Segregation distortion detected in six rice F2populations generated from reciprocal hybrids at three altitudes

Abstract

SummaryThis paper presents investigations of segregation distortion of six rice F2populations generated from reciprocal F1hybrids grown at three locations varied at altitudes from 400 to 2200 m. The F1s were derived from reciprocal crosses between cv. XMG, which is ajaponicalandrace traditionally grown at 2650 m altitude, and cv. N34, which is ajaponicarestorer possessing a fertility restoring (Rf) gene and cytoplasm of male sterility (CMS) donated by anindicacultivar. Among nine morphological traits of the F2populations, only one was in normal distribution, eight were distorted in all or at least one population. Out of 16 polymorphic PCR markers, 10 markers distributed on 7 chromosomes were significantly distorted. Among these markers, RMAN7 and RM257 were distorted in both of the reciprocal populations, which suggested that nuclear genes had strong effects on segregation distortion. The other makers were distorted only in the populations with cytoplasm donated by XMG or N34. The results indicated that segregation of DNA markers was affected by cytoplasm background. Segregation distribution was also affected by altitude, since segregation distortions of most of the markers were detected not in all the three populations generated from F1grown at the three altitudes, but only in one population from F1grown at one altitude. Marker M45461, which is located withinRf-1locus, was severely distorted towards N34 in all the populations with cytoplasm donated by N34, but not in the populations with cytoplasm provided by XMG. The results indicated that interaction between CMS andRfgene had strong effects on distortion. Results of this study indicated thatjaponicacytoplasm did not cause distortion favouring a special parent, butindicacytoplasm made distortion favouring a maternal parent. The results suggested thatindicacytoplasm was not well compatible withjaponicanuclear background, whilejaponicacytoplasm did not have such trouble withindicanuclei. This study also found that the six F2populations were divergent into two groups due to difference of cytoplasm background.