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There are two evolutionary pathways in the genus of Brassica, one is rapa/oleracea lineage and the other is nigra lineage. Based on the morphological characteristics and nuclear RAPD or RFLP markers, genus Raphanus was thought more closely related to nigra lineage than to rapa/oleracea lineage (Song et al., 1990; Thormann et al., 1994). RFLP data of both chloroplast and mitochondria revealed that Raphanus is more closely related to rapa/oleracea lineage (Palmer and Herbon, 1988; Warwick and Black, 1991; Pradhan et al., 1992). We have previously demonstrated that Raphanus sativus is more closely related to nigra lineage using nuclear intergenic spacer between 5S rDNA and internal transcribed spacer region between 18S and 25S rDNA. In this study, we analyzed DNA sequences from different regions of chloroplast and showed that Raphanus sativus was closely related to rapa/oleracea lineage than to nigra lineage. These results suggest that Raphanus sativus is a hybrid between B. rapa/oleracea and B nigra lineages as proposed by Song et al (1990). The split time between these two lineages and the divergent time of Raphanus was also determined based on these chloroplast DNA sequences.
Loropetalum chinense, one of three species in its genus in China, is distributed primarily in Hunan and Jiangxi Provinces. By establishing a Loropetalum gene bank and reviewing research on its varieties, genetic traits, and genetic diversity, we hope to promote the full yet sustainable use of this valuable, regionally varied natural resource. Our results will help promote the development of a broader resource economy.
Off-season flowering in red pitaya (Hylocereus sp.), a long-day plant, can be achieved using night-breaking (NB) treatment. Among the stages of bud development, stage 0 referred to induced but not yet differentiate any bracteole and stage 3 was the stage right before emerging floral buds and the bracteole differentiation was completed. Unlike floral bud emergence, bracteole differentiation was independent of the daylength and strongly influenced by the environmental temperature. The buds of higher stages were more effective in response to NB treatment and more sensitive to chilling injury (CI). Consequently, off-season flowers in autumn and winter trials were derived mainly from stage 2 and 3 buds and from stage 0 and 1 buds, respectively. In southern Taiwan, low night temperature between 10 Jan. and 7 Feb. 2011 may be the major factor, which delay bud development in off-season production. Therefore, we conducted a heating experiment in winter off-season production to proof our hypothesis and concluded that NB treatment should be applied along with night temperature elevation or after mid-February when the minimum night temperature is increasing.
Pedicularis rex C. B. Clarke ex Maxim., an endemic species with potential horticultural traits from Himalaya, has a unique cup-like petiole structure and highly infraspecific floral variation among members of the lousewort genus (Orobanchaceae). We developed 13 microsatellite markers from three microsatellite-enriched libraries (AG, AC, and AAG) of P. rex with a modified biotin–streptavidin capture technique. Polymorphism of each locus was assessed in 22 individuals with representation of five populations of P. rex. Number of alleles per locus (A) ranged from two to seven with an average of 4.38. The observed and expected heterozygosities varied from 0.03 to 0.86 and 0.45 to 0.84, respectively. Additionally, among the 13 identified microsatellite markers, 11 of them were successfully amplified in species P. thamnophila, and five of them showed polymorphisms. This study may provide important information for further investigation on the population genetics, introduction, and acclimatization of P. rex and its congeners.
Traffic resistance of turfgrasses is an essential indicator of urban recreational and sports turf quality (TQ). In our study, four turfgrass species were investigated for their wear resistance. A self-made traffic simulator was used to determine the wear resistance of the study turf area in a 2-year field trial (2019–20). The experimental plots were established using a randomized block design with three replicates. The morphological characteristics, soil physical properties, and physiological indices of the grasses were analyzed. Using the acquired quantitative data, we set the turf cover index (TCI), the turf quality index (TQI), and the shoot density index (SDI) as the wear tolerance index, and assessed the correlations among these morphological characteristics, soil physical properties, physiological indices, and wear tolerance. ‘Lanyin III’ zoysiagrass and ‘Tifgreen’ hybrid bermudagrass provided relatively greater wear tolerance, followed by ‘Qingdao’ zoysiagrass and common bermudagrass after 12 weeks of traffic exposure in 2019 and 2020. Traffic changes the soil physical properties and affects the physiological metabolism of turfgrasses. Leaf morphology characteristics and the mechanical strength of these grasses were related significantly to TCI, TQI, and SDI, and most physiological responses and soil properties correlated significantly with TCI and TQI. Our findings of the correlations among physiological responses, soil properties, leaf morphology, and wear tolerance will allow grass breeders to evaluate their breeding procedures more efficiently.