Study On Dedifferentiation Characteristics From Immature Wheat Embryos In Guanzhong District Of Shaanxi Province

In order to select the optimum genotype for immature embryo culture, immature embryo from 12 common wheat genotypes included the improved cultivars and lines in Guanzhong district of Shaanxi province were cultured on both mediumI (MS with 2,4-D) and mediumll (MS with 2,4-D and KT), and the dedifferentiation Characteristics was investigated. In addition ,effects of embryo size, inoculation method and 4℃ treatment time on callus induction were discussed. The results showed:(1) Time of callus formation among the cultivars was obviously different. Qianjinzao that induced callus at 100% was only after inoculated 5 days, while other cultivars had not achieved after cultured for 25 days. 75.0%of the 12 cultivars relatively evenly formed callus.(2) The callus induction frequencies ranged from 66.4%~ 100.0% among the materials, and 75.0%of them induced callus at more than 90%.(3) The embryogenesis callus formation rates ranged from 0.0%~48.1% among the tested materials. Majority of materials had relative parallel in the tendency of higher or lower frequency through the actual frequency fluctuated between the two media. The fact implied that the trait might be stably expressed. The embryogenesis callus formation rates could be promoted by KT.(4) The direct germination of cultured immature embryos was observed. The germination frequency was varied with the cultivars and media. Of the cultivars, the highest was Shanong 78, at 53.7%, and the lowest was just 9.5%. The germination frequency could be increased by KT. However, the direct germination might be efficiently restrained by using the medium with lower KT and suitable 2,4-D. The suitable induction medium was MS+2,4-D2.0mg/L+KT0.2mg/L.(5) In conclusion, of the tested genotypes, Xiaoyan22, Shanmai150 and Xiaoyan6hao displayed excellent tissue culture response due to the higher callus induction frequency and more excellent somatic embryogenetic competence.(6) When different ages of immature embryos were cultured , their frequencies of callus induction and of embryogenic callus induction were significantly different . In YangLing district, the suitable age of immature embryos of XiaoYan22 was 14d.Scutella up was better inoculation method.