German chamomile (Matricaria chamomilla L.), is one of the common medicinal plants cultivated most significantly for its pharmacological applications. Environmental stresses, especially cold stress, affect the total amount of active ingredient in plants. The effects of various temperatures, including 25, 10, 5, and 0 °C at flowering stage, were investigated on important traits of 5 German chamomile genotypes ('Bodegold', 'Isfahan', 'Ahwaz', 'Zabol', and 'Shiraz'). A number of important morpho-physiological traits were measured and essential oil was extracted (using hydro-distillation method) from flowers. According to the results of variance analysis, genotypes had significant differences for the measured traits except for the number of shoots per plant, the number of flowers, and flower diameter. Temperature affected all the traits significantly, except for root length, root dry weight, and relative water content. Interaction of genotype and temperature was significant for the number of flowers, percentage of electrolyte leakage, and percentage of essential oil. The results indicated that, essential oil percentage increased from 25 °C to 10 °C and then decreased with increasing cold stress in all the studied genotypes. 'Shiraz' genotype indicated the highest values regarding root length (31.66 cm) and root dry weight (0.32 mg). The highest value of plant height (53.44 cm) was observed in 'Zabol' genotype. 'Bodegold' (1.51%) and 'Isfahan' (1.44%) genotypes had the highest essential oil percentage in the cold-stress condition (5 °C). But this trend was not observed for the number of flowers per plant. Classification of genotypes showed that in conditions with high possibility of chilling stress occurrence at flowering stage, 'Bodegold' genotype is the most efficient followed by 'Isfahan' genotype. On the other hand, 'Bodegold' genotype can be crossed with 'Ahwaz' and 'Zabol' genotypes in order to improve the cold tolerance of new genotypes. These findings can help the researchers to investigate gene expression and identifying genes involved in cold tolerance of chamomile plants.

德国洋甘菊（洋甘菊chamomillaL.），是因其药理学应用而得到最重大栽培的常见药用植物之一。环境胁迫，特别是冷胁迫，影响植物中活性成分的总量。对5种德国洋甘菊基因型的重要性状（“ Bodegold”，“ Isfahan”，“ Ahwaz”，“ Zabol”和“设拉子”）。测量了许多重要的形态生理特性，并从花中提取了香精油（使用水蒸馏法）。根据方差分析的结果，基因型在所测量的性状上具有显着差异，除了每株植物的芽数，花朵数和花朵直径。温度显着影响所有性状，除根长，根干重和相对含水量外。基因型和温度的相互作用对于花朵数量，电解质泄漏百分比和精油百分比而言非常重要。结果表明，在所有研究的基因型中，精油百分比从25°C升高到10°C，然后随着冷胁迫的增加而降低。“设拉子”基因型显示出有关根长（31.66 cm）和根干重（0.32 mg）的最高值。在“ Zabol”基因型中观察到最高的株高值（53.44 cm）。'Bodegold'（1.51％）和'Isfahan'（1.44％）基因型在冷应激条件下（5°C）具有最高的精油百分比。但是，对于每株植物的花数没有观察到这种趋势。基因型的分类显示，在开花期出现极冷胁迫的条件下，“ Bodegold”基因型是最有效的，其次是“ Isfahan”基因型。另一方面，“ Bodegold”基因型可以与“ Ahwaz”和“ Zabol”基因型杂交，以提高新基因型的耐寒性。这些发现可以帮助研究人员研究基因表达并鉴定与甘菊植物耐寒性有关的基因。