Germplasm resources for increasing the genetic diversity of global cultivated sunflower

Abstract

Genebanks are a rich source of genetic diversity that can be readily exploited for crop improvement. The USDA-ARS established a cultivated sunflower germplasm collection at the National Plant Germplasm System, North Central Regional Plant Introduction Station at Ames, Iowa in1948. A wild Helianthus germplasm collection was established at the USDA-ARS Bushland, Texas station in 1976. Presently, both collections are maintained and managed at Ames, Iowa. The genus Helianthus consists of 52 species and 19 subspecies, with 14 annual and 38 perennial species. Over 30 explorations in the past 35 years have resulted in the assemblage of a wild sunflower collection that is the most complete in the world. Currently, the sunflower collections contain 4087 accessions: 1886 cultivated H. annuus accessions and 2201 wild accessions of which 1359 accessions are annual and 842 are perennial species. This germplasm is an important current and future genetic resource to combat emerging pests and environmental challenges, helping to maintain sunflower as a viable major global oilseed crop and preserve it for future generations.

Ancient DNA reveals the timing and persistence of organellar genetic bottlenecks over 3,000 years of sunflower domestication and improvement

“…The history of directed breeding of domesticated sunflower lines with crop wild relatives strongly suggests Class 3 was introduced from H. petolaris during the establishment of the hybrid crop agricultural system (Seiler, Qi, & Marek, ). Class 4 was likely also introduced during crop improvement, potentially from H. argophyllus , the sunflower species which has been most frequently crossed with domesticated lines to impart disease and parasite resistance (Seiler & Fredrick Marek, ). Indeed, it is perhaps surprising that additional non‐ H. annuus haplotypes were not more commonly observed, as breeders have introduced allelic variation for novel traits (e.g., resistance against a range of pathogens) by prolific and repeated introgression of genetic material from other Helianthus species.…”

Utilization of Sunflower Crop Wild Relatives for Cultivated Sunflower Improvement

“…Host‐plant resistance is one of the most durable types of resistance to the ever‐evolving pathogens and is an environmentally friendly means of disease control. A recent survey of the literature for references to resistance of sunflower CWR to pathogens and parasites included 44 references for annual species and 119 for perennial species (Seiler and Marek, 2011). Twelve of the fourteen annual species were cited, with the most frequently cited species being H. argophyllus (32), followed by H. petiolaris (15), wild H. annuus (15), Helianthus debilis Nutt.…”

A Crop Wild Relative Inventory for Mexico

“…Projected production value Accumulated production area Projected production area (Metwally et al, 1996), powdery mildew resistance (Formisano et al, 2010) (Hajjar and Hodgkin, 2007;Christov, 2008;Seiler and Malek, 2011), rust resistance (Hajjar and Hodgkin, 2007;Seiler and Malek, 2011), cytoplasmic male sterility (Hajjar and Hodgkin, 2007;Christov, 2008), fertility restoration genes (Horn, 2002;Christov, 2008), seed oil content (Christov, 2008;Vear, 2011) Helianthus californicus DC.…”