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

在收获向日葵种子（向日葵）L.）在10和25°C时处于休眠状态且发芽差。种子对低温（10°C）的敏感性是由胚胎休眠引起的，而被膜（果皮和种皮）则在25°C时抑制了发芽。当整个瘦果的发芽率高于临界值20％时，去除果皮可大大改善种子发芽率。我们使用了107个种子批次，分别对应于2015年，2016年和2017年在法国（中部和南部）和西班牙（南部）的不同产区种植的26种基因型，我们研究了农业环境因素对收获时休眠深度的影响。对所有种子批次进行的主成分分析（PCA）均未显示基因型（品种或雌性）和生产年份对休眠强度的任何显着影响，但揭示了农业气候条件的作用。对开花后用化学干燥剂处理过的植物进行的实验田间试验表明，在母本植物种子成熟过程中加速干燥会降低休眠度。我们的数据还表明，从播种到收获的整个发育周期的持续时间最长，收获时的休眠期最低。我们提供了由遗传和环境因素调节休眠强度的新见解，这些因素可能在种子生产中有实际应用。收获时最低的休眠状态 我们提供了由遗传和环境因素调节休眠强度的新见解，这些因素可能在种子生产中有实际应用。收获时最低的休眠状态 我们提供了由遗传和环境因素调节休眠强度的新见解，这些因素可能在种子生产中有实际应用。