|Vasal, Surinder - CIMMYT, MEXICO|
|Oscar-Lizarazu, Oscar - CROP&SOIL, OSU, CORVALLIS|
Submitted to: Book Chapter
Publication Type: Book / Chapter
Publication Acceptance Date: July 15, 2005
Publication Date: December 15, 2005
Citation: Vasal, S.K., Oscar-Lizarazu, O., Jauhar, P.P. 2005. Genetic enhancement of maize by cytogenetic manipulation, and breeding for yield, stress tolerance, and high protein quality. Genetic Resources, Chromosome Engineering, and Crop Improvement 64:159-197, CRC Press, Boca Raton, FL. Technical Abstract: Maize (Zea mays L.), a cross-pollinated crop of worldwide importance, was domesticated from its wild progenitor teosinte, some 6,250 years ago. It occupies an important position as a food, feed, and industrial grain crop, contributing to global grain pool of 1800 million metric tons annually. It is grown on 140 million hectares with a production of about 600 million metric tons valued at 65 billion US dollars. It constitutes a staple human diet consumed in a variety of ways in at least 22 countries, mostly in Africa and Latin America. Being a C4 plant, it exhibits a great yield potential per unit of land, has wide adaptation, and surpasses other crops in genetic variability and diversity occurring naturally or created through conscious breeding efforts over the last 70 years. Maize is also a unique organism for cytogenetic research. Genetic, cytogenetic, and phylogenetic evidence suggest that maize (2n = 20) is an ancient segmental allotetraploid, although it is a functional diploid. More importantly, it lends itself to cytogenetic manipulation. In this article we provide an overview of basic cytogenetics of maize, its cytogenetic manipulation, and germplasm enhancement by incorporating chromatin from other cereals, and its improvement by traditional breeding. An in-depth treatment is given to heterosis breeding for stress tolerance and improved nutritional quality. The development of quality protein maize is a scientific breakthrough and a great success story, whose fruits are being conveyed to several developing countries. The use of apomixis as means of harnessing hybrid vigor is also described. The information provided in this article should help further genetic improvement of maize to help feed an ever-increasing human population.