Browsing by Author "Tunya, G.O"

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    Growth of ranunculus cutflower under tropical high altitude conditions.
    (Horticultural Association of Kenya, 2009) Mayoli, Rose N.; Isutsa, Dorcas K.; Tunya, G.O; ; ;
    Cutflower production and marketing is partly challenged by lack of new, exciting and improved varieties to satisfy customer needs of a different flower. Ranunculus (Ranunculus asiaticus L.) is a bulbous plant that originated in the Mediterranean basin region where growth and development take place optimally in cool, moist winter season. The extent of dormancy breaking and growth of this flower in tropical conditions is not known. Consequently, the present research studied the effects of shade and gibberellic acid (GA3) in breaking dormancy and reducing high light intensity and high temperature so as to assure optimal growth of R. asiaticus under tropical conditions. The fixed factors were: four GA3 levels (0, 100, 500 and 1500 mg/L) and three shade intensities (0%, 40% and 80% shade). The experiment was laid out in split plots arranged in randomised complete block design, replicated three times and repeated in two seasons. Tuberous roots were soaked in the respective GA3 concentrations for 10 minutes followed by planting under shaded plots. Data were recorded from sprouting through tuberous root formation stages. Season 1 (June to November 2006) was characterised by cool temperatures, whereas season 2 (December 2006 to April 2007) was characterised by warm temperatures. The 80% shade promoted significantly longer stems. Nevertheless, early flowering, highest quality flower stem diameter, flower bud initiation, flower head diameter and tuberous root fresh weight resulted for 40% shade. These quality parameters were highest in tuberous roots that had been soaked in 100 mg/L GA3 pre-plant. Therefore, growers in tropical high altitudes should use 80%, 40% and 0% shade in hot, warm and cool seasons, respectively. Pre-soaking of the tuberous roots in 100 to 500 mg/L GA3 is optional, depending on the desired growth magnitude and speed desired.
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    Growth of ranunculus cutflower under tropical high altitude conditions. 2: Effects of GA3 and shade on light intensity and temperature modification
    (Horticultural Association of Kenya, 2009) Mayoli, Rose N.; Isutsa, Dorcas K.; Tunya, G.O; ; ;
    Customer needs of a different flower are increasing over time worldwide. Many bulbous plants including ranunculus fit the category of a different flower because they are not known. Ranunculus(Ranunculus asiaticusL.),commonly known as Persian Buttercup or Asiatic Crowfoot,is a bulbous plant native of the cool Mediterranean basinregion. The growth of GA3and shade-treated ranunculus cutflower in relation to lightintensity (LI) and temperature under tropical high altitude conditions is not documented. An experiment was conducted to determine these relationships.The fixed factors were four GA3levels (0, 100, 500, 1500 mg/L) and three shade levels (0%, 40% and 80%shade). The experiment was set up in split plots arranged in randomised complete block design, replicated three times and repeated once. Tuberous roots were soaked in the respective GA3solutions for 10 minutes followed by planting under the shaded plots.Data were recorded from sprouting through tuberous root formation stages.The relationship of sprouting was negative quadratic with LI, positive linear with soil temperature (ST) in season 1 (cool), and negative linear with ST in season 2 (warm). The relationship of time to flower formation with LI was negative linear in season 1 and positive linear in season 2. The relationships of flower stem length with LI and air temperature (AT) were negative linear. The relationships of flower buds per stem, flower stem diameter, flower head diameter and tuberous root fresh weight with either LI or AT were negative quadratic. Therefore, shade modifies both LI and temperature that then interact in influencing growth of GA3-treated ranunculus. About 40000 lux LI and moderate seasonal temperature, both prevailing under 40% shade are ideal for best growth of ranunculus. Shade should be applied as follows: 0%, 40% and 80% in cool, warm and hot seasons, respectively.