A new gene for elongated-uppermost-internode

14. A new gene for elongated-uppermost-internode R,C. Yang, S.L. R.H. Huang and Q.P. Zang Institute of Genetics and Crop Breeding, Fujian Agricultural University, Fujian 350002, China J.N. Rutger and Carnahan (1981) reported that elongation of the uppermost internode was controlled by a recessive gene eui. Virmani (1987) transferred the eui gene to indica restorer rice IR50, by backcrossing. He and Shen (1987) developed a new CMS line Zhen-ChangA without panicle enclosure by introducing eui gene into Zhenshan 97A. In 1998, we identified two types of mutants possessing elongated uppermost internode from M2 population of Xieqingzao B (XQZ B) treated with r-rays, and designated the mutants as Zieqingzao eB- l(XQZ eB-l) and Xieqingzao eB-2 (XQZ eB-2). Both mutants showed longer cuim length than that of origin parent, XQZ eB-l being the longest (Table 1).. However, the increased cuim length of XQZ eB-2 is completely due to elongation of the uppermost internode, and the increased culm length of XQZ eB-l is due not only to the elongation of the first uppermost, but also the elongation of the lower internodes. The proportion of uppermost internode length to entire cuim length among XQZ B, XQZ eB-1 and XQZ eB-2 was 54.6%, 65.0%, 54.3%, respectively, and that of the second internode was 27.9%, 22.2%, 32.2%, respectively. Therefore, it was assumed that eui gene of XQZ eB-2 may be different from that of XQZ eB-1. The culm length of F, plants of XQZ eB-1 / XQZ B, XQZ eB-2 / XQZ B and XQZ eB-2 was similar to that of XQZ B. The culm length of F2 plants of XQZ eB-1 / XQZ eB-1 / XQZ B and XQZ eB-2 I XQZ B were grouped into two types. One corresponded to the cuim length of XQZ B and the other to the cuim lengths of XQZ eB-1 or XQZ eB-2, and their segration ratios showd a good fit to 3:1 - These results showed that single recessive genes are responsible for cuim length modifications. The F2 plants of XQZ eB-1 I XQZ eB-2 segregated into three types, corresponding to the cuim length of XQZ B, XQZ eB-1 and XQZ eB-2. The data showed a good fit to the 9:3:4 ratio. Thus, it was concluded that the recessive genes for modification of cuim length of XQZ eB-1 and XQZ eB2, are nonallelic. The F1 plants of XQZ eB-2 11R50-eui showed normal semidwarf height. However, the F1 plants of XQZ eB- 1 / 1R50-eui had elongated culms. These results indicated that the recessive gene of XQZ eB-2 is non-allelic to eui, and the recessive gene of XQZ eB-1 is allelic to eul. This gene was designated as ew2. References Rutger, J.N. and Hi... Carnahan, 1981. A fourth genetic element to facilitate hybrid cereal production �a recessive tall in rice. Crop Sci. 21: 373-376. Virmani, S.S., RD. Dalmacio and M.T Lopez, 1988. eui gene for elongated uppermost internode transferred to indica rice. IRRN 13(6): 6. He Zuhua and Shea Zongtan, 199!. Inheritance of panicle exsertion and improvement of male sterile line rice. QineseJ.RiceSci.5(!): 1-6.

14. A new gene for elongated-uppermost-internode
R,C. Yang, S.L. R.H. Huang and Q.P. Zang

Institute of Genetics and Crop Breeding, Fujian Agricultural University,
Fujian 350002, China

J.N. Rutger and Carnahan (1981) reported that elongation of the uppermost internode was controlled by a recessive gene eui. Virmani (1987) transferred the eui gene to indica restorer rice IR50, by backcrossing. He and Shen (1987) developed a new CMS line Zhen-ChangA without panicle enclosure by introducing eui gene into Zhenshan 97A. In 1998, we identified two types of mutants possessing elongated uppermost internode from M2 population of Xieqingzao B (XQZ B) treated with r-rays, and designated the mutants as Zieqingzao eB- l(XQZ eB-l) and Xieqingzao eB-2 (XQZ eB-2).

Both mutants showed longer cuim length than that of origin parent, XQZ eB-l being the longest (Table 1).. However, the increased cuim length of XQZ eB-2 is completely due to elongation of the uppermost internode, and the increased culm length of XQZ eB-l is due not only to the elongation of the first uppermost, but also the elongation of the lower internodes. The proportion of uppermost internode length to entire cuim length among XQZ B, XQZ eB-1 and XQZ eB-2 was 54.6%, 65.0%, 54.3%, respectively, and that of the second internode was 27.9%, 22.2%, 32.2%, respectively. Therefore, it was assumed that eui gene of XQZ eB-2 may be different from that of XQZ eB-1.

The culm length of F, plants of XQZ eB-1 / XQZ B, XQZ eB-2 / XQZ B and XQZ eB-2 was similar to that of XQZ B. The culm length of F2 plants of XQZ eB-1 / XQZ eB-1 / XQZ B and XQZ eB-2 I XQZ B were grouped into two types. One corresponded to the cuim length of XQZ B and the other to the cuim lengths of XQZ eB-1 or XQZ eB-2, and their segration ratios showd a good fit to 3:1 - These results showed that single recessive genes are responsible for cuim length modifications. The F2 plants of XQZ eB-1 I XQZ eB-2 segregated into three types, corresponding to the cuim length of XQZ B, XQZ eB-1 and XQZ eB-2. The data showed a good fit to the 9:3:4 ratio. Thus, it was concluded that the recessive genes for modification of cuim length of XQZ eB-1 and XQZ eB2, are nonallelic.

The F1 plants of XQZ eB-2 11R50-eui showed normal semidwarf height. However, the F1 plants of XQZ eB- 1 / 1R50-eui had elongated culms. These results indicated that the recessive gene of XQZ eB-2 is non-allelic to eui, and the recessive gene of XQZ eB-1 is allelic to eul. This gene was designated as ew2.

References

Rutger, J.N. and Hi... Carnahan, 1981. A fourth genetic element to facilitate hybrid cereal production �a recessive tall in rice. Crop Sci. 21: 373-376.

Virmani, S.S., RD. Dalmacio and M.T Lopez, 1988. eui gene for elongated uppermost internode transferred to indica rice. IRRN 13(6): 6.

He Zuhua and Shea Zongtan, 199!. Inheritance of panicle exsertion and improvement of male sterile line rice. QineseJ.RiceSci.5(!): 1-6.