Expression Characteristics and Borer Resistance of Bt Gene of Transgenic cry1C~* Super Japonica Rice

[Objective] The paper was to study the expression characteristics and borer resistance of Bt gene of Songjing 9 （1C^＊）. [Method] With super japonica rice Songjing 9 as the receptor, transgenic crylC^＊ super japonica rice Songjing 9 （1C^＊） regulated by ubi promoter was created by agrobacterium-mediated genetic transformation method. Ten strains of transgenic super japonica rice formed from different transformation events were planted in the field; the Tt-mRNA of leaf, stem-sheath and young spikelet at booting stage were detected by real-time fluorescent quantitative PCR; the Bt protein content of leaf, stem-sheath and young spikelet and harvested brown rice were detected by enzyme-linked immunosorbent assay （ELISA）; the white head rate damaged by Chilo suppressalis was manually investigated. [Result] The Bt-mRNA and Bt protein content of various organs and Bt protein content of mature brown rice at booting stage of Songjing 9 （1C^＊） significantly differed among strains; there was no correlation relationship in Bt-mRNA and Bt protein content between leaf and stem-sheath, between leaf and young spikelet, and between stem-sheath and young spikelet; there was no relation between Bt-mRNA or Bt protein content of leaf, stem-sheath and young spikelet and Bt protein content of brown rice; there was positive correlation between Bt-mRNA and Bt protein content in the same organ such as leaf, stem-sheath and young spikelet at booting stage; such strains as Songjing 9 （1C^＊）, whether the Bt gene expression was high or low, showed good resistance against C.suppressalis. This indicated that there were differences in Bt gene expression in different strains of transgenic cry1C^＊ super japonica rice or different organs of the same strain; there was no relation in Bt gene expression among different organs; the Bt-mRNA and protein content of the same organ usually had consistent expression; the Bt gene expression of various organs had nothing to do with the Bt protein content of brown rice. [Conclusion] The Bt gene and its expression cassette can meet the requirement of cultivating japonica rice varieties against stem borers.

The insecticide resistance in stripped stem borer,Chilo suppressalis(Walker)

The stripped stem borer (SSB),Chilo suppressalis (Walker) is one ofthe major insect pests of rice in Chi-na. Chemical control has been acommon practice in SSB managementsince 1950s. Insecticides used in-cluded BHC before 1983; organophos-

Identification of Bt-transgenic Rice Plants for Resistance to Stripe Stem Borer (Chilo suppressalis) and Genetic Analysis of the Transgenes

Resistance to herbicide Basta was used to identify Bt-transgenic rice plants and the progenies of crosses between the Bt-transgenic rice and the rice varieties cultivated in the Huang Huai area of China. The results demonstrated that the Basta-positive rice plants were highly resistant to stripe stem borer (Chilo sup-pressalis) both in the laboratory and field tests. Both cryIA (b) and bar genes were expressed and co-inherited in both self ing and crossing progenies. Mendelian segregation of the marker gene bar was observed in F2 and BC1 progenies. The results implicates that it is possible to transfer cryIA (b) gene into other cultivated varieties through crosses and back crosses.

Mechanism of rice variety resistance to the yellow stem borer,Scirpophaga incertulas (Walker)

Yellow stem borer(YSB),Scir-pophaga incertulas(Walker)has be-come the main rice insect pest onceagain along the Changjiang Riversince 1990s.Unfortunately,no ricevariety with resistance to YSB hasbeen reported so far.Japonica Zhen-dao 2 with moderate resistance toYSB was found.In 10 rice vari-eties with different resistance levels,YSB individuals showed distinct de-velopmental rates,and the asyn-chronous development even occurredin the same rice variety.In this

Selection of Maize Genotypes Resistant to Pink Stem Borer and Sugarcane Borer

Maize is an important economic crop grown in Nigeria. Its production is dramatically affect by the pink stem borer--Sesamia caIamistis （Hampson, Noctuidae） and sugarcane borer--Eldana saccharina （Walker, Pyralidae） that are endemic in Southeastern Nigeria. In areas of stress, existing genotypes may marginally do well due to their inherent capabilities. Therefore, it is possible to find useful genes in such areas of stress, since such genes have been responsible for the survival of host crops over the years. Evaluation study was conducted for a range of agronomic characteristics and resistance attributes for 209 local maize collections from Southeastern Nigeria along with three improved check varieties. Field trials were conducted at three locations in a total of four environments in 2001. Highly significant genotypic variances as were noted in all the traits, are indicative of the magnitude of variation that exists among the genotypes, thus providing the opportunity of selection for desirable traits. Furthermore, four traits, namely, leaf feeding, ear damage, stalk lodging and yield were used from across the environments to construct a rank summation index （RSI）, which was used to rank the entries for resistance to stem borers. This RSI led to the identification of 11 genotypes which represents the best 5% of the 212 genotypes in resistance ability. Genotype AMA TZBR-WC1 （from International Institute of Tropical Agriculture （IITA）, Ibadan） had the best overall resistance levels, followed by genotypes SE NG-77 and SE NG-67 （from Umuahia North）, SE NG-62 （from Ikwuano）, SE NG-148 （from Ukwa West）, SE NG-106 （from Bende）, SE NG-119 （from Isiala Ngwa）, SE NG-33 （from Ikwuano） and SE NG-65 （from Umuahia North）.