Response of different cultivars of fennel (Foeniculum vulgare) to irrigation and planting dates in Isfahan, Iran

Decreasing water supply adversely affects morphological and physiological processes in plants. The adverse effects of drought and water stress on crop yield may be more pronounced at some particular growth stage depending upon the nature of crop species and even genotypes within the species. A split-split plot design within randomized complete block design with three replications was used to study the responses of different fennel cultivars to disruption of irrigation and planting dates in 2004 at Research Farm, Isfahan, Iran. Main plots were irrigation disruption in different stages (I-1-Irrigation until the beginning of stem elongation, I-2-Irrigation until the end of stem elongation, I-3-Irrigation until umbel formation, I-4-Irrigation until seed filling and I-5-Full irrigation), the sub-plots were 30 March and 25 April, and sub-sub-plots were five different cultivars, namely, Isfahan, Yazd, Shiraz, CN.uk and B.uk. Irrigation had significant effect on number of incomplete umbels, number of lateral branches, seed number and 1000-seed weight, and planting date had significant effect on number of seeds. The effect of cultivar was significant on number of incomplete umbels and seed number. The maximum number of umbels, umbelets, lateral branches, seed number, seed yield and 1000-seed weight were obtained by full irrigation (I-5). Plantation of CN.uk cultivar on 30 March obtained the highest number of umbels, number of umbelets per umbel, number of seeds and seed yield. Also, the maximum 1000-seed weight was related to 30 March. It seems that cultivation of CN.uk on 30 March with full irrigation was suitable in this region.