The Effect of 1-MCP on grain size and yield-related traits of Eragrostis tef

Teff is an Ethiopean cereal that has the potential for increased global production. However, as a very small-seeded grain, it experiences high levels of post-harvest loss. As ethylene is reported to have a negative effect on grain size, this study sought to test whether 1-methylcyclopropene (1-MCP), an ethylene action inhibitor, is a suitable molecule to improve grain size of teff as well as to determine the optimum application time and concentration. The 1-MCP treatment was evaluated on well-watered plants as well as plants subjected to moderate water stress, with the stress treatment imposed one week before the expected flowering date. Application of 1 PPM 1-MCP to individual panicles improved grain size and thousand-grain weight (TGW) by 22% and 29% under moderate water stress and 10% and 16% under well-watered conditions, respectively. It also increased yield per panicle. However, when applied to whole plants it was not effective, due to the extended flowering time of teff and differing responses of panicles at different developmental stages. These observations suggest that genetic modification leading to lower production of endogenous ethylene could benefit grain size in teff. However, 1-MCP treatment is unlikely to be effective in the field.