Chapter 16 Agrobacterium-Mediated Genetic Transformation of Peanut Agrobacterium-Mediated Genetic Transformation of Peanut P. Bhatnagar-Mathur V. Anjaiah P. B. Kirti Kiran K. Sharma INTRODUCTION Legumes are important sources of dietary proteins and fats in developing countries of the semiarid tropics where peanut (Arachis hypogaea L.) is one of the important food legume crops. It is a rich source of protein (23 per- cent) and edible oil (43 percent; Norden, 1980) and is considered one of the principal economic crops of the world. The genus Arachis belongs to the subfamily Papilionaceae of the family Fabaceae. It is native to South Amer- ica and comprises diploid (2n = 20), tetraploid (2n = 40) and octaploid (2n = 80) species. Peanut is a seed-propagating, self-pollinating crop originating from Brazil. The geographical classification of peanut is delineated into six re- gions: the Americas, Africa, Asia, Near East, Europe, and Oceania (Greg- ory et al., 1980). The total area under peanut cultivation is over 24.8 million hectares and the world’s production is over 32.8 million tons per year, with an average yield of 1.32 tons per hectare (Rao and Nigam, 2001). India is the major producer of peanut, with a total production of 8.9 million tons per year. Peanuts are utilized in several ways; the edible oil is important for hu- man consumption and the meal is used for livestock feed. It is also used di- rectly for food in industrial countries including the United States, Canada, and the European Union. Handbook of New Technologies for Genetic Improvement of Legumes © 2008 by The Haworth Press, Taylor & Francis Group. All rights reserved. doi:10.1300/5424_16 227