Adaptive Winter Squash

Winter-Squash-Excel-Document

Our breeding project (San JosexWaltham) is more productive than other squash we have grown.

• Weather: the 2017 season was relatively cool and wet. Squash were transplanted the first week of May, and we began harvesting the first week of August, through frost in late October, with the main harvest coming the third week of August. It rained at some point in the day more than half of the days (53) during the 105-day growing period. There were only 14 days at 90 degrees or above, most of them coming in mid-to mid- late July. Average high temperature was 84. (In other words, it was not hot or dry this season. Two values that we would like to develop resistance for.)
• All varieties were affected by Downy Mildew. We had early infection this season: all varieties had leaf lesions by the end of May (typically we see in early to mid-June). All varieties grew past infection to still produce crop. Varieties most affected based on initial loss were: Segualca (25%), Noob Taub (10%), Cuban Neck Pumpkin (10%), and Greek Sweet Red (10%). A low average weight (Nutterbutter and JMS6823), reduced storage ability (Nutterbutter, JMS6823, and Segualca), and bland flavor (Carrizo, San Jose Mountain Club Squash, Thai Kang Kob, and South Anna) also suggest significant stress either because of Downy Mildew or humidity or heat or a combination of all of the above.
• We did not have extensive insect pressure this season. Although spotted cucumber beetles (early in the season) and squash bugs (Coreidae) (late in the season) were present, they were not present in significant enough numbers for us to consider them a factor in overall production.
• We created a “Resistance Value” based on # of fruit, %loss, taste, and storage. Although it is not completely comprehensive, we do believe that it accurately reflects heat, drought, insect, and disease resistance on our farm. To calculate, we divided # of fruit/plant average by 3 (our minimum goal for production) then multiplied by 100 to give a 100s value number and then multiplied that number by .4 (as we decided that overall production was the most important value based on discussion with farmers and amongst ourselves). We gave taste and storage value equal weight. We calculated the taste value by multiplying taste number first by 10 to give a 100s value number and then multiplied that number by .25. We calculated storage value by assigning 0, 25, 50, 75, or 100 to a given variety based on how long it stored and then multiplied it by .25. Finally, we subtracted percentage loss from 100 and multiplied it by 0.1. Because most of our plants typically survive stress but justproduce poorer quality fruits, we gave %loss the lowest percentage value (10%). If  percentage loss numbers were more significant, we would increase this percentage.
• Based on this resistance value, the best performing varieties were: San JosexWaltham cross, Upper Ground Sweet Potato 2017, Upper Ground Sweet Potato 2016, Tahitian Butternut, and Ayote (in that order). Note that none of these varieties produced our minimum of 3 fruit/plant.
• Also, note that our goal is a butternut-shaped fruit. None of the best performing varieties are a strictly butternut-shaped fruit. San JosexWaltham cross produces a butternut shape but also produces a pumpkin-type and a bell. We hope to be able to select for the butternut shape. Tahitian Butternut produces a very long neck butternut that is too large for many of our CSA members. Tahitian Butternut could likely also be selected for a shorter neck. The other three (Upper Ground Sweet Potato 2016 and 2017 and Ayote) do not appear to have butternut genetics.
• Another one of our goal is a 3-4 lb. fruit. That is the size that our CSA members have been the happiest with. All of our best performing squash except for Tahitian Butternut are too large in their current form. However, we did not separate out genetic lines of San JosexWaltham cross when weighing. It is likely that the butternut-shape is less heavy than other shapes. We may be able to select for a smaller San Jose cross just by selecting for butternut shape.
• Taste is obviously a subjective value. It includes both taste and texture as compared to butternut squash. These values reflect the opinion of 17 of our CSA members. Taste tests were performed on 11/4/17. Taste of some varieties can improve in storage. At this point, all squash had been in storage for at least 2 months. A note: our CSA members loved Upper Ground Sweet Potato 2016 (seed selected on our farm). They gave it an “11”. If you are not worried about other parameters such as size and shape, it is a great squash! It would be particularly good for holiday dishes such as pies.

Evaluating-Winter-Squash

Year Two Data Summary:

• Weather: 2018 was a more typical growing season than 2017.  Although our rainfall for the year was quite high, rainfall during the squash growing season was average, as were temperatures.  It still was not reflective of the hotter or drier seasons, such as 2011, 2012, 2015, or 2016, alnd therefore, we still do not have any data that reflects heat and drought resistance.  
• There was much less Downy Mildew this season.  It arrived later (early June) than 2017, and did not have the humid conditions that allowed it to thrive in 2017.  I also think that we have narrowed in on several quite resistant varieties, and thus, DM pressure was less evident.  We did not loose any squash plants to DM pressure this season prior to fruiting.  Also, although subjective, many of our CSA members and taste testers remarked that these were the best squash that they had ever tasted, which reflects less stress.  
• We used the same “Resistance Value” we developed in 2017 based on # of fruit, %loss, taste, and storage. Although it is not completely comprehensive, we do believe that it accurately reflects heat, drought, insect, and disease resistance on our farm.  Based on this resistance value, the best performing varieties were: San JosexWaltham cross, Greek Sweet Red, Tahitian Butternut, Upper Ground Sweet Potato and VA Select (in that order). Note that none of these varieties produced our minimum of 3 fruit/plant.
• 2018-Winter-Squash-Harvest-and-RV 
• Also, note that our goal is a butternut-shaped fruit. None of the best performing varieties are a strictly butternut-shaped fruit. San JosexWaltham cross produces a butternut shape but also produces a pumpkin-type and a bell. We hope to be able to continue to select for the butternut shape. Interestingly, the best producing plants (225, 226, and 227) were all butternut shape, so we will breed off of this stock.  Tahitian Butternut produces a very long neck butternut that is too large for many of our CSA members. Tahitian Butternut could likely also be selected for a shorter neck. Greek Sweet Red is also much too large and Upper Ground Sweet Potato does not have butternut genetics. 
• Another one of our goal is a 3-4 lb. fruit. That is the size that our CSA members have been the happiest with. All of our best performing squash, except VA Select, are still too large. However, the best performing squash from our cross all weighed about 4.5#. By continuing these gene lines, we should arrive at a 4# squash.
• Taste is obviously a subjective value. It includes both taste and texture as compared to butternut squash.  All best performers received between 7-9.  For San JosexWaltham Cross, please see detailed taste opinions in that file.  There is still quite a bit of variability, although it corresponds with gene pool and shape, allowing us to breed quite easily.  Two of the best performers (225 and 226) received 10 for taste, which is qutie encouraging to us.  
• Community-Reviews-SJ-Cross-Gene-Pool
• We plan to continue breeding and selection work using #225, #226, and #227 (and possibly #443) with the help of Crooked Road Farm in Knoxville, TN.  We also have identified some potential pumpkin genetics (#224, #443, and #447) that Anna Laura Reeve and Jessica Tezak will grow out for us in their community gardens in 2019.