Charles A. Mullins

1All cultivars performed well. ‘Dividend’ had a high marketable yield, heavy fruit, a high smoothness rating, but was rated as relatively light in color. ‘Dividend’ was one of the least attractive zucchini type cultivars. ‘Fortune’ and ‘Cougar’ outyielded ‘Dixie’, ‘Sunglo’, and ‘Suwanee’of the yellow fruited cultivars. The straight neck cultivars generally had higher yields than the crookneck cultivars. Fruit of ‘Gentry’ were very smooth.

Summer squash is grown in home gardens and in large commercial acreage in Tennessee. Squash is grown commercially for fresh market and for processing. Squash has been one of the most profitable fresh market vegetable crops in recent years, especially in the fall season. ‘Dixie’ has been one of the major yellow crookneck cultivars for many years, although many new cultivars are available and are recommended for production in Tennessee. Likewise ‘Senator’ has been a major zucchini type cultivar, but many other outstanding cultivars are available. Many of the new cultivars have mildew and/or virus tolerance. An experiment was conducted at the Plateau Experiment Station at Crossville, TN in 2000 to evaluate performance of 15 summer squash cultivars.

The site was prepared for planting by conventional tillage in late April. Fertilizer was broadcast at 300 lb/A of 15-15-15 before final disking on June 2. Plots were direct seeded on June 2. Plot size was one row, 10 ft long and contained 10 plants with 5 hills (2 plants/hill) each spaced 2 ft apart in the row. Rows were spaced five feet apart. Experimental plot design was a randomized complete block with four replications. Plots were cultivated for weed control on June 26. Carbaryl (Sevin XLR) at 1 lb ai/A was applied for insect control on July 5.

Eight harvests were made between July 14 and August 2. Yields were recorded by number and weight of marketable, oversize, and cull fruit. Fruit were measured for length and diameter, and rated for characteristics at the July 31 harvest date. Three to five fruit were used for these determinations. Ratings were made on a 1 to 10 scale with 10 being the smoothest, straightest, darkest, or most attractive appearance.

Maturity was very concentrated for all cultivars as only eight harvests were made, but yields were in the expected range. Production appeared to have ceased and no more harvests were made after August 2. ‘Dividend’ was among the most productive cultivars, and ‘HMX 9728' was among the least productive zucchini type cultivars in marketable yield (Table 1). The zucchini cultivars produced more oversized squash than the yellow cultivars. ‘HMX 9728' produced one of the highest yields of oversized zucchini-type fruit while ‘Cashflow’ and ‘HMX 8714' produced a lower yield of oversized fruit. ‘Dixie’ produced more oversized fruit than ‘Fortune’ of the yellow fruited cultivars. Marketable fruit of ‘Dividend’ weighed more than marketable fruit of any other cultivar. Marketable fruit of ‘Sunbrite’ weighed more than marketable fruit of ‘Gentry’ and ‘Sunglo’ of the yellow fruited cultivars. ‘Cashflow’ and ‘HMX 8714' were longer than ‘Hurricane’ and ‘Sensation’ of the zucchini cultivars. ‘Fortune’ was longer than ‘Gentry’ and ‘Sunglo’ of the yellow fruited cultivars. Fruit diameter was similar for most cultivars, but ‘Suwanee’ had a larger diameter than ‘Sunglo’.

The length to diameter ratio was larger for ‘Cashflow’ than for ‘Sensation’ of the zucchini type and for ‘Enterprise’ than for ‘Gentry’ and ‘Suwanee’ of the yellow fruited cultivars (Table 2). All cultivars were rated high for smoothness. ‘Sunbrite’, ‘Sunglo’ and ‘Suwanee’ were among the most curved squash and would be classed as yellow crookneck. ‘Dixie’ fruit had less curvature than in most years. ‘Dividend’ was lighter in color than all zucchini-type cultivars except ‘Sensation’. The yellow cultivars were rated very similar in color. ‘Dividend’ was rated as one of the least attractive zucchini type cultivars, but was not unacceptable in appearance. ‘Gentry’ was rated as a highly attractive yellow fruited cultivar.

Table 1. Yield of summer squash cultivars evaluated at The University of Tennessee Plateau Experiment Station at Crossville, 2000.