The difficulties of cultivation, such as climatic conditions, stimulate breeders to develop new, more resistant to different weather conditions, as well as to disease varieties.
Ihe isi ike nke ịkụ ihe, dị ka ọnọdụ ihu igwe, na-akpali ndị ịzụlite ịzụlite ọhụrụ, na-eguzogide ọgwụ dị iche iche na ọnọdụ ihu igwe dị iche iche, yana ọrịa dịgasị iche iche.