[Studies on character variation of parent of "Ganzaoxian 47" by space mutation]

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.

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.

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.

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.