Salta; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta; Argentin

Molecular identification and pathogenicity of Rhizoctonia spp. recovered from seed and soil samples of the main bean growing area of Argentina

The objective of this study was to perform the molecular and pathogenic characterization of Rhizoctonia solani in bean seed and soil samples from fields with root rot symptoms in northwestern Argentina. Fifty-two Rhizoctonia spp. isolates were collected in ten naturally infested bean fields and characterized by morphological traits, DNA sequencing, and pathogenicity. The mycelium color, the pattern of sclerotia formation, and the number of nuclei per hyphal cell were determined for each isolate. According to the variability in the rDNA-ITS region, isolates were identified as R. solani (85%), Waitea circinata var. zeae (Rhizoctonia zeae) (2%) and Rhizoctonia spp. (13%). Most isolates of R. solani (92%) were found to belong to the anastomosis group (AG) AG 4, including seven AG 4 HG-I and nine AG 4 HG-III isolates. AGs obtained from soil samples were more variable than those obtained from seed samples. Molecular identification of the isolates was in agreement with their morphological characterization. In addition, aggressiveness of the isolates towards bean seedlings was assessed in the greenhouse. Four virulence categories were defined according to the disease reaction on root and foliar tissues, which showed great variability in virulence among the isolates. Our results suggest that both seed and soil-borne inoculum may play a significant role in pathogen dispersal in the region. This is the first study on Rhizoctonia species and AGs in bean seed and soil in this region and it may contribute towards an efficient control strategy for bean diseases caused by Rhizoctonia species.Fil: Spedaletti, Yamila Andrea. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Salta-Jujuy. Estación Experimental Agropecuaria Salta; ArgentinaFil: Mercado Cárdenas, Guadalupe Eugenia. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Salta-Jujuy. Estación Experimental Agropecuaria Salta; ArgentinaFil: Taboada, Gisel María. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Salta-Jujuy. Estación Experimental Agropecuaria Salta; Argentina. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Salta-Jujuy. Estación Experimental Agropecuaria Salta; ArgentinaFil: Aban, Carla Luciana. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Salta-Jujuy. Estación Experimental Agropecuaria Salta; ArgentinaFil: Aparicio González, Mónica Alicia. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Salta-Jujuy. Estación Experimental Agropecuaria Salta; ArgentinaFil: Rodriguero, Marcela Silvia. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Salta-Jujuy. Estación Experimental Agropecuaria Salta; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Ecología, Genética y Evolución. Laboratorio de Ecología Funcional; ArgentinaFil: Vizgarra, Oscar. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto de Tecnología Agroindustrial del Noroeste Argentino. Provincia de Tucumán. Ministerio de Desarrollo Productivo. Estación Experimental Agroindustrial "Obispo Colombres" (p). Instituto de Tecnología Agroindustrial del Noroeste Argentino; ArgentinaFil: Sühring, Silvia Susana. Universidad Nacional de Salta. Facultad de Ciencias Naturales; ArgentinaFil: Galindez, Guadalupe. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Salta-Jujuy. Estación Experimental Agropecuaria Salta; Argentina. Universidad Nacional de Salta. Facultad de Ciencias Naturales; ArgentinaFil: Galván, Marta Zulema. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Salta-Jujuy. Estación Experimental Agropecuaria Salta; Argentin

Review: Genetic diversity and population structure of cotton (Gossypium hirsutum L. race latifolium H.) using microsatellite markers

Cotton (Gossypium spp.) is the world’s leading natural fiber crop and is cultivated in diverse temperate and tropical areas. In this sense, molecular markers are important tools for polymorphism identification in genetic diversity analyses. The objective of this study was to evaluate genetic diversity and population structure in tetraploid cotton (Gossypium hirsutum L. race latifolium H.) by means of microsatellite markers. 43 cultivars and inbred lines from Africa, United States and Brazil were analyzed. From a total of 33 SSRs markers, 15 markers revealed 104 polymorphic SSR alleles. Four groups were identified applying different methods (the probabilistic method, Principal Coordinates Analysis and Neighbor Joining tree). American cultivars and inbred lines were included in group I; African cultivars in group II; and Brazilian cultivars in groups II, III and IV. The FST index indicated high genetic variability among the cultivars and inbred lines studied. In general, American cultivars were the most divergent compared to African and Brazilian ones. The dissimilarity index ranged from 0.06 to 0.90 and the lowest genetic divergence was observed between TAMCOT22 and TAM96WD-69s(L). Combination of American cultivars and inbred lines with African and Brazilian cultivars is recommended for obtaining superior segregant in order to improve yield.Key words: Dissimilarity index, Gossypium hirsutum L., polymorphism, SSRs markers