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Use of herbicide-resistant genic male sterility in hybrid rice seed production

Kim, Sung Soo, Jung, Jae Youn, Jeong, Seung Kwon, Lee, Dong Sun, Chen, Li Juan, Suh, Hak Soo
Euphytica 2007 v.156 no.3 pp. 297-303
Oryza sativa, rice, transgenic plants, genetic transformation, Agrobacterium tumefaciens, herbicide resistance, reporter genes, glufosinate, plant fertility, hybrids, outcrossing
One of the difficult problems in hybrid rice seed production is the low outcrossing frequency and requirement for much labor to produce hybrid seeds. In order to simplify the process of hybrid rice seed production, herbicide-resistant photoperiod sensitive genic male sterile (HRPGMS) rice was utilized in this study. The herbicide resistance gene bar was transferred into the photoperiod sensitive genic male sterile (PGMS) rice 920S by Agrobacterium-mediated transformation and the HRPGMS line YA3530ms with good agronomic characteristics was bred by applying conventional pedigree breeding technique. The seeds of HRPGMS and pollen parent were mixed with the ratio of 4:1 in weight, and were sowed in seedling box. The mixed seedlings of HRPGMS and pollen parent grown for 30 days were transplanted by the small transplanting machine in the field. The herbicide glufosinate ammonium was sprayed at 7 days after flowering to kill all the plants of pollen parent, whereas hybrid seeds were harvested from the survived HRPGMS parent at maturity. The outcrossing frequency of HRPGMS line from two combinations in 2002 and from five combinations in 2004 were compared with a control cultivated by the conventional 2-line system. As the result, the mean outcrossing frequency in HRPGMS of the treatments were 10.6-24.5% compared with 5.5% in PGMS of the control in 2002, and that were 24.7-32.0% compared with 7.5% in the control in 2004. Consequently, using HRPGMS in two-line system was proved to be a new method that would simplify the process of hybrid rice seed production and to increase outcrossing frequency without any artificial supplementary pollination processes.