Reproductive success and germination in different genotypes of perennial fennel ( <i>Foeniculum vulgare</i> Mill.) with different culture age

Abstract Various genetic and environmental factors influence plant reproductive success, manifesting at different growth stages, fertilisation and germination. Fennel ( Foeniculum vulgare Mill.) is a perennial plant with significant medicinal and nutritional value; however, limited information regarding its reproductive success has been reported in various studies. This research investigated the reproductive processes of fennel in 12 genotypes and three planting ages (1‐, 2‐ and 3‐year‐old) over two agronomic years (2020 and 2021) in Pakdasht, Iran. Traits related to reproduction were evaluated, including the seed‐to‐ovule ratio ( S / O ), fruit‐to‐flower ratio ( F / F ), seed yield and germination at different temperatures. The results indicated that the highest number of surviving plants was observed in 1‐year‐old genotypes, while the highest seed yield was recorded in 2‐year‐old plants (in 2020) and 3‐year‐old plants (in 2021). The S / O and F / F ratios varied between 0.23 and 0.77 and 0.23 and 0.88, respectively. The highest germination percentage was recorded in 1‐year‐old plants at 10°C. Genotypes with a higher number of inflorescences and an S / O ratio close to 1 are suitable options for improving yield. Considering the slow growth of fennel in the first year and the impact of temperature on germination, appropriate planting timing and utilising winter colds are effective in optimising germination and seedling establishment. This research provides insights into the reproductive processes of fennel and offers strategies for improving yield by selecting suitable genotypes and adopting optimal cultivation practices.