A group of researchers from North Carolina State and Purdue universities have identified a winning combination for pollenizers of seedless watermelon varieties.

They found three pollenizer varieties that not only shed substantial amounts of male pollen but also are resistant to Fusarium root rot, according to a news release.

Seedless watermelons need male pollen from a seeded variety to set fruit.

But because seeded watermelons have fallen out of favor in many areas of the country, growers either don't harvest the seeded pollenizers or sell them for a fraction of the price of seedless varieties.

More recently, several seed companies have offered pollenizer varieties that produce male pollen but set very small fruit, taking up less space in a seedless watermelon field.

In trials led by Chris Gunter, NCSU assistant horticultural science professor, the researchers found three pollenizer varieties produced the most male flowers—SP-1, Sidekick and 5WDL 6146, according to the release.

They also looked at the time of the bloom, since male flowers need to be shedding pollen when female blossoms are open and receptive.

In addition, the researchers evaluated varieties for resistance to Fusarium wilt, which can kill or stunt susceptible plants.

Of the top pollen producers, Sidekick and 5WDL 6146 also were more resistant to Fusarium wilt.

Although the varieties Ace and Pinnacle were even more resistant to Fusarium wilt, they produced fewer male flowers.

Daniel Egel, an Extension plant pathologist at Purdue University in Vincennes, Ind., co-authored the article on pollenizers with Gunter that was published in the October issue of HortTechnology.