By John Lewis, Horticulturist
Over the winter months many of you would have been thinking about what strawberry varieties to order and how many to plant this coming spring. There are a few new ones to consider and perhaps it isn’t too late to order a few plants to see how they perform at your location. My experience is that strawberry varieties can perform very differently on different soil types and in different climates so it is important to take it slow with new varieties, starting with a couple rows next to your old standbys to see how they compare.
A good example on an on-farm test plot for new varieties was conducted from 2009-2011 at Webster Farms in the Annapolis Valley on their ‘Cornwallis’ sandy soils and warmer Valley growing season. Like all good growers, the Webster’s do the research first and make sure a new variety is well adapted to their site, management practices, and marketing needs before making any significant investment in larger plantings. Table 1 shows the first and second year yields of several standard varieties and upcoming varieties of interest.
A few things are particularly noteworthy about the data. First off, you can see how much the yields and fruit size can vary from first to second harvests, some increasing and some decreasing, demonstrating the importance of more than one year of harvest data before making any conclusions. Case in point, Wendy’s yield dropped significantly in the second season while that of the three numbered varieties out of the Kentville breeding program jumped dramatically in the second harvest. Interestingly, plant establishment by the latter three lines was slow in the planting year and probably accounted for the relatively poor first year yields.
Yield decline in the second harvest year may indicate plant mortality to root rot diseases like the “black root rot complex” or ‘Phytophthora’ species. If you have soil pathogen issues on your farm, it is even more important to evaluate new varieties on your farm under these conditions. A variety description may indicate resistance to a pest such as Phytophthora fragariae (red stele disease) but there are numerous races of this pathogen and no single variety is resistant to all of them. Also, the races occurring on a given site vary and unless you test a so-called ‘resistant’ variety on your site you will not know if it is resistant to the races present in your soil.
Getting back to the Webster trial data, how did individual lines/varieties perform at this site? In the early season category, no variety was as early as the standard variety ‘Wendy’ but ‘K93-20’, newly named ‘Laurel’, was closest. The yield of Laurel was very similar to that of Wendy but the fruit size was smaller, particularly in the second year. Observationally, the most distinguishing characteristic of Laurel was its flavour, which was described as exceptional, making it a winner for U-Pick operations.
There really wasn’t an early midseason standard variety in the trial but a variety like ‘Brunswick’ would fit this category and would have been interesting to compare with early-midseason lines like ‘K04-12’ and ‘K04-21’ out of the Kentville breeding program, ‘Darselect’ out of France, and ‘La Clé des Champs’ out of Quebec. From a yield standpoint, Darselect had the best yields of the four varieties, accompanied by very good fruit size. Harvest observations described this berry as “large, orange, firm with average to good flavour”. The only negative comment was that berries sometimes appeared dull or lacking a shine or bloom that we often associate with healthy berries. The literature notes this characteristic about Darselect and there are reports that it can be remedied with periodic magnesium sprays. Overall, I was impressed with this variety over the two years and think it would be particularly suited to distant shipping where size, firmness, and shelf-life are essential traits.
The yields of the other three early mid-season varieties were similar but La Clé des Champ and K04-21 had slightly larger berries. La Clé was described as being a “pretty berry that was easy to pick, but was very soft with a sometimes bland flavour”. K04-21 was an exciting berry in that it had an “excellent flavour and a firm, almost crisp texture” but variable fruit size, and problems with pollination in the second fruiting year were a concern. Surprisingly, K04-12 appears to be the most promising of these three due to its “excellent appearance, firmness, flavour, and ease of picking”, despite its average yield and fruit size.
The two later mid-season varieties in the trial were ‘Mira’ and the Kentville selection ‘K99-22’. Unfortunately, yield data was not collected in the first year for Mira but it was reported to have been excellent and with good size. Second year yields were still very good but fruit size fell off rapidly and was the lowest in the trial in the second harvest year. Fruit were also described as being “tart and stemmy”. Although the second year yield of K99-22 was comparable to Mira, its first year yield was quite low, probably due to poor stand establishment. In contrast to Mira, fruit size of K99-22 was excellent and was consistently so over the two harvest years, and the berry was described as having “a beautiful bright red bloom with large fancy hulls”. Flavour was rated average to excellent and berries were reported to be firm and easy to pick. The size and greater quality traits of K99-22 over Mira warrant a closer examination of this variety at Webster Farms.
There were two late season varieties evaluated in the trial – ‘Valley Sunset’, the new late season variety out of the Kentville breeding program, and ‘Record’, a late season variety from Italy. Looking at the yield, fruit size and season data you would think these were the same variety but in quality and appearance they were much different at Webster Farms. While Record was positively described as having large, uniform, fairly firm berries, it was negatively reported to have a pinky-orange color that often appeared “grubby”. It was reported to be difficult to pick, tended to free-hull, and had a bland, sometimes off-flavour that was undesirable. Angular leaf spot and proneness to Botrytis fruit rot were also negative features noted for this variety at Webster Farm. Conversely, Valley Sunset was described as a “large, firm berry with good texture, flavour, and appearance”. Berry size held well through harvest, although king berries were sometimes rough in appearance, occasionally with green tips and there was some sunscald reported with this variety. Certainly of these two late varieties, Valley Sunset was the better performer but its susceptibility to sunscald in the hot Annapolis Valley climate is a concern.
In conclusion, it is important to recognize that these results are site specific and should be a guide only to other growers. They are meant as an encouragement to get out there and set up your own trials! On-farm variety trails such as reported here are easy to conduct and need not be replicated. Single rows of new lines and varieties can provide outstanding insights on performance at your location. Take care to protect the plots and collect the yield data carefully. Equally important, take careful observations on berry appearance, firmness, flavour and ease of picking - yield and fruit size matter little if any of these other measures are unacceptable. Lastly, take at least two years of harvest data as specific weaknesses or strengths of varieties often don’t show up until a second harvest.