The wide geographical distribution of the rice plant ( Oryza sativa L.) and its long history of cultivation in Asian countries have led to the development of a great diversity of varietal types. Similarly, workers in various rice-growing countries use different terms to designate identical morphological and physiological characters, agronomic traits, gene symbols, and cultural practices. Whereas varietal diversity in germ plasm is desired in rice breeding, variations in nomenclature hinder scientific communication among the workers. Workers long have recognized the need for uniformity in genetic nomenclature of rice. This led the International Rice Commission in 1959 to adopt a set of genetic symbols. Comprehensive reviews of genetic studies and linkage analysis have been published. The. | Technical Bulletin 4 December 1965 THE MORPHOLOGY AND VARIETAL CHARACTERISTICS OF THE RICE PLANT TE-TZU CHANG Geneticist and ELISEO A. BARDENAS Assistant Taxonomist Illustrated by ARNULFO . C. DEL ROSARIO Artist-Ilustrator THE INTERNATIONAL RICE RESEARCH INSTITUTE Los Banos Laguna The Philippines Mail Address Manila Hotel Manila CONTENTS Introduction . 3 Morphology of the Rice Plant . 5 Seedling morphology . 5 Vegetative organs . 5 Roots . 5 Culm . 6 Leaves . 7 Floral organs . 7 Panicle . 7 Spikelets . 7 Flower . 11 Trade Terms . 12 Growth stages of the rice plant . 12 Glossary of morphologic terms . 13 Botanical and Agronomic Traits Useful in Varietal Classification and Identification . 17 Seedling characteristics . 17 Adult plant characteristics . 18 Classification of cultivated varieties of O. sativa. 26 Mutant Traits . 27 Variations in anthocyanin pigmentation . 27 Variations in non-anthocyanin pigmentation . 27 Modifications in size and shape . 27 Presence or absence of structures . 28 Modifications in structure . 28 Modifications in chemical composition . 28 Modifications in growth habit . 28 Modifications in other physiological characters . 28 Glossary of mutant traits and gene symbols . 29 Acknowledgments . 32 References . 33 Subject Index . 36 Introduction The wide geographical distribution of the rice plant Oryza sativa L. and its long history of Cultivation in Asian countries have led to the development of a great diversity of varietal types. Similarly workers in various rice-growing countries use different terms to designate identical morphological and physiological characters agronomic traits gene symbols and cultural practices. Whereas varietal diversity in germ plasm is desired in rice breeding variations in nomenclature hinder scientific communication among the workers. Workers long have recognized the need for uniformity in genetic nomenclature of rice. This led the International Rice Commission in 1959 to adopt a set of genetic symbols. .
