Source: Answers to AgProfessional editor questions and StollerUSA news release.

Farmers know that for optimum pollination to occur plants require a specific and ideal temperature range. With the increasing temperature trend or instability in weather patterns, many growers are experiencing true yield drag due to high heat conditions at the critical pollination stage.

As farmers evaluate yields and factors impacting yields, increasing temperatures should rank among the top concerns. Experts have tracked carbon dioxide levels in the atmosphere increasing from 332 parts per million (ppm) to 360 ppm in the last 50 years. At a plant level this increases photosynthesis but also increases the likelihood of extreme high heat temperatures, according to researchers at StollerUSA.

In answer to this common grower concern, researchers at Stoller are conducting studies on how to improve pollination in high heat conditions. They know that when the temperature exceeds the optimum level for fertilization of pollen tubes, the results are abortion of both flowers and young fruit. The lack of sugar movement in the plant's cells into the male organ of the plant is the root cause for lower pollination and yields in all crops.

A recent study monitored the movement of sugars in the plant and synthesis level of a key enzyme, invertase. As temperatures were increased beyond the optimal level researchers noted that the level of invertase was greatly reduced.

When a proprietary formulation of cytokinin manufactured by Stoller, X-Cyte, was applied to the plants, researchers witnessed a measurable increase in the levels of the invertase enzyme and the level of successful pollination.

"It appears that the high heat inhibits plants from synthesizing enough cytokinin for proper pollination," summarizes Ron Salzman, Ph.D., director of biosciences at Stoller Enterprises. "With a simple foliar application we can overcome this natural plant reaction, improve the levels of invertase and improve crop yields."

Although further studies are underway, the early first results indicate a foliar application of X-Cyte increases the flower activity and fertility on most crops. To date, X-Cyte has been successfully used to promote cell division in plants where the root system needs to be re-established due to severe stress, for normal growth of new roots, leaves, seed, storage tissue or fruit. The pollination promotion is a newer discovery.

Most of Stoller's work has been done with corn and wheat, although soybeans, barley, cotton, rice, peanuts and canola have also been included in initial studies. Of all the crops in agricultural production, corn is the most sensitive to temperature variation during the time of pollination. Each crop tends to have a unique temperature where maximum fertility is obtained. As the temperatures increases above this amount, fertility begins to decrease, notes Salzman.

Jerry Stoller, president and CEO of Stoller, is confident of determinations his company's researchers have made about the timing of an X-Cyte application to impact pollination. "The application of X-Cyte in order to stimulate pollination and flower fertility must be made approximately two to seven days before the pollination or flower period occurs. For corn and wheat, it should be applied at tassel appearance and seed head appearance. For crops like soybean or cotton, it should be applied approximately at the 10 percent flowering stage since the early flowers are always more fertile. It is the later flowers that have weaker pollination. This application may need to be repeated on multiple flowering crops every 14 days after 10 percent flowering has been observed," he said. But he also notes a single application should have "a very high degree of relevance."

"A yield increase will be dependent upon how excessive the temperatures are at the time of pollination and flower fertility. The higher the temperatures, the greater the yield increase will be as compared to the untreated plants," Stoller contends.

"There is also indication that the application of X-Cyte will have a significant benefit during the periods of low moisture conditions. Since the moisture evaporation from the plants acts as the plant's air conditioner, the plant leaves, tassels and flowers will be greatly increased if there is a lack of evapotranspiration (loss of water through evaporation from the leaves)," he also said.

Research has shown that it is not uncommon to receive yield increases from 10 percent to 30 percent over control plots depending upon the severity of the temperatures during this critical period, according to Stoller's early research.

StollerUSA's mission is to help producers enhance yields by maximizing genetic expression. Stoller products contain proprietary technology to ensure optimum plant growth and yields by maintaining appropriate hormone balance in combination with supporting nutrients. StollerUSA is celebrating 40 years in agribusiness. It is based in Houston and actively engaged in basic and practical research to enhance crop productivity in more than 50 countries.