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.
============================================================================= Varieties cm lines ========================================================= V41-A Wu10A Yar-Ai-Zhao A P203A MS5777A ============================================================================= 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.