The Capsicum genus, which originates from the American continent, contains species with a chromosome number of n=12. The plants have white, lilac or purple flowers, and hollow fruit of very varied shape and size, containing glands alongside the veins that produce a pungent alkaloid known as capsaicin. The majority of varieties in the species C. annuum, grown in the largest volume throughout the world and consumed as fresh vegetables or ground spices, are non-pungent. Interspecific crosses are often possible between C. annuum and related, white-flowered species, thus facilitating breeding for resistance against various diseases and pests and the search for new, valuable traits. Species with lilac and purple flowers can be crossed with each other, but direct crosses with white-flowered species are unsuccessful.
We have found a form of resistance lacking host cell death, effective in cucumber against infection of
, in bean against
, as well as in pepper against the Obuda pepper virus and
. In addition to the own pathogens of the host plants, this defense reaction, accompanied by cell enlargement and stimulated cell division, was also efficient against pathogen species that are in incompatible relationship with the given host plants (the nonhosts). This general defense reaction may manifest itself in different intensities: in cell enlargement of only a few plant cells or enlargement and proliferation of cells to such a degree that results in compaction of even larger tissue parts.