Investment

Lentil production in Australia is mostly focussed on highly productive regions in the Yorke Peninsula in South Australia and the Wimmera region of Victoria, where upwards of 600,000 tonnes are produced annually. One of the main reasons for adaptation to these regions are the highly alkaline soils which are preferred by lentils. Acidic soils found across most of the southern Australian cropping region are acidic and severely inhibit the expansion of lentil production.

This project aims to address this issue by characterising genetic diversity for acid soil tolerance using a high throughput, controlled environment assay, ensuring the assay represents what occurs on acid soils in the field, and developing improved germplasm for breeding programs. Acidic soils can limit crop production multiple ways depending on the elemental composition of the soil. Acidity per se can affect growth and is exacerbated when soils contain high levels of aluminium and manganese. These elements are more soluble at low pH, with Al3+ and Mn2+ ions being toxic to root growth. Genetic tolerance to these ions has been identified in many crop species but little work has been done to characterise this variation in lentils. The effect of these ions on crop growth is further exacerbated by water and nutrient availability as the damaged roots may struggle to provide these components for adequate crop growth.

The project has a major focus on developing controlled environment assays that rank germplasm responses to acidity in the same way as plants grown on acid soils. To achieve this, there is a strong focus on screening germplasm in target expansion areas of NSW and WA. Sites will be chosen with moderate levels of acidity and detailed soil analysis undertaken to identify major constraints of the test soils. Control plots treated with lime will facilitate adequate crop growth and further quantify the acidity response. Simultaneously, hydroponic assays will be used to mimic the soil constraints and maximise the likelihood for establishing a robust assay with field relevance.

A key project outcome will be characterised improved germplasm delivered to breeders for incorporation into breeding programs. Once field relevant hydroponic assay conditions are established, they will be used to screen a diversity panel of over 300 lines, which will be used to identify DNA markers for acid soil tolerance for implementation into breeding programs. Lines showing the best tolerance to acid soils also will be intercrossed and advanced generation populations developed using speed breeding approaches to rapidly generate new germplasm with improved levels of tolerance. These will be evaluated under both hydroponic assay and field conditions.

The project will leverage other GRDC investments that have identified acid tolerant rhizobia to ensure the combination of improved genetics and acid tolerant rhizobia provide the potential to produce step changes in lentil productivity in acid soils and open up new areas for cropping of this valuable commodity.