Effects of agroclimatic conditions on sunflower seed dormancy at harvest

At harvest sunflower seeds (Helianthus annuus L.) are dormant and poorly germinate at 10 25 °C. Seed sensitivity to low temperatures (10 °C) results from an embryo dormancy whereas the envelopes (pericarp seed coats) inhibit germination Removal of pericarp greatly improved when whole achenes was higher than critical value 20 %. Using 107 batches corresponding 26 genotypes cultivated in 2015, 2016 2017 various production areas France (Center South) Spain (South), we investigated effects agro-environmental factors on depth harvest. A principal Component Analysis (PCA) performed with all did not show any significant effect genotype (variety or female) year intensity dormancy, but it revealed role agro-climatic conditions. Experimental field trials plants treated by a chemical desiccant after flowering demonstrated that accelerated desiccation during maturation mother plant associated lower dormancy. Our data also suggest longest duration developmental cycle sowing harvest, lowest We provide new insights into modulation genetic environmental which might have practical applications production.