38. Cytoplasmic-genetic male sterile Japonica varieties

James Taillebois and Elcio Perpetuo Guimaraes

Brazilian National Research Center for Rice and Beans CNPAF/EMBRAPA CP179 47000 Goiania GO, Brazil


We tried to sterilize five upland Japonica varieties (IRAT 103, IRAT 141, IRAT 313 and IRAT 314) through the use of five cytoplasmic male sterile lines having different sources of cytosterility (V 41 A, Wu 10A, Yar-Ai-Zhao A, P203A and MS 577A). The results are given in Table 1.


Table 1. Sterilization of different upland varieties with diverse male sterile cytoplasms.

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Varieties                                  cm lines
                    =========================================================
                    V41-A      Wu10A     Yar-Ai-Zhao A   P203A     MS5777A
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IRAT 103              S*        S**         S**           F**       PF\s\**
IRAT 141              PF**      S**         -             F*        S*
IRAT 144              PF\s\**   PF\s\**     S*            F*        S*
IRAT 313              S**       PF\s\**     S**           F*        S*
IRAT 314              S**       PF**        S*            -         S*
=============================================================================
S=total sterility; PF=spikelet fertility between 5% to 50%; F=spikelet fertility between 50% to 100%; s=segregation for spikelet fertility; *= observation of BC2; **=observation of BC3



We have obtained male sterile upland lines with four of the five cytoplasms. Only the cytoplasm of P 203 A was unable to induce sterility. The F\1S\ of P230A with IRAT 103, IRAT 141, IRAT 144 and IRAT 313 were completely sterile but the backcrosses to these varieties yielded partially to completely fertile progenies. These results show that the cytoplasm of Wu 10A and P203 A which were considered identical are in fact different.

These Japonica male sterile lines will permit the determination of restorer/maintainer relationships of Japonica varieties without encountering intervarietal hybrid sterility problems.