Caraway (Carum carvi) is a medicinal and aromatic plant of the Apiaceae family with a long history of cultivation. To this day, improvements in yield and essential oil content are desirable. In the past, line breeding was used to increase essential oil content with the final intention of combining inbred lines to a synthetic variety by outcrossing. Outcrossing should overcome inbreeding depression and exploit heterosis vice versa. In this study, we wanted to detect whether and to what extent heterosis can be exploited in caraway. In a randomized complete block design with two years of growing and four repetitions per year and genotype, we compared 18 inbred lines with 18 corresponding F₁ populations produced in a polycross. In addition to yield, we estimated the beginning of flowering, the end of flowering, maturity, height, thousand-grain weight, stalk attachment rate, shattering rate and essential oil content. Linear mixed models were used to compute variance components, heritability and best linear unbiased estimates. As major result, we detected the existence of better parent heterosis in caraway. To summarize, outcrossing led to a significant increase in yield, thousand-grain weight and height and to an earlier beginning of flowering, end of flowering and maturity. In two-year data, no effect of outcrossing on the essential oil content was observed, but single year data revealed slight effects. We found strong negative correlations between developmental traits and yield. Hence, selection of early developing genotypes seems highly recommendable. Results make us confident that improved annual varieties can be introduced soon.

香菜（Carum carvi）是伞形科的药用芳香植物，栽培历史悠久。时至今日，产量和精油含量的改进仍是可取的。过去，系育种用于增加精油含量，最终目的是通过异交将近交系与合成品种相结合。异交应克服近交衰退，反之亦然利用杂种优势。在这项研究中，我们想检测是否可以在葛缕子中利用杂种优势以及在多大程度上利用杂种优势。在具有两年生长和每年四次重复和基因型的随机完整区组设计中，我们将 18 个自交系与 18 个相应的 F ₁在多交中产生的种群。除了产量，我们还估算了开花的开始、开花的结束、成熟度、高度、千粒重、茎附着率、落叶率和精油含量。线性混合模型用于计算方差分量、遗传力和最佳线性无偏估计。作为主要结果，我们检测到葛缕子中存在更好的亲本杂种优势。总而言之，异交导致产量、千粒重和高度的显着增加，以及更早的开花开始、开花结束和成熟。在两年的数据中，没有观察到异交对精油含量的影响，但一年的数据显示出轻微的影响。我们发现发育性状和产量之间存在很强的负相关。因此，选择早期发育的基因型似乎非常值得推荐。结果使我们相信，可以很快引入改良的一年生品种。