Chengdu Institute of Biology, Academia Sinica, Chengdu 610015, China
Esterase isoenzymes of rice have been analyzed in most cases with seeds. This study aims to identify interspecific hybrids. The use of seeds is not desirable not only because F1 seeds are limited on account of crossing barrier, but the seeds are destroyed when used for analysis. We have used leaf blades for isozyme analysis.
The blades of flag leaves were sampled from male-sterile lines 765-5A and 209A and an autotetraploid line 77021 of Oryza sativa, an O. officinalis and an 0. grandiglumis strain, and their hybrids obtained by the embryo rescue method.
Table 1. Expression of esterase bands 9A, 10A and 12A from flag leaf-blades
of parents and hybrids
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Material Cross 9A 10A 12A
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O. sativa, 765-5A Female - + ++
O. sativa, 209A Female + ++ -
O. sativa, 77021 (4X) Female - - +++
O. officinalis Male ++++ +++ ++++
765-5A x O. officinalis F1 ++++ + + ++++
209A x O. officinalis F1 ++++ +++ ++++
77021 x O. officinalis F1 ++++ +++ ++++
O. grandiglumis Male + + ++
765-5A x O. grandiglumis F1 ++
209A x O. grandiglumis F1 ++++ +++ ++++
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++++ Maximum staining strength, - Null.
Polyamide gel electrophoresis was used for esterase analysis.
A total of 47 anodic bands were found and numbered 1A to 47A according to their decreasing mobilities. Of these, 9A, 10A and 12A showed higher staining strength and larger width than other bands, and were called "characteristic" bands.
Observations of the three bands in the parents and hybrids are shown in Table 1. Three O. sativa strains had one or two of the three bands. O. officinalis had all the three bands. Its hybrids with O. sativa also showed the three bands. In O. grandiglumis, only 12A was stained strongly. Its hybrids with O. sativa showed either 12A (X765-5A) or 9A and 10A (X209A).
Cytological identification of hybrids is difficult because of small chromosome size, and identification by morphological characters is sometimes unreliable. The Est isozymes sampled from juvenile to flag leaves are stable and useful for identification.