Posts Tagged: Albion
Comparison of Triform 80 and a Novel Fumigant in Fusarium Infested Soil
Introduction: With the discontinuation of methyl bromide as a possibility for pre-plant soil fumigation, we at UCCE have been very active in looking for viable alternatives. One alternative, identified by the test name TRX58, having a fairly high vapor pressure and already having certain uses in agriculture, was a good one to try.
Materials and Methods: Work was done in a field known to experience pressure from the plant pathogen Fusarium oxysporum f. sp. fragariae . Application of the test material TRX58 (550 lb per acre) and the grower check of Triform 80 (34 gal per acre) was done on October 5, 2015, shanked in followed by tarping with totally impermeable film (TIF). So as to obtain adequate fumigation and coverage, both the materials were applied in blocks 22 feet wide and 200 feet long with each block replicated twice. Two strips of 11 feet wide were placed between the fumigated plots, designated as untreated checks and not treated.
Planting of the strawberry varieties Cabrillo, Albion, Sweet Ann, San Andreas and Monterey was done on Nov 17. Plots were maintained as any other on the farm with adequate fertility and irrigation. Pick stations of 20 plants per variety x 4 replicates and commencing in April fruit harvest in all plots was done once a week and fruit weighed.
Statistical analysis is as below, and broken up into two halves (April + May) and then also given as a total.
Discussion: Triform 80 is indisputably the better treatment, but it is also indisputable that TRX58 is better than doing nothing, which as one can see from the photos is not wise in this sort of situation. It is also notable that variety such as San Andreas which is known to be "resistant" (actually tolerant is the better word) to Fusarium still loses a little bit more than half of its yield in unfumigated soil. There is a strong case being made here for treatment of soil to maintain good strawberry yields.
A deep bow of gratitude to Miguel Ramos for letting me do this work in his field, to Mark Curtice from Lassen Canyon Nurseries who gave us the plants, and then to Trical who did the fumigation.
People should realize that without the efforts of all these people working together, we would be doing very little novel fumigation research right now.
Statistical summary in 10 lb boxes per acre for first two months of study. Click on image to embiggen.
Statistical summary in 10 lb boxes per acre for total harvest. Click on image to embiggen.
June 29, 2016. Untreated control.
June 29, 2016. TRX treated plot.
June 29, 2016. Triform 80 treated plot.
Sept 3, 2016. Monterey in untreated control.
Sept 3, 2016 Monterey in Triform 80 treated plot.
A Comment on Vigor in Strawberry Varieties
A recent article referred to one of the reasons that growers need access to new strawberry varieties is that there is an inherent loss in vigor through the propagation process. That growers need access to new varieties to remain competitive is absolutely true, but that they need access to new varieties because the existing ones decline in vigor is not.
Plants do not invariably “lose their pep after years of cloning”. Indeed, reputable nurseries avoid a loss of vigor in a variety by periodically going back to meristem culture in order to keep their plant stock strong and productive. It does happen (especially in some formerly popular caneberry varieties - compare Ollalieberry in the field today to what was around in the early nineties) that older varieties of less demand don't have the meristem work done as frequently and subsequently become less vital over time.
What is meristem culture? Meristem culture is the excision of a cluster of actively dividing cells from the meristem (tip) of a newly formed strawberry runner, followed by surface sterilization, placement on a special medium, subsequent rooting, gradual acclimation of the new plant and transfer to a secure greenhouse. While some cases of genetic instability from repeatedly doing meristem culture have been noted in the literature, this cannot be described as a drift towards a loss in vigor of a variety. At any rate, programs for production of true to type (identical) plant stock using meristem culture have been used for a long time at any of the strawberry nurseries in business today.
A good example of how well and long a popular variety can be maintained through meristem culture would be the strawberry variety ‘Chandler'. Chandler continues to be widely planted by direct marketers because consumers just love its flavor and quality. Consider though that this variety was patented in 1984 by the University of California, and has had no apparent loss in vigor in all this time because the nurseries continue to go back to meristem culture to maintain it.
Growers have rumored that the variety ‘Albion' has been losing its vigor, but work at the Pomology Field Station in Watsonville over several years shows that this was not at all true. The Albion grown at this field station has experienced NO loss in yield since it was first released. Rather the rumored "loss in vigor" of the very widely planted Albion is almost certainly because of the industry wide steady drift away from methyl bromide fumigation to less effective alternatives like 1,3-D and chloropicrin.
Strawberry meristem culture. Photo courtesy USDA-ARS
Repaso de enfriamiento en las variedades de día neutro Albion, Monterey y San Andreas
Tuve el placer hace poco de conversar con el Dr. Doug Shaw, experto de fresa de UC Davis, acerca del concepto de enfriamiento en la fresa combinado con el deseo de unos productores de nuestro distrito de reducir esto a un nivel significativo, aun hasta cero en algunos casos.
De repaso, favor de recordarse que el requisito de enfriamiento de fresa en California consta de dos partes esenciales. Una parte es lo que acumula la planta en el campo antes de ser cosechada, y la otra es la acumulación de enfriamiento después de ser cosechado y la planta está en el frigorífico. Hay una diferencia muy grande entre los dos y uno no suplantará el otro. Enfriamiento en el campo toma lugar cuando la planta este todavía en el suelo, abajo del cielo abierto y manteniendo todas sus hojas. Enfriamiento suplemental toma lugar después de que la planta sea cosechada completamente desfoliada y ocurre en una temperatura constantemente fría y oscura (véase Foto 1 abajo).
Acumulación de enfriamiento, sobre todo enfriamiento suplemental, en el trasplante de fresa lo hace más fuerte y más hábil de sobrepasar los desafíos de ser trasplantado y el periodo productivo más allá.
Tal como se ha sacado através de mejoramiento de la fresa de UC algo de sensibilidad al enfriamiento en las variedades de Albion, Monterey y especialmente San Andreas, es posible cultivar estas variedades con cantidades de enfriamiento suplemental menor de lo recomendado de 10 a 18 días. Sin embargo, los productores quienes eligen de reducir el enfriamiento abajo de esta magnitud deben de reconocer el riesgo a lo que están entrando. Esto no es un ejercicio para novicios, de tal manera que si el clima o las condiciones del cultivo tornen desfavorables, las plantas con menos de lo recomendado del enfriamiento y el vigor careciente correspondiente sufrirán más que las plantas con lo adecuado. Aun más, mientras las variedades de UC de día neutro tratadas con menos enfriamiento de los 10 a 18 días recomendados sí pueden producir fruta más tempranas que las demás, debido probablemente a la fecha más temprana de plantación, estas plantas probablemente no producirán en forma optima en términos de rendimiento y calidad además de demostrar una tendencia de producir fruta más pequeña más tarde en la estación.
En único caso donde uno podría querría cortar el periodo de enfriamiento suplemental sería si la cosecha de los trasplantes es tan tarde que un mínimo de enfriamiento de 10 días resultará en una fecha de plantación tan tarde que se comprometerá el establecimiento y crecimiento de la planta nueva.
Afuera de eso, se mantiene la recomendación de dar a las variedades día neutro 10 a 18 días de enfriamiento suplemental.
Una caja de trasplantes, rumbo al frigorífico para el enfriamiento suplemental.
Review of Chill for the UC Day Neutral Strawberry Varieties Albion, San Andreas and Monterey
I had a conversation quite recently with Doug Shaw, UC plant breeder, concerning the concept of chill in the day neutral varieties and the desire of some Central Coast growers to reduce the recommended amounts significantly, even all the way down to zero days of chill:
In the way of review, please recall that chill requirement in strawberry in California is made up of two essential parts. One part is what the plant accumulates in the field before being harvested, and the other is accumulation of chill after harvest and the plant is in storage. There is a big difference between the two and one does not supplant the other. In-field chill takes place when the plant is still in the soil, out in the open and still has all its leaves. Supplemental chill takes place after harvest of the plant and occurs in a constant near freezing temperature, in the dark and the plant has none to very few leaves left (Figure 1 below).
Accumulation of chill, especially supplemental chill, in the strawberry transplant makes it stronger and better able to survive the stress of plant harvest, transplant and the growing season beyond.
As some of the chill sensitivity has been bred out of the modern UC day neutral varieties such as Albion, Monterey and especially San Andreas, it is indeed possible to grow these varieties with less than the recommended amounts (10-18 days) of supplemental chill. However, those who choose to reduce chill below these amounts should recognize the amount of risk they are taking and that this is not an exercise for those still using training wheels. Should growing conditions take a turn for the worse, these underchilled plants do not have the vigor to help them pull through and will suffer more than those adequately chilled. Moreover, while UC day neutral strawberry plants chilled significantly less than the recommended 10-18 days can produce fruit earlier than others (probably owing to the earlier planting date), these plants quite likely will not perform optimally in terms of overall yield and quality along with showing a tendency to produce smaller fruit later on in the season.
The only case where one would want to go short on supplemental chilling time would be if the plant harvest was so late that a minimum chill time of 10 days would result in a planting date so late that it would compromise plant growth and establishment.
Other than that, it is still recommended to give the UC day neutral varieties 10-18 days of supplemental chill.
Trimmed transplants being packaged in box with polyethylene lining, ready for placement into the cooler for supplemental chilling.