Rice Genetics IV - IRRI books - International Rice Research Institute

● The Rockefeller Foundation established an International Program onRice Biotechnology in 1985.● Yamada et al obtained regeneration from protoplasts in 1985.● McCouch et al constructed the first molecular genetic linkage map in1988.● Transgenic rice plants were produced first by three groups: Toriyama etal, Zhang and Wu, and Zhang et al in 1988.● The Second International Rice Genetics Symposium was held at IRRI in1990 and a uniform chromosome numbering system was established.● The Rice Genome Research Program (RGRP) began at Tsukuba in 1991.● Ahn and Tanksley constructed comparative linkage maps of the rice andmaize genomes in 1993.● The yeast artificial chromosome (YAC) library in rice was establishedby the RGRP and a bacterial artificial chromosome (BAC) library by Wanget al in 1995.● The first agronomically important gene in rice, Xa21, was cloned bySong et al through map-based cloning in 1995.● The Third International Rice Genetics Symposium was held in Manila in1995 and the correct orientation of morphological and molecular geneticmaps was established.● An international network on rice genome sequencing was established in1998 under the leadership of the RGRP.● Projects on functional genomics began in 1999.Rice is now the model plant for genetic research among crop plants. However, thiswas not the case till about 15 years ago. In fact, the status of rice genetics was farbehind that of maize, wheat, tomato, and barley. An agreed system of chromosomenumbering in rice did not exist. Linkage groups were poorly known and their independencehad not been tested. Nomenclature for gene symbolization was not uniformlyfollowed and rice geneticists had no platform to discuss and enhance internationalcollaboration in rice genetics. However, a series of events starting in 1985 havecontributed much to elevate rice to its present state of preeminence. Here we reviewthe major milestones in rice genetics during the 20th century.Rice karyotypeKuwada (1910) first reported the basic chromosome number (n=12) in rice from thestudy of microsporogenesis, megasporogenesis, and mitosis. Since then, many workershave confirmed this number. The somatic chromosomes of rice, however, are verysmall and difficult to distinguish from each other. The individual chromosomes areeasy to identify at the pachytene stage of meiosis and Shastry et al (1960) describedthe pachytene chromosome complement for the first time. They numbered the chromosomesin decreasing order of length, with the longest as 1 and the shortest as 12.Kurata et al (1981) also analyzed the pachytene chromosome complement of Japa-4 Khush and Brar