Propagation of

Seedless Watermelon

Beth Peske

                              

 

Figure 1: Seedless Watermelon

Introduction

How exactly are seedless watermelons grown?  I am hoping by the end of this report you will have a better understanding of the process.  This paper discusses the development of the seed, planting guidelines, requirements, pollination, and several varieties being offered.

 

I. Seed Development

A typical watermelon contains 2 sets of chromosomes, referred to as diploid (2N); whereas, a seedless watermelon is made up of 3 sets of chromosomes, called a triploid (3N).  In order to produce a 3N watermelon, the 2N watermelon needs to be crossed with a 4N (tetraploid) watermelon that is produced by a Colchicine treatment (see figure 2).

 

The 3N watermelon receives 1 set of chromosomes from one (the 2N or 4N) and 2 sets from the other.  By having an odd number, 3 sets of chromosomes, the 3N watermelon cannot divide evenly.  The odd division causes sterility in the plant; however, when pollinated, the plant is able develop fruit and the translucent hulls that contain nonviable eggs are unnoticeable when eaten.

 

Figure 2

 

 

II. Planting

There are two options one can use when planting seedless watermelons.  The first option is by direct seeding.  When planting the seed, planting depth and soil temperature are extremely important.  The seeds should be planted at a depth of 4 inches and soil temperature must be at least 70°F.  If any lower, germination will be greatly reduced.

 

The second option would be to grow the seed indoors. When growing indoors the temperature should remain at 75-85°F during germination.  Transplant in the garden when the plants have no more than 3 true leaves.  Any larger the growth will be stunted, producing poor yield.

 

It is important to purchase new seed for your seedless watermelons every year.  This is because the seed only lasts for 10-12 months.

 

III. Requirements

Being a warm-season crop, seedless watermelons will grow best in high temperatures.  Temperatures during the day should be around 80-95°F and night temperatures should be in the range of 60-70°F.  If the temperature drops lower than those listed, growth will decrease.

 

IV. Pollination

Like in all fruiting plants, the flowers (female) must be pollinated in order for fruit to be produced.  In watermelon production, there must be pollination that occurs between the seedless and the typical watermelon.  This is called cross-pollination.  This is an extremely easy process to accomplish.  Planting one third of your garden with the typical watermelon will greatly enhance the production of seedless watermelon.

 

V. Varieties

 

Seedless Rainbow Collection

Figure 3

Top left: Watermelon Everglade Hybrid

Top right: Watermelon Park's Lemon Ice Hybrid

Bottom: Watermelon Orange Sunshine

 

The variety, Watermelon Everglade, germinates in 80 days.  The fruit produced by Everglade can reach up to 14 pounds, the size of a bowling ball.  The rind offers a unique color, black!  Everglade also offers a beneficial thick rind, protecting the edible inside from being damaged.

 

The second variety, Park’s Lemon Ice, grows to be approximately a 15 pound oblong watermelon.  The rind resembles the typical watermelon color, dark green and light green stripes.

 

The last variety, Orange Sunshine, is stated to be the best tasting seedless watermelon, thanks to its high sugar content.  This variety is an oblong striped watermelon and can grow up to 12 pounds.    

 

VI. References

 

Park Seed Company.  2006.  Best Taste, Highest Yields, No Seeds! A collection of 3

varieties of seedless watermelon. http://www.parkseed.com/webapp/wcs

/stores/servlet/StoreCatalogDisplay?storeId=10101&catalogId=10101&langId=-1&mainPage=prod2working&ItemId=90245&scChannel=Top%20Ten%20Fruits.

 

Relf, Diane.  April 1997.  Seedless Watermelons. http://ext.vt.edu/departments

/envirohort/factsheets2/fruithome/mar94pr4.html.

 

Welsh, Dr. Douglas F..  2000.  Where Do Seedless Watermelons Come From?  http://

aggie-horticulture.tamu.edu/extension/newsletters/hortupdate

/may00/h5may00.html.

 

Pictures from:

 

Figure 1: http://www.azfamily.com/sharedcontent/features/dailyimages/090305melon.jpg

Figure 2: http://waynesword.palomar.edu/images/gordgen1.gif

Figure 3: http://www.parkseed.com/product_images/90245.jpg