Australian growers plant their fields with vigorous cuttings of "disease-free" sweetpotato vines, harvested from on-farm nurseries, or sourced from dedicated cutting suppliers. This allows them to produce the highest per hectare yields of quality sweetpotatoes anywhere in the world.
Currently the bulk of Australia’s commercial planting material originates from Eric Coleman’s farm west of Rockhampton, isolated from the main sweetpotato production areas.
Investigating the best techniques for generating vigorous sprouts from nursery plant beds has been a substantial research target for sweetpotato scientists in recent years.
Queensland Department of Agriculture and Fisheries' (DAF) principal horticulturist Craig Henderson, (Henderson RDE) and former a DAF scientist at Gatton, said when the research was first started, there were nearly as many different styles of nursery plant beds as there were growers.
"Although we’re only half way through the current project, we’ve already highlighted several must-do issues you need to address for successful sweetpotato sprout nurseries," Mr Henderson said.
The Australian sweetpotato industry is starting to move quickly to a range of different types and cultivars, many sourced from the breeding program at Louisiana State University in the United States.
These new sweetpotatoes come with a range of benefits, such as nematode resistance, more reliable shapes and sizes, as well as diverse colours, flavours and prospective human health attributes.
However, they also come with several challenges.
"Some of the new cultivars can be tough to work with in our Australian nursery plant beds," Mr Henderson said.
"Because they have different climates and production systems in the USA, we’re having to find our own way a bit.
"For example, one of the new nematode resistant cultivars needs a certain amount of heat before it will sprout.
"So we’ve tried pre-heating the roots before bedding, and increasing bed temperatures with plastic mulch.
"Unfortunately, the same cultivar is very prone to breaking down and rotting in warm conditions."
Although he’s moved to Victoria, Mr Henderson said he still values conducting research at the DAF Gatton Research Facility.
"Because it’s isolated from the main sweetpotato production areas, we get less hammered by the sweetpotato pests and diseases, and so our research experiments have less complications," he said.
"We can get more precise management of agronomy. We can also do destructive measurements, or implement weird treatments, without interfering with a commercial grower’s operations."
According to the science, the current best-practice nursery plant beds should be able to generate around 250 sprouts per square metre every 18 to 21 days for at least four sequential harvests.
"We’d like to see most of the industry capable of hitting that mark in the next few years, even with the challenges of new cultivars and changing pest management pressures," Mr Henderson said.
Read more at www.goodfruitandvegetables.com.au.
