Also in the 1960s, another development would worsen this slippery slide towards seed dependence. U.S. seed companies introduced their commercial version of the F1 corn hybrid developed decades earlier in the public sector.6 (F1 means the first filial generation after crossing two different parental lines). Unlike heirloom varieties, F1 hybrids did not breed true. When their seeds were replanted, the offsprings' characteristics segregated and the desirable traits were expressed weakly or irregularly in subsequent generations. So, regardless of the benefits the current crop offered, saving seeds became pointless.
Corn farmers had to buy hybrid seeds from the seed suppliers every planting season. Obviously they still had the option to go back to traditional varieties, but government technicians promoted the hybrid varieties aggressively and extended highly subsidized credit to farmers who used them. So the use of F1 hybrids among corn farmers grew.
As more farmers abandoned their traditional corn, these varieties became scarce and gradually disappeared. Commercial hybrid corn varieties eventually dominated the seed corn market, like the HYVs did among rice farmers. But with a difference. If seed buying had been an occasional purchase in the past when seeds produced their own kind, hybrids led to repeat sales season after season, turning seeds into highly profitable commodities.
As the seed business became more profitable, giant agrochemical firms began buying up the seed companies that had established themselves in the market. A similar corporate trend towards F1 hybrids emerged in the vegetable sector and, later, in the rice sector, a trend that continues today.7 8 9
F1 hybrids mark the beginning of corporate efforts to gain full control over seeds, especially in major staple crops and vegetables. They also represent the first technology in agriculture explicitly meant to end the farmers' age-old practice of saving part of their harvest to use as seed in the next planting season. This counter-productive technology strikes at the very heart of sustainability and the seed commons.
Commercial seed breeders took care that non-hybrid varieties would remain under their control too. Their demand for exclusive rights over varieties they developed eventually gave rise to the 1961 Convention for the Protection of New Varieties of Plants. This convention defined plant breeders' rights, mandated plant variety protection and established an international union, the UPOV, to work for plant breeders' interests. As countries acceded to UPOV agreements, they moved to adopt counter-productive national seed laws that limited the freedom of farmers to exchange seeds or to sell them. Subsequent UPOV agreements (1972, 1978, 1991) became more and more restrictive of farmers' rights.10
It was a two-pronged offensive against seed-saving and exchange: the technology of hybrids and new laws and international agreements restricting farmers' options over seeds.