It is not recommended. Grain harvested from a hybrid corn field gives rise to plants of the so-called second generation, or F2, which lose part of their hybrid vigor. In a study by Embrapa Maize and Sorghum, using second-generation seeds reduced grain productivity by an average of 20% to 30.5%, depending on the type of hybrid.
In the case of transgenic corn, there is an additional problem: F2 plants do not express the technology in the same way as plants from the original seed. Here is why.
A single-cross hybrid, the type that dominates the Brazilian market, results from crossing two inbred lines, that is, genetically pure lines. The seed from this cross is the F1 generation.
F1 plants are homogeneous and uniform, and express the so-called hybrid vigor, or heterosis: a performance superior to that of the lines that originated them. According to Embrapa, this maximum vigor only appears in the F1 generation.
The F1 plants in the field produce grain that is already the next generation, F2. When this grain is saved and planted, the genetic traits segregate, and the plants are no longer representative of the original hybrid.
According to an article available in the Embrapa repository, a field planted with F2 seeds does not have the same homogeneity and uniformity as a field planted with F1 seeds. With the loss of hybrid vigor, there is also a loss of productivity, which can be significant depending on the cultivar's genetics.
A study by Embrapa Maize and Sorghum, published in the journal Pesquisa Agropecuária Brasileira, compared 20 hybrids and their following generations in Sete Lagoas (MG) and Guaíra (SP). When second-generation seeds were used, the average reduction in grain production was:
Hybrid type
Average productivity reduction
Three-way hybrid
30.5%
Single-cross hybrid
27%
Double-cross hybrid
20%
In addition to the drop in production, the plants of the following generations had a longer cycle, with later flowering and more grain moisture at harvest, and were shorter, with ears set lower on the stalk.
The study dates from 1985 and evaluated hybrids available at that time. Therefore, the percentages found should be understood within the conditions and genetic materials evaluated in the research. Even so, the results demonstrate the effect of using second-generation seeds on agronomic traits and productivity.
In transgenic corn, the problem is greater. According to the article in the Embrapa repository, because of genetic segregation, F2 plants will not express the insect resistance and herbicide tolerance genes in the same way as F1 plants. As a result, crop management may be compromised.
In practice, the grower plants expecting the protection of the technology, but some of the plants may not have it. For those who use Bt corn, it is also worth understanding how the refuge area helps preserve this technology over the seasons.
Hybrid seed costs more because its production is expensive and time-consuming, and transgenic seed also includes the cost of the technology. That is why some growers save grain, thinking they will save money.
But according to the Embrapa article, the institution's studies have already shown that the higher cost of transgenic hybrid seed is more than offset by lower spending on pesticides. The article's conclusion is straightforward: there is no technical or economic justification for using F2 seeds.
Adding up the productivity loss, the uneven field and incomplete pest protection, saving on seed tends to cost dearly at harvest.
When replanting grain harvested from a hybrid corn, the grower is not planting the same hybrid again. In the F2 generation, genetic segregation occurs, with loss of uniformity and part of the hybrid vigor observed in the F1 generation, which can compromise crop performance.
That is why using new hybrid seeds every season allows you to start planting with the genetics, uniformity and agronomic traits expected for that hybrid.
Geneze Sementes, part of the Limagrain group, offers corn hybrids developed for production systems.
Start the next season by choosing the right genetics for your field.
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