Identification and characterization of somatic rice chromosomes by imaging methods.

Somatic rice chromosomes from 30 spreads were analyzed by imaging methods. Morphological characters of each of the 12 rice chromosomes were obtained both by the imaging methods and by visual inspection. The numerical data of relative length, arm ratio, and condensation pattern (CP) were statistically analyzed. The descriptive morphological information obtained was also summarized into numbers of "key characters" or essential short sentences to characterize the traits. The fitness probability or the appearing frequencies of the key character for each of the 30 chromosomes was calculated. Altogether, 118 key characters were extracted to distinguish each rice chromosome. Furthermore, several "discriminants" or critical key characters were determined among the key characters, and a discrimination chart or flowchart to identify all the rice chromosomes was constructed using the discriminants.