Ploidy determination and agronomic characterization of small burnet germplasm
Small burnet (Sanguisorba minor Scop.) is an evergreen forb readily utilized by livestock and wildlife that lacks persistence under heavy grazing. Our objective was to characterize all available National Plant Germplasm System (NPGS) small burnet germplasm for ploidy level and agronomic characteristics before initiating a breeding program. Ploidy level was determined by flow cytometry. Forage yield, flowering date, mortality, growth habit, and leafiness were determined at two locations in Utah. Of the materials tested 68% were tetraploids (2n = 4x = 28) and 32% octaploids (2n = 8x = 56). Significant variation was observed for all traits. Mean forage yield of the small burnet was 1.45 Mg ha–1, ranging from not measurable to 2.96 Mg ha–1 compared to Ladak alfalfa (Medicago sativa L.) at 2.28 mg ha–1. Flowering date varied among accessions by 12 d while mortality ranged from 0 to 100%. Variation was displayed in growth habit, including prostrate and upright forms, and leafiness. The range among accessions was similar within the two ploidy levels for all traits except flowering date which was 2 d earlier in the octaploids. It was shown that tetraploids and octaploids are present in roughly a 2:1 ratio in the NPGS small burnet germplasm. The forage production of some small burnet accessions can be comparable to alfalfa, and phenotypic variation is such that the germplasm has potential for improvement through recurrent selection.