“块茎”的英语？

马铃薯是块茎植物.The potato is a tuber plant.由这类马玲薯产生的块茎中茎斑驳症状不易观察到.In tubers from such potatoes stem mottle symptoms are rarely observed.芽长成新株,新株生出新的块茎.The buds grow into new plants which produce new tubers....