So crop breeders must race to develop varieties with the right R genes before new disease strains render existing varieties useless.

因而农作物培育者需要赶在新型疾病使现有品种失去价值之前，开发具有正确的R基因的品种。

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So crop breeders must race to develop varieties with the right R genes before new disease strains render existing varieties useless.

因而农作物培育者需要赶在新型疾病使现有品种失去价值之前，开发具有正确的R基因的品种。

youdao