Multi-Year Trial Show Positive Effect of Chemical Regulators on Crocus sativus Growth and Development When Treated under Dormancy

Stigma produced in flowers of Crocus sativus plants are most valued part due to accumulation of metabolite compound Crocin and Safranal. To find out whether suitable growth regulators could be identified to overcome the inability of small-medium corms towards flowering and check the effect on the plant growth, three set of Crocus sativus corms were primed with eight reported chemical regulators, before break of dormancy. The results of three consecutive years trial under rain protected shade net conditions showed significant increment in flowering number under Gibberellin (GA3), Ca(NO3)2 and KNO3 treatments. The GA3 and Ca(NO3)2 priming showed positive effect on increased stigma length. The AgNO3 along with 2,3,5-triiodobenzoic acid (TIBA) also showed increment in few select parameters, albeit, with reduced effectiveness. The Indole-3-acetic acid (IAA) priming improved plant vigour and corm yield. Safranal and Crocin content was evaluated under UPLC. This is first report to assess the role of TIBA, IAA, and Ca(NO3)2 in flowering in Crocus sativus. Multiple year trial validates the priming effectiveness of these growth regulators. Overall, results suggest that GA3 and Ca(NO3)2 can be utilised for large scale exogenous application in Crocus sativus for increase in growth vigour and flowering yield.