Browsing by Author "Hu, Ying"

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    Genomics-based diversity analysis of Vanilla species using a Vanilla planifolia draft genome and Genotyping-By-Sequencing
    Hu, Ying; Resende Jr., Marcio F. R.; Bombarely, Aureliano; Brym, Maria; Bassil, Elias; Chambers, Alan H. (Springer Nature, 2019-03-04)
    Demand for all-natural vanilla flavor is increasing, but its botanical source, Vanilla planifolia, faces critical challenges arising from a narrow germplasm base and supply limitations. Genomics tools are the key to overcoming these limitations by enabling advanced genetics and plant breeding for new cultivars with improved yield and quality. The objective of this work was to establish the genomic resources needed to facilitate analysis of diversity among Vanilla accessions and to provide a resource to analyze other Vanilla collections. A V. planifolia draft genome was assembled and used to identify 521,732 single nucleotide polymorphism (SNP) markers using Genotyping-By-Sequencing (GBS). The draft genome had a size of 2.20 Gb representing 97% of the estimated genome size. A filtered set of 5,082 SNPs was used to genotype a living collection of 112 Vanilla accessions from 23 species including native Florida species. Principal component analysis of the genetic distances, population structure, and the maternally inherited rbcL gene identified putative hybrids, misidentified accessions, significant diversity within V. planifolia, and evidence for 12 clusters that separate accessions by species. These results validate the efficiency of genomics-based tools to characterize and identify genetic diversity in Vanilla and provide a significant tool for genomics-assisted plant breeding.
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    Motivation, Usability and Their Interrelationships in a Self-paced Online Learning Environment
    Hu, Ying (Virginia Tech, 2008-08-29)
    This study addressed how usability improvement and motivational design affect learners' motivation and learning performance in a self-paced, online learning environment. The study also investigated the interrelationships between commonly-used usability measures and the motivation measures based on Keller's ARCS model. A two-phase study approach was used. In Phase I, an existing self-paced, online safety training tutorial was used as the baseline. Two alternative designs were developed with improved usability and motivational design based on the ARCS model. In Phase II, the effects of the three interface designs were evaluated through a three-group, generalized randomized block covariate design experiment. A total of seventy-two college students (48 males and 24 females) participated in the usability testing and the online training session using one of the interface designs. Both quantitative and qualitative data were collected and analyzed. Results suggested a significant interface design effect on learner motivation. Learners who used the interface design with both usability improvement and motivational design applied (the UM group) showed the highest level of motivation. In particular, the attention level of the learners in the UM group was significantly higher than the baseline group. Results also indicated motivation differences between genders. Females showed higher scores than males in overall motivation score and in each of the four subscales of attention, relevance, confidence, and satisfaction. No significant difference in learning performance was found among the three treatment groups using different interface designs. None of the usability or motivation measures was a significant predictor of learning performance. Small to medium positive correlations were found between usability satisfaction and three motivation measures, i.e., attention, relevance and satisfaction. Content analysis identified a number of interface design components to be relevant to learners' motivation components: overall appearance, graphics/multimedia, text appearance, page layout, navigation, and paging/scrolling. Implications and design recommendations for online tutorial interface design were discussed. Additional discussion was provided regarding the online learning environment and the integration of usability, motivation, and instructional design and technology.