Bioscience in brief
What are intraspecific or F1 hybrids?
How do you make an F1 hybrid? I
The first stage of hybrid seed development is the generation of the parent inbred lines. Selected plants are carefully pollinated by hand by taking pollen from the tassel (the male flower, drawn in pink in the illustration) and placing it on top of the ears (female flowers, yellow in the illustration).
The resulting seeds are harvested and planted, and the process (called selfing or inbreeding) is repeated for several generations (up to 7 or 8) to achieve genetic uniformity in the lines. This means that all the plants that are grown from the seeds from one plant look and respond the same way to the environment and to pests and diseases. Due to inbreeding depression – the reduced fitness of the plants due to low levels of genetic diversity- inbred lines also tend to be smaller and with lower fertility levels.
Inbred lines are screened for desired agronomic characteristics to match the requirements of the sites for which F1 hybrid seeds are being developed: suitability to environmental conditions such as soil type, climate and resistance to prevalent pests and diseases. Most of inbred lines generated during the first stage of the process of developing F1 hybrid seeds are discarded because they fail to meet the required agronomic characteristics.