Various characteristics of soybeans play important roles in the soybean oil quality. In this study, soybean chemical traits and ten characteristic parameters of soybean oil quality were evaluated for 58 varieties to determine the relationship between soybean chemical traits and the soybean oil quality characteristics by correlation analysis. After 7 of 58 soybean oil variety products were set as outliers by the Box-plot method, an evaluation model for the overall soybean oil quality was established based on ten parameters. Cluster analysis was used to classify 51 soybean oil varieties into three quality grades based on the oil quality evaluation model. A prediction model for the quality of the soybean oil based on the chemical traits of soybeans was constructed by stepwise regression. The relative errors between the actual values and the predicted values of the validation varieties were less than 10%. This study suggested that the total oil, daidzin, total phenolic, stearic acid, linolenic acid and ɑ-tocopherol contents may be useful for predicting the quality of soybean oil. Therefore, our study provides a valuable method to evaluate the quality of soybean oil products and important information for generating soybean varieties for soybean oil processing.

Drought stress at germination stage is an important environmental stress limiting crop yield. Hence, our study investigated comparative root transcriptome profiles of four contrasting soybean genotypes viz., drought-tolerant (PI342618B/DTP & A214/DTL) and drought-sensitive (NN86-4/DSP & A195/DSL) under drought stress using RNA-Seq approach. Total of 4850 and 6272 differentially expressed genes (DEGs) were identified in tolerant (DTP & DTL) and sensitive (DSP & DSL) genotypes, respectively. Principle component analysis (PCA) and correlation analysis revealed higher correlation of DTP with DTL. Both gene ontology (GO) and MapMan analyses showed drought response was enriched in the DEGs associated with water and auxin transport, cell wall/membrane, antioxidant activity, catalytic activity, secondary metabolism, signaling and transcription factor (TF) activities. Out of 981 DEGs screened from above terms, only 547 showed consistent opposite expression between contrasting genotypes. Twenty-eight DEGs of 547 were located on Chr.08 rich in QTLs and “Hotspot regions” associated with drought stress, and eight of them showed non-synonymous SNP polymorphism. Hence, ten genes (including above eight genes plus two hub genes) were predicated as possible candidates regulating drought tolerance, which needs further functional validation. Overall, the transcriptome profiling provided in-depth understanding about the genetic mechanism and candidate genes underlying drought tolerance in soybean.