Origin, domestication, taxonomy, botanical description, genetics and cytogenetics, genetc diversity and breeding of cashew (Anacardium occidentale L.)

Cashew belongs to the family Anacardiaceae, the genus Anacardium and species A. occidentale. Cashew is considered native of tropical America, not-withstanding the uncertainty in defining its natural distribu-tion, due to its long association with man. It was suggested that it originated in the restinga, meaning the low vegetation found in the sandy soil along the coast of Eastern and Northeastern Brazil. Anacardiaceae is a moderately large family consisting of Ca 74 genera and 600 species. It is subdivided into five tribes, namely Anacardieae, Spondiadeae, Semecarpeae, Rhoeae, and Dobineae. The tribe Anacardieae consists of 8 genera, namely, Androtium, Buchanania, Bouea, Gluta, Swintonia, Mangifera, Fegimanra and Anacardium. Within Central and South America as many as 20 species of Anacardium are known to exist. Anacardium L. is a small genus of trees, shrubs and sub-shrubs indigenous to the tropics. Some authors report 10 species and others until 20 species. It is native to Latin America, having a primary center of diversity in Amazon and a secondary center in the Planalto of Brazil. Of all, only cashew (A. occidentale) is of economic importance because of its edible apple and nutritious kernel. The cashew tree (Anacardium occidentale L.) is indigenous to Brazil and is an evergreen nut-bearing tropical plant that grows in latitude 15° north and south of the equator. There is a fact that not everyone knows about cashew fruit, this is a dry, non-self-opening fruit, kidney-shaped, about 2 to 3 cm long, hard outer shell, sunken face. The tree produces a long, fleshy stalk, called a cashew apple, which resembles a small pear. The color may be red, yellow or mixture of colors. The mature cashew apple can be eaten fresh as well as cooked. At the end of this stalk grows the kidney-shaped cashew nut that many know and love. Because of that, we often assume that the bulging stem is the fruit, and the “cashew nut” is the seed. Cashew is a source of food, income, industrial raw materials and foreign exchange for many countries of Africa, Asia and Latin America. Morphologically, the architecture of cashew tree makes it a foremost tree crop for reclaiming land area to enhanced productivity, through the prevention of desertification and soil erosion. The drought resistant, evergreen cashew tree is economically grown for its nut, apple and wood. Products derived from the nuts include the world’s highly delighted roasted kernel snacks, kernel oil, cashew nut shell liquid, and from the apple: juice, jam and alcohol among others. Cashew wood is also used for furniture and fishing boats. Of all, cashew nut is the most economic part of the cashew tree providing foreign exchange earnings for producer countries. Cultivation and processing activities in cashew provides employment and income generation for women and smallholder farmers. Women are particularly involved in the cashew sub-sector more than in any other cash crop. So far 61 varieties in India have been released for cultivation as a result of evaluation of germplasm collection and hybridization and selection. These varieties have been released from different research centers of SAUs and DCR (formerly NRCC). Among them 34 are selections and 27 are hybrids. Soft wood grafting technique has been found to be the best method of propagation and it is recommended for commercial multiplication of cashew varieties. In this review article Origin, Domestication, Taxonomy, Botanical Description, Genetics and Cytogenetics, Genetc Diversity, Breeding, Uses, Nutritional Value, Health Benefits of Cashew are discussed.