EFFECTS OF DONOR PLANT-GROWTH STATUS AND PRECULTURE TEMPERATURE ON ISOLATED MICROSPORE CULTURE ABILITY IN JAPONICA RICE (ORYZA-SATIVA L)

The effects of donor plant growth status and preculture temperature on isolated microspore culture ability were investigated in japonica ric e. Although the duration of collecting materials in the field could be extended by arranging earlier or later sowing time, donor plants sown only in normal and earlier season could grow well, and microspores of these plants had a good culture response. The plating efficiencies of the three batches of donor materials sown on different dates were 1.5 1, 1.45, 0.28 calli for each plated anther, respectively, and only cal li derived from microspores of donor plants sown in the earlier and no rmal season had an ability to regenerate green plantlets. Moreover, th e microspore culture efficiency could be improved by using alternative temperature during preculture stage. The preculture of rice microspor es at 24 degrees C for 3 days followed by 27 degrees C for 2 days or 3 5 degrees C for 12 h followed by 27 degrees C for 4.5 days had a highe r culture efficiency than that of precultured at a sustained temperatu re 27 degrees C for 5 days. Besides, the culture efficiency was declin ed obviously if precultured at 35 degrees C for 1 day at first.