Perennial crops have been suggested as a way to increase sustainable agricultural production, while providing multiple ecosystem services (Glover et al., 2010). Tetraploid interspecific hybrids (2n = 4x =68) between the perennial Helianthus tuberosus L. (2n = 6x = 102) and annual H. annuus L. (2n = 2x = 34) are currently being examined for use as a perennial crop (Hulke and Wyse, 2008; Cox et al., 2010). Experimental populations have had extensive phenotype data available for domestication and perennial traits (Kantar et al., 2014). We project that 40,470 ha (100,000 ac) of perennial sunflower would be planted in the U.S. if this crop were currently available. The primary goal of the perennial sunflower breeding program at the University of Minnesota is to develop varieties for production of oil while producing ecosystem services at the landscape level. However, progress within the program has been hindered by the polyploid nature of the current material. The use of diploid material, which has been recently initiated should allow for more rapid progress to be made with respect to cultivar release.
The basic breeding strategy has been to develop open pollinated populations with improved plant architecture, seed yield, and flowering characteristics, created from the best individual crosses. We slightly modified this strategy in 2014, by selecting our elite populations based on different characteristics of our ideotype, with the goal of recombining the elite populations together, thereby recovering a population more closely resembling our ideotype. In 2014, we planted seed-increase plots consisting of segregating IM1F1, IM2F1, and IM3F1 as well as evaluating these materials for further breeding. We continued to see improvements based on our selection scheme (Figure 1). Two breeding populations, MN370 and MN409, showed great promise compared to the other breeding populations. The improved selections showed increased head size and seed yield.
Additionally new breeding populations based on diploid genetics have been initiated. Multiple plants from H. divaracatus accessions sourced from all over the country were crossed to both the H. annuus lines HA89 (historically used in genetic studies) and HA412-HO (the reference genome for H. annuus sequencing). This material is currently being evaluated in St. Paul Minnesota. In addition, direct domestication populations are being created as well as interspecific populations.
We made progress developing genomic resources for the perennial sunflower breeding program. We utilized genotype-by-sequencing (GBS) to generate single nucleotide polymorphisms (SNPs) within the tetraploid interspecific hybrid population. We compared the GBS data to the H. annuus reference genome to generate markers that were specific to H. annuus and to H. tuberosus within the interspecific hybrid breeding population. These markers were used for marker trait association with tuber production.
Further work was conducted to create genomic resources for the diploid population. A reference transcriptome was created for H. divaracatus. Multiple populations and wide ranging sequencing will allow the breeding program to short-cut the historically long and expensive process of marker development. These markers will be used to develop the first comprehensive H. divaracatus linkage map and a linkage map of the interspecific H. annuus x H. divaracatus hybrids. Furthermore, the markers will be applied towards genetic mapping of important traits (tuber production, rhizome production and winter hardiness) with positive associations will be used for MAS in the breeding program. The markers will also be useful for examining other wild perennial Helianthus species that could be used as novel trait donors.
Kevin Betts, Senior Scientist, Department of Agronomy and Plant Genetics
Yaniv Brandvain, Assistant Professor, Department of Plant Biology
Adam Herman, Post Doctoral Associate, Department of Plant Biology
Brent Hulke, Research Geneticist, USDA-ARS, Fargo, ND
Michael Kantar, Assistant Professor, University of Hawaii
George Linz, USDA-APHIS Wildlife Services, Bismarck, ND
Loren Rieseberg, Professor, Department of Botany, University of British Columbia
Robert Stupar, Associate Professor, Department of Agronomy and Plant Genetics
Don Wyse, Professor, Department of Agronomy and Plant Genetics
Minnesota Varietal Development Fund
Minnesota Agricultural Experiment Station
Forever Green Initiative
National Sunflower Association
SCIE 300 SO Podcast - Michael Kantar & Sunflower Perenniality in Agriculture
Perennial Sunflower Breeding at the University of Minnesota
University of British Columbia
USDA-ARS, Northern Crop Science Laboratory