Panicle Development of A lines and R lines in Hybrid Rice Seed Production

Abstract

In order to set a planting plan of A and R lines for their synchronization to increase efficiency of hybrid seed production, the study was conducted in Pathum Thani Rice Research Center during 2006-2008 using 5 A lines and 7 R line. There were 2 experiments, the effect of planting date on panicle development of A lines and R lines under field condition and the effect of planting date on phyllochron interval and panicle development of A lines and R lines in pot experiment. It was found that the difference in duration of panicle development among 5 A lines and 7R lines and planting date. For A lines, IR79156A and IR80156A showed the most variation of panicle development, while IR80151A showed the least variation. For R lines, HR02001-2-3-3-1-7-2R showed the most variation of panicle development, while JN29-11-1-B-12-5-5R showed the least variation. A lines showed quicker panicle development and emergence than R lines in all varieties. Therefore, to set a planting plan of hybrid rice seed production, R lines must be planted before A lines. The rate of phyllochron interval on A lines main stem was 5.0-5.6 days/leaf and on R lines main stem was 5.4-6.2 days/leaf. The total leaf number of A lines and R lines were in the range of 13.5-15.4 and 15.7-17.5, respectively. Four promising hybrid rice varieties were PTT06001H, PTT06029H, PTT06008H and PTT06022H. The planting plan of their A and R lines was to plant R lines 3-21 days before A lines, depending on the combination and planting date. Alternately, A lines should be planted after R lines reach a stage of 2.0-6.1 leaf development.