Seedlings planting terms and row spacings influence on fennel seed yield formation
Authors: Knyazyuk O. , Melnyk I. , Horbatyuk V. , Lytvin Kh. 
Published: September 2019

Fennel is a perennial plant though the crop is used as biennial. Growing fennel seedlings and planting it in open ground at the phase of 4–5 leaves reduces the growing season and increases crop productivity of the plant. The beginning of growth phases and development of fennel plants depends on the seedlings planting time. The accelerated process of the crop budding phase is noted at its early planting on April 20. The large-scale flowering of fennel was noted only 19 days after planting and fruit formation – after 27 days for seedlings planting on May 10.
It was found that linear growth of seedlings at the early stage of planting (April 20) was the largest at row spacing of 15 cm and was 38,6 cm at the flowering period of fennel, that is 12,2 cm larger than in the 45 cm row spacing.
The linear growth of crops in the main phases of fennel vegetation was lower for planting seedlings on May 10 compared to April 20.
A faster acceleration of the growth and development phases as well as linear growth of fennel was noted for early planting of seedlings – on April 20.
After planting fennels seedlings in the open ground, it was found that plants grow slowly (2–3 cm per decade) until the budding stage, and from the budding to fruit formation stage the growth rate of plants increased by 11.0–17.8 cm.
Phenological observation of fennel plants leaf apparatus formation was carried out immediately after the shoots appearance. It was established that the first pair of true leaves formed in 10 days after sowing of seeds in the greenhouse, and the fifth pair of leaves – in 50–55 days.
The leaves weight grew most during the budding stage – the fruit production of fennel plants depended on the seedlings planting time. The maximum value was noted for planting on May 10 and for 45 cm row spacing and made 10.86 g.
The main indicator of fennel performance is its fruits and seeds weight. Plant mass and its individual parts grew and the ratio of green mass parts changed during the growth and development of the crop.
Thus, the leaves weight on the experimental sites was 2.1–3.1 g or 37.5–38.3 % at the budding phase. Leaves weight was 4.7–7.8 cm2/m2 or 38.0–51.7 % during the fennel fruit formation.
At the budding phase the leaves weight increased by 8.1 % for planting the seedlings with an intermediate row of 15 cm (compared to 45 cm row spacing) respectively, and the leaves weight was 13,7 % higher by the fruit formation time. The plants density in the area (intermediate row 15 cm) contributed to increase in individual fennel productivity (green mass of plants). The maximum yield of fennel seeds in the experimental sites was noted for the row spacing of 45 cm – 5.9 kg/10 m2.
Thus, the most favorable conditions for fennel growth and development are under seedling planting on April 20, as the maximum yield is noted here. The denser placement of plants in the area (15 cm spacing) contributes to individual productivity increase (green plant weight, including leaves and stalks). Increasing the row width (up to 45 cm) contributed to the maximum yield of fennel seeds up to 5,9 kg/10 m2.
Key words: fennel, seedlings planting terms, row width, productivity, leaf apparatus.