Researches on Variation Effects of Two Three-Line Hybrid Rice Maintainer Line of Space Mutants

The variations in traits of space mutated offspring of two maintainer lines of three line hybrid rice, HT-B and Y Huanong B, were studied. The results showed that the SP₁ generation displayed varying degrees of impairment ingerminationrate, bud length, and seeding height, but no evident variation in the other economic traits was found compared with the control. Positive and negative variations in several agricultural traitsemerged in SP₂ and SP₃ generations and an unusually wide range of variations were discovered in amylose content (AC) from extremely low AC（w=1.66%） in waxy mutantand to extremely high AC (w=38.03%) in non-waxy mutant. The pollen sterility and the selfing mature rate of the offspring from test cross between SP₄ mutants and their correspondent male sterile lines were also studied. The maintaining ability for male sterility greatly varies in the space mutants, and completely fertile strains found in the offspring from the test cross are promising resources for novel elite maintainer lines.