dinitroaniline

The research by AHRI PhD student Jinyi Chen (now Dr Jinyi Chen!) documents both target site and non-target site resistance to dinitroaniline herbicides in Lolium individuals. We are long accustomed to documenting multiple mechanisms of resistance existing within Lolium individuals/populations because of the high genetic diversity and obligate cross-pollination between Lolium which enables multiple resistance mechanisms to be a frequent occurrence.  In this particular Lolium population, resistance to dinitroaniline herbicides is due to a mutation in the alpha tubulin gene (Val-202-Phe) and non-target site enhanced rates of dinitroaniline herbicide trifluralin metabolism.   Unequivocal evidence for the target site Val-202-Phe mutation endowing resistance was obtained by expressing in transgenic rice, where it endowed resistance.

The increasing number of weedy species resistant to dinitroaniline herbicides warrants studies on the evolutionary factors contributing to resistance evolution, including genetic inheritance of resistance traits.

In this study, the researchers investigated the genetic control of trifluralin resistance in a well-characterised Lolium rigidum Gaud. (annual ryegrass) population from Western Australia. This population was purified to contain plants homozygous for the Val-202-Phe α-tubulin mutation, and used as the resistant (R) parents and crossed with susceptible (S) parents to produce eight reciprocal F1 families.