What are the problems associated with hybrid rice breeding?
In contrast to inbred rice variety development, hybrid rice breeding is more complicated, costly, and technologically intensive. F1 hybrid seed that is sold to farmers is produced every year by crossing two genetically different inbred lines; the parental inbreds are selected for crossing because they give rise to highly productive, heterotic F1 hybrids. Because rice is a naturally inbreeding species, it is difficult to obtain high levels of out-crossing, due in large part to the enclosed floret morphology that helps to enforce the inbreeding habit. To encourage outcrossing, hybrid rice breeders use a male sterile lines (generally either a two-line or the three-line system), but it remains challenging to achieve reliable and economically viable levels of out-crossing during F1 hybrid seed production.
In contrast to inbred rice variety development, hybrid rice breeding is more complicated, more costly and more technologically intensive. F1 hybrid seed that is sold to farmers is produced every year by crossing two, genetically different inbred lines; the parental inbreds are selected for crossing because they rise to highly productive, heterotic F1 hybrids. Because rice is a naturally inbreeding species, it is difficult to obtain high levels of out-crossing, due in large part to the enclosed floret morphology that helps to enforce the inbreeding habit. To encourage outcrossing, hybrid rice breeders use a male sterility system (generally either a two-line or the three-line system), but it remains challenging to achieve reliable and economically viable levels of out-crossing during F1 hybrid seed production.
