Journal of Hawaiian and Pacific Agriculture, 2000, Volume 11
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Contributed Papers
- B.W.
Mathews, J.R. Carpenter, E. Cleveland, Z. Gibson and R.Y. Niino-Dupont. 2000. Perennial Forage Peanut (Arachis pintoi) in Pastures
for Raising Replacement Heifers/Stocker Steers in Hawai`i. vol. 11,
1-10.
- Abstract: During 1998 and 1999 pastures of perennial forage peanut (Arachis pintoi cv. Amarillo) mixed with common guinea grass [Panicum maximum (Jacq.) L.] were used to determine the effects of stocking rate (SR) on the performance of 280-kg Brangus heifers and steers (Bos spp.) and forage production and nutritive value under Hawaiian lowland conditions. Average daily gain was outstanding, ranging from 0.72 to 0.95 kg at SR of 2 to 5 head ha-1 in 1998, and 0.88 to 1.07 kg at SR of 3 to 6 head ha-1 in 1999. Forage peanut consistently comprised about 25 to 30 percent of the total palatable herbage mass in all pastures. Total digestible nutrient concentration averaged 608 g kg-1 dry matter (DM) for forage peanut and 658 g kg-1 DM for guinea grass, but as expected, the total cell wall or neutral detergent fiber concentration was substantially lower for forage peanut (423 g kg-1 DM) than guinea grass (585 g kg-1 DM). Nitrogen concentration averaged 33.1 and 16.9 g kg-1 for forage peanut and guinea grass, respectively. Under the conditions of our two-year study, it was demonstrated that forage peanut holds potential as an N2-fixing pasture legume in commercial cattle operations in Hawai`i due to its nutritional value, persistence under high SR, and N contribution to the pasture sward.
- Michael
Tanabe and Sandra Baerh. 2000. In vitro Triple Indexing of Edible
Ginger (Zingiber officinale). vol. 11, 11-15.
- Abstract: As in vitro triple indexing protocol was successfully developed for detecting Pseudomonas solanacearum in Zingiber officinale explants. A combination of nutrient broth solution and polymerase chain reaction (PCR) were used to detect the pathogen over 3 generations of plantlet growth. The development of new generation of shoots was paramount to the success of this protocol. In this regard, it was determined that shoot development was influenced by rhizome harvest dates and method of excision from the mother plant. Rhizomes expressing dormancy in the field also expressed dormancy in vitro. A wedge shoot excision cut was much more effective than a flat shoot excision cut in reducing time to development of the next generation.
- Mike A. Nagao, Elodie B. Ho-a, Melvin S. Nishina and Francis Zee.
2000. December Pruning of Vegetative Flushes Affects Flowering of 'Kaimana'
Lychee in Hawai`i. vol. 11, 17-21.
- Abstract: Vegetative flushing in late autumn and early winter is associated with irregular flowering of lychee (Litchi chinenesis Sonn) trees during spring and can result in inconsistent yields. This study was conducted to determine if pruning of vegetative flushes emerging on 'Kaimana' lychee trees in early winter could enhance spring flowering. Results of this study showed that vegetative flushing during the winter reduced flowering of Kaimana trees and that pruning of young flushes, which emerged during early December, stimulated flowering. Pruning of emerging vegetative flushes significantly increased the number of panicles developing on trees in February compared to trees on which flushing branches were left unpruned. Pruning also increased the number of panicles developing on each pruned branch by stimulating the production of multiple inflorescences from nodes located immediately below the pruned terminal.
- Mike
A. Nagao and Elodie B. Ho-a. 2000. Stimulating Longan Flowering
in Hawai`i with Potassium Chlorate. vol. 11, 23-27.
- Abstract: Synchronous flowering and uniform fruit set of longan [Dimocarpus longan (Lour.) Steud.] cultivars were stimulated 2 months after soil applications of potassium chlorate (KClO3). Trees were treated by broadcasting KClO3 at 250 or 500 g/tree onto the soil surface beneath the tree canopies and irrigating the material into the root zone. Foliar applications containing of 2.0 g/l KClO3 also stimulated flowering within 2 months after application, but flowering was limited to the treated branches. Since flowering is more synchronous in treated trees, fruit maturation should be monitored closely so that fruits are harvested when they attain optimum quality as over maturation may result in less than optimal quality.
- M.C. Garcia, P.S. Leung, C.F. Chilcutt and B. Tabashnik. 2000.
Short-Term Economic Analysis of Control of Diamondback Moth in Hawai`i
with Bacillus thuringiensis and Other Insecticides. vol. 11,
29-40.
- Abstract: The diamondback moth (Plutella xylostella) is the major insect pest of cabbage, watercress, and other cole crops in Hawai`i. A benefit-cost model is developed to determine the efficacy of two pest management regimes, i.e., Baccillus thuringiensis (Bt) and synthetic insecticides under two doses, i.e., high and low in controlling diamondback moth (DBM) populations and resistance development by DBM by quantifying the tradeoffs in net revenue over three years between the prevailing pest management practice in cabbage production in Hawai`i and treatment with Bt or synthetic insecticides, under various combinations of DBM immigrants/generation (MIG)1 and size of the pesticide refuge (REF)2. Model results indicate large potential net gains to adopting low dose insecticide alternatives. However, potential improvement in net revenue from the status quo benchmark model using the high dose insecticide options are sensitive to the state of nature.
- Christian
P. Giardina, Daniel M. White and Susan C. White. 2000. The
Effects of Fertilization on Biomass Production of 15 yr old Eucalypus
saligna Trees. vol. 11, 41-44.
- Abstract: In most young plantation forests, nutrient supply limits biomass production. Less is known about the effects of fertilization on biomass production in later stages of stand development. In general, fertilizer responses in later stages of development are expected to be small because forest growth declines sharply with age. In contrast to these expectations, we found that fertilization of 15 year old Eucalyptus saligna trees resulted in a 5 fold increase in woody biomass production, suggesting that fertilization of older Eucalyptus plantings in Hawai`i may be a cost-effective way to increase wood production.
- Lorna H. Tsutsumi. 2000. Queen Rearing in East Hawai`i. vol. 11,
45-50.
- Abstract: Though honey bees flourish in many parts of the east side (Hilo) of the island of Hawai`i, one of the beekeeping activities which has been limited to the west side (Kona) of the island is queen rearing. This study was conducted to determine if queen rearing could be done in east Hawai`i and assess the possibility of queen rearing in east Hawai`i on a commercial basis. One hundred and twenty grafted larvae were placed into starter and finishing hives. The completed queen cells were placed into nucleus hives and the mated queens were removed at the end of the process. The number of completed queen cells and mated queens were recorded. This procedure was repeated approximately every two weeks from January through April in 1998 and 1999. Monthly rainfall data for Hilo and Kona was obtained for 1998 and 1999. The results showed a decrease in the number of completed queen cells from January through April for both 1998 and 1999. However, the number of completed queen cells was much lower in 1999 than in 1998. The reduction in completed queen cells in 1999 compared to 1998 appears to be related to the increase in rainfall (6.14 inches per month in 1998 and 13.41 inches per month in 1999) in 1999. The results indicate that queen rearing is possible on the east side of Hawai`i but queen rearing on a large commercial scale would be risky due to the unpredictable weather conditions from year to year.
- Erik
R. Cleveland, Gilbert R. Hollis and Alton M. Okinaka. 2000. A Survey
of Breeding and Selection Practices Among Hawai`i, Illinois, and Iowa
Pork Producers. vol. 11, 51-59.
- Abstract: A questionnaire was developed and used to survey the use of various swine breeding practices among commercial pork producers in 1988 and 1989. For this survey a total of 890 questionnaires were collected from the states of Hawai`i, Illinois, and Iowa. Less than 15% of those surveyed were using purchased gilts as their only source of replacement females. Most producers were using at least some home-raised gilts as replacement females. For Illinois and Iowa producers, rotational crossbreeding systems were the most popular. In Hawai`i, the rotaterminal system was slightly more popular than the rotational crossbreeding program. Producers were asked to list breeds found in the ancestry of their crossbred sows. For that question, the Yorkshire, Duroc, and Hampshire breeds were most frequently listed. Producers were also asked which sire breeds they were using to produce market hogs. Duroc and Hampshire sires were slightly more popular in Illinois and Iowa herds. Among Hawai`i producers Hampshire and Yorkshire sires were most frequently used to produce market hogs. Producers were asked to rate the degree of importance of various criteria that might be used in selecting breeding stock suppliers. Health status and health program of the herd received high scores in all three states. Producers were also asked to rate the degree of importance of various criteria that might be used in selecting boars. For Illinois and Iowa producers, growth rate, feet & legs, and feed conversion received high scores. Among Hawai`i producers surveyed, backfat, growth rate, litter size, and feet & legs received high scores. Over 40% of the responders were using performance tested boars. When tested boars are available, 81% of the responders indicated that they do use performance records in making selection decisions. Over 95% of the producers felt that there was a need to verify health, testing, and selection practices used by breeding stock suppliers.