Response of conventional and imidazolinone-resistant chickpea (Cicer arietinum L.) cultivars to imazamox and/or imazethapyr applied post-emergence

Abstract

Chickpea (Cicer arietinum L.) production in the Northern Great Plains is limited by very few broadleaf weed control options. Field experiments were conducted at two locations in 2012 and at three locations in 2013 in Saskatchewan, Canada, to examine the performance of the conventional and the imidazolinone (IMI) resistant chickpea cultivars to post-emergence application of imazamox or imazethapyr applied alone or in tank-mix. Treatments included imazamox (20 and 40 g a.i. ha−1), imazethapyr (50 and 100 g a.i. ha−1), and a tank-mixture of imazamox (35%) + imazethapyr (35%) (30 and 60 g a.i. ha−1). Conventional cultivars, CDC Luna and CDC Corinne, showed moderate to severe injury compared with resistant cultivars, CDC Alma and CDC Cory, which showed minimal to no injury. Plant height was arrested and node development slowed for conventional cultivars treated with IMI herbicides. This susceptibility to IMI herbicides was also noted with a delay in flowering and maturity. Despite a significant negative response, CDC Luna and CDC Corinne were able to recover throughout the growing season resulting in no yield loss from IMI treatments at all locations, except one. Resistant cultivars, CDC Alma and CDC Cory, demonstrated no significant injury from IMI herbicide compared with the untreated controls. These results show the potential to use IMI herbicides in the resistant chickpea cultivars, expanding the currently limited options for broadleaf weed control in chickpea cultivation.