arabidopsis, FT is also a point of integration of floral-promoting and -inhibiting signals initiated by vernalization, gibberellins, and plant developmental signals ( Samach et al., 2000 ). In citrus, floral induction is generally considered to be
Eduardo J. Chica and L. Gene Albrigo
Neil O. Anderson
The increasing number of crops being grown for the floriculture market has frustrated educators faced with limited classroom and laboratory time. Time constraints necessitate selection of crops to serve as examples of floral induction treatment(s) and provide an accurate scope of production requirements for all cultivated species. Since flowers are the primary reason for purchasing most floricultural products—with the notable exception of cut and potted foliage—the various treatments required for flower bud initiation and development were used to categorize potted plants. New and old crops (>70 species) are categorized for flower bud initiation and development requirements, including photoperiod (short, long day, day neutral; facultative/obligate responses), vernalization, temperature, autonomous, rest period, and dormancy. Crop-specific temperature, irradiance, and photoperiod interactions are noted, as well as temperature × photoperiod interactions. A course syllabus can be modified to ensure that at least one crop from each category is presented to serve as a model. It is recommended that the class focuses on example crop(s) from each floral induction category and then reviews other crops within each category for differences or similarities. This method allows coverage of floral induction categories without leaving information gaps in the students' understanding. This method was used with students in the Fall 1999, floriculture production class (Hort 4051) at the University of Minnesota, St. Paul.
Xiuren Zhang, David G. Himelrick, Floyd M. Woods, and Robert C. Ebel
`Chandler' strawberry plants (Fragaria Xananassa Duch.) were greenhouse grown under natural lighting and then placed into growth chambers at two constant temperatures of 16 and 26 °C and 2 daylengths of 9 h (SD) and 9-h photoperiod (NI) which was night interrupted with 3 hours of incandescent radiation at 30-45 μmol·s-1·m-2 PAR. Plants were given different numbers of inductive cycles in growth chambers and then moved to the greenhouse. Flowering and growth were monitored. Flowering was completely inhibited at 26 °C, regardless of pretreatment growing conditions such as pot sizes and plant ages, photoperiod, and inductive cycles. At 16 °C, SD promoted floral induction compared to NI under all inductive cycles except a 7-day induction. The minimum number of inductive cycles required at 16 °C for floral induction was dependent on photoperiod and prior greenhouse treatment. Flowering rate was also affected by greenhouse treatment, photoperiod, and inductive cycles. Runner production was affected by photoperiod and temperature × inductive cycle.
Fernando Ramírez, Thomas L. Davenport, Gerhard Fischer, and Julio Cesar Augusto Pinzón
-Elisea, 1997 ; Núñez-Elisea and Davenport, 1995 ). The age of the last flush of vegetative stems, thus, appears to be the primary factor regulating floral induction in warm climates. Bueno and Valmayor (1974) indicated that leaves must become brittle as
Gilles Galopin, Laurent Crespel, Jean C. Mauget, and Philippe Morel
to floral induction. Thus, temperatures below 18 °C ( Bailey and Weiler, 1984 ; Post, 1942 ) and a short photoperiod of less than 12 h ( Guo et al., 1995 ; Morita et al., 1980 ; Shanks et al., 1986 ) are favorable to floral transformation. Despite
Ryan M. Warner
responses ( Erwin and Warner, 2002 ; Mattson and Erwin, 2005 ). This presents greenhouse growers with the considerable challenge of simultaneously producing flowering crops of species with different photoperiodic requirements for floral induction. For
Yihua Chen, Peng Jiang, Shivegowda Thammannagowda, Haiying Liang, and H. Dayton Wilde
expression in the peach shoot apex was not detected during floral induction, differentiation, or mature floral bud stages ( Fig. 2B ). PpTFL1 , however, was expressed during vegetative bud development. Similar to peach, TFL1 expression was absent or low
Eduardo J. Chica and L. Gene Albrigo
Yanofsky, 1995 ; Weigel and Nilsson, 1995 ) and with earlier reports of the microscopical differentiation of floral meristems in citrus only after floral induction is over ( Abbot, 1935 ). Although the patterns of expression of CsSL1 (the ortholog of