Effects Of AgNO₃, GA₃ & S-3307 On Rice Anther Culture And New Methods Of Ploidy Identification For Regenerated Plantlet

Since the first haploid plants were regenerated from rice anthers in 1968, anther culture has been widely integrated in breeding programmes of this cereal crop, thus permitting rapid production of homozygous DH lines from F1 hybrids. However, two problems were encountered with the development of rice anther culture. The first was low efficiency of anther culturability of rice, especially of indica. The second was cumbersome ploidy determination methods and chromosome duplication of regenerated plantlets obtained from rice anther culture. Some researches had been done and the primary results were summarized as following:1. The single and combinated effects of AgNO3, S-3307 and GA3 on anther culture of indica rice varieties were studied. After AgNO3 S-3307 and GA3 were supplemented to the callus induction medium or regeneration medium separately, the ratio of callus induction (CI) and frequency of green plantlet regeneration (GPR) increased significantly. Interestingly, a rebounding phenomenon of CI was found when AgNO3 was supplemented to the callus induction medium. The combination of two of the three supplements could promote CI and GPR. compared with CK. When S-3307 combinated with one of the other two, inhibitory actions were observed. The combination of AgNO3 and GA3 could promote CI and GPR. Thus, the supplement on rice anther culture might be optimal or not, dependent on the different combinated effects of materials supplemented to the medium.2. Stomatal (stomatal length, stomatal width, stomatal frequency, chloroplast number of guard cell) and morphological characters (plant height, length and width of penultimate leaves, length and width of antepenultimate leaves, glume length, glume width, anther length, anther width, panicle length) were evaluated in order to explore rapid indirect methods to identify haploids from diploids in anther-derived japonica rice plants. The results revealed that seven traits from the fourteen characters could be used to determine the ploidy levels of rice plants successfully. Of stomatal characters, stomatal length and chloroplast number could identify haploid plants from diploids. Of a series of morphological characters, five traits were available in determination of ploidy levels of rice plants. The results and methods performed in this study indicated that the efficiency of determining ploidy levels of anther-derived riceplants could be increased rapidly and the early determination of anther-derived rice plants could benefit anther culture before chromosome-doubling treatment.