Progress 10/01/06 to 09/30/10
Outputs
OUTPUTS: Kaimana is the most important lychee (Litchi chinenesis) cultivar in Hawaii, since it requires less chilling for flower initiation. Crop nutrition is important for consistent production since over fertilization can reduce flowering. To determine the range of mineral nutrient concentration in leaves of well-producing trees and amount of nutrients depleted from the soil during harvest, leaf samples were collected from terminal branches at the onset of panicle emergence, and mature Kaimana fruit were collected from several orchards near Hilo on the Island of Hawaii. Flower induction of longan (Dimocarpus longan) with potassium chlorate has improved fruit availability, but the material can be explosive and hard to purchase, transport and store. As an alternative, studies were conducted with chlorite and hypochlorite (bleach) to induce flowering. A principal factor affecting fertilizer requirements for longan is the amount of nutrients in the harvested crop which represents the minimum quantity that will need replacement through fertilizer application. A study to monitor longan (cv. Biew Kiew) fruit growth, fruit quality, and patterns of moisture and nutrient accumulation during fruit development was completed. An outbreak of armored scale infestation on rambutan (Nephelium lappaceum) trees was discovered at the University of Hawaii Waiakea Agricultural Research Station in 2008. Subsequently growers reported heavy scale infestations in the Hamakua district. Infestations were characteristic, because scales were white, pencil shaped and about 0.5 mm in length, aggregated in clusters and appeared oriented in a single direction. Infestation is problematic since scales are quarantine pests, and rambutan fruits with infestations are rejected for export to the US mainland. Insect samples were submitted to the CTAHR Agricultural Diagnostic Center for identification, and the Waiakea Station surveyed for bio-control activity. During anthesis panicles on rambutan cultivars were examined to determine the frequency of hermaphroditic functionally male (HFM) flowers which are the pollen source during fruit set. Applications of naphthaleneacetic acid (NAA) to R7, R9, R134, R162, R167, R156 Red, R156 Yellow, Binjai, Jitlee and Rongrien panicles containing predominantly hermaphroditic functionally female (HFF) flowers were made to stimulate development of HFM. A paper describing involvement of poor pollination in the production of deformed fruit in Hawai'i rambutan orchards has been published and is available on-line. Results from lychee, longan and rambutan studies were presented to the tropical fruit industry at the 18th, 19th and 20th Annual Hawaii International Tropical Fruit Growers Conferences. To identify and prioritize bottlenecks facing Hawaii's specialty tropical fruit industry and determine actions and agencies to alleviate bottlenecks, participants at the 18th Annual Hawaii International Tropical Fruit Growers Conference in Kona, HI in 2008 met in commodity focus groups for the Sapindaceae (lychee, longan, rambutan) and Moraceae family (breadfruit, jackfruit, fig), and for cacao, banana, mango, citrus and other specialty fruits. PARTICIPANTS: The USDA CSREES Special Research Grant Agricultural Diversification-Tropical Specialty Fruit Research and Development program and the County of Hawaii Department of Research and Development are acknowledged for their funding support of the project. Industry support from tropical fruit growers was provided thorough use of their orchard for research and outreach activities. Collaboration with the Hawaii Tropical Fruit Growers association and the County of Hawaii, Department of Research and Development provided the opportunity to educate and transfer information to producers through presentations and proceedings from the 18th, 19th and 20th Annual International Tropical Fruit Conference. This annual conference for producers and marketers of Hawaii's specialty tropical fruits is convened to provide this industry with the latest research and extension updates. TARGET AUDIENCES: The target audience consisted of specialty tropical fruit producers, the Hawaii Tropical Fruit Growers association, Hawaii Farm Bureau Federation members, USDA, university and international scientists and extension personnel, processors and marketers of specialty fruit crops. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
Mean leaf concentrations for N, P, K, Ca, Mg and S were 1.73%, 0.24%, 0.87% 0.58%, 0.32% and 0.16%, in Kaimana terminals at the onset of flowering. Better flowering occurred, if leaf N was between 1.59 to 1.73%. Fruits had a sigmoid growth pattern, rapidly increased in weight between 6 and 12 weeks and attained maximum weight (22.6 to 36.8 g) at 12 to15 weeks. Accumulation of N, P, K, Ca, and Mg in fruits followed a sigmoid pattern and reached maximum concentrations at 12 weeks. Dry weight concentrations of N, P, K, Ca and Mg in mature fruits were 0.79%, 0.14%, 1.01%, 0.15% and 0.17%, respectively, and fruit analyses showed that at harvest, 100 kg of fresh fruit contained 170.4, 30.0, 220.5, 30.0, and 40.2 g of N, P, K, Ca and Mg, respectively. N and K accumulated rapidly in fruits during the 6th to 12th week while leaf N and K decreased. Adequate irrigation and nutrition during 6th to 12th week were critical for good fruit development. Biew Kiew longan fruits had a sigmoid growth pattern and matured at 24 weeks when total soluble solids (TSS) content reached a maximum of 19.2%. Fruit weight increased slightly after 24 weeks, but quality decreased due to reduction in TSS and increased seed germination. Nutrient analyses of mature fruits showed that at harvest 100 kg of fresh fruits accumulated 292.4 g N, 398.6 g K, 100.3 g Ca, 48.0 g P and 45.1 g Mg. Fertilizer with a ratio of 2-1-4 was considered appropriate during fruit development, and trees required adequate irrigation between 12 and 24 weeks to attain optimum fruit size. Hypochlorite induction of longan flowering with bleach resulted from chlorate present in the bleach solution. Chlorate in bleach induced flowering to the same or greater extent as equivalent quantities of potassium chlorate, suggesting that chlorate was the active ingredient for flowering. Rambutan growers learned the cause for deformed fruit and learned to identify hermaphroditic functionally male (HFM) and true male flowers which are pollen sources for fruit set. Incorporation of Silengkeng and males trees in an orchard or treating hermaphroditic functionally female panicles with NAA, increased frequency of HFM flowers and reduced incidence of fruit without arils. Rambutan scale (Aulacaspis alisiana) caused the scale outbreak in 2008, and growers learned of its impact on fruit export at the 18th Annual Hawaii International Tropical Fruit Growers Conference in 2008. Damage symptoms and scale infestations were displayed to enable growers to identify the pest. Growers learned that bio-control insects were found with infestations, and chemical control was available with buprofezin. To coordinate the state's research and extension programs for tropical fruits, an industry analysis document was published and focused on research and extension priorities for production, handling and marketing. The document (Industry Analysis: Identifying Research and Extension Priorities for Hawaii's Avocado, Banana, Citrus and Specialty Fruits. Univ. of Hawaii CTAHR Cooperative Extension Service Economic Issues Jan 2009, E1-17) was published on the CTAHR website http://www.ctahr.hawaii.edu/oc/freepubs/pdf/EI-17.pdf.
Publications
- No publications reported this period
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Progress 10/01/08 to 09/30/09
Outputs
OUTPUTS: Longan (Dimocarpus longan) cultivation has increased dramatically, but a constraint in production is lack of information on fertilizer requirements for sustained production. A principal factor influencing fertilizer requirements includes the amount of nutrient elements in the harvested crop which represents the quantity that will need replacement through fertilizer applications. A study to monitor longan (cv. Biew Kiew) fruit growth, fruit quality, patterns of moisture and nutrient accumulation during fruit development was initiated. Nutrient compositions of leaves and fruits are monitored during fruit growth to develop nutrient management guidelines for this cultivar. Samples are collected from several orchards near Hilo Hawaii from trees that were treated with potassium chlorate to stimulate uniform flowering. Leaf samples are collected from terminal branches at the onset of panicle emergence and through the fruit development period. Tree phenology is also monitored by recording the level of flowering on trees at monthly intervals based on the percent of terminal shoots bearing flower panicles and the percent of terminals with vegetative flushes. An outbreak of armored scale insect infestation on rambutan (Nephelium lappaceum) trees was discovered by the project leader on leaves and fruits at the University of Hawaii Waiakea Agricultural Research Station in 2008. Subsequently, growers in the Hamakua district reported heavy scale infestations were also present in their orchards. Infestations were very characteristic, because the scales which are white, pencil shaped and about 0.5 mm in length, aggregate in clusters and appear to be lined up in a single direction. The infestation is extremely troubling since scales are quarantine pests, and rambutan fruits with infestations are rejected for export to the US mainland. Samples were submitted to the UH CTAHR Agricultural Diagnostic Center for identification, and the infestation at the Waiakea Station surveyed for evidence of bio-control activity. Tropical fruit production and management has been identified as a CTAHR initiative, however coordinating the state's research and extension resources and furthering development of Hawaii's tropical fruit industries require an industry analysis that assesses the current condition of these industries, identifies bottlenecks to expansion and sustainability and develops action plans to alleviate the bottlenecks. To identify and prioritize bottlenecks facing the specialty tropical fruit industry and determine actions and agencies to alleviate bottlenecks, participants at the 18th Annual Hawaii International Tropical Fruit Growers Conference in Keauhou-Kona, HI on September, 2008 met in commodity focus groups. These breakout sessions focused on crops in the Sapindaceae family (lychee, longan, rambutan), Moraceae family (breadfruit, jackfruit, fig), cacao, banana, mango, citrus and other specialty fruits. During each facilitated session, bottlenecks, actions and agencies responsible for addressing these bottlenecks were recorded, compiled and shared with conference participants. PARTICIPANTS: The USDA CSREES Special Research Grant Agricultural Diversification-Tropical Specialty Fruit Research and Development program and the County of Hawaii Department of Research and Development are acknowledged for their funding support of the project. Industry support from tropical fruit growers was provided thorough use of their orchard. Collaboration with the Hawaii Tropical Fruit Growers association and the County of Hawaii, Department of Research and Development provided the opportunity to educate and transfer information to producers through presentations and proceedings from the Annual International Tropical Fruit Conference. This annual conference for producers and marketers of Hawaii's specialty tropical fruits is convened to provide this industry with the latest research and extension updates. TARGET AUDIENCES: The target audience consisted of specialty tropical fruit producers, the Hawaii Tropical Fruit Growers association, Hawaii Farm Bureau Federation members, USDA, university and international scientists and extension personnel, processors and marketers of Sapindaceae fruit crops. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
Longan fruits in the phenology study exhibited a sigmoid growth pattern and matured at about 24 weeks after anthesis when total soluble solids (brix) content reached its maximum (19.2%). Fruit weight increased most rapidly between 12 and 24 weeks after anthesis; moisture accumulation was also greatest between 12 and 24 weeks and accounted for 73 to 77% of the final weight of mature fruits. Although fruit weight increased slightly after 24 weeks, fruit quality decreased due to a reduction in soluble solids and increased seed germination. The rambutan scale (Aulacaspis alisiana) was confirmed as the cause of the scale outbreak on rambutan trees at the university research farm and grower orchards. Although first reported in Hawaii in 1989, it was not a concern until the recent outbreak. To alert and educate the industry about this pest problem and its impact on fruit export, a presentation was made to growers and other participants at the 18th Annual Hawaii International Tropical Fruit Growers Conference held in Kailua-Kona, Hawaii in September, 2008. In the presentation, images of damage symptoms on the leaves (chlorotic spots on the upper leaf surface) and scale infestations on leaves and fruits were displayed to enable growers to identify the pest. Growers were also alerted that a number of bio-control insects were found feeding on the infestations, and that chemical control options are available with buprofezin, which is registered for scale control in rambutan, longan and lychee. The impact on export is problematic, since fruits with visible surface infestations of live or dead scales will be rejected for export to the US mainland. A copy of the presentation will be published in the 2008 conference proceedings. To coordinate the state's research and extension resources dealing with tropical fruits, an industry analysis document was authored by the project leader which focuses on setting research and extension priorities for tropical fruit management, production, handling and marketing. The document (Industry Analysis: Identifying Research and Extension Priorities for Hawaii's Avocado, Banana, Citrus and Specialty Fruits. Univ. of Hawaii CTAHR Cooperative Extension Service Economic Issues Jan 2009, E1-17) was published and is also available on the CTAHR website http://www.ctahr.hawaii.edu/oc/freepubs/pdf/EI-17.pdf. Research and extension priorities identified for Sapindaceae fruits included: (1) lack of marketing plans and postharvest technology, (2) Lack of improved production methods, (3) lack of development for value-added products.
Publications
- Nagao, M., 2009. Industry Analysis: Identifying Research and Extension Priorities for Hawaii's Avocado, Banana, Citrus and Specialty Fruits. Univ. of Hawaii CTAHR Cooperative Extension Service Economic Issues Jan 2009, E1-17. available: http://www.ctahr.hawaii.edu/oc/freepubs/pdf/EI-17.pdf
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Progress 10/01/07 to 09/30/08
Outputs
OUTPUTS: Kaimana is the most widely grown lychee (Litchi chinenesis) cultivar in Hawaii, due to its ability to flower consistently under mild temperatures. Understanding nutrient requirements for Kaimana trees are important to achieve consistent production since over fertilization can reduce flowering. A study to monitor Kaimana fruit growth, fruit quality, patterns of moisture and nutrient accumulation during fruit development was completed; nutrient composition of leaves was also monitored during fruit growth to develop nutrient management guidelines for this cultivar. Leaf and fruit samples were collected from an orchard at 61 m elevation in Panaewa, near Hilo, Hawaii. Trees were well grown and historically had consistent yields. Leaf samples were collected from terminal branches at the onset of panicle emergence and throughout the fruit development period. Samples were comprised of leaflets from the most recently matured leaf below the panicle on randomly selected flowering terminals. Tree phenology also was monitored by recording the level of flowering on trees at monthly intervals based on the percent of terminal shoots bearing flower panicles and the percent of terminals producing vegetative flushes. Fresh and dry weights were recorded for each fruit sample and all samples were analyzed by the University of HI Agricultural Diagnostic Service Center for N, P, K, Ca, Mg and micronutrients. Results from this study were presented at the Seventeenth Annual International Tropical Fruit Conference in Hilo, Hawaii in October 2007 and published in the proceedings of the annual conference. The meeting was sponsored by the Hawaii Tropical Fruit Growers association and the County of Hawaii, Department of Research and Development. Deformed fruit that lack or have a poorly developed aril has been a problem for rambutan (Nephelium lappaceum) growers in Hawaii. A paper describing the involvement of poor pollination in the production of deformed fruit in Hawai'i orchards has been published and is available on-line. With the exception of Silengkeng, cultivars planted in Hawai'i produce large numbers of hermaphroditic functionally female (HFF) and a small number or lack hermaphroditic functionally male (HFM) flowers for pollination. Silengkeng panicles produce large numbers of HFM flowers throughout the anthesis period which makes it a suitable pollinator cultivar. Application of the plant growth regulator, naphthaleneacetic acid (NAA) to R7, R9, R134, R162, R167, R156 Red, R156 Yellow, Binjai, Jitlee and Rongrien panicles containing predominantly hermaphroditic functionally female (HFF) flowers stimulates development of HFM flowers within 6 days after treatment. By 12 days after treatment, production of HFM flowers is decreased. Only floral buds where the apex of the pistil begins protruding through the unopened sepals are responsive to NAA. Pollen taken from naturally produced HFM flowers from Silengkeng panicles and from HFM flowers produced after NAA treatment is viable and germinate within 24 hours after incubation in a culture medium. PARTICIPANTS: The Hawaii Department of Agriculture, Hawaii Farm Bureau Federation and USDA CSREES Special Research Grant Agricultural Diversification-Tropical Specialty Fruit Research and Development program are acknowledged for their partial funding support of the project. Industry support from a tropical fruit grower, Philip Ito, was provided thorough use of his orchard. Collaboration with the Hawaii Tropical Fruit Growers association and the County of Hawaii, Department of Research and Development provided the opportunity to educate and transfer information to producers through presentations and proceedings from the Seventeenth Annual International Tropical Fruit Conference in October, 2007. This annual conference for producers and marketers of Hawaii's specialty tropical fruits is convened to provide this industry with the latest research and extension updates. Nutrient analyses of leaf and fruit samples were conducted by the University of Hawaii Agricultural Diagnostic Service Center. TARGET AUDIENCES: The target audience consisted of specialty tropical fruit producers, the Hawaii Tropical Fruit Growers association, Hawaii Farm Bureau Federation members, USDA and university scientists and extension personnel, processors and marketers of Sapindaceae fruit crops. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
Kaimana lychee fruits exhibit a sigmoid growth pattern, with rapid increases in fruit weight occurring between 6 and 12 weeks after anthesis; maximum fruit weight is attained at 12 to15 weeks. Moisture accumulation is also greatest during the 6th to 12th week and accounted for 78% of the final weight of mature fruits. Accumulation of N, P, K, Ca, and Mg in fruits also follows a sigmoid pattern, parallels fruit growth and reaches maximum concentrations at 12 weeks after anthesis. Rapid increases in nutrient uptake between week 6 and 12 are most evident with N and K. Changes in foliar concentrations for N, P and K follow similar patterns. Leaf concentrations are highest at panicle emergence and decrease during fruit development, with the steepest decline coinciding with the period when fruits exhibit their most rapid increase in growth. A gradual increase in leaf Ca and Mg occurs during fruit development and appears to be related to leaf age. The data illustrate the importance of adequate nutrition for optimum fruit growth and for maintaining the vegetative health of producing trees. Adequate moisture (irrigation and/or rainfall) during 6th to 12th week after flowering is also critical for good fruit development. Since rapid accumulations of N and K occur in fruits during the 6th to 12th week of development and are associated with decreases in leaf N and K, trees should be well fertilized during this period to provide trees with adequate nutrition. Fruit quality studies show that total soluble solids (TSS) are at near optimum levels at 9 weeks after anthesis, well before fruits attain full maturity at 15 weeks. Poor eating quality is due to a high acidity levels rather than low TSS in immature fruits. The study provides information to help growers assess the nutritional status of Kaimana lychee trees through leaf analysis, and establishes a baseline for nutrient management of Kaimana lychee trees grown in Hawaii based on nutrient accumulation and redistribution during fruit development. The overall goal is to develop information for more consistent production of lychee in the warm environments found in Hawaii. Rambutan producers understand the cause behind production of deformed fruit and are able to identify hermaphroditic functionally male (HFM) and true male flowers, which are the pollen sources for good fruit set. Incorporating Silengkeng and males trees in a rambutan orchard or treating HFF panicles with NAA at the appropriate stage of development can be strategies for increasing the frequency of male flowers and fruit set and reducing the development of deformed fruit without arils.
Publications
- Kawabata, A.K., Nagao, M.A. and Awong, L.K. 2008. Production of male flowers on rambutan (Nephelium lappaceum L.) trees in Hawai'i. J. Hawaiian and Pacific Agric. 15: available http://www.uhh.hawaii.edu/academics/cafnrm/research/JournalofHawaiian andPacificAgriculture2008vol.15.php.
- Nagao, M.A., Awong, L.K., Kawabata, A.M. and Cabral, S.K. 2007. Pattern of nutrient levels in Kaimana lychee leaves and fruits. Page 54 to 60 in Proc. 17th Annual International Tropical Fruit Conference. Hilo, HI.
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Progress 10/01/06 to 09/30/07
Outputs
OUTPUTS: Kaimana is the most important lychee (Litchi chinenesis) cultivar grown in Hawaii, because it has a low-chilling requirement for flower initiation. However mineral nutrition also plays a critical role in flowering since over fertilization can reduce flowering. Steps to understanding nutrient requirements for Kaimana trees include determining the range of mineral nutrient concentration in leaves of well-producing trees and determining the amount of mineral nutrients depleted from the soil due to harvesting of mature fruits. Collection of leaf samples from Kaimana lychee trees in an orchard located at 61 m elevation in Panaewa, near Hilo, Hawaii was initiated over 4 fruiting seasons between 2002 and 2006. The orchard contained well grown trees and historically had consistent yields. At the onset of the study, the trees were 5 years old and grown in a Papai extremely stony muck soil. Leaf samples were collected from terminal branches at the onset of panicle emergence. Each
sample was comprised of leaflets from the most recently matured leaf below the panicle on 12 randomly selected flowering terminals from each tree. Tree phenology also was monitored at the Panaewa orchard, by recording the level of flowering on Kaimana trees at monthly intervals based on the percent of terminal shoots bearing flower panicles and the percent of terminals producing vegetative flushes. Data were taken between 2002 and 2006. Samples of mature Kaimana fruit were collected from 5 different orchards located in Keaau (76 m elevation), Panaewa (2 orchards at 61 m elevation), and Kurtistown (orchards at 244 m and at 257 m elevation) on the eastern shore of Hawaii Island over 3 harvest seasons (2004-2006). Soils in the orchards ranged from a Papai extremely stony muck to an Olaa silty clay loam. In 2006, the lychee trees were between 10 and 16 years-old. Fruits were harvested 13 to 17 weeks after full bloom when the pericarp was uniformly red. At least 0.454 to 0.908 kg of fresh
whole fruits were harvested at each sampling period. All leaf and fruit samples were rinsed in distilled water and dried until a constant weight was obtained. The fresh and dry weight was recorded for each fruit sample and all samples were analyzed for N, P, K, Ca, Mg and micronutrients. Results from this study were presented at the Sixteenth Annual International Tropical Fruit Conference in Kailua-Kona Hawaii in October 2006 and published in the proceedings of the annual conference. The meeting was sponsored by the Hawaii Tropical Fruit Growers association and the County of Hawaii, Department of Research and Development. Flower induction of longan (Dimocarpus longan) with potassium chlorate has improved the availability of fruit, but potassium chlorate is potentially explosive and often difficult to purchase, transport and store. Previous reports suggest that hypochlorite enhances natural longan flower induction. A study was conducted to demonstrate that chlorite- and hypochlorite-
(bleach) induced off-season longan flowering was similar to chlorate-treated trees.
PARTICIPANTS: The Hawaii Department of Agriculture and the Hawaii Farm Bureau Federation are acknowledged for their partial funding support of the project. Industry support from tropical fruit growers, Robert Hamilton, Philip Ito and Jean Higaki, was provided thorough use of their orchards. Collaboration with the USDA Pacific Basin Agricultural Research Center, Hawaii Tropical Fruit Growers association and the County of Hawaii, Department of Research and Development provided the opportunity to conduct the research, and educate and transfer information to producers through presentations and proceedings from the Sixteenth Annual International Tropical Fruit Conference in October, 2006. Nutrient analyses of leaf and fruit samples were conducted by the University of Hawaii Agricultural Diagnostic Service Center.
TARGET AUDIENCES: The target audience consisted of tropical fruit producers, the Hawaii Tropical Fruit Growers association, Hawaii Farm Bureau Federation and its members, processors and marketers of Sapindaceae fruit crops.
Impacts
Over 4 production seasons the mean leaf nutrient concentrations for N, P, K, Ca, Mg and S were 1.73%, 0.24%, 0.87% 0.58%, 0.32% and 0.16%, respectively. All leaf samples contained concentrations of K and Mg similar to levels recommended from Australian research. Phenology data showed that a higher level of flowering was obtained in 3 of the 4 seasons when leaf N concentrations were 1.59 to 1.73% at the onset of flowering. The highest concentration of leaf N (1.87%) at the onset of the flowering season was present in trees during the year with the lowest amount of flowering. In 3 of the 4 years P concentrations were slightly higher than concentrations reported in Australia but fell within the acceptable range in the 4th year. Ca concentrations were slightly lower than recommended levels in 3 of the 4 seasons but were adequate in year 4. The weight of individual Kaimana fruits ranged between 22.6 to 36.8 g. Moisture content of each fruit from all locations sample ranged
from 77.2% to 79.7% with a mean of 78.3%. The relative order for macro-nutrient concentration in mature Kaimana fruit was K > N > Mg > P ≥ Ca, and concentrations of N, P, K, Ca and Mg based on the dry weight of mature fruits were 0.79%, 0.14%, 1.01%, 0.15% and 0.17%, respectively. The mineral nutrient concentration in the fruit varied slightly when compared over the different growing locations and years. Results of the fruit analysis when converted to grams of each nutrient element contained in 100 kg fresh lychee fruits showed that at harvest, a 100 kg crop of Kaimana fruit contained 170.4, 30.0, 220.5, 30.0, and 40.2 g of N, P, K, Ca and Mg, respectively. The concentration of other nutrients (Na, S, Fe, Mn, Zn, Cu, and B) was small (less than 20.0 g in 100 kg crop). This study provided information to help growers assess the nutritional status of Kaimana lychee trees through leaf analysis, and established a baseline for nutrient replenishment of Kaimana lychee trees grown in
Hawaii based on nutrient removal during harvesting of mature fruits. The overall goal was to develop information for more consistent production of lychee in the warm environments found in Hawaii production areas. Hypochlorite induction of flowering with bleach was likely the result of chlorate in the bleach solution. Chlorate was present in the leachate from potted longan trees treated with bleach and was detected in the bleach before soil application. The quantity of chlorate found in the bleach induced flowering to the same or greater extent as equivalent quantities of potassium chlorate, suggesting that chlorate was an active ingredient responsible for longan flowering.
Publications
- Kawabata, A.M., Nagao, M.A., and Pena, L.K. 2006. Nutrient requirements during Kaimana lychee production. Page 54 to 60 in Proc. 16th Annual International Tropical Fruit Conference. Kailua-Kona, HI.
- Matsumoto, T.K., Nagao, M.A. and Mackey,B. 2007. Off-season flower induction of longan with potassium chlorate, sodium chlorite and sodium hypochlorite. HortTechnology 17(3):296-300.
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