Several growers emphasized the need to know the soil history to determine what cultivar to grow

The nature of this sample suggests a significant, but not surprising, overlap between those growers more generally willing to work with researchers and those experimenting with various production techniques. Importantly, many growers I attempted to contact were not reach able and/or had gone out of business, and even three of those I did interview had retired or all but exited strawberry production. In the interviews, conducted in 2018 and 2019, I was able to reframe questions that had not quite worked in the surveys, as well as probe on the more difficult questions . Before completing them, I reached saturation, such that additional interviews were no longer producing more themes or deepening understanding, which substantiated that the sample size was sufficient . Research assistants transcribed and coded interview data with NVivo qualitative research software , identifying ideas and themes that further elucidated the more bounded questions asked in the survey. Alongside these two primary sources of data , I reviewed limited discussions about cultivars from my previous project and notes taken from short discussions with growers at field days and follow-up phone calls for the survey. These additional data were thoroughly in keeping with survey and interview data, providing further triangulation of the findings. While the strawberry industry has long enjoyed the benefits of strawberries bred with multiple aims, emphasis in one area often comes at the expense of another . Since UC began its breeding program in the 1940s, growers have generally adopted those varieties with high productivity traits . An important question, therefore, was within the current context of fumigant restrictions and the emergence of novel diseases, to what extent disease resistance had become a desirable trait.To prevent them from choosing all, it asked them for their top three priorities. As seen in table 1, growers mostly wanted high yields, especially if a variation on the same theme, long steady yields,producción macetas 25 litros was included. While interest in resistance to soilborne diseases and in marketability were not negligible, they appeared as secondary priorities. These preferences were corroborated by answers to a question about which cultivars had been planted for the 2016 marketing year .

Of the UC varieties, Cabrillo, Monterey and Fronteras were the most planted and they are high yield performers. In a recent trial involving equal plot sizes, Fronteras produced an average cumulative marketable fruit weight of 11,000 grams per plot, with Monterey producing close to 9,500 per plot. Of these two cultivars, Monterey allegedly has better flavor. San Andreas, the next most widely planted cultivar, is most associated with Fusarium resistance, but in that same experiment yielded only a little over 7,000 grams per plot. The notably flavorful Albion, which is popular among growers selling in farmers markets, although was not often planted by survey respondents , yielded only about 6,500 grams per plot . Answers to a third question further clarified the dimensions of the trade-off between yield and disease resistance. Asked about the maximum decline in yield a grower would accept in a cultivar with high levels of resistance to soilborne diseases and no change in production costs, most growers reported that no or only a minimal yield decline was acceptable . Qualitative responses and interviews provided additional evidence that growers tended to choose yield over pathogen resistance and helped clarify their rationale. Of the 20 growers interviewed, 15 said yield was a high priority, albeit not without some hedging. Many recognized the importance of marketability characteristics, acknowledging that a strawberry that lacks flavor, for example, would turn off consumers. For that reason, they were more likely to grow Monterey than even higher yielding varieties, and some shippers insisted that they grow a marketable variety such as Monterey. Growers who use proprietary varieties because they sell to shippers who require them to have somewhat less choice in what they grow. The shipper sets priorities, and Driscoll’s, in particular, has allegedly prioritized flavor and disease resistance over yield in their breeding. Growers who favor work ing with these shippers do so because they obtain higher prices, making up for the loss of yield. Still, my interview data showed that when given a choice these growers, too, favor yield, especially because they are paid the same no matter what they grow. When I pressed on questions of why yield remained a priority for those selling in wholesale markets when they also complained of low prices, I learned of a significant collective action problem. Most growers recognized that it made sense for the industry to reduce supply but felt that it was folly personally to choose a lower-yielding variety.

This is the technological tread mill problem first identified by agricultural economist Willard Cochrane in 1958. Cochrane noted the tendency of farmers to adopt technologies that reduce costs because early adopt ers make additional profits as their expenses decline . As he also noted, such tendencies eventually negatively affect crop prices because other farmers join in, supply increases overall and price competition ensues, driving some out of business. In the case of adoption of a higher-yielding variety, rather than reducing cost, the output increases with little additional effort, making such a strategy nearly irresistible. As one grower put it, “We’re in a competitive environment. We like to say we don’t grow a commodity, but there are commodity-like characteristics. So if you have a variety and neighbor selling into same market, if he’s more productive he will have an edge.” In addition to low prices, fixed costs such as land leases and land preparation are extremely high and in creasing in strawberry production. Labor costs, though variable, have risen considerably with labor shortages and new minimum wage and overtime laws. Therefore, growers feel they need to sell as many berries as they can to be economically viable. As another grower said, “You could have the best fruit around, but if you don’t have yield you can never make any money. . . . I mean our costs are going through the roof. The only way we can bring some of the costs down is through yield.” At the same time,hydroponic growing systems growers also questioned this logic, asserting that the industry was under mining itself by continuing to breed and grow ever more high-yielding varieties: “So we want these varieties to give out more numbers and last longer, but it’s hurting us in the long run. . . . It seems like people think that if I plant 100 acres and make such amount of dollars, if I put 200 acres in, I’m going to make double that, but it doesn’t work that way.” This observation is corroborated by the most recent statistics on historical trends reported by the USDA National Agricultural Statistics Service. Utilized production of strawberries grown in California increased from 539 million pounds in 1974 to 3,015 million pounds in 2012, an increase of 559%; grower prices increased only from 29 cents per pound to 80 cents per pound, an increase of 276%, in that same time period . It is not that growers were oblivious to the need for disease resistance, but some were making a calculated decision that the yield benefits of a cultivar outweighed the risk of plant loss.

As one grower said, “We can have 30% die out of Radiance due to soilborne pathogens and still beat the yield on San Andreas.” More often, growers had not experienced enough plant loss to make disease resistance a priority: “If we begin to see more Vert or other pathogens, we will worry more. Right now, all is cool.” Some growers, though, who had experienced disease loss were more inclined to let go of leases on diseased land than give up on the yield or marketability advantages of a cultivar. There were exceptions, too. After that, he “switched soils,” but that soil was infested too, and he lost 32% of Monterey that year. He then turned to growing almost entirely San Andreas. Not surprisingly, it was growers with organic fields who were most interested in disease resistant varieties. With fumigation still available, growers with conventional fields remained relatively uninterested in these varieties. Understanding that most growers were unwilling to trade off yield for pathogen resistance because soil fumigants were available, I wanted to explore in more depth what role pathogen-resistant cultivars could play in reducing the use of soil fumigation. The survey included two questions about what prevents growers from reducing their use of preplant soil fumigation and what currently encourages them to reduce their use of preplant soil fumigation. It asked them to choose all answers that applied. Answers to these questions aligned with previous studies and reports . Growers most often chose “crop loss/ potential crop loss” as the condition that prevented them from reducing their use of preplant fumigation . Buyer and lease conditions played a role, as well — for instance, some leases require that growers fumigate so that the lessors, often vegetable growers, get the benefits of fumigation. On the flip side, regulatory pressures, including restrictions on fumigation in the form of buffer zones, were most encouraging growers to reduce fumigation, with opportunities such as en try into organics or land with low disease pressure also playing roles . Qualitative responses and interviews corroborated and nuanced the latter answers. Several growers emphasized how fumigant restrictions had pushed them to find alternative means to grow strawberries and discussed organic certification and the accompanying price premium as a way of offsetting the potential costs and crop losses of forgoing fumigation. In these in stances, they saw disease-resistant varieties as enabling such a transition: “Without disease-resistant varieties, conventional strawberries require the use of fumigants. If they become unavailable, organic is the best alternative.” The trade-off is noteworthy given that growers have to give up other pesticides besides fumigants to be certified organic. A few growers mentioned their willingness to give up fumigation without converting to organics, simply because of fumigation costs. And a few growers noted that organic prices might be too weak to make that trade-off. One wrote in the survey, “If I were organic [I’d reduce fumigation use], but they don’t have the price either right now.” Even the many interviewees who have organic programs were not at this time considering transitioning their entire operation; instead, they were choosing fields for their organic programs where soil conditions make them viable, often areas with low disease pressure. That organic markets were nevertheless the main factor incentivizing fumigant reduction was confirmed by answers to a question about whether there were any conditions in which growers would consider eliminating the use of preplant soil fumigation, not including transitioning to organic. Only 10 growers replied to this question, but seven said no, with two maybes and one yes. When asked to comment about what, if any, conditions might lead growers to eliminate preplant soil fumigation altogether within the next 5 years, surveyed growers mentioned cultivars completely resistant to all major soilborne diseases — not just simply tolerant to diseases, which is what the best cultivars are today. Growers basically wanted alternatives that wouldn’t forgo yield, quality or higher profit — in other words, something foolproof. In an interview, one grower was emphatic on this point: “It has to be proven to me, I gotta see it. . . . But I’m not going to do it because [the UC breeder] says ‘Oh, by the way, I have this variety that’s resistant to Macrophomina, you don’t need to fume.’ Well, let me see that, you know what I mean?” The more personalized setting of the interviews also allowed me to explore what growers would do if fumigants were taken away. Here I learned that while such a possibility heightened interest in disease-resistant varieties, several said that they would leave strawberries or retire early, and many said they would move to soilless regimes. As it happens, one of the challenges of soilless systems is finding cultivars that work in those settings. The performance of existing varieties is reportedly subpar. Those interested in remaining “on ground” clarified that disease-resistant varieties would be helpful, but they would need to adopt other tools as well, such as nonchemical modes of soil disinfestation, making breeding for disease resistance only a partial solution. One grower said, “Just having a variety that is tolerant of x, y or z only does so much. . . . . That would be just like added insurance.”