Growing season climate affects phenological development, seed yield and seed quality of dill (Anethum graveolens)

Dill seed production was investigated over two seasons, comprising a spring growing cycle (SGC) and an autumn growing cycle (AGC). The effects of growing cycle on phenological traits, yield and quality of dill seeds formed on different umbels of the mother plant were investigated. Significant differences were noted in the flowering period, seed yield and quality parameters. The SGC resulted in a shorter time from sowing to bolting and flowering initiation compared with the AGC. Plant height, number of umbels/plant, number of umbelets/ umbel, umbel diameter, umbel length and seed weight/plant increased in the AGC. In contrast, decreased germination at 20/30??C and at 13??C, and increased mean germination time at 20/30??C in AGC indicated lower seed quality compared with SGC. Primary umbels produced the best yield and higher quality seeds, followed by the secondary umbels while tertiary umbels gave poor yield and quality seeds in both SGC and AGC. In conclusion, AGC was advisable for higher seed yield, but SGC resulted in higher seed quality compared with the AGC. This highlights the need to select a suitable growing cycle to guarantee high seed yield and quality for each seed production environment.