Lotus (Nelumbo nucifera Gaertn.), also called Asian lotus, is an aquatic herbaceous perennial plant. N. nucifera has an extremely long history in cultivation as a vegetable, medicinal, and ornamental plant in Eastern countries (Wang and Zhang, 2004). Lotus rhizome is one of the major vegetables in Asia. Recently, lotus has become a potential crop in Australia (Nguyen, 2001), New Zealand (Follett and Douglas, 2003), and the United States (Tian et al., 2006). Lotus is usually planted in a tilled pond or rice field for vegetable production or planted in containers, small ponds, and lakes for ornamental uses. Planting time is often between late spring and early summer (Sou and Fujishige, 1995) with plant growth ending in the fall under natural conditions. Growth and yield of lotus may be influenced by diverse factors such as genotype (Zhou et al., 2004), media (Li and Qian, 1994; Meyer, 1930; Wang and Zhang, 2004), water depth (Nguyen, 2001; Snow, 2000; Wang and Zhang, 2004), light (Li et al., 2000; Snow, 2000), temperature (Meyer, 1930), planting time and propagation methods (Katori et al., 2002; Wang and Zhang, 2004), planting techniques (Min et al., 2006; Sang et al., 1994; Shen et al., 2001; Wen, 1987), fertilization (Hicks, 2005; Li and Qian, 1994; Orimoto and Takai, 2007; Song et al., 2006; Sou and Fujishige, 1995; Zhang et al., 1994), and other environmental factors (Hicks, 2005; Nguyen, 2001).
Cultivar selection and cultivation techniques are dependent on the environmental setting of the lotus plant. Lotus can be propagated by seeds, rhizome divisions with viable growing points, and tissue culture. Effects of propagation methods and planting techniques on yield of lotus have been much reported (Katori et al., 2002; Min et al., 2006; Sang et al., 1994; Shen et al., 2001; Wang and Zhang, 2004; Wen, 1987). Propagation by division of running stems (nonenlarged rhizomes or straps) during the growing season cannot only save stock rhizomes and reduce cost, but also increase efficiency and prolong flowering period of plants and may replace plants that do not survive early in the year (Wang and Zhang, 2004). Days to flowering are significantly shorter in the strap propagation method than in the enlarged rhizome propagation method where flowering time is delayed (Katori et al., 2002). Plants generated through the rhizome strap method also produce larger flowers.
Off-season cultivation methods have been developed to meet the demands of the market. Availability of vegetable rhizomes could be advanced to June by growing edible lotus earlier in the season (Fu et al., 1994). Flowering lotus generally blooms from June to August, but population flowering time can be extended to early October when lotus is propagated by dividing growing plants in July (Deng et al., 1990). It is feasible to prolong flowering time of lotus through the winter when plants are planted in a heated greenhouse (Li et al., 2000). If the technologies of advancing and delaying flowering are incorporated, three cycles of population flowering are possible in 1 year (Wang and Zhang, 2004). Reports indicate that production of lotus cut flowers may be on a year-round schedule (Chomachalow, 2004). However, little information is available on effects of planting time on overall lotus performance in various climatic regions. Productive organs of lotus plants are nutrient sinks. Disbudding of lotus would possibly increase plant yield of lotus rhizomes and other plant growth indices. The major goal of this study was to investigate effects of planting time and disbudding on lotus growth and development in containers.
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