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Begonia × benariensis series varieties have high ornamental and economic value and are excellent varieties for large-area group planting in gardens and green areas. At present, the B. × benariensis series varieties grown in China rely on foreign imports, and the price of imported germplasm resources is expensive, which greatly increases the cost of flower enterprises. In view of this, B. × benariensis (2n = 2x = 34) was used as the material, the callus was treated with colchicine to induce polyploid plants, and the polyploid plants were subjected to morphology, DNA content identification, and stomatal identification, as well as comparisons of the morphophysiological indexes of the plants. The results showed that the polyploid was better induced with the treatment of 0.05% colchicine for 4 h, and the induction rate was 46.67%. Among the mutagenized plants, there were 42 triploids (2n = 3x = 51) and 98 tetraploids (2n = 4x = 68). The stomatal density of diploid leaves was about 1.09 times that of the triploid and 1.67 times that of the tetraploid, the defense cells of the leaves increased gradually, and the stomatal density decreased; with the increase in ploidy, the height of the plants increased, while the crown width decreased; the maximum length and width of the leaves decreased, the color of the leaves became darker, and the chlorophyll content increased. This study provides abundant variation materials and technical support for the selection and breeding of new varieties of B. × benariensis in the future. [ABSTRACT FROM AUTHOR]

With the scarcity of fresh water resources and the increase in labor prices, rice cultivation is changing from transplanting to direct seeding. Weedy rice is a malignant weed with strong drought tolerance in seed germination in direct-seeding rice fields. As the same species of cultivated rice (Oryza sativa L.), weedy rice (Oryza sativa f. spontanea) has the potential of domestication into direct-seeding rice with strong drought tolerance in seed germination by changing a few unfavorable traits. The red pericarp, one of the harmful traits of weedy rice, seriously affects the quality and commercial value of cultivated rice. The recently developed CRISPR/Cas9 (Clustered Regular Interspaced Short Palindromic Repeats) technology can accurately edit the function of genes, providing a possibility for the directed evolution. Weedy rice (WRL-162) with red pericarp was used as a mutant material. Two mutation sites, upstream and downstream of the 14 bp differential fragment of exon 6 of Rc gene, were designed using the CRISPR-Cas9 gene-editing technique. Consequently, three mutant types in T1 generation weedy rice with CRISPR-Cas9 vector changed from red to white pericarp. One mutant type in T1 generation weedy rice with CRISPR-Cas9 vector maintained red pericarp. Comparing the wild type of weedy rice and rice variety control (Nipponbare), mutant types in T3 generation weedy rice without CRISPR-Cas9 vector significantly improved the drought resistance in seed germination. In addition, there was no significant difference in panicle number, seed setting rate per plant, grain length and width between wild type and T3 generation mutant weedy rice without CRISPR-Cas9 vector. Comparing the wild type, some mutant types in T3 generation weedy rice without CRISPR-Cas9 vector significantly decreased plant height, decreased spikelet number per main panicle, decreased plump seed number per main panicle, and increased 1000-grain weight. Our results showed that the Rc gene editing using CRISPR/Cas9 technology can not only remove the harmful pericarp character of weedy rice, but also improve drought tolerance in seed germination. This study might provide new insights for the utilization of weedy rice as germplasm resources for direct-seeding rice by precisely editing genes to remove unfavorable traits. [ABSTRACT FROM AUTHOR]

Unmanned aerial vehicles (UAVs) equipped with spectral sensors have become useful in the fast and non-destructive assessment of crop growth, endurance and resource dynamics. This study is intended to inspect the capabilities of UAV-onboard multispectral sensors for non-destructive phenotype variables, including leaf area index (LAI), leaf mass per area (LMA) and specific leaf area (SLA) of rapeseed oil at different growth stages. In addition, the raw image data with high ground resolution (20 cm) were resampled to 30, 50 and 100 cm to determine the influence of resolution on the estimation of phenotype variables by using vegetation indices (VIs). Quadratic polynomial regression was applied to the quantitative analysis at different resolutions and growth stages. The coefficient of determination (R2) and root mean square error results indicated the significant accuracy of the LAI estimation, wherein the highest R2 values were attained by RVI = 0.93 and MTVI2 = 0.89 at the elongation stage. The noise equivalent of sensitivity and uncertainty analyses at the different growth stages accounted for the sensitivity of VIs, which revealed the optimal VIs of RVI, MTVI2 and MSAVI in the LAI estimation. LMA and SLA, which showed significant accuracies at (R2 = 0.85, 0.81) and (R2 = 0.85, 0.71), were estimated on the basis of the predicted leaf dry weight and LAI at the elongation and flowering stages, respectively. No significant variations were observed in the measured regression coefficients using different resolution images. Results demonstrated the significant potential of UAV-onboard multispectral sensor and empirical method for the non-destructive retrieval of crop canopy variables. [ABSTRACT FROM AUTHOR]