Harvest lupins for seed sooner, rather than later

Lupin growers looking to retain seed have been advised to harvest crops as soon as possible, rather than risk poor crop establishment from grain affected by rain.

Department of Primary Industries and Regional Development (DPIRD) senior research scientist Martin Harries said late season rainfall could reduce germination rates of lupins held over for planting in future years.

“With widespread, variable spring rainfall this season and crops maturing at different times, it is important for growers to evaluate their harvest program carefully and to prioritise lupin crops destined for seed,” Dr Harries said.

“While lupins can stand up to some weather events without shedding, crops destined for seed should be harvested as soon as possible to avoid the risk of rainfall reducing the production potential of next year’s crops.”

Previous research by DPIRD in conjunction with the Grains Research and Development Corporation found a substantial reduction in germination rates in seed from wet lupin pods.

“Laboratory experiments showed seed exposed to one wetting and drying cycle reduced seed germination by five to 10 per cent, two cycles by 10 to 20 per cent and three cycles by 35 to 45 per cent,” he said.

“These results were reflected in field trials under simulated rainfall conditions.”

Dr Harries said while many variables could influence the severity of rain damage on mature seeds within pods, the impact on germination rates was conclusive.

“Each rainfall event causes what is referred to as ‘accelerated aging’, where each time it rains the seed in the pod wets and the germination process starts again, depleting seed vigour,” he said.

“The more times the mature plant is exposed to rainfall, the more its energy reserves are reduced, along with its ability to establish as a healthy plant, which can ultimately impact yield.”

Dr Harries advised growers to get their lupin seed tested before sowing, even if harvesting early, to make sure they have quality seed for next year’s plantings.

“Good seed comes from paddocks with good nutrition that have grown well and have not been exposed to rainfall,” he said.

“Storage conditions over summer are also important and aeration is a good way to maintain the quality of the retained seed, while testing helps growers know what they are sowing.”