Hint: Plants within a certain group that are less vulnerable to attack by plant pests or diseases are resistant varieties. These are also indicated by codes in seed catalogues, which can differ from company to company.
Improving yield stability through the production of disease-resistant crops is one of the major challenges to food security in the 21st century. The lack of molecular tools, growth logistics, generation time and detailed genetic annotations, hence the power of model plant species, is often impeded by crop research. The use of models, especially the use of mutants, has largely influenced our knowledge of plant immunity today. Plants are exposed to a wide variety of pests and pathogens, including bacteria, fungi, oomycetes, viruses, nematodes and insects, but this contributes to disease only in particular encounters. However, due to pre-harvest pests and pathogens, an average of 26 percent of global crop production is lost each year.
These solutions must be successful, with no adverse effect on plant agronomy, and deployed thoughtfully for use in the field. Often, a possible allergen or toxin must not be added. For local solutions, expensive enforcement of biotech crops is prohibitive. Breeding is very labor intensive and time consuming for durable disease resistance. It may take decades to integrate single gene resistance, which is the most straightforward form of quality to pick, into a marketable plant product. By crossing them with wild varieties that have a disease resistance gene, our crops could be made disease resistant. This helps to develop a new breed that is highly disease resistant and carries the characteristics of existing crops.
Hence, the correct answer is (B) By crossing them with their wild relatives.
Plant disease resistance defends plants in two ways from pathogens: by pre-formed structures and chemicals, and through the immune system's infection-induced responses. Plants are consistently immune to certain pathogens but succumb to other resistance.