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Richard A. Criley

The flowers of pakalana are initiated under long days (LD) at 18C or above. At 21 and 24C, inflorescence initiation occurs after 3 weeks of LD, and the clusters grow to 6 mm in another 2 weeks, but at 18C, about 12 weeks are required to achieve the 6-mm length. This length is critical, as a shorter stage often fails to develop further. From a length of 6 mm, clusters develop to anthesis in 3 to 4 weeks at 24C, 4 to 5 weeks at 21C, and 6 to 7 weeks at 18C. This work is important to the production of pakalana flowers for Hawaii's winter lei flower trade.

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Richard A. Criley

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Richard A. Criley

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Richard A. Criley

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Richard A. Criley*

As part of a research study on growth and flower production of 20 commercial heliconia cultivars, plants were established at the Waimanalo Research Farm (Oahu) of the Univ. of Hawaii in July 1999. This report focuses on Heliconia ×rauliniana. Five plants in 7.6 L pots were planted at spacings of 2.5 M in row, with between row spacings of 3 M. Beginning a month later, newly emerged shoots were tagged every four weeks. At flowering, the shoots were harvested and leaf counts made. The information derived from the data include time frame from shoot emergence to flower, rate of shoot production, percentage of shoots from each tag date that flowered and the periodicity of flowering in a two year period. The range of times from shoot emergence to harvest was 208 to 450 days. In the first 12 months following planting, the average cumulative new shoot production since planting was 77 shoots per plant, while more than 58 inflorescences per plant were produced from the tagged stems for a 75% productivity rating. H. X rauliniana evidenced periodic flowering behavior, with peak flowering in the April to June period, that suggested it is a short-day plant for flower initiation.

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Richard A. Criley and Setapong Lekawatana

Although in florescences of H. chartacea `Sexy Pink' can be harvested year'round in Hawaii, flowering is heaviest during the summer while demand is higher during winter months. The research was directed at identifying influences affecting the timing and rate of flower development, Dissection of apices of pseudostems which began development during June-July showed reproductive development (3-6 cm) in Jan-Feb when @6 leaves had unfurled. Some pseudostems had aborted the growing point after initiation had occurred. Data from 141 flowering pseudostems over 2 years of sampling showed that approx. 46 weeks were required from shoot emergence to flowering. Seasonal variation existed for leaf number and developmental period. The paper will analyze the influence of temperature on these two components of flowering.

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Osamu Kawabata and Richard A. Criley

MacroMixer, a microcomputer spreadsheet program, offers 15 commonly used nutrient sources for quick formulation of a macronutrient mix in solution culture. The program displays the total concentration of each macro-element and the contribution of each source when the user specifies the desired volume of the mix and the amount of source considered. This program, used with trial and error, eases computational complexity, as sources may contain more than one controlled macro-element.

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Funoh Kwon and Richard A. Criley

Bright red bracts with white flowers are produced by H. angusta from Sept through Dec in Hawaii. The inflorescences are valued as cut-flowers and the species is potentially adaptable as a seasonal potted plant. Sakai et al (1990) reported the LD responsiveness of this species, but-additional detail was necessary to permit scheduling. EK's PhD thesis developed a model for flowering in which the minimum day length requirement to initiate was 13 hr for 7 wk with another 15-16 wk required for development irrespective of the day length (12-18 hr) or temperature (14-22C). As with other phozoperiodically sensitive heliconias, 3 unfurled leaves were required to respond to LD. A growing degree model was developed to determine the time necessary to reach the 3-leaf stage. A 30-year temperature record was used to estimate the latest shoot emergence date that would permit initiation, development, and flowering under Honolulu conditions. The model was validated by comparison with commercial production records. Sakai et al. 1990. Bul Heliconia Soc Intl 4(4):10-11

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Osamu Kawabata and Richard A. Criley

An aqueous solution of dikegulac-sodium at 0, 2000, 4000, 6000, or 8000 mg a.i./liter was sprayed on a mature Murraya paniculata hedge as the first leaves expanded on newly developing lateral shoots after trimming. The lateral shoots from each 0.09-m2 hedge surface elongated less and the coefficient of variation (cv) decreased as the growth regulator concentration increased. Application of dikegulac-sodium at 4000 mg a.i./liter to the most distal leaf on topped, single-leader seedlings inhibited the elongation of distal shoots while it enhanced proximal shoot growth. Dikegulac-sodium spray between 4000 and 6000 mg a.i./liter to the hedge decreased apical dominance among lateral shoots and enhanced uniform regrowth without causing visible damages. The cv reduction was attributed to the growth regulator-induced weakening of apical dominance. Chemical name used: sodium salt of 2,3:4,6-bis-O-(1-methylethylidene)-α-l-xylo-2-hexulofuranosonic acid (dikegulac-sodium).

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Osamu Kawabata and Richard A. Criley

In solution culture experiments, determining the quantity of nutrient sources to dispense in a solution mix is time consuming. When a source contains more than one controlled element (e.g., calcium nitrate [Ca(NO3)2]), a change made to control one element (Ca) requires an adjustment to the other element (N). To ease the computational chore, MacroMixer, an application program for mixing macro-nutrients, was developed using a spreadsheet for microcomputers.

MacroMixer consists of two parts. The first part computes the weight (volume for a liquid) of source necessary to give the target element concentration from each source. The second part computes the total concentration for each macro-element from a set of sources in the final mix. The total volume of the mix is specified at the beginning of program, but it can be changed later. Users can obtain a required weight for each source using the first part to use as a starting value in the second part. Adjustments are made among sources to achieve target element concentrations in the final mix.

The spreadsheet format hides computational formulae and constants for a clear view of solution composition; thus users are encouraged to exercise trial and error to achieve the most balanced mix. Using this program, we quickly formulated 13 mixes used in a 5 K-levels × 5 Ca-levels partial factorial experiment.