Basic Information - Genetics, Genomics and Breeding of Crop Plants - page 31

Germany, Bulgaria, Romania, Czech Republic, Hungary, Russia, Serbia,
India, China, and Mexico. Notable is the collection at the Institute of Field
and Vegetable Crops, Novi Sad, Serbia, which contains 39 of the 51 wild
species (IBPGR 1984; Cuk and Seiler 1985; Atlagic ' et al. 2006). The wild
species collection of the Dobroudja Agricultural Institute (DAI) at General
Toshevo, Bulgaria, is also notable, containing 428 accessions representing
37 of the 51 species of Helianthus (Christov et al. 2001). The wild species
collection maintained at INRA, Montpellier, France, has more than 600
accessions of 45 of the 51 wild sunflower species (Serieys 1992). The
Institudo de Agricultura Sostenible (CSIC), Cordoba, Spain, maintains 44
annual and perennial accessions of Helianthus (Ruso et al. 1996). The genetic
diversity of the wild species can make a significant contribution to sunflower
in many countries by providing genes for resistance (tolerance) to pests and
environmental stresses, allowing the crop to become and remain
economically viable.
Diversity in germplasm also is critical to crop breeding programs, but to
date it has not been fully exploited (Harlan 1976). Several species have
contributed specific characteristics for sunflower improvement. The wild
species are adapted to a wide range of habitats and possess considerable
variability for most agronomic, and achene quality characters, and reaction
to insects and disease pathogens (Thompson et al. 1981; Jan and Seiler
2007). More detailed discussions about the use and potential value of wild
species for sunflower breeding programs can be found in Seiler (1988, 1992,
1996, 2002), Seiler and Rieseberg (1997), Skoric (1988, 1992), and Jan and
Seiler (2007).
The wild species have provided many agronomically important traits
for the cultivated sunflower. The estimated economic contribution of the
wild species to the cultivated sunflower is US$384 million per year (Prescott-
Allen and Prescott-Allen 1986). Another estimate is US$269.5 million per
year (Phillips and Meilleur 1998). The greatest value is derived from the
PET 1 (French) CMS cytoplasm from H. petiolaris . Wild Helianthus species
have been a good source of genes for resistance to pathogens of economically
important diseases. Much of the value is derived from disease resistance
genes for rust, downy mildew, Verticillium wilt, Alternaria leaf spot, powdery
mildew, Phomopsis stem canker, Sclerotinia wilt/rot, broomrape and more
recently, salt tolerance genes that have been identified and transferred into
cultivated sunflower. One trait not accounted for in the estimates mentioned
above is herbicide tolerance. A wild population of H. annuus from Kansas
has been identified as a source for resistance to imidazolinone and
sulfonylurea herbicides, and these traits have been transferred into cultivated
sunflower (Al-Khatib et al. 1998; Al-Khatib and Miller 2000). In addition,
these two herbicides control broomrape in areas of the world where this
parasitic weed attacks sunflower (Alonso et al. 1998). Thus, herbicide