RESUMO
OBJECTIVE: To breed a new variety from "86-70 selective line"--a late-maturing early indica rice variety with small spike, light grain and weak disease resistance by space mutation. METHOD: Dry seeds of "86-70 selective line" were carried by recoverable satellite, to a near earth orbit and sowed and planted on the earth after recovery, heritance and variation of the characters of SP1- SP9 generation were observed. RESULT: Because of comprehensive space mutation, the characters of their progenies were segregated and varied in many aspects and directions, and the segregated and varied characters were found to be heritable; by selecting early-maturing mutants from these progenies and cultivating them directionally, a new rice variety "Ganzaoxian 47 " was bred. In comparison with its parent, "Ganzaoxian 47" had superior agronomic and economic characters, significantly strong resistance to rice blast and so on, its filled grains per spike [correction of spile], kilo-grain weight and yield were increased by 37.9%, 5.3% and 22.5% respectively, but its growth and developmental duration were shortened by 14 d. CONCLUSION: This study provided a new demonstration for space mutation breeding by recoverable satellite, and indicated that space mutation was an effective and new approach to agricultural crops breeding.
