这里的strain什么意思?Twenty leading super rice strains will be cultivated by 2010,he said.

这里的strain什么意思?Twenty leading super rice strains will be cultivated by 2010,he said.
这里的strain什么意思?
Twenty leading super rice strains will be cultivated by 2010,he said.

这里的strain什么意思?Twenty leading super rice strains will be cultivated by 2010,he said.
品种