Effect of nano and macro iron sprays on growth, flowering, seed and oil yielding attributes in calendula (Calendula officinalis L.)

The investigation was executed with nine treatments viz. nano forms of ferrous sulfide (7, 14, 21, 28 ppm) and macro ferrous sulphate (0.2, 0.4, 0.6, 0.8 per cent) along with control, and were applied as foliar sprays after 30 days of transplanting on two varieties of calendula namely Fiesta Gitana Mix’ and ‘Fiesta Yellow’ during 2018 and 2019. The experiment was laid out in factorial randomized block design with three replications. Application of 0.8 % FeSO4 recorded maximum number of branches (26.75), plant height (29.73 cm), plant spread (45.17 cm), number of leaves (22.63) and seed test weight (15.63 g) and number of flowers per plant (134.04). However, application of 0.2% macro FeSO4 resulted in early bud appearance (50.50 days) and higher flower diameter (8.09 cm). ‘Fiesta Gitana Mix’ outperformed over ‘Fiesta Yellow’ for most of the vegetative and floral characters. The ‘Fiesta Yellow’ variety with oil content (13.97%) had an edge over ‘Fiesta Gitana Mix’.