New pulse variety and agronomy update 2015

Larn McMurray¹, Mick Lines¹, Jeff Paull², Dili Mao¹, Amanda Pearce³, Matt Rodda⁴, Jason Brand⁴,

¹SARDI Clare, ²University of Adelaide, ³SARDI Struan, ⁴DEPI Victoria.

Keywords:  pulse varieties, herbicide tolerance, green lentils.

Take home messages

• The new faba bean, PBA Samira, and lentil, PBA Jumbo2, were not overly favoured by dry finishing conditions in 2014. However they still offer very high yields, improved disease and other agronomic advantages over older varieties and are available for 2015 sowings;
• XT lentil varieties have improved tolerance to residues of Group B herbicides compared with conventional lentils but still can incur yield loss in some situations;
• New green lentil varieties provide growers with an opportunity to manage production and marketing risks but are a higher input lentil and require careful consideration; and
• No field pea, lupin or chickpea varieties were released in 2014, however correct varietal choice and optimum agronomic and disease management practices are required to maximise production of current varieties, refer to the SARDI Crop Sowing Guide and PBA variety brochures for details.

New red lentil opportunity

The recently released variety, PBA Jumbo2, continues to be the highest yielding Australian lentil after topping the statewide NVT and Pulse Breeding Australia (PBA) trials in 2014. In a performance not quite as impressive as previous years it still finished 12 per cent above Nugget, two per cent above PBA Ace, three per cent above PBA Blitz and six per cent above PBA Flash across all trials last year. PBA Jumbo2 has been released as a replacement for PBA Jumbo although their large grey coloured grain size is about the only feature they share in common. It has improved agronomic characteristics over PBA Jumbo, including greater early vigour and improved lodging, disease and shattering resistance. It is rated as resistant to both ascochyta blight (AB) and botrytis grey mould (BGM), however monitoring for disease is still recommended. As with other large seeded varieties, PBA Jumbo2 is well suited to the post-harvest removal of small broadleaf weeds seeds, however it does not have the XT herbicide technology.

PBA Jumbo2 has a large and vigorous plant type that aids in weed competition and sets up high yield potential. Conversely it often has a lot of biomass to carry through dry finishes, however to date it appears to be able to do this better than other large varieties such as PBA Ace and the green lentil varieties, as seen by its impressive if not slightly subdued yield performance in 2014. Agronomic work is currently ongoing to investigate if seeding rate and sowing date manipulation are required to optimise its performance across a range of seasons and environments.

Improved weed control in lentil

Research by the Southern Region Pulse Agronomy (SPA) program and PBA has focused on improving Group B herbicide tolerance in lentil. Group B herbicides, including Imidazolinone (Imi) and Sulfonyl Ureas (SU), applied in cereal phases of the crop rotation can aid weed control across the whole farming system due to their residual activity. However, their use can also reduce subsequent pulse production, particularly on alkaline, high pH, light textured soils where their residual life is often extended.

Two lentil varieties, PBA Herald XT and PBA Hurricane XT, are now commercially available with a permit allowing the post-emergent use of Imazethapyr. Research by SPA during 2013 and 2014 in lentil producing regions of South Australia and Victoria aimed to confirm this in-crop tolerance as well as exploring benefits from potential improved residual tolerance. Trials were set up at various locations to simulate residual Group B herbicide carry-over through the application of treatments at either very low rates post sowing pre-emergent (PSPE) (Figure 1) or commercial rates pre-sowing in autumn (Figure 2).

Key findings from the agronomic herbicide trials

• Response of lentils to herbicide treatments varied with seasonal conditions, method of herbicide incorporation, stubble coverage, soil texture and fertility.
• Treatments that showed high plant damage generally incurred high yield losses, however low levels of chlorosulfuron plant damage still resulted in significant yield loss in some trials.
• XT lentil varieties showed improved tolerance compared to conventional lentil varieties to all treatments, however they still incurred yield loss to some chemistries under certain conditions, indicating low safety margins to these chemistries (Figure 2).
• Chlorsulfuron and triasulfuron were the most damaging treatments in the trials. Metsulfuron was found to be the safest of the sulfonylurea chemistries tested.
• It is important to note that all existing product label rates, plant-back periods and directions for use must still be adhered to. Further research is required to identify if sufficient crop safety exists in XT lentils to seek changes to label recommendations for other Group B herbicides.

Figure 1: Effect of various Group B chemistries applied PSPE at 4 application rates on the grain yield of PBA Hurricane XT^A and Nipper^A lentils, Pinery, 2013. Solid horizontal line indicates untreated variety yield, with shading showing associated error.

Figure 2: Effect of various Group B chemistries and application rates on grain yield of PBA Hurricane XT^A and Nipper^A lentils, Pinery, 2013. 'Residual' treatments were applied on the 25th of March, PSPE treatments were applied on the 26th of May. Solid horizontal line indicates untreated variety yield, with shading showing associated error. 

Bright future for weed control in pulses

Building on the success of the lentil research, the SARDI pre-breeding project has developed Group B tolerant faba bean and Group C tolerant lentil germplasm. Agronomic field trials in South Australia in 2014 confirmed faba bean lines with tolerance to a range of Imi chemistries and early generation PBA yield trials have identified lines with good adaptation to southern Australia. Preliminary field validation trials also confirmed a very high level of metribuzin tolerance (10-20 times) in lentil germplasm. This material has now been ‘crossed’ with the Group B tolerant lines with the aim of developing dual herbicide tolerant (Group B+C) varieties. The project is now expanding into the development of novel herbicide tolerance in both kabuli and desi chickpea.

Green lentil opportunities

Australian lentil production is dominated by red lentils, however internationally there is a large market for green (yellow cotyledon) lentils and there is also a small domestic market. Canada traditionally has produced more green lentils than red but in recent years has trended to greater production of the latter with an estimated 1.1 MT of reds produced in 2014 compared with 0.59 MT of greens. Canadian lentil area estimates for 2015 are currently at record levels of 3.8 to 4.0 million acres, as growers respond to high prices, and again red lentil production is likely to dominate.  The Australian green lentil industry is currently infantile but its existence may allow some growers to spread their production and marketing risks, particularly if production trends and seasonal forces combine in Canada to help produce large world wide red lentil stocks.

Green lentils are generally sold and consumed whole with the seed coat intact and the markets prefer large uniform seed size with good green colour retention (lack of bleaching) and an absence of seed blemishes such as disease and wrinkled seed coat. There are also some smaller markets for medium and small sized green lentils. The combination of the above characteristics have been hard to achieve under Australian conditions, particularly as the initial green variety, Matilda, was medium in size and susceptible to disease. Boomer, released in 2005 with a larger seed size and improved disease resistance enabled successful production in some areas, however it was prone to shatter and acceptable seed colour often difficult to achieve. Further breeding progress by PBA has resulted in the 2014 release of PBA Giant (large) and PBA Greenfield (medium) that will help growers produce a more marketable product.

PBA Giant is the largest seeded Australian green lentil, broadly adapted with similar yield and improved shattering resistance compared to Boomer. It produces a slightly larger and more consistent seed size, average diameter 5.8 mm. It has moderate resistance to AB but is rated moderately susceptible to BGM and monitoring and timely application of fungicides will be important to ensure the control of disease, including strategic fungicide applications at podding to minimise seed staining from AB. Although improved over Boomer, PBA Giant has a shattering rating of MR/MS and therefore timely harvest is still vital to prevent seed loss and bleaching of coat colour.

PBA Greenfield is the highest yielding Australian green lentil available, broadly adapted with good early vigour and moderate resistance to AB and BGM. PBA Greenfield is mid flowering and like other green lentils is mid to late in maturity. In long term trials it has produced grain yields averaging 11 to 14 per cent higher than the red lentil variety Nugget and averages 11 per cent higher grain yields than Boomer. PBA Greenfield has improved shattering resistance over both Boomer and PBA Giant with an MR rating, however timely harvest is still important to produce good coloured seed. This may also be aided by strategic fungicide applications during podding to minimise seed staining from AB.

Going green?

Before considering green lentil production, growers need to consider a number of production, storage and marketing issues with green lentils, including:

• visual appearance of seed is very important, therefore good disease and insect control and timely harvest is required, production in environments where there is a lower risk of climatic events affecting seed quality issues such as wrinkled seed coat, bleaching or delayed harvest will also aid in producing a marketable product;
• production is small and new in Australia, understand marketing opportunities prior to deciding to grow them and have the capability for on farm storage;
• larger plant type with increased early vigour and often later maturity than reds, this combination leads to a plant type that reaches earlier canopy closure, is more prone to lodging, more prone to early onset of BGM and can be more difficult to achieve effective canopy penetration with late season foliar sprays. Consider a slight delay in sowing time and reduction in seeding rate in favourable environments; and
• no green lentil has the XT herbicide technology, but their larger plant size is more competitive with weeds and larger seed size is well suited to the post harvest removal of smaller weed seeds.

New faba bean variety PBA Samira - yield and agronomic performance

South Australian NVT and PBA trials were still being collated at the time of going to print but analysis of the trials available showed that PBA Samira was similar in yield to other varieties in 2014. This was slightly down on its long term average yield performance where it has shown a five per cent advantage over all other varieties in most districts of South Australia. It appears that the slightly larger seeded and relatively later flowering varieties such as PBA Rana and PBA Samira may have suffered more in the dry finish last year compared with Farah.

PBA Samira has a mid flowering timing (similar to Nura and PBA Rana) and is five to 10 days later than Fiesta VF and Farah, but matures at the same time as these varieties. PBA Samira is resistant to ascochyta blight, including the new strain recently identified in South Australia. It is moderately susceptible to chocolate spot and rust, and susceptible to Cercospora leaf spot. Seed of PBA Samira is slightly larger than Fiesta VF, Farah and Nura with a similar seed colour.

Agronomic sowing date trials at Tarlee in the Mid North last year also found Farah and PBA Samira performed similarly in the absence of any significant disease pressure. However PBA Samira was higher yielding than Nura and PBA Rana particularly at the early sowing time (28 April compared with 12 May). Trial findings appear to be suggesting that PBA Samira is well suited to early sowing dates perhaps due to its combination of slightly later flowering and good disease resistance.

Faba bean ‘necking’ 2014

Necking, where the faba bean plant remains erect but a proportion of the stem ‘necks’ over between 90 and 180 degrees, was prevalent in research trials and commercial crops in 2014. This phenomenon is thought to be due to moisture stressed plants being subjected to heat and wind events during the reproductive phase. Variety susceptibility/resistance to necking has been noted but the effect on grain yield and seed size is largely unknown although harvestability is often reduced.

Table 1: Standing ability and necking scores of faba bean varieties from PBA and NVT trials, southern Australia, 2014 (data source: University of Adelaide, SARDI, NVT).

Results from across a number of trials in 2014 (Table 1) show a range of variety responses to necking with Nura the most susceptible and sometimes PBA Samira and PBA Rana worse than Farah. Interestingly  the results for necking were different to lodging with generally Nura and PBA Samira showing improved results over Farah, although apart from at Maitland lodging was generally low in 2014.

08 8842 6265
larn.mcmurray@sa.gov.au