Hybrid Maize Revisited

Over the years ECHO has been asked to give advice concerning whether or not to use hybrid seed. We carry very few hybrid varieties in our seed bank because we expect people who receive seed to multiply it locally. Now some new information about this old question, specifically about maize, has come to our attention.

In an article in EDN 64, we discussed the effect of introducing hybrid maize seed in Nicaragua after hurricane Mitch. Farmers in that area had traditionally used open-pollinated (OP) maize varieties and saved their seed. There was concern that introducing hybrid maize varieties might contaminate the local maize.

We concluded: “Assuming that the new hybrid was adapted to the growing conditions in Nicaragua, planting it should not result in disaster—in fact it may confer some genetic material to existing varieties that would prove beneficial.” There is now evidence that this has in fact happened in Mexico through a process called “creolization.” We found information about it in a paper from the International Food Policy Research Institute (IFPRI) titled “The Impact of Improved Maize Germplasm on Poverty Alleviation: The Case of Tuxpeno-Derived Material in Mexico” (Mauricio R. Bellon, et al. Food Consumption and Nutrition Division Discussion Paper No. 162, IFPRI, 2003.)

The Research Method

The study was undertaken to determine how farmers in lowland tropical Mexico use improved maize germplasm, and if it was helping to alleviate poverty in selected communities in Oaxaca and Chiapas. Farmers were found to use improved varieties, traditional varieties (commonly referred to as landraces) and varieties that they recognized as crosses between hybrids and landraces (these crosses were called “creolized” (acrillado)).

For 40 years the government has promoted improved varieties of maize—both hybrid and open-pollinated. Recent traditional studies that focused on comparing traditional with improved varieties found that only about one quarter of the maize planted in the country was of an improved variety.

In this study the researchers, taking a social science approach, asked farmers to classify their maize seed more broadly. They asked what characteristics other than yield were important to them. The results were also analyzed among different income levels: “extreme poor,” “poor” and “non-poor.”

The researchers found that farmers classified maize seed into two broad groups: either “variety” maize, that is, seed from a bag; or “creole” (criollo), a term that includes recycled, creolized and traditional land races.

However the farmers do recognize that “variety” maize will become “creolized” over time to become “creole” or traditional. The authors were able therefore to confidently classify the maize seed planted as: 1) Hybrid (from a bag); 2) Recycled hybrid—hybrid seed that has been saved and replanted up to 4 years; 3) Improved Open Pollinated Varieties (from a bag or recycled for up to 4 years); 4) Creolized—recycled from 4 to 15 years; or 5) Landrace—not from a bag, planted for many years and usually bearing the name of a known race of maize.

The poorer farmers in Oaxaca tended to use creolized and landrace varieties more than improved varieties. In Chiapas, about half of the acreage of poor farmers was planted to creolized and landrace maize. The two main reasons given were economics and confidence levels. Farmers expressed more confidence in the landraces and creolized varieties than in the improved varieties, because they had seen the former growing and felt they had become acclimatized. These varieties were saved from one season to the next, sometimes traded socially, and if purchased, were significantly less expensive than seed sold in bags.

The Creolization Process

Maize became creolized over time through crossing between varieties that were planted near each other. Sometimes, but not often, this was done deliberately.

Improved varieties also became creolized as farmers saved seed from fields sown to those varieties. Scientists referred to this process as “recycling.” Both hybrid and OP varieties were found to be recycled. A variety that had been recycled more than 4 years was considered creolized, and after 15 years became a traditional landrace variety.

Conclusions

The research team concluded that improved varieties of maize do eventually benefit the poor farmers because the local varieties are improved through the process of creolization. Some of the implications of this conclusion are:

1. Introducing improved varieties of maize is a good thing— as Dr. Hallauer was quoted in EDN 64: “the introduction of new genetic material may…improve the performance of the local open-pollinated varieties.”
2. Characteristics other than yield need to be considered in comparing maize varieties in field trials and in selecting seed for maize improvement efforts. Some of the more important characteristics identified by farmers in this study were resistance to lodging, ease of shelling and yield of dough (masa) when making tortillas.
3. Maize breeding does not stop when a variety is released. This phenomenon has also been recognized in the recent emergence of “participatory plant breeding” as a crop improvement strategy.
4. Any maize extension program should include a component that helps strengthen the ability of the farmers to deliberately identify and select for traits that are important to them.
5. Do not rule out hybrid seed corn just because farmers may not be able to continue purchasing seed. Farmers will likely not have serious problems if they save seed from the hybrid varieties. Importantly, some of the superior genetic traits will be passed on to local varieties planted nearby. With careful annual selection of the best corn for seed, gradual year-to-year improvement in “creolized” local varieties is quite possible.
6. Help farmers learn to explain what qualities are most important to them and then help them learn how to select for those traits. (see Amaranth to Zai Holes, pp. 77-78)

Where can you get improved seed? Whenever possible, try to test varieties promoted by the national research institute of your country, even if they are hybrids.

Another option for trial-size quantities of maize seed is to contact CIMMYT, the international research institute in the CGIAR system responsible for maize. Tell them what organization you work for and what in particular you are looking for. The more specific you can be about the climate, soil and other environmental conditions or any specific problems farmers are facing with maize, the better they can help. Contact information: CIMMYT; Apdo. Postal 6-641; 06600 Mexico, D.F., Mexico; Tel: +52(55) 5804-2004; Fax: +52(55) 5804-7558. http://www.cimmyt.org/