Chifumi Nagai - Academia.edu (original) (raw)

Papers by Chifumi Nagai

Agriculture

Coffee is an important agricultural crop for the State of Hawaii. Developing new coffee cultivars... more Coffee is an important agricultural crop for the State of Hawaii. Developing new coffee cultivars with resistance to damaging pests and diseases is crucial for improving production and maintaining the profitability of the industry. With the recent discovery of Hemileia vastatrix, coffee leaf rust (CLR), to Hawaii there is a strong interest in replanting with CLR-resistant germplasm. However, when selecting an appropriate cultivar for replanting, susceptibility to other pathogens, such as plant-parasitic nematodes, should be taken into consideration. Meloidogyne konaensis, the Kona coffee root-knot nematode, causes severe destruction of the root system, reducing the yield and causing the mortality of susceptible Coffea arabica cv. Typica trees. Fortunately, resistance to root-knot nematodes has been found in some C. arabica germplasm. In this study, accessions of wild Ethiopian C. arabica and two CLR-resistant C. arabica cultivars, Tupi-HI and Obata, were evaluated for resistance to ...

La genetique d'association et la selection genomique sont devenues des methodes importantes d... more La genetique d'association et la selection genomique sont devenues des methodes importantes dans les programes d'amelioration de la reproduction des cultures perennes, de maniere a accelerer les efforts de reproduction et d'accroitre l'efficacite de la selection. Ce sont des bonnes alternatives a l'approche classique de cartographie par caracteres quantitatives. Le programme de recherche d'amelioration du cacaoyer de l'USDA-ARS et Mars Inc. a permis le developpement dans plusieurs pays de populations de cacaoyer selectionnees pour leurs genes de resistance au balai de sorciere, a la moniliose et a la pourriture brune des cabosses, mais egalement pour leurs caracteres de productivite. Les QTL associes a ces traits ont ete identifie; Cependant, certaines de ces associations sont specifiques a certaines populations et sont influencees par leurs interactions avec l'environnement De plus, la majorite de ces caracteres sont controlees par plusieurs genes a ...

Genetic Resources and Crop Evolution, 2021

Coffee is one of the most important agricultural commodities worldwide, significantly contributin... more Coffee is one of the most important agricultural commodities worldwide, significantly contributing to the economies of many coffee-producing countries. Globally over 2.2 billion cups of coffee are consumed daily with over 400 million of those consumed in the United States alone. The two main cultivated species of coffee are Coffea arabica L. (Arabica coffee) and C. canephora A. Froehner (robusta coffee). The 2020/2021 global production for Arabica coffee has been forecast at 6.1 million tons and at 4.5 million tons for robusta coffee. Demand is predicted to increase in the coming years. In order to meet growing demands for coffee, additional investments in advancing coffee research are needed to deal with challenges posed by climate change and associated impacts such as higher incidence of insect pests and plant pathogens, resulting in lower productivity. To tackle the challenges faced by coffee growers in the United States, a coffee genetic resource conservation and research program has been initiated by the United States Department of Agriculture, Agricultural Research Service (USDA-ARS), National Plant Germplasm System (NPGS). A coffee genetic resources collection is being established at the USDA-ARS Pacific Basin Agricultural Research Center in Hilo, Hawai’i with a back-up collection at the USDA-ARS Tropical Agricultural Research Station in Mayaguez, Puerto Rico. To help guide the development of the NPGS coffee genetic resource collection, the present coffee crop vulnerability statement developed by the Coffee and Cacao Crop Germplasm Committee provides background information about the crop, threats to coffee genetic resources, current status of coffee genetic resources and capacities, and projected future needs of coffee research, breeding, and production.

Journal of Heredity, 1985

... O 1985, American Genetic Association. ABSTRACT: Electrophoretic studies of maize peroxidases ... more ... O 1985, American Genetic Association. ABSTRACT: Electrophoretic studies of maize peroxidases have revealed 13 major en-zymes, for which genetic polymorphisms are described. Data from natural and hybrid populations ...

Association mapping is becoming important in perennial crops because it is a better alternative t... more Association mapping is becoming important in perennial crops because it is a better alternative to the classical QTL's mapping approaches. The development of large breeding populations (F2, backcrosses and recombinant inbred populations) is a requirement of QTL's discovery; however, this process requires years in cacao because of its long and slow growing reproductive cycle. In a previous study, a population of cacao in Hawaii was characterized using SSR markers and it was determined that it belonged to the Trinitario and Upper Amazon Forastero by Trinitario hybrid groups. One hundred productive and fifty-one unproductive plants from this population were selected and fingerprinted using 80 SSR markers equally distributed across the cacao linkage groups. Yield data for pod and bean characters from the selected and unselected plants were also collected from 2007 until 2009. The objective of this study were to investigate the possible association between SSR markers and yield t...

Tropical Plant Biology, 2011

... Differentially Expressed Between Two Cultivars of Coffea arabica L. Ratnesh Singh & Beth ... more ... Differentially Expressed Between Two Cultivars of Coffea arabica L. Ratnesh Singh & Beth Irikura & Chifumi Nagai & Henrik H. Albert & Monto Kumagai & Robert E. Paull & Paul H. Moore & Ming-Li Wang ... 2003; Anthony et al. 2002; Lashermes et al. 1996; Orozco-castillo et al. ...

Theoretical and Applied Genetics, 2004

Journal of Plant Physiology, 2004

We have studied the purine alkaloid content and purine metabolism in Theobroma cacao fruits at di... more We have studied the purine alkaloid content and purine metabolism in Theobroma cacao fruits at differing growth stages: Stage A (young small fruit, fresh weight, ca. 2 g); stage B (medium size fruit, fresh weight, ca. 100 g) and stage C (large size, fresh weight, ca. 500 g). The major purine alkaloid in stage A fruits (mainly pericarp) was theobromine (0.7 micromol g(-1) fresh weight), followed by caffeine (0.09 micromol g(-1) fresh weight). The theobromine content of the pericarp decreased sharply with tissue age, and the caffeine content decreased gradually. A large amount of theobromine (22 micromol g(-1) fresh weight) had accumulated in seeds (mainly cotyledons) of stage C fruits. Theobromine was found also in the seed coat and placenta. Tracer experiments with [8-(14)C]adenine show that the major sites of theobromine synthesis are the young pericarp and cotyledons of T. cacao fruits. Limited amounts of purine alkaloids may be transported from the pericarp to seed tissue, but most purine alkaloids that accumulated in seeds appeared to be synthesised in cotyledons. Degradation of [8-(14)C]theobromine and [8-(14)C]caffeine to CO2 via 3-methylxanthine and ureides (allantoin and allantoic acid) was detected only in the pericarp of stage C fruits.

Journal of Agricultural and Food Chemistry, 2013

Changes occurring in phenolic compounds and purine alkaloids, during the growth of seeds of cacao... more Changes occurring in phenolic compounds and purine alkaloids, during the growth of seeds of cacao (Theobroma cacao) cv. Trinitario, were investigated using HPLC-MS/MS. Extracts of seeds with a fresh weight of 125, 700, 1550, and 2050 mg (stages 1-4, respectively) were analyzed. The phenolic compounds present in highest concentrations in developing and mature seeds (stages 3 and 4) were flavonols and flavan-3-ols. Flavan-3-ols existed as monomers of epicatechin and catechin and as procyanidins. Type B procyanidins were major components and varied from dimers to pentadecamer. Two anthocyanins, cyanidin-3-O-arabinoside and cyanidin-3-O-galactoside, along with the N-phenylpropernoyl-l-amino acids, N-caffeoyl-l-aspartate, N-coumaroyl-l-aspartate, N-coumaroyl-3-hydroxytyrosine (clovamide), and N-coumaroyltyrosine (deoxyclovamide), and the purine alkaloids theobromine and caffeine, were present in stage 3 and 4 seeds. Other purine alkaloids, such as theophylline and additional methylxanthines, did not occur in detectable quantities. Flavan-3-ols were the only components to accumulate in detectable quantities in young seeds at developmental stages 1 and 2.

Introduction Koa (Acacia koa) is currently the most important commercialized hardwood in Hawai&#3... more Introduction Koa (Acacia koa) is currently the most important commercialized hardwood in Hawai'r's forests. A sustainable supply of koa will depend on reforestation with the best adapted seed sources and perhaps with vegetatively propagated cultivars having unique traits. At present, koa forests are in a serious state of decline, and improvement appears warranted if sustainable supply is to be achieved. Vegetative (clonal) propagation provides large numbers of genetically identical plants. Conventional methods include cutting and grafting, while in vitro micropropagation is a more recent approach. These methods would be useful to propagate koa trees selected for superior growth and stem form, disease and insect tolerance, .and desirable wood characteristics such as curly or fiddleback grain. Clonal propagation could provide opportunities for commercial-scale production of koa. Furthermore, clonal koa trees would be useful for breeders in testing for adaptability and developi...

Plant Disease

Hawaii’s coffee industry, produced commercially on six islands by over 1,470 growers on ~10,000 a... more Hawaii’s coffee industry, produced commercially on six islands by over 1,470 growers on ~10,000 acres, is conservatively valued at $100M per year (USDA NASS 2023). Until late October 2020, Hawaii was the only major coffee producing region of the world that was free of Coffee Leaf Rust (CLR). Growers are currently facing their most formidable production challenge with the arrival of Hemileia vastatrix Berk. & Broome, the most economically devastating pathogen of coffee worldwide. Since its introduction (Keith et al. 2022), CLR has rapidly spread throughout the state and can be found on coffee farms and feral coffee throughout the six islands. Implementation of CLR control measures will be difficult in Hawaii, given the extreme environmental heterogeneity, differences in management practices, high production costs, and labor shortages. Compounding these challenges is that all coffee genotypes grown on a large scale in the state are susceptible to CLR. More than 55 different rust races...

Genetic and biochemical properties of principal peroxidases of maize, Px3 and Px7, were determine... more Genetic and biochemical properties of principal peroxidases of maize, Px3 and Px7, were determined and their changes during development of morphological mutants were examined. Horizontal gel electrophoresis was applied for resolution of peroxidase isozyme bands. An unusual Px3 allele, Px3-6, produced two bands electrophoresing similar to those produced by alleles Px3-1 and Px3-2. A hypothesis was tested that Px3-6 is a gene duplication. Densitometric methods identified the S and F bands of Px3-6 to be electrophoretically identical to those of Px3-1(S) and Px3-2(F). Electrophoresis under varying gel concentrations showed no evidence of differences in mobility and size between S and F bands from Px3-6(SF), Px3-1(S) and PX3-2(F) alleles. Genetic results suggested that Px3-6 (SF) allele is a tandem duplication of Px3 genes. Chromosomal location of Px3 locus previously assigned to Chromosome 7, was determined using gene markers o2, Pn, s1 and Tp, and waxy translocation 7-9a. The most pro...