The wet weather experienced during the recent harvest may have affected pulse seed quality, leading to discolouration or wrinkled and loose seed coats.
South Australian Research and Development Institute senior pulse pathologist, Jenny Davidson, says it is therefore important to test seed quality and germination particularly on any seed that was downgraded at harvest for reasons such as poor cotyledon colour, wrinkled seed coat, field mould, and shrivelled seed.
“If seed dried out before the embryo started to grow it could still be viable for sowing but seedling vigour may be compromised,” Ms Davidson advises.
While seed dressings help protect good quality seed against seedling disease, growers are advised to check with the supplier or manufacturer of seed dressings and chemical treatments to determine if they will impact on the vigour and emergence of weather-affected seed.
Ms Davidson says there are many infected stubbles remaining from last year and these will produce a large number of disease spores.
Growers are therefore encouraged to use good quality seed with seed dressings on lentil, chickpea and early sown field pea. This will reduce the transfer of seed-borne disease to the new seedling, and thiabendazole-based products will reduce seedling infection from airborne spores.
According to Ms Davidson, many pulse crops suffered from a high incidence and high severity of ascochyta blight and Botrytis diseases (botrytis grey mould or chocolate spot) in the 2010 season.
“It is therefore important to make sure that seed for 2011 is free of seed-borne diseases and seed testing is recommended. If seed has no visible sign of disease, this does not mean it is not infected. Only testing will determine whether disease is present.”
Ms Davidson reports that very few virus issues were detected in pulse crops in the 2010 season, most likely due to the cool, wet conditions that reduced aphid numbers. As such, seed is unlikely to have a high infection level.
“There were incidences of Pea Seed borne Mosaic Virus (PSbMV) staining on faba bean seed, but transmission of this virus to the seedlings is reportedly very low.”
Ms Davidson reminds growers that it is imperative they ensure the lentil seed they plan to sow is pure for variety since there is a 1% limit for impure varieties.
“Growers need to be aware that there are varieties with different seed coat colours, for example PBA Flash , and Aldinga are green, Northfield is tan, and Nugget, PBA Bounty , Nipper and PBA Blitz are grey and the green lentil variety Boomer has a yellow cotyledon along with its green seed coat.”
To assist growers in determining whether grain is viable for sowing and what is an appropriate and effective seed management program, the GRDC has published a detailed Retaining Seed fact sheet.
The fact sheet was distributed in the January/February edition of Ground Cover magazine, is accessible via www.grdc.com.au/GRDC_FS_Retainingseed
and is also available free (plus postage and handling) through GRDC’s Ground Cover Direct – freecall 1800 110044 or email email@example.com.
Growers are encouraged to report pulse disease issues to Jenny Davidson on 08 8303 9389 or firstname.lastname@example.org, or Rohan Kimber on 08 8303 9380 or email@example.com.
More information about pulse diseases is also available from the GRDC, via www.grdc.com.au/diseaselinks.
Caption: SA Research and Development Institute senior pulse pathologist, Jenny Davidson, says it is important to test pulse seed quality and germination particularly on any seed that was downgraded at harvest for any reason.