Gibberellic acid (GA) is a well-characterized plant hormone, which plays a critical role in various plant growth and development. including stem elongation, floral indcution and seed development. GA is known to cause enlargement of ripening fruits and, especially in grapevines, GA shows a unique function: the induction of seedlessness in seeded grape varieties. However, despite extensive previous studies about GA, there has been no clear verification of the mechanism that induces seedlessness in grapes. To understand how GA treatment results in artificial parthenocarpy of seeded grapes at molecular levels, we analyzed transcriptional changes in seeded grapes with and without GA application in various inflorescence developmental stages using RNA-seq. At 14 days before flowering (DBF), seeded grapes were treated with 100 ppm GA and clusters were collected at three developmental stages: 7 DBF, full bloom, and 5 days after flowering (DAF). Of a total of 28,974 genes that were mapped to grape genome reference sequences, 7,013 and 9,064 genes were up- and down-regulated, respectively, in the GA-treated grape as compared to the non-GA-treated control at 7 DBF, full bloom, and 5 DAF. Clustering analysis revealed that these genes could be grouped into 9 clusters with different expression patterns. We also carried out functional annotation based on gene ontology categories. There were significant differences in the expression of the GA and auxin-related gene families. These findings expand our understanding of the complex molecular and cellular mechanisms of GA-induced parthenocarpy of grapes and provide a foundation for future studies on seed development in grapevines.

Our study is performed to confirm the level of genetic diversity and population structure with 80 maize inbred lines (40 waxy inbred lines and 40 flint inbred lines) and to explain the genetic basis of agronomic traits using an association mapping. The 200 SSR loci are confirmed a total of 1,610 alleles in total 80 maize inbred lines. The average number of alleles per locus was 8.05. The average GD was 0.72. The average PIC value was 0.68. The average MAF was 0.40. Population structure was revealed for K=2. Total 80 maize inbred lines were divided by groups I, II and admixed group. The 14 waxy inbred lines were assigned to group I. The 45 inbred lines include 5 waxy inbred lines and 40 flint inbred lines were contained to group II. The 21 waxy inbred lines were contained in the admixed group with lower than membership threshold 0.8. Association mapping between 200 SSR markers and 10 phenotypic traits of waxy/flint maize inbred lines were performed by Q GLM and Q+K MLM. In significant level at 0.01, 72 SSR markers were associated with 10 phenotypic traits using Q GLM. The 4 marker-trait association were detected in Q+K MLM. The results derived from this study will be used for designing efficient new maize breeding programs.