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

Perennial crops show promise for sustainable agricultural production while providing ecosystem services (maintaining healthy soil, controlling erosion, improving water quality, and enhancing wildlife habitat). Perennial crops could also provide economically viable cropping option to farmers. Sunflower (Helianthus annuus L.) is an ideal crop for perennialization because of existing genetic resources and a wide variety of end-uses. The objective of this research was to evaluate interspecific hybrids between perennial Helianthus tuberosus L. (2n = 6x = 102) and annual H. annuus L. (2n = 2x = 34) for perenniality and agronomic traits; assessing their utility in developing a perennial seed crop. Field trials indicated that seed yield traits were positively correlated with head traits. Tuber traits, which are required for perenniality, and seed yield traits were not correlated, indicating that simultaneous selection may be able to target high yielding lines that also tuberize. The F1 individuals were intermated for one generation and the intermated F1 (IM1F1) showed increases in head size (up to 20%) compared to the best F1 individual. The lack of correlation between tuber and seed traits coupled with phenotypic improvement after one generation of intermating suggest that the best improvement strategy for perennial sunflower is a recurrent selection program focusing on yield.