Taylor's Gold seems prone to reversion
An Oregon researcher is experimenting with techniques to improve the russeting.
Southern Oregon pear growers have a long history of growing Comice and are able to use the precocious quince rootstocks to overcome the variety's reluctance to bear.
In fact, it's their second major variety after Bosc.
But Medford area orchardists have had the same problems as their counterparts in Washington State when it comes to producing a smoothly russeted Taylor's Gold, which is a sport of Comice. The finish tends to be blotchy.
Dr. David Sugar, plant pathologist at Oregon State University's Southern Oregon Research and Extension Center at Central Point, said everyone assumed at first that the problem was a climatic one, and that the growing conditions in the drier areas of Oregon and Washington were not as conducive to russeting as those in New Zealand, where the sport was discovered. Though russeting does vary from year to year, depending on the weather, Sugar wonders if the genetic characteristics of the plant material are involved.
At an international pear symposium in Portugal earlier this year, a researcher from Spain told Sugar that at his research station he can produce Taylor's Gold with very good russet, even though the climate there is similar to the drier parts of the Pacific Northwest. However, in the discussion it came to light that Taylor's Gold was prone to reversion from highly russeted to poorly russeted, but could also revert back from less russeted to more russeted, which suggests that the variety is not very stable. Sugar, who has also seen differences in the amount of russeting, believes reversion in Taylor's Gold might occur to the same extent as red Bartlett reverts to green Bartlett.
Since many growers in the United States appear to be having difficulty growing well-russeted Taylor's Gold, there's been speculation that the material brought into the country from New Zealand was from a source that was a reversion, and that the russeting problems may be genetic.
But Nancy Fowler-Johnson, general manager of Fowler Nurseries in Newcastle, California, doubts that the imported material was a reversion and said some growers in wetter areas are having success with the variety. Fowler Nurseries is one of three West-Coast nurseries that propagated and sold trees after the wood was introduced to the United States by ENZA. Fowler-Johnson said three different clones of Taylor's Gold were brought into the country through the national quarantine and virus-testing program in Prosser, Washington. Fowler Nurseries tracked the three clones, kept them separate in the nursery, and recorded which clones their grower customers received. All the clones have performed similarly, she said.
However, her nursery is testing a new clone, which was found in an orchard in a poor russeting area but appears to russet easily. "We're in hopes that maybe this other clone will prove to be better," she said.
If it does, Fowler's customers who bought Taylor's Gold might be offered wood to graft their trees over to the new clone.
Sugar said he's keen to make Taylor's Gold work, either by acquiring appropriate genetic material or perfecting a russeting treatment.
He has been experimenting to try to induce russet but has found --Taylor's Gold to be much more insensitive to copper than is Bosc. Copper is sometimes applied to Bosc as a late-season fireblight spray, which has the side effect of promoting russet. But that treatment does not work as well with Taylor's Gold, Sugar reported, though he's had some success with higher dosages of copper, more frequent applications, and the addition of a surfactant.
However, the level of success has also been dependent on the weather conditions, he said. "If it's wet during the postbloom period, I can get pretty good success with copper at higher doses. But in a dry spring, it seems like copper has very, very little effect, regardless of the dosage, so I'm still working that out."