Grapevine l eaf rust (GLR) c aused b y Phakopsora euvitis diminishes fruit quality and reduces yield in viticulture, making it one of the world’s most significant fruit crop threats. To develop GLR-resistant grape varieties, substantial efforts have been made to select rust-resistant genes and determine effective strategies f or achieving durab le resistance in grapevines. This study aims to identify genetic resources resistant to GLR by investigating disease incidence in vineyards and symptom development in grapevines inoculated with pathogens. Fifty-seven genotypes from Ampelopsis brevipedunculata, Vitis acerifolia, V. aestivalis, V. amurensis, V. cinerea, V. coignetiae, V. flexuosa, V. labrusca, V. labruscana, V. rotundifolia, and V. vinifera were evaluated for rust disease incidence over four years (2021 –2024) at Yeunganm University. Three plants per genotype were potted and sprayed with a pathogen suspension to assess disease incidence on their adaxial leaf surfaces in a greenhouse. Variation in resistance to GLR was observed among genotypes within each species. Resistant genotypes of V. coignetiae exhibited no symptoms on their leaves, while severe infections were noted in the leaves of susceptible genotypes of A. brevipedunculata, V. amurensis, V. flexuosa, V. labruscana, and V. vinifera. None of the tested V. rotundifolia genotypes displayed yellow pustules and remained unaffected for three weeks after artificial inoculation. These findings highlight the potential of V. rotundifolia and V. coignetiae as valuable genetic resources for breeding rust-resistant grapevines. Chlorophyll content was comparable across all uninfected genotypes. While resistant genotypes maintained relatively stable chlorophyll levels, the average chlorophyll content in the majority of susceptible genotypes was significantly lower following inoculation than before. This negative relationship indicates a general decline in photosynthetic capacity due to disease development in grapevines. Identifying resistant genotypes among both resistant and susceptible genotypes across different Vitis species provides crucial insights for developing new grape varieties with improved resistance to GLR.
Background: Passive or therapist-assisted stretching, followed by scapular stabilization exercises, has been shown to be effective. However, most previous studies have focused on stretching individual muscles or specific movement directions, often neglecting the role of active scapular stretching. Objects: This study aimed to compare changes in the muscle activity of the lower trapezius (LT), serratus anterior (SA), and upper trapezius (UT), as well as the scapular posterior tilt (SPT) angle before and after scapular circle (SC) stretching during SPT exercise. Methods: Twenty participants were recruited for this study. Electromyography electrodes were attached to the LT, SA, and UT. Muscle activity and the posterior scapular tilt angle were measured while performing the SPT exercises. After the SC stretch, the measurements were repeated in the same manner. The LT, SA, and UT electromyography activities and SPT angles were analyzed using paired t-tests. Results: LT activity was significantly higher in the SC stretch plus SPT exercise compared with in the SPT exercise alone (p = 0.018). There were no significant differences in SA activity between the SPT and SC stretch plus SPT exercise conditions (p = 0.812). UT activity significantly increased in the SC stretch plus SPT exercise compared with that in the SPT exercise (p = 0.001). The SPT angle was significantly enhanced during SPT exercise after the SC stretching compared to that without SC stretching (p = 0.009). The RSP improved by 2.32% compared to the initial posture when only the SPT was performed, and improved by 9.95% when the SPT was performed after the SC stretching. Conclusion: These results suggest that performing SC stretching prior to SPT exercise may effectively improve scapular alignment and posture, even when UT activation increases more than of the LT. Elevated UT activity highlights the need to address muscular balance in corrective exercise design.
Background: The purpose of this study was to compare gluteus medius (Gmed) and quadratus lumborum (QL) muscle activities and the Gmed/QL activity ratio, during five hip abduction exercises in individuals with Gmed weakness. Objects: Nineteen participants with clinically identified Gmed weakness performed five hip abduction exercises: side-lying hip abduction (SHA), side-bridge (SB), SB using sling (SB-sling), SB with hip abduction (SB-HA), and SB-HA using sling (SB-HA-sling). Surface electromyography recorded Gmed and QL, normalized to %maximum voluntary isometric contraction (%MVIC). A repeated-measures ANOVA was used to assess differences across conditions. Results: Significant differences were found in Gmed (F = 68.980, p = 0.001) and QL (F = 10.676, p = 0.001) activation across exercises. Gmed activity was highest in SB-HA (61.77 ± 14.46 %MVIC), while SHA produced the highest Gmed/QL activity ratio (1.70 ± 0.26), indicating more selective Gmed activation. SB and SB-sling showed lower Gmed activity and higher QL activation. SB-HA-sling resulted in moderate Gmed activation without significantly increasing QL activation. Conclusion: The SB-HA exercise is effective for co-activating Gmed and QL, while SHA and SB-HA-sling are better suited for selectively targeting Gmed with minimal QL compensation. These findings support exercise selection based on specific rehabilitation goals.