AFLP Analysis and Trait Evaluation of Bt Transgenic Sugarcane Lines

[ Objective] A large number of high-quality Bt transgenic sugarcane lines were obtained using transgenic technologies. This study aimed to explore the genetic background, genetic diversity, important traits and relationship between the heredity and phenotype of these transgenic sugarcane lines, thereby providing basis for further effective utilization and preservation of insect-resistant germplasm resources and improving breeding efficiency of insect-resistant sugarcane in China. [Method] By using six AFLP primers with high polymorphism, the genetic diversity of 13 Bt transgenic sugarcane lines and their donor varieties was analyzed. Growth assay and insect-resistance identification were carried out in a quarantine greenhouse with conventional methods. Evaluation of important economic traits was conducted in the field with conventional methods. [ Result] The polymorphism rate was relatively low. Specifically, the polymorphism rate of the first group was 21.00%, the polymorphism rate of the second group was 31.80%, and the total polymorphism rate was 42.50%. Cluster analysis showed that 13 Bt transgenic sugarcane lines and their donor varieties were divided into two categories, the genetic similarity coefficient between two categories was 0.54. All the six materials in the first group were clustered into category Ⅰ, with genetic similarity of 0. 921 ; nine materials in the second group were clustered into category Ⅱ, with genetic similarity of 0. 898. Bt transgenic sugarcane lines showed abundant phenotypic types and significant trait variations, and the economic traits were generally worse than donor varieties. The insect resistance of 13 Bt transgenic sugarcane lines was divided into five grades. [ Conclusion] The first-generation Bt transgenic sugarcane lines have low genetic diversity, abundant trait variations, high insect resistance and generally poor economic traits, which can only be used as germplasm resources for hybridization. Introducing Bt gene into multiple donors will to some extent improve the genetic diversity of sugarcane germplasm resources, but the increasing rate is relatively low. It is preliminarily considered that the genetic diversity of insect-resistant sugarcane germplasm resources should be improved by continuous hybridization and backcrossing of Bt transgenic lines with high-quality parents, thus laying foundation for breeding high-quality insect-resistant sugarcane varieties.

Moving-window bis-correlation coefficients method for visible and near-infrared spectral discriminant analysis with applications

The moving window bis corelation coefficients(MW BiCC)was proposed and employed for the discriminant analysis of transgenic sugarcane leaves and B-thalassemia with visible and near-infrared(Vis NIR)spectroscopy.The well-performed moving window principal component analysis linear discriminant analysis(MWPCA-LDA)was also conducted for comparison.A total of 306 transgenic(positive)and 150 nont ransgenic(negative)leave samples of sugarcane were collected and divided to calibration,prediction,and validation.The diffuse reflection spectra were corected using Savitzky-Golay(SG)smoothing with first-order derivative(d=1),third-degree polynomial(p=3)and 25 smpothing points(m=25).The selected waveband was 736-1054nm with MW-BiCC,and the positive and negative validation recognition rates(V_REC^(+),VREC^(-))were 100%,98.0%,which achieved the same effect as MWPCA-LDA.Another example,the 93 B-thalassemia(positive)and 148 nonthalassemia(negative)of human hemolytic samples were colloctod.The transmission spectra were corrected using SG smoothing withd=1,p=3 and m=53.Using M W-BiCC,many best wavebands were selected(e.g.,1116-1146,17941848 and 22842342nm).The V_REC^(+)and V_REC^(-)were both 100%,which achieved the same effect as MW-PCA-LDA.Importantly,the BICC only required ca lculating correlation cofficients between the spectrum of prediction sample and the average spectra of two types of calibration samples.Thus,BiCC was very simple in algorithm,and expected to obtain more applications.The results first confirmed the feasibility of distinguishing B-thalassemia and normal control samples by NIR spectroscopy,and provided a promising simple tool for large population thalassemia screening.