Business magnate Steve Jobs, of Apple Inc. fame, is quoted as saying, “Innovation is the ability to see change as an opportunity.” It’s where you imagine the future and fill in the gaps.
Craig Kallsen, University of California Cooperative Extension pistachio farm advisor in Kern County, has been doing so for over a decade in trying to develop new pistachio cultivars to supersede the traditional Kerman.
“The way Kerman was harvested became synonymous with how pistachios, in general, should be harvested,” he wrote in a report for the UC Division of Agriculture and Natural Resources.
Western Farm Press asked Kallsen for a status report on some new varieties being tested in the San Joaquin Valley, like the Golden Hills, Lost Hills, and Gumdrop varieties that have now been in the ground in long-term experimental trials for several years.
“We’re still in the learning curve with Lost Hills and Golden Hills, both of which were released in 2004-2005, and we haven’t really even started yet with Gumdrop, released in 2016,” Kallsen said. “Right now, both Lost and Golden are acting as ‘controls’ in trials with new advanced breeding selections.”
Finding a “preferred” cultivar runs contrary to the goal of his breeding program. “One of our objectives has been to develop a diversity of cultivars — in addition to Kerman — so that something exists that will better fit the diversity of our various growing conditions and the goals of the industry,” he said.
As an example, he cites the release of cultivars with a range of harvest maturity dates so existing harvesting equipment and hulling facilities can be used more efficiently by spreading out the timing of the harvest and reducing the need for additional machinery and capacity.
“There is no perfect or better cultivar,” he emphasizes. “We need all of these cultivars to spread out the season to reduce ‘the big bump’ when Kerman is ready for harvest.”
Pluses and minuses
Research to date has uncovered several pluses and a few minuses on the tested trio. “If you want early harvest, you plant Gumdrop, even though its nut quality and perhaps yield is not as good as Golden Hills,” he said.
“The disadvantages are that it’s hot when ready for harvest, it doesn’t hold well on the tree and requires more than one shake, and no processors are open,” he said. “Gumdrop was released with large corporations in mind because they can plant larger acreage and do their own early processing, extending the use of their facilities and resources without having to increase capacity.”
While Gumdrop would be the preferred cultivar to allow earlier opening of processing plants, other varieties offer different advantages. Golden Hills, for example, has a better split nut percentage and a higher percentage of harvested material going to the process plant. That said, Golden Hills is more susceptible to leaf scorch than is Kerman. Another drawback is that Golden does not tolerate as much water and boron in the soil as does Kerman.
“If you have high salts, especially boron, Kerman remains the preferred cultivar,” Kallsen said.
Kallsen cautions that different cultivars have a better fit depending on the goals and conditions of individual growers and it is difficult to convey their varying strengths and weaknesses in short news articles versus lengthier research papers.
And those lengthier research articles are being written continually as new field information becomes available. As the fortune cookie predicts, “More will be revealed.”
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