One characteristic of hybrids is that they usually a【小题1】 a higher yield than c【小题2】 crops. However, whether it was possible to develop a hybrid of self-pollinating plants such as rice was a matter of great d【小题3】. The common a【小题4】 then was that it could not be done. Through i【小题5】 effort, Yuan o【小题6】 enormous technical d【小题7】 to develop the first hybrid rice that could be used for f【小题8】 in 1974. This hybrid e【小题9】 farmers to e【小题10】 their output greatly.