New herbicide tolerances in pulses

Take home messages

• Group B herbicide tolerant varieties are currently registered for lentils and faba beans.
• Group B tolerances for chickpea and field pea are between 2-5 years away.
• Registration for Group C and Group I tolerance in all pulses are in the pipeline.
• Timelines reflect the fact that chemical registrations add time to varietal release.

Background

Pulses have limited in-crop herbicide options. However, with the development of breeding techniques involving mutagenesis, pulse germplasm has been developed with herbicide tolerances.

Lentils have been the first pulse to have registration for the group B chemistry combination of imazamox and imazapyr. Varieties with this tolerance include PBA HeraldXT, PBA HurricaneXT, PBA HallmarkXT and PBA HighlandXT. PBA Bendoc is the first faba bean that has similar tolerance to the same group B chemistry combination. This tolerance has also been developed in field peas and chickpeas with maximum residue limit (MRL) testing likely to commence in a few years. Tolerances to group C and group I chemistries have been passed on to all pulse breeding programs, however breeding line development and the chemical registration processes indicate potential new varieties are unlikely to be available in the marketplace for several years. The registration process is a critical component to variety release to ensure appropriate use of chemistries.

Key Question 1: What pulse varieties are available with group B herbicide tolerance?

Lentils:

• PBA HeraldXT
• PBA HurricaneXT
• PBA HallmarkXT
• PBA HighlandXT

Faba Bean:

• PBA Bendoc

PBA Hurricane XT was released in 2015 and quickly dominated the market as a group B tolerant lentil with yield potential far exceeding the original tolerant line of PBA Herald XT. Other releases include PBA Hallmark XT and more recently, PBA Highland XT. PBA Highland XT was specifically selected for release in the Victorian Mallee and its yield approaches that of the best conventional variety, PBA Jumbo2 (Table 1).

Table 1. NVT yield data showing the potential of PBA Highland XT in the Mallee regions of Victoria and SA.

Key Question 2: What new chemistries do the breeding programs have access to and what are the approximate timelines of when the varieties will be available?

Tolerance to group B chemistries has also been developed in chickpeas and field peas. Initial lines are undergoing seed multiplication and it is anticipated that MRL testing will commence shortly. In addition, the lentil, field pea, chickpea and faba bean breeding programs all have access to mutations conferring tolerance to group C and group I chemistries. The particular herbicides that have been targeted are Metribuzin® and Lontrel®. Metribuzin tolerance mutations affect photosystem II in plants and thereby come with an inherent yield penalty. Testing against a range of herbicides within the specific chemical groups is underway at SARDI, while the breeding programs investigate variations of potential lines in field trials and undertake crossing of the mutation lines.

Seed bulk ups are also occurring and it is anticipated that MRL testing of prescribed herbicides will commence once lines are close to commercialisation.

Acknowledgements

The research undertaken as part of this project is made possible by the significant contributions of growers through both trial cooperation and the support of the GRDC and the author would like to thank them for their continued support.

Contact details

Dr. Garry Rosewarne
Agriculture Victoria
110 Natimuk Road Horsham Vic 3400
0477 616 759
garry.rosewarne@agriculture.vic.gov.au