Calcium carbide-induced changes in germination, morpho-phenological and yield traits in cucumber (cucumis sativus)

Abstract

Calcium carbide (CaC2) is a well-known source of acetylene and ethylene gases. Its use as a plant growth regulator could be an innovative approach for vegetable production if applied in suitable formulation. Different rates of CaC2 (10, 20, 30 and 40 mg plate-1) were evaluated regarding seed germination and morphological characteristics under controlled conditions. The results showed that germination rate was significantly improved by using low rates of CaC2 (10 to 30 mg CaC2 plate-1) while the highest rate of CaC2 (40 mg plate-1) suppressed germination rate of cucumber seeds. Likewise, lower rates of CaC2 were also found effective in enhancing the root and hypocotyl lengths, number of lateral roots and fresh weight of seedling while the highest rate of CaC2 was proved inhibitory. It was recorded that the CaC2 induced improvement in seed germination was significantly correlated (r = 0.75) with magnitude of ethylene production during imbibition. Moreover, a pot experiment was conducted under natural conditions to select optimum rate and coating material of CaC2 regarding growth and yield parameters of cucumber. It was found that all rates of CaC2, irrespective of coating materials, exhibited new primary branches, early female flowering and fruit maturity. Maximum response regarding female flower count, fruit yield and ethylene emission was obtained by the application of paint coated CaC2 at 300 mg pot-1, which resulted in 34% more fruit yield compared to control plants.