Effects of Light Quality on Growth and Morphogenesis of 'Muscat Bailey A' Grapevine in vitro

Two-node microcuttings were used in this study to evaluate the effect of different qualities of LED lights on growth and morphogenesis of 'Muscat Bailey A' grapevines cultured in vitro. Among red-blue mix light treatments, plants in the treatments of 9R, 8R1B, 6R3B and 2R7B had higher percentages of shoot regeneration but there was no significant difference in the percentage of rooting among treatments. The fresh weight and dry weight of leaf, leaf number, leaf area and average primary root length in the 8R1B treatment were the highest. Plants in the treatment of 9R had the highest shoot length, internode length and primary root number. The fresh weight and dry weight of root and secondary root number in 6R3B treatment were the highest. Among red-blue ratio with infrared light treatments, the highest percentage of shoot regeneration was 100% for the treatments of 5R3B1IR, 3R5B1IR and 4R3B2IR, and the lowest one was obtained in the treatment of 3R4B2IR which was only 53.3%. The highest percentage of rooting, shoot fresh weight, shoot dry weight, leaf number, node number, shoot length and internode length were obtained in the treatment of 7R1B1IR. In summary, growth and development of grapevine plantlets were better under higher ratio of red to blue light. Therefore, higher ratio of red to blue light should be used during the early stage of in vitro microcutting of grapevines.