Transgenic cotton varieties, commercially available since 1996, have been widely adopted in the Mid-South. One would expect that toxins inside a plant to control insects and the ability to spray a broad-spectrum herbicide over the top of the crop would reduce production risk. Certainly they provide flexibility in farm management.

In this article we take the data from a replicated study and look at the variability of returns associated with different transgenic technologies in cotton.

Field studies were initiated in 2001, 2002 and 2003 at the Northeast Research and Extension Center (NEREC) at Keiser, Ark., and the Southeast Branch Experiment Station (SEBES) at Rohwer, Ark.

Roundup Ready, Bollgard, stacked gene and conventional cotton varieties were planted at each location each year.

All the plots were managed to maximize yields according to University of Arkansas Cooperative Extension Service recommendations. Herbicide systems and insecticide applications were chosen on the basis of the genetic capabilities for each cultivar.

At both locations, the two center rows of each plot were machine harvested.

Plot yields were multiplied by the base Arkansas Commodity Credit Corporation loan rate to arrive at gross returns for each treatment.

Treatment costs — including seed and technology fee, herbicide, insecticide, and application costs — were determined for each cultivar and subtracted from gross returns to calculate the returns over weed and insect control costs per cultivar.

Fourteen cultivars were grown over the three-year period. We divided them into four technology groups: conventional, Roundup Ready, Bollgard, and stacked gene. Each cultivar tested contained four replications in each year. The mean, standard deviation, and coefficient of variation of returns were calculated for each technology group.

There are multiple ways to measure and analyze risk. One way is to compare the coefficient of variation between alternative investments. The coefficient of variation tells us how many dollars of risk are associated with each dollar of expected return. Thus it utilizes both the level of profit expected and the amount of variation in that profit.

In southeast Arkansas the stacked gene technology provided the greatest average returns and the lowest coefficient of variation. There was 35 cents of risk associated with each dollar of return.

In northeast Arkansas the Roundup Ready technology provided the greatest average return and the lowest coefficient of variation with 37 cents of risk associated with each dollar of return.

This is a somewhat simplistic comparison of transgenic technologies and certainly does not paint the whole picture for selecting cotton varieties. This analysis is limited by the cotton varieties that were chosen to use in the study. We continue to analyze profitability and production risk associated with new technology.

This one data set seems to indicate that in southeast Arkansas the stacked gene varieties have been a good choice for farmers. In northeast Arkansas, the Roundup Ready varieties appear to be a good fit.

As you select varieties and make other farm management decisions, your county Extension agents have access to information that can help.

Many of the details of the study cited in this article are published in the proceedings of the 2004 Beltwide Cotton Conferences held at San Antonio, Texas.