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United States Department of Agriculture

Agricultural Research Service

Title: Objectives of Sugar Beet Breeding - Resistance to the Curly Top Virus

Author
item Panella, Leonard

Submitted to: Genetics and Breeding of Sugar Beet
Publication Type: Book / Chapter
Publication Acceptance Date: December 15, 2003
Publication Date: May 1, 2005
Citation: Panella, L.W. 2005. Objectives of sugar beet breeding - Resistance to Parasites, Viruses, Curly top. pp. 74-76. In (eds. E. Biancardi, L. G. Campbell, G.N. Skaracis, & M. De Biaggi) Genetics and Breeding of Sugar Beet. Science Publishers, Inc. Enfield (NH), USA. 2005 (Book Chapter)

Interpretive Summary: Beet curly top virus (BCTV) is transmitted by the beet leafhopper, that attacks sugar beet throughout the semi-arid areas in the western United States, south-western Canada, Mexico, the Mediterranean basin, Turkey and Iran. The sugar beet industry in California was begun in the 1870s, and shortly thereafter BCTV symptoms were observed on beets grown there. In 1912 the first beets were grown in southern Idaho and in 1919 yields dropped almost 50% from the previous year due to BCTV. Although host plant resistance to BCTV was observed in the early 1900s, breeding programs were not initiated until 15 years later. Selection of roots showing resistance in heavily infested fields proved effective, and the first resistant open-pollinated variety, US 1, was released in 1933, and was in extensive use by 1934. At the USDA-ARS station in Salinas California, McFarlane made a major effort to produce germplasm resistant to BCTV and other important diseases, e.g., BCTV and yellowing virus resistant . This effort has continued under the direction of R. T. Lewellen. The work started by J. Gaskill in combining curly top resistance with leaf spot and Rhizoctonia root rot resistance was continued by R. Hecker and G. Smith along with E. G. Ruppel. This work is carried on in the breeding program of L. Panella and L. E. Hanson. Early studies by Abegg and Owen described a partially dominant genetic factor. Later studies by Murphy and co-workers indicated a more intermediate resistance under mild to moderate curly top pressure, however, in later generations this intermediate resistance broke down. Under severe curly top exposure, and when hybrids between more curly top susceptible parents were studied, the genetic nature of BCTV appeared more complex.

Technical Abstract: Beet curly top virus (BCTV) is a gemini virus transmitted by the beet leafhopper, Circulifer tenellus (Baker), that attacks sugar beet throughout the semi-arid areas in the western United States, south-western Canada, Mexico, the Mediterranean basin, Turkey and Iran. The sugar beet industry in California was begun in the 1870s, and shortly thereafter BCTV symptoms were observed on beets grown there. In 1912 the first beets were grown in southern Idaho and in 1919 yields dropped almost 50% from the previous year due to BCTV. Although host plant resistance to BCTV was observed in the early 1900s, breeding programs were not initiated until 15 years later. Mass selection of roots showing resistance in heavily infested fields proved effective, and the first resistant open-pollinated variety, US 1, was released in 1933 by E. Carsner and D. A. Pack, and was in extensive use by 1934. Although twenty years of mass selection had been successful in producing resistant open-pollinated populations, with the advent of hybrid varieties it was realized that inbreeding and progeny testing was necessary to continue to improve the varieties and convert open-pollinated varieties to monogerm, O-type parents. At the USDA-ARS station in Salinas California, McFarlane made a major effort to produce germplasm resistant to BCTV and other important diseases, e.g., BCTV and yellowing virus resistant . This effort has continued under the direction of R. T. Lewellen. The work started by J. Gaskill in combining curly top resistance with Cercospora and Rhizoctonia resistance was continued by R. Hecker and G. Smith along with E. G. Ruppel and, through inbreeding, resulted in the FC600 series of monogerm, O-Type, and CMS equivalent releases. This work is carried on in the breeding program of L. Panella and L. E. Hanson. Early studies by Abegg and Owen described a partially dominant genetic factor, C, linked to the gene for crown color, R, by 20 to 30%. Later studies by Murphy and co-workers indicated a more intermediate (additive) resistance in F1 hybrids under mild to moderate curly top pressure, however, in later generations this intermediate resistance broke down. Under severe curly top exposure, and when hybrids between more curly top susceptible parents were studied, the genetic nature of BCTV appeared more complex. Although it is believed resistance is polygenic, there are no definitive estimates of heritability or number of loci controlling resistance in the literature.

Last Modified: 10/1/2014
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