Banana is an agricultural crop that is reproduced by cloning. Which if the following statements best explains why banana crops are so vulnerable to devastating epidemics of pathogenic fungi and other pests? A. Banana plant clones are all the same genetically, so a disease strain that can attack one plant can attack all the plants in the crop B. Clones are more likely to acquire genetic mutations that make them susceptible to disease. C. Banana plants grow in the tropics, which contain a higher diversity of plant diseases. D. Banana plants have lowered fitness due to a greater frequency of homozygous deleterious recessive alleles.
The correct answer is A. Clones are genetically identical to each other and thus, if some pathogen can efficiently infect some plant, it will obviously infect its clones.
Some mutations may happen in clones and make them a bit different from each other. However, mutations are random and will not be the same in all clones. Thus, clones cannot acquire the same genetic mutations that make them susceptible to disease. At the same time, homozygous deleterious recessive alleles may lead to genetic disease, but not the infectious ones. Finally, banana plants are not only grown in tropics.