Worldwide, freesia is mainly grown as a cut flower, and it is well-adapted to cooler climates. The plant is grown from corms. Using temperature treatments after lifting, flower induction and initiation can be controlled for year-round flowering
William B. Miller
Shanshan Seng, Jian Wu, Jiahui Liang, Fengqin Zhang, Qiuyan Yang, Junna He, and Mingfang Yi
Worldwide, gladiolus is a commercially sold cut flower, whose sales rank the second highest among bulb flowers ( Wu et al., 2015 ). Corms and cormels are the only materials used for commercial propagation. Yearly, gladiolus produces new corms and
Susan S. Han, Abraham H. Halevy, Roy M. Sachs, and Michael S. Reid
Flowering of brodiaea (Triteleia laxa syn. Brodiaea laxa `Queen Fabiola') did not have an obligate requirement for manipulation of temperature or photoperiod. Vernalization of corms reduced the greenhouse forcing phase but did not alter the number of flowers per inflorescence or scape length. Long photoperiods hastened flowering but decreased flower quality and flowering percentage. Scape length, which was not affected by photoperiod or mother corm size, was increased when plants were grown at night temperatures < 10C. Diameter of the apical meristem in the dormant corm, flowering percentage, and flower quality were not affected by a 10-fold increase in corm size above a critical weight (0.6 g). In contrast, the weight and number of daughter corms were closely correlated with mother corm size. The optimum planting depth for brodiaea corms was 10 cm below the soil surface.
Effects of methyl disulfide (MeS2) on sprouting and phytohormones in dormant corms of spring-flowering gladiolus (Gladiolu×Tubergenii Hort. `Charm') were studied. Corms treated with MeS2 sprouted 30 days earlier than nontreated corms. The concentrations of endogenous promoters in the corm tissue increased and inhibitors decreased within 24 h of treatments. High concentration of inhibitors were present in the nontreated corms.
Theo J. Blom and Brian D. Piott
Four freesia cultivars were exposed to 24 hour·day-1 high-pressure sodium (HPS) lighting during various stages of their development. Upon emergence, freesia plants were exposed to the following four lighting treatments: 1) ambient; 2) ambient until shoot length was 5 to 8 cm followed by HPS lighting until flowering; 3) HPS lighting until shoot length was 5 to 8 cm followed by ambient lighting; and 4) continuous HPS lighting. Supplemental HPS lighting was provided at 37 μmol·m-2·s-1 at plant level in a glasshouse. Continuous lighting or lighting during flower development hastened flowering but reduced the number of flowering stems per corm, as well as stem length and weight. Lighting during the vegetative and flower initiation periods produced minor effects. The main benefit of supplemental lighting was found in total corm weight.
The ornamental flowering bulb Brodiaea laxa Benth. `Queen Fabiola' was grown with or without arbuscular mycorrhizal fungal (AMF) inoculum in pasteurized or nonpasteurized soil to determine if inoculation altered flower and corm production. The first growing cycle after planting, mycorrhizal inoculation decreased the days to anthesis and increased the number of flowers produced per inflorescence and flower longevity. It also affected the quality of the daughter corm, which influenced flowering the following year. Inoculated plants produced larger daughter corms and more cormels than uninoculated plants, and allocated more biomass to the corms than the cormels, which lowered the average weight of the cormels. Corms produced by inoculated plants also had higher concentration of nitrogen, potassium, zinc, and nonreducing sugars than those produced by uninoculated plants. The beneficial effects of AMF inoculation on flowering and corm/cormel production were generally increased by soil pasteurization. The results indicate that mycorrhizal inoculation may enhance commercial cut flower and corm production of this crop.
George J. Wulster and Thomas J. Gianfagna
Growth and flowering of Freesia hybrida Bailey for the container-plant market can be controlled chemically using growth retardants and environmentally by cold storage of corms at 5C for 2 to 6 weeks before planting. Corms stored at 5C for 4 weeks flowered 20 days earlier than corms not stored at 5C. Preplant 5C storage of corms also reduced leaf and flower height. An ancymidol soil drench (3 mg) reduced leaf height and flower height by more than 50% and delayed flowering by 9 days. Combining growth regulator application with cold storage of corms produced the greatest reduction in leaf height and flower height. Moreover, plants flowered earlier than controls when corms were stored for at least 4 weeks, regardless of growth regulator treatment. Chemical name used: α-cyclopropyl-α- (4-methoxyphenyl) -5-pyrimidine methanol (ancymidol).
Raja Ram, Debasish Mukherjee, and Sandeep Manuja
The effects of BA, ethephon, and GA3 on freshly harvested cormels of three cultivars of Gladiolus sp. were studied for 3 years. The treatment with 400 mg·L-1 ethephon significantly reduced the dormancy period by 17.5 days as compared to control, while BA and GA3 were found to be less effective. Among all treatments, ethepon at 400 mg·L-1 was found to be the most effective in altering the days to sprout, sprouting percentage, corm size and production and development of cormels. While GA3 at 100 mg·L-1 increased growth of corms and cormels, BA at 25 mg·L-1 increased growth of corms and cormels. BA at 25 mg·L-1 only influenced the sprouting percentage of cormels. Along with reducing the dormancy period, the plant growth regulators stimulated growth and development of corms and cormels. Chemical names used: benzyladenine (BA); 2-chloroethylphosphonic acid (ethephon); gibberellic acid (GA3).
Nancy Philman, Murdock Ray Gillis, and Michael E. Kane
Commercial micropropagation of wetland plants used for habitat restoration provides an alternative to field collection and facilitates production of difficult-to-propagate species and possibly selection of ecotypes that are physiologically adapted to specific habitat conditions. Knowledge of the degree of ecotypic variation within and between wetland populations is very limited. The feasibility of screening ecotypic differences in growth of micropropagated wetland plants, following acclimatization, was examined using Sagittaria latifolia Willd. (Duck-potato), a highly variable rhizomatous herbaceous wetland species that is widely distributed in southeastern Canada and the eastern United States. Plants were obtained from populations in Rhode Island, North Carolina, South Carolina, and Florida. Stage I cultures of each Sagittaria latifolia ecotype were established from surface-sterilized rhizome shoot-tips cultured in a liquid basal medium (BM) consisting of half-strength Murashige and Skoog mineral salts, 0.56 mM myo-inositol and 1.2 μM thiamine supplemented with 87.6 mM sucrose. Stage I cultures were indexed for cultivable bacteria prior to clonal multiplication of each ecotype by rhizome production on agar-solidified BM supplemented with 1.1 μM benzyladenine (BA). At 4-week intervals for 24 months, Stage II microcuttings of each ecotype were acclimatized and rooted in soilless growing medium under intermittent mist for 10 days. Plantlets were transferred to a shadehouse (50% sunlight reduction) and maintained under prevailing environmental conditions. Plant height, leaf length and number, rhizome number, corm number and weight, and flowering were determined 6 weeks post-transplant. Significant seasonal differences in leaf growth, rhizome production, corm formation and flowering were observed between ecotypes. During the growing season, induction of corm formation occurred progressively earlier in the more northern ecotypes.
Rajendra P. Maurya* and Champa lal Nagda*
In a field experiment, uniform sized corms of gladiolus (Gladiolus grandiflorus L. cv. Oscar) were planted in last week of October at a distance of 30 cm. between rows and 20 cm. between plants. The effect of GA (50, 100 ppm), Cycocel (500, 1000) and NAA (50, 100 ppm) on gladiolus plants. It was concluded that foliar application of 100 ppm GA3 at 45 days after corm planting has shown superiority in all vegetative, floral characters and corm & cormel yield viz., plant height (128.53 cm), number of leaves (8.57) per plant, spike length (108.33 cm), spike weight (128.87 g), number of florets (17.60) per spike, size of second florets (15.07 cm), number of spikes (1.67) per plant, size of largest corm (7.52 cm), number of corms (1.80) per plant, number of cormels (11.53) per plant and weight of corms (79.33 g) per plant. Whereas, a highest longevity of florets opening or survival on spike (20.33 days) was recorded in 1000 ppm Cycocel.