Scientists from DuPont Pioneer used gene-silencing approach to modulate the levels of ethylene biosynthesis in corn and study its effect on grain yield under drought conditions in the field. The results of the study were released in Plant Biotechnology Journal.

Commercially relevant transgenic events were created with down-regulated ACC synthases (ACSs), enzymes that catalyse the rate-limiting step in ethylene biosynthesis. These events exhibit decreased release of ethylene to approximately half compared with non-transgenic nulls. Field tests of the transgenic hybrids and controls were conducted in drought-stress and rain-fed areas in the U.S.

Results of yield data showed that transgenic events had significantly increased grain yield compared with the controls, with the best event having a 0.58 Mg/ha (9.3 bushel/acre) increase after a flowering period drought stress. Furthermore, secondary traits analysis showed that there was a consistent decrease in the anthesis-silking interval and a concomitant increase in kernel number/ear in transgene-positive events versus controls. Selected events were also field tested under a low-nitrogen treatment, and the best event was found to have a significant 0.44 Mg/ha (7.1 bushel/acre) yield increase.

Based on the results, it was concluded that down-regulating the ethylene biosynthetic pathway can improve the grain yield of maize under abiotic stress conditions.

Read the abstract at http://www.ncbi.nlm.nih.gov/pubmed/24618117.