Research On Stress Resitance Realated Gene Of Heavy Ions Irradiated Maize

As a new means of radiation breeding, heavy ion irradiation mutagenesis technique isusually adopted in mutation breeding workflows. It has many advantages, including highlinear energy transfer (LET) values, high mutation rate, low physiological damage. In thisthesis, heavy ion irradiation mutagenesis techniques, molecular biology experiments and cropfield testing are combined to study maize (Zea mays L.) breeding. The main results are asfollows:(1) With heavy ion radiation technology, the genetic stable mutations were used byhybrid test in field to breeding new cultivars, which were named as FushengⅠ, Fusheng Ⅱand Fusheng Ⅵ. The mRNA level of the four resistance-related genes, ZmPPDK, ZmMnSOD,ZmPLC, ZmAtg8, after drought stress were assayed by quantitative PCR method, withZhengdan958as the control. Significance changes were observed in the fourresistance-related genes in all cultivars. With increasing of the stress time, the expression levelof different genes increased first and then decreased. After drought stress, the expression levelof resistance-related genes in FushengⅡwas higher than that of Zhengdan958.(2) After drought stress, the photosynthetic rates changed greatly in different cultivars ofmaize. Compared with Zhengdan958cultivars, Fusheng Ⅱcultivars has a higherphotosynthetic rates either in normal culture condition or in drought stress circumstances.However, FushengⅠand Fusheng Ⅵ cultivars have no significant difference compared withthe control. Based on the experimental results of photosynthetic rate, the expression of eachresistance-related genes and crop field testing, one can draw a conclusion that Fusheng Ⅱcultivars not only has high yield, high photosynthetic rates, but also has strong resistancecharacteristics.(3) After7Li heavy ion irradiation，the germination rate, plant height and seed proteindiversity of maize changed significantly. The above three traits all showed "saddle" like trendwith dose increase. Compared with the control, maize irradiated by10Gy dose7Li heavy ionshowed the most obvious changes.