Breeders develop peach varieties for early season
also reduce thepit splitsor stains that have affected early canning peaches. “In some cases, we’re seeing fruit stay firmas long as three weeks after it is ripe,” Gradziel said. “Wehave a largenumber of advanced selections.” Early 6 is a second new early variety still in the grower review process that he said ripens five days after harvest but stays ripe until the Andross time period; resists brown rot, fire blight and bruising; isproductive; andearns goodscoresonpit splitting and red pit stains. TheKader variety, alreadypatentedand released, ripens two days after Carson, holds until the Andross slot, is productive and has lowpit splits, Gradziel said. “We’ve been able to develop varieties that fit the rightmaturity timewithout the problems of previous varieties,” he said. “Wehave a lot of goodgeneticmaterial we can put into the California background.” One of the priorities for future peach breeding will be developing varieties suited to using labor-savingmachines for harvesting, pruningandother operations. Employment costs remain an issue in the canning peach business : In a recent decade, California acreage and production declined around 25% as lower-cost Chinese canned peaches flooded the market. Another challenge farmers could face is setting good volumes of fruit in seasons after a warmer-than-ideal winter.
“We have had very good chill this year, better than we have seen the last few years,” said Roger Duncan, UCCE farm advisor based inModesto. Although last winter provided enough cold weather for the trees, some recent winters have not, andGradziel pointed to evidence that chill time could be an issue in the future. “We want to see uniform flowering un- der changingclimates,”he said. “Youwant concentrated blooms with a high density of flowers. Ross has relatively low chill re- quirements, and we have selections that flower even earlier.” Vilmos is a recently patented and re- leasedUCvariety that ripenswithAndross but holds until the Ross time slot, has low pit splits, resists brown rot and canbloom uniformly even after low-chill winters. Because canning peaches stay in the ground a long time, even after a variety is released, growers participate in on-farm trials to learn if the variety will continue to produce well as it ages. “You need long-term testing for pro- cessingpeaches, becauseprofitability de- pendson the last 10yearsout of 20yearsof production,”Gradziel said. “Fresh-market varieties can be turned over quicker. The selections growers would try depend on the time, the growing conditions and the qualities you’re looking for.” ( Bo b J o hn s on i s a r e p o r t e r i n Sacramento. He may be contacted at bjohn11135@gmail.com.)
ByBob Johnson The addition of an expanded range of genetic material from around the world has improved the ability of University of California researchers to develop new peach varieties that suit the changing needs of the state’s farmers. Peach types from Brazil and South Africa are contributing germplasm that fruit breeders said should enable them to develop varieties that yield better, resist diseases, avoid browning or have other desired horticultural characteristics. “Wehad to introducenewgermplasm,” said Tom Gradziel, UC Davis geneticist with a specialty on the genetics and breeding of peaches and almonds. “We have a lot ofmaterials in the pipelinewith good quality.” The peach breeding program’s most recent efforts have been trainedondevel- opingnewvarieties that avoid fruit quality issues for theearlier slots in the succession of harvests for canners. “In the last several years, we have em- phasized early and very early varieties,” Gradziel said, as he discussed the new Kader, Vilmos, Early 6 and Ogawa vari- eties, and pointed toward efforts to meet future needs. Hemadehis remarksonadvances inthe
breeding program during the California Cling Peach Day webinar, sponsored by UC Cooperative Extension and the California Cling Peach Board. Cling peach growers need numerous, high-quality varieties that ripen in se- quence, to keep harvest crews and can- neries occupied at a steady pace. UC Davis has released or is in the pro- cess of releasing four new canning peach varieties with an emphasis on the ear- ly-season harvest slots, which Gradziel said has been a weak period. “Ogawa ripens early and has brown rot resistance that might make it a candidate for organic production,” he said. This new, brown rot-resistant variety, which is still in grower trials, ripens three daysbefore theearly-seasonCeresCarson variety, but Gradziel said it holds well on the tree and lasts until the Loadel slot. In addition to superior brown-rot scores, he said Ogawa, with genetic ori- gins in Brazil, has also shown good yield and brix in trials. It is oneof the recentUCclingpeachva- rieties that feature the ability to hold well on the trees after first ripening, which al- lows better flexibility for single-pass har- vesting and maintaining a steady flow to the cannery. Many of the early varieties
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March 24, 2021 Ag Alert 11
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