Scientists at the international rice research institute ( irri ) doubt it is possible to improve productivity as much as is needed through better farming practices or the adoption of new strains derived from conventional cross - breeding 国际粮食研究所的科学家们怀疑人们还能通过提高种植技术和采用传统杂交技术产生的新稻种来提高粮食产量,以便满足需求。