Rice Genetics Newsletter, Vol. 17

2.	*Tagging of an elongated-uppermost-internode gene eui2* using microsatellite markers**
	S.L. YANG¹, H.L. MA¹, Q.P. XUE², B. WANG² and R.C. YANG¹ 1) 1nstitute of Genetics and Crop Breeding, Fujian Agricultural University, Fuzhou, 350002. 2) 1nstitute of Genetics, Chinese Academy of Science, Beijing, 100101, China

Elongated uppermost internode gene is very useful for seed producition of hybrid rice. If the gene is incorporated into the restorer parent of hybrid rice, it would be somewhat taller. A taller restorer parent would aid windblown pollen dispersal on the semidwarf

male sterile parent in hybrid seed production plots (Rutger and Carnaham, 1981; Virmani, 1988). When incorporated into sterile line, this gene would cause better exertion of panicles (Shen et al. 1987).

So far, two eui genes have been reported. One was identified as a mutant in a japonica variety by Rutger and Carnahan (1981). Librojo and Khush (1987) located it on chromosome 5 through the use of primary trisomics. Wu et al. (1999) found a RFLP marker, RG435 on chromosome 5 linked with eui at genetic distance 33.6 cM. Another such gene eui2, was a mutant from an indica parent XQZeB-2 (Yang et al. 1999). We determined the location of eui2 gene using microsatellite markers.

An F₃ population was produced from F₂ individuals from the cross of XQZeB-2 (with eui2) x AJNT (with Eui) to identify molecular markers linked with the eui2 gene. Bulk segregant analysis was performed using microsatellite. One hundred and eighty-six microsatellite markers were screened. Fifty-four homozygous plants (Eui / Eui or eui / eui) from F₃ population were surveyed. The linkage analysis with Mapmaker 3.0 revealed that eui2 was linked to RM258, RM269, RM271 and RM304 located in the middle of long arm of chromosome 10. The genetic distances from the four markers to eui2 were 12.0 cM, 12.9 cM, 35.1 cM and 1.4 cM, respectively (Fig. 1). It was thus confirmed that eui2 is located on chromosome 10.

The identification of eui2 makes it possible to develop hybrid rice with sterile lines (A lines) and restorer lines (R lines) possessing different eui genes which would reduce the need for application of GA3 for both of parental lines.

References

Librojo, A.L. and G.S. Khush, 1986. Chromosomal location of some mutant genes through the use of primary trisomics in rice. In: Rice Genetics, IRRI, Manila. p 249-255.

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

Shen, Z., C. Yang and Z. He, 1987. Studies on eliminating panicle enclosure in WA-type MS line of rice (Oryza sative subsp. indica). Chinese J. Rice Sci. 1(2): 95-99. (in Chinese)

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

Wu, Y., Z. He, J. Dong, D. Li, H. Lin, J. Zhuang, J. Lu and K. Zheng, 1988. The RFLP of Tagging of eui gene in rice. Chinese J. Rice Sci. 12(2): 119-120. (in Chinese)

Yang, R.C., S.L. Yang, Q.Q. Zhang and R.H. Huang, 1999. A new elongated uppermost internode gene. RGN 16: 41-43.