M.S. - Horticulture

Permanent URI for this collectionhttps://hdl.handle.net/10125/2074

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Tissue Culture of Pineapple Ananas comosus (L.) Merr. Var. Cayenne Lisse: a Method of Asexual Propagation
(University of Hawaii at Manoa, 1979) Zepeda, Ceasar A.
Evaluation of 13 Rootstocks for 3 Sweet Omage Clones for Tolerance to Tristeza Virus at Malama-ki, Hawaii
(University of Hawaii at Manoa, 1979) Zee, Francis Tso Ping
Fifteen-year old 'Washington Navel', 'Valencia', 'Pera', and 'Ortanique' cultivars grafted on thirteen citrus rootstock species and hybrids were evaluated for tristeza tolerance at the University of Hawaii, Malama-Ki Experimental Farm. One hundred percent natural infestation of all experimental trees was detected and confirmed by use of Immunodiffusion test and the viral inclusion staining technique. Cultivars grafted on sour orange, 'Sampson' tangelo and Citrus amblycarpa rootstocks were lost due to tristeza prior to 1972. 'Batangas' and rough lemon were rootstocks that produced the most vigorous growth. 1978 seasonal production was high with trees on rough lemon, 'Batangas', 'Rangpur', 'Kona orange', 'Cleopatra' and Citrus sunki. Upright growth habit was observed with trees on 'Cleopatra' and 'Rangpur' rootstocks. The best quality fruit was harvested from trees grafted on Citrus sunki and 'Cleopatra' rootstocks. 'Heen naran' performed well with 'Washington Navel' but was not a satisfactory rootstock for the other three cultivars. In this experiment, Citrus taiwanica, 'Siamelo' and 'Troyer' were not desirable rootstocks due to poor production. Citrus amblycarpa, 'Sampson' tangelo and sour orange were not suitable rootstocks for oranges and mandarins because of their susceptibility to tristeza virus.
Enzyme Activities of Maize (Zea Mays L.) Endosperm Cultures Following Sucrose Supplementation
(University of Hawaii at Manoa, 1974) Yu, Ting-Ting
Nutritional Aspects of the Physiology of Tipbum Disorder in Head Lettuce
(University of Hawaii at Manoa, 1980) Yanagi, Ann Aya
Pollination and Fruit Set of Acerola
(University of Hawaii at Manoa, 1960) Yamane, George M.
Ethylene Biosynthesis, Perception, and Sinaling-Related Gene Expression During Papaya Fruit (Carica papaya L.) Ripening
(University of Hawaii at Manoa, 2012) Wu, Ping-Fang
A gaseous plant growth regulator, ethylene, plays an important role during plant growth and development and includes ethylene dependent fruit ripening. Fruit ripening is a series of biochemical, physiological and structural events that lead to maturity. Papaya (Carica papaya) is a typical climacteric fruit that which performs dramatic changes in color, texture, and flavor during fruit ripening. Fruit ripening process was considered highly related to the biosynthesis of ethylene which is mainly controlled by the SAM (S-Adenosyl methionine synthetase. Methionine adenosyltransferase), ACS (1- aminocyclopropane-l-carboxylic acid synthase), and ACO (1-aminocyclopropane-lcarboxylic acid oxidase) genes. In addition, the ethylene receptors in Arabidopsis and tomato have been shown to be involved in effecting fruit development and the timing of fruit ripening, respectively. Ethylene signaling transduction gene expressions, such as CTR (Constituted Triple Response), EIN2 (Ethylene Insensitivity 2), EIN3/EILs (Ethylene Insensitivity 3 and Ethylene Insensitivity 3- Like proteins) and ERF (Ethylene Response Factors) are also involved in the ripening processing. The full sequencing of the papaya genome, coupled with microarray technology, provides a chance to determine the expressions of genes at specific fruit developmental stages. Thirty-four genes involved in ethylene biosynthesis (SAM, ACS, ACO, and ETO), perception (ETR) and the signaling transduction pathway (RAN, CTR, EIN2, EIN3/EIL1, and ERF) were selected from 24,421 predicted genes in papaya genome. Four developmental stages: mature green, the 25% color, 80% color and 100 color stage were investigated. The ethylene biosynthesis genes seemed to be expressed before the initiation of fruit ripening, and declined once the System 2 ethylene production was started. The ethylene receptors have been shown to be involved in the regulation of tomato fruit ripening. Our results showed fewer number of ethylene receptors than in tomato and Arabidopsis and also showed a possible role in controlling the initiation of papaya fruit ripening. More genes related to the ethylene signaling transduction pathway did not change in expression level during fruit maturation and ripening, except for CTR and RAN. CTRl and RAN are considered as negative regulator in the signaling pathway and a copper transporter associated with ethylene receptor respectively. In papaya, changes in sugar content, production of flavor constituents and rapid pulp softening during ripening can affect the quality and cause serious postharvest losses during transportation and storage. Knowing the ethylene-related gene expression during papaya fruit development and ripening may be helpful in regulating the timing of ripening, in order to control the fruit quality and reduce the postharvest losses.
Some Factors Affecting Growth of Citrus Rootstock Seedlings in Hawaii
(University of Hawaii at Manoa, 1966) Worku, Zemedu
Atrazine Drift Studies with Horticultural Crops
(University of Hawaii at Manoa, 1966) Wong, Melvin K.
The feasibility of diagnosing atrazine drift accurately with physical symptoms and tissue analysis was studied extensively with cucumber plants. Concentrations of atrazine ranging from 0.0005 to 1.0 lb. active/A were sprayed on mature cucumber plants. Although the physical symptoms resembled many other types of damage, the symptoms were sufficiently distinct to be used as secondary evidence along with tissue analyses. Physical symptoms appeared initially 2 or 3 days after the spraying as marginal and/or intervenal chlorosis. These chlorotic symptoms turned briefly to a bleached-white color on the leaves, which became necrotic within 5 days after spraying. The H. S.P.A. Method, an ultraviolet spectrophotometrlc method, was evaluated and found suitable to detect the presence of atrazine in cucumber tissue at levels where physical symptoms were difficult to detect and essentially no damage occurred. Although the addition of alumina columns to the H.S.P.A. Method was not necessary with cucumber leaves under the test conditions, they were beneficial when snap beans were analyzed. Alumina columns decreased interfering background and were not responsible for any loss of atrazine. To determine the best time to sample, cucumber plots were sprayed with 0.1 lb. active/A atrazine and harvested 12 hours, 1, 2, 4 and 7 days after the spraying. The samples were analyzed using the H.S.P.A. Method. The sampling time experiment showed a rapid decrease of atrazine from the time of spraying to 4 days after the spraying and very little decrease of atrazine from 4 to 7 days. For consistency samples should be taken 4 to 7 days after the suspected drift even though an earlier sampling would give higher tissue readings. After 7 days the damaged leaves started to fall from the plant. In all field experiments the sampling of only the most damaged leaves proved to be a very satisfactory procedure.
Embryological Study of Reproductive Barriers in Interspecific Crosses Between Carica Papaya L. and C. Cauliflora Jacq.
(University of Hawaii at Manoa, 1987) Wenslaff, Timothy Frank
The nature of sexual incompatibility between C. papaya L. and C. cauliflora Jacq. was examined. Pollen tube fluorescent staining studies revealed no inhibition of pollen tube development. Serial sections of developing hybrid-crossed ovules revealed significant postzygotic abnormalities, with reciprocal hybrid differences. On C. papaya females pollinated by C. cauliflora, embryos aborted at a microscopic, undifferentiated stage beginning about the 45th day, normal endosperm was lacking, and intact pollen tubes persisted a shorter time than in intraspecific ovules. On C. cauliflora females pollinated by C. papaya, abortion was evident in some ovules by the 45th day, but in others polyembryony was observed, with differentiation ranging from none to fully differentiated. A minority of mature seeds yielded large, fully-formed multiple embryos; there appeared to be potential for ^ vitro germination. No endosperm was found. All embryos in both reciprocal hybrid crosses appeared to derive from the hybrid zygote, based on their orientation and location in the ovule.
Genetic Transformation of Papaya (Carica Papaya, L.) Cultivar Kapoho by Particle Bombardment
(University of Hawaii at Manoa, 1996) Wang, Xiaohu
Papaya transformation systems were developed by Fitch et al. (1991) at the University of Hawaii, and transgenic 'Sunset' papayas with papaya ringspot virus (PRV) coat protein (cp) gene showed complete resistance to papaya ringspot virus (PRV) in the field tests (Manshardt et al, 1994). In our studies, we transformed 'Kapoho' papaya, the major crop on the Big Island, Hawaii, based on Fitch’s (1991) papaya transformation systems, and obtained transgenic 'Kapoho' papaya plants. The coat protein (cp) gene of PRV, along with a kanamycin selective marker gene (neomycin phosphotransferase, NPTII) and a Pglucuronidase (GUS) reporter gene, were constructed into the same plasmid vector by our collaborators at Cornell University and transformed into papaya tissue by particle bombardment. Transgenic 'Kapoho' papaya plants were obtained following somatic embryogenesis from hypocotyl callus on kanamycin selective medium and showed GUS positive expression. Immature zygotic embryos were excised and bombarded with gold particles. Following different treatments of indole-3-butyric acid (IBA), chimeric hypocotyls were harvested on germination medium 20 days after bombardment. Somatic embryogenesis from sections of chimeric transgenic hypocotyls occurred on induction medium and the transgenic embryos were cultured on selective induction medium or maturation medium with different concentrations of kanamycin for eight months. Then, the embryos were regenerated on germination medium without kanamycin. GUS was assayed in all experimental steps, and different GUS positive results were observed at different developmental stages. ELISA assays of coat protein and NPTII in chimeric transgenic hypocotyls showed positive expression and a high efficiency of transformation.
Genetic and Cultural Control of Anthurium Burrowing Nematode Radopholus Citrophilus
(University of Hawaii at Manoa, 1996) Wang, Koon-Hui
Cinder medium is able to decrease burrowing nematode damage in 'Alii'. This provides a supplemental method to manage anthurium decline on burrowing nematode intolerant cultivars. Burrowing nematode can invade Anthurium shoot tissues, thus propagation by shoot top cutting cannot guarantee nematode-free planting materials. In vitro screening for burrowing nematode tolerant and resistant cultivars identified 'Midori' as standard tolerant and 'Nitta' as standard susceptible cultivars. Future breeding could select progenies that are more tolerant than 'Midori' and moderately low in nematode parasitism index [log (Rf+1) of progeny / log(Rf+l) of 'Nitta’], where Rf is final nematode number / initial nematode number. Nonparametric parameters and parameters adjusted to initial reading and uninoculated reading are effective in evaluating burrowing nematode tolerance. Based on in vitro screening, Anthurium pittieri and A. ravenii were evaluated as tolerant species. A. rayenii, A. aripoense and A. pittieri were evaluated as resistant species. (Ca+Mg)/K is negatively correlated with burrowing nematode tolerance and resistance in Anthurium and could provide a good marker for nematode resistance and tolerance selection.
Genetic Analysis of Morphological Characters of Recombinant Inbred Lines with Molecular Markers in Maize
(University of Hawaii at Manoa, 1999) Wang, Bingtian
Ninety-four recombinant inbred lines of maize (Zea may L.) derived from Hi31 (conversion of B68 from stiff stalk synthetic) and Ki 14 (inbred from Suwan 1, Thailand) were planted in Waimanalo, HI in 1998. This study was to identify quantitative trait loci (QTLs) for 45 targeted morphological traits by use of restriction fragment length polymorphism markers. Composite interval mapping method was used for characterization of QTLs. Husk number and pericarp thickness variations were each affected by three major QTLs. Two genomic regions were associated with tassel type, leaning stalk, central spike length and cob color. The correlation between pericarp thickness and stalk stiffness was significant. Other correlations among plant stature traits were constent with published literature. A genetic study of tassel type (erect vs. floppy) was also conducted on an F2 population derived from inbreds su2 and su9, and on their testcross progenies. The results showed that the erect character was dominant, and that two genes were involved in tassel type development.
The Identification of a Suitable Irradication Dosage for Mutation Induction in Zamioculcas Zamiifolia (lodd.) and the Polyploidization of Z. Zamiifolia and Marsdenia Floribunda
(University of Hawaii at Manoa, 2006) Vanzie-Canton, Susana D.
Radiation mutation has been successfully used to create a great variety of ornamental crop cultivars by supplementing existing germplasm and improving existing cultivars, and chemical mutagens such as colchicine and oryzalin have been used to create new plant cultivars by doubling the chromosome number of the treated plant material to produce tetraploids. The main objective of this thesis research was to develop protocols to create tetraploid plants of Zamioculcas zamiifolia (Lodd.) Engl., an important foliage plant, and Marsdenia jloribunda (Brongn.), an important lei flower plant, and to determine the LD50 of ZZ leaflets. ZZ leaflets and M floribunda seeds were treated with colchicine at various concentrations and durations in order to induce ploidy changes and regenerate polyploids. Five ZZ tetraploids and one M. floribunda tetraploid were produced using colchicine. A tissue culture protocol was also developed for the oryzalin treatment of ZZ callus for the in vitro polyploidy induction of ZZ. The LD50 of ZZ leaflets irradiated with x-rays was calculated as 20±1 Gy. A ZZ germplasm collection was also initiated to provide ZZ plant material for use in future breeding studies.
Inheritance of Resistance to Tomato Spotted Wilt Virus in Tomatoes (Lycopersicon Esculentum Mill.)
(University of Hawaii at Manoa, 1983) Upreti, Gopi
Chromosome Numbers. Karyotype and Crossability of Some Manihot Species
(University of Hawaii at Manoa, 1972) Umanah, Effiong Etim
Factors Affecting Macadamia Nut Stability
(University of Hawaii at Manoa, 1988) Tsumura, Tsuyoshi
The Inheritance of Seedcoat Color in Phaseolus Vulgaris
(University of Hawaii at Manoa, 1977) Troy, Joanne
The Influence of Rootstocks on Some Fruit and Tree Characters of Avocado (Persea Americana L.)
(University of Hawaii at Manoa, 1971) Toxopeus, Henderikus Riepko
Differential Response of Vegetable Soybean Varieties to Fertility Levels and Seasons
(University of Hawaii at Manoa, 1963) Thipphawong, Bounnong
The Effect of N Source. N Rate and a Vesicular-arbuscular Mysorrhizal Fungus on Nitrogen Leaching and Elemental Composition in Bermudagrass Turf
(University of Hawaii at Manoa, 1983) Tavares, James William
A glasshouse experiment was conducted to determine the effect of two sources and three rates of N and a mycorrhizal fungus on nitrogen leaching through common bermudagrass (Cynodon dactylon (L.) Pers.) grown on crushed basalt. Growth parameters were also measured to determine responses of common bermudagrass to N source, N rate and mycorrhizal infection. More NO3-N was leached from calcium nitrate than from ammonium sulphate. N lost as nitrate was 23%, 23% and 35% of N applied for the 24.4, 48.8 and 73.2 kg N/ha rates respectively of calcium nitrate. N lost as nitrate from ammonium sulphate was 21%, 12% and 10% of the N applied for the 24.4, 48.8 and 73.2 kg N/ha rates respectively. There was no effect of raycorrhiza on leaching loss of nitrogen. Root dry weights of mycorrhizal plants averaged 18854 kg/ha while non-mycorrhizal plants averaged 9819 kg /ha. Root dry weights were greater when ammonium sulphate was the source of N than with calcium nitrate. With increasing levels of N, there were increasing concentrations of N, K and Mg in the clippings. Ca concentration of clippings decreased with increasing ammonium sulphate levels. Silicon uptake was enhanced by mycorrhizal fungi. Higher concentrations were found in both roots and shoots of mycorrhizal plants. VAM infection levels decreased with increasing levels of anunonium sulphate and remained the same with increasing levels of calcium nitrate. VAM infection levels also decreased with increasing depths. Higher average VAM infection levels with ammonium sulphate indicates a possible preference by the fungus for ammonium over nitrate.

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