Effects of the foliar application of methanol on the yield and growth of rice (Oryza sativa cv. Shiroudi)

Approximately two decades have passed since it was reported that the foliar application of methanol increased plant biomass and yield. Many subsequent reports have been published concerning the ability or inability to reproduce these initial observations. To evaluate the effect of methanol on rice (Oryza sativa cv. Shiroudi) yield and rice components, a field experiment was conducted at the Tonekabon Rice Research Station in Iran in 2012 and 2013. The experiment had a randomized complete block design (RCBD) with three replicates. The plants were treated with aqueous methanol solutions (0, 6, 12, 18, and 24% (v/v)). Methanol was sprayed on the rice foliage three times during the experimental period at two-week intervals. The results indicated that, in general, the methanol did not affect rice growth or yield and seemed to be ineffective as a growth enhancer, so foliar spraying of aqueous methanol cannot be recommended for rice. The negative results could be due to the absence of Methylobacterium sp. or that the effects are cultivar-specific because positive effects on the growth and yield of rice have been reported in other cultivars.