Registration of three sunflower germplasms with quantitative resistance to race F of broomrape.
Broomrape is a parasitic angiosperm that infects sunflower roots, causing severe crop losses in many areas, particularly in southern Europe and the Black Sea region (Melero-Vara, 1999). Until recently, commercial hybrids cultivated in Spain were resistant to races A through E of broomrape. Resistance to races A through E has been reported to be monogenic and dominant (Vranceanu et al., 1980). A new race F was first reported in 1995 in Spain and it is now present in vast areas of southern and central regions of the country (Alonso et al., 1996). Several sources of resistance to race F of broomrape have been identified in wild and cultivated sunflower and released (Jan et al., 2002; Fernandez-Martinez et al., 2004). Resistance to race F has been found to be controlled by one (Perez-Vich et al., 2002) or two major genes (Rodriguez-Ojeda et al., 2001; Akhtouch et al., 2002). Breeding programs conducted in Spain in recent years have devoted many resources to incorporating genetic resistance to race F into elite inbred lines. Despite such efforts, new broomrape populations have been found to overcome the recently developed resistance to race F (Molinero-Ruiz and Melero-Vara, 2005). Sunflower breeding for resistance to broomrape has been nearly exclusively based on the utilization of major genes conferring qualitative or vertical resistance, which is rapidly overcome by the parasite. The combination of vertical and horizontal resistance has been proposed for a more efficient disease control and development of durable resistance in sunflower (Vear, 2005).
AM-1 through AM-3 were selected from cultivated sunflower germplasm that initially exhibited segregation for resistance to race F of broomrape. AM-1 was selected from the USDA-ARS accession PI 307941, which corresponds to the Russian cultivar VNIIMK 6540. AM-2 was developed from the USDA-ARS accession PI 431521, which corresponds to the Romanian cultivar Romsun V-1352. AM-3 was derived from the USDA-ARS accession AMES 3429, which corresponds to the Russian cultivar VIR 101.
Plants of the accessions PI 307941 and AMES 3429 were evaluated for broomrape race F reaction in greenhouse pots in 1997 and 1998 (Fernandez-Martinez et al., 2000). Plants of the accession PI 431521 were evaluated under similar conditions in 1998 and 1999. Since the three accessions showed both symptomless and infected plants, the latter having emerged or underground broomrape stalks, a selection consisting of disease screening and head-to-row self pollination of symptomless plants was performed. Screening for reaction to race F of broomrape was conducted in greenhouse pots in 2000 and 2001, and under field conditions in 2002, 2003, and 2004. Artificial inoculation was used in all screenings as described by Fernandez-Martinez et al. (2000). Both symptomless and infected plants were observed in all generations, despite a strong selection pressure based on the selection of symptomless plants. However, both the incidence (percentage of infected plants) and the disease severity (number of broomrape stalks per infected sunflower plant) were reduced in the first cycles of selection, indicating the presence of quantitative or horizontal resistance mechanisms rather than qualitative or vertical ones. After five cycles of selection, AM-1 through AM-3 were formed in 2004 by bulking seeds from 30 to 50 plants.
The three germplasms were evaluated together with the original populations for reaction to race F of broomrape in a replicated field trial conducted in 2005 using artificial inoculation. AM-1 showed an incidence of 13.6% with 1.3 [+ or -] 0.7 broomrape stalks per plant, compared to an incidence of 21.7% with 2.7 [+ or -] 2.0 broomrape stalks per plant in the original population PI 307941. AM-2 showed an incidence of 17.9% with 1.9 [+ or -] 1.2 broomrape stalks per plant, compared to an incidence of 85.2% with 13.4 [+ or -] 11.0 broomrape stalks per plant in the original population PI 431520. AM-3 showed an incidence of 36.2% with 1.8 [+ or -] 0.9 broomrape stalks per plant, compared to an incidence of 86.8% with 16.3 [+ or -] 11.2 broomrape stalks per plant in the original population AMES 3429. The susceptible inbred line P1380 (Fermindez-Martfnez et al., 2000) was used as check, showing an incidence of 100% with 16.2 [+ or -] 11.7 broomrape stalks per plant.
These germplasms will be useful as genetic sources of quantitative genetic resistance to race F of broomrape in sunflower. Limited quantities of seed are available on request from the corresponding author for the first 5 yr. In the U.S., small quantities of seed may be obtained from the National Plant Germplasm System (NPGS). Recipients of seed are asked to make appropriate recognition of the source of the germplasm if it is used in the development of a new cultivar, germplasm, parental line or genetic stock. U.S. Plant Variety Protection will not be requested for these germplasms.
Akhtouch, B., J. Munoz-Ruz, J.M. Melero-Vara, J.M. Fernandez-Martinez, and J. Dominguez. 2002. Inheritance of resistance to race F of broomrape in sunflower lines of different origins. Plant Breed. 121:266-268.
Alonso, L.C., J. Fernandez-Escobar, G. Lopez, M. Rodriguez-Ojeda, and F. Sallago. 1996. New highly virulent sunflower broomrape (Orobanche cernua Loefl.) pathothype in Spain. p. 639-644. In M.T. Moreno et al. (ed.) Advances in parasitic plant research. Proc. 6th Int. Symp. Parasitic Weeds, Cordoba, Spain. 16-18 April 1996. Congresos y Jornadas 36/96. Direccion General de Investigacion Agraria, Consejeria de Agricultura y Pesca, Sevilla, Spain.
Fernandez-Martinez, J.M., J.M. Melero-Vara, J. Munoz-Ruz, J. Ruso, and J. Dominguez. 2000. Selection of wild and cultivated sunflower for resistance to a new broomrape race that overcomes resistance to the [Or.sub.5] gene. Crop Sci. 40:550-555.
Fernandez-Martinez, J.M., B. Perez-Vich, B. Akhtouch, L. Velasco, J. Munoz-Ruz, J.M. Melero-Vara, and J. Dominguez. 2004. Registration of four sunflower germplasms resistant to race F of broomrape. Crop Sci. 44:1033-1034.
Jan, C.C., J.M. Fernandez-Martinez, J. Ruso, and J. Munoz-Ruz. 2002. Registration of four sunflower germplasms with resistance to Orobanche cumana race E Crop Sci. 42:2217-2218.
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Molinero-Ruiz, M.L., and J.M. Melero-Vara. 2005. Virulence and aggressiveness of sunflower broomrape (Orobanche cumana) populations overcoming the Or5 gene. p. 165-169. In G.J. Seiler (ed.) Proc. 16th Int. Sunflower Conf., Fargo, ND. 29 Aug.-2 Sept. 2004. Int. Sunflower Assoc., Paris.
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Rodriguez-Ojeda, M.I., J. Fernandez-Escobar, and L.C. Alonso. 2001. Sunflower inbred line (KI-374), carrying two recessive genes for resistance against a highly virulent Spanish population of Orobanche cernua Loefl./O. cumana Wallr. race "F". p. 208-211. In A. Fer et al. (ed.) Proc. 7th Int. Parasitic Weed Symp., Nantes, France. 5-8 June 2001. Univ. of Nantes, France.
Vear, F. 2005. Breeding for durable resistance to the main diseases of sunflower, p. 15-28. In G.J. Seiler (ed.) Proc. 16th Int. Sunflower Conf., Fargo, ND. 29 Aug.-2 Sept. 2004. Int. Sunflower Assoc., Paris.
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B. PEREZ-VICH, L. VELASCO, J. MUNOZ-RUZ, J. DOMINGUEZ, AND J.M. FERNANDEZ-MARTINEZ
B. Perez-Vich, L. Velasco, J. Munoz-Ruz, and J.M. Fernandez-Martinez, Instituto de Agricultura Sostenible (CSIC), Apartado 4084, E-14080 Cordoba, Spain; J. Dominguez, CIFA Alameda del Obispo, IFAPA. CICE. Junta de Andalucia, Apartado 3092, Cordoba, Spain. Registration by CSSA. Received 2 Sept. 2005. * Corresponding author (firstname.lastname@example.org).
Published in Crop Sci. 46:1406-1407 (2006).
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|Title Annotation:||REGISTRATIONS OF CULTIVARS|
|Author:||Perez-Vich, B.; Velasco, L.; Munoz-Ruz, J.; Dominguez, J.; Fernandez-Martinez, J.M.|
|Date:||May 1, 2006|
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