Two-pronged breeding approach producing new mandarin varieties
LOW-SEED versions of two popular US mandarins have been developed in Australia through the efforts of citrus breeders at the Queensland Department of Agriculture and Fisheries (DAF).
Innovation on two fronts is required when introducing new varieties.
At the checkout, consumers make buying choices based on characteristics such as flavour, seed count and peelability.
However, at the orchard level, unless a mandarin is profitable for the grower, it will never get to the consumer.
The importance of balancing these factors is front-of-mind for the DAF team.
“We have material at all stages of development,” said Malcolm Smith of the DAF Bundaberg Research Station.
“There’s material that’s been commercial for about 10 years or more now, and from there we stretch all the way back to generating new hybrids. We have various selections at different points along that line.
“There are two that will produce commercial fruit for the first time this year, and then there are three varieties following along behind that.”
Mr Smith said the promising mandarin releases included low-seed versions of Fremont and Daisy.
“The Fremont will produce fruit for the first time this season, and the Daisy will be producing next year,” he said.
“After that we have three of our own hybrids that also have low seed numbers. They’re really quite exciting. Up until now we’ve just had existing varieties with lower seeds but the ones that are coming through in the next two or three years are actually totally new varieties. It’s the first time that’s happened.”
Critically, DAF is ensuring that inbuilt resistance to common diseases is a standard feature of all future releases.
“The one we’ve put a fair bit of effort into over the past few years has been Alternaria; we’ve got that pretty well controlled now in terms of breeding so all of our new hybrids that come through over the next five to 10 years will be genetically resistant.”
Mr Smith said at the same time work to minimise granulation in Imperial mandarins through rootstock selection was under way at three sites.
“We have three large trials planted out: two in Gayndah and one in Emerald. We’re looking at some of the new rootstock hybrids we’ve generated here in Bundaberg.
“Then, in our nursery we have another trial with another set of genetic material.”
The project was based on developing rootstocks to resist both citrus tristeza virus and phytophthora, he said.
“There’s no point having a rootstock that reduces granulation if it’s going to fall over in the field after three years.”