Evaluating an interspecific Helianthus annuus × Helianthus tuberosus population for use in a perennial sunflower breeding program

•We examine an interspecific Helianthus annuus×Helianthus tuberosus population.•We can easily identify true interspecific hybrids.•Intermated F1 (IM1F1) have increased flower size (up to 20%) compared to the F1.•Perennial habit segregates in a simple fashion even if the genetics are complex.•The best improvement strategy is a recurrent selection program focusing on yield.