Production of Asiatic Hybrid Lily ‘Beni no Mai’ with More than Two Flowers within One Year from Bulbils Influenced by Development Stage, Flower Bud Removal, and Temperature Manipulation

Abstract

Background and objective: The objective of this study was to produce Asiatic hybrid lily with more than two flowers in one year starting from bulbils. This study was to force 'Beni no Mai' bulbils influenced by harvesting date, flower bud removal, and temperature manipulation and to evaluate dormancy and maturity by nuclear magnetic resonance imaging (NMRI) and carbohydrates analysis.Methods: In experiment 1, bulbils were harvested at 0-30 days after anthesis (DAA), and were divided into 7 stages. And, soluble monosaccharides and monosaccharide constituents of bulbils were analyzed. In experiment 2, flower buds of plants that flowered on 21 April were not removed or removed on 1, 13, and 25 April. Bulbils harvested were divided into four groups and planted after cold treatment. In experiment 3, bulbils received a sequential temperature (SEQ CD) treatments for three weeks at 2.5, 5.0, and 7.5°C, 1 week at 10, 12.5, and 15°C, and 3 weeks at 2.5, 5.0, and 7.5°C. In experiment 4, bulbils were harvested 0-70 DAA, and were subjected to spin-spin lattice relaxation time by NMRI.Results: The bulbils harvested at 30 DAA produced two flowers within 282 days, and were better in growth. The bulbils harvested at 30 DAA showed higher concentration of soluble glucose and lower concentration of non-cellulosic neutral glucose. Growth of bulbils removed flower buds before flowering were better than those of bulbils that flower bud was removed at anthesis and 13 Apr. However, the number of flowers of bulbils harvested from plants removed flower buds on 1 Apr. were less than 2. The SEQ CD treatment of 7.5°C/3W-15°C/1W-5°C/3W in bulbils could produce the plants with 2.2 flowers within 300 days after planting. When bulbils were harvested at 0-28 DAA, yellow color corresponding to T2 relaxation time of 15-20 ms was dominant, and bulbils harvested at 56-70 DAA showed T2 relaxation time of 35-50 ms and 50-100 ms.Conclusion: Considering the results of soluble carbohydrate content and T2 relaxation time of bulbils, it was found that the bulbils had a shallower dormancy and were more mature at 30-42 DAA than before 28 DAA. Also, when these bulbils were planted after SEQ CD treatment at 7.5°C/3W-15°C/1W-5°C/3W, plants with two or more flowers could be produced within one year.