Morpho-physiological and phenological changes induced by smooth amaranth allelopathic effects in various types of dry bean

ABSTRACT: A pot experiment was carried out in order to evaluate the allelopathic effects caused by smooth amaranth dry shoot extracts (0% as control, 5, 10, 15, and 20% w/v) on some morpho-physiological characteristics and phenology of three different types of dry beans. The experiment was conducted at the Faculty of Agriculture, University of Tabriz, Tabriz, in 2012. The results revealed that total chlorophyll content (SPAD), number of developed leaves, stem length, and total plant dry matter were negatively affected by allelopathic effect caused by smooth amaranth aqueous extracts. Plants received greater concentrations of extract (15 and 20% w/v) matured later due to delayed flowering, but differential reactions were observed depending on the dry bean type. Though the red bean had the lowest total dry matter, exhibited the fluctuations at extract levels over the other dry beans. Considerable losses of grain yield were recorded at 15and 20% extract concentrations. Among the dry beans, the pinto bean (cv. Sadry) performed satisfactorily, so it can be introduced as a high-tolerant crop for cultivating in fields where high smooth amaranth population limits bean productivity.