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Nutrient field studies were conducted on papaya, Carica papaya `Kapoho Solo' under rocky soil conditions in Puna, Hawaii. The objective of the study was to establish the relationship between boron (B) petiole tissue levels of trees with deformed and normal fruits. Field surveys indicated that trees with deformed fruits had 25% less B than normal trees. A 4.05 hectare field was treated with rates of 0, 1.12, 3.92 and 5.04 kilograms of B per hectare. By-weekly tissue results showed that B levels increased from 4 to 10 weeks after application with the 16 week levels substantially higher than the control trees. The results showed that maintaining the tissue B levels over 25 ppm B corrected the deformed fruit condition of papaya. Commercial fertilizer blends have been formulated with 0.3% B which is now used semi-annually on all commercial plantings.
Abstract
Seed germination of Alexandra palm [Archontophoenix alexandrae (F. J. Muell,) H. Wendl & Drude] was accelerated by presoaking for 24 or 72 hours in water, and further accelerated by a 72 hour treatment with 100 or 1000 ppm, gibberellic acid (GA), but not with benzyladenine (BA) or naphthaleneacetic acid (NAA).
Monitoring the nutrient status of a crop by soil and tissue analysis is an important tool in maximizing yields and avoiding nutrient deficiencies or toxicities. A nutritional management system is presented that uses a computer database to compile periodic soil and leaf tissue analyses to assist in the development of rational fertilizer recommendations for banana and macadamia nut orchards. Database management allows the Extension Agent to organize parameters (soil type, rainfall, elevation, tree age, tree spacing, and previous fertilizer practices) used in nutritional recommendations for individual farms. Graphs depicting nutrient trends over time and comparison of nutrient levels to nutritional standards, present visual illustrations of problems and encourage grower acceptance of fertilizer recommendations. Growers are also able to see graphic responses to application of corrective fertilizers and soil amendments.
To study the vegetative flushing pattern of M. integrifolia (cvs. Keaau, Kau and Kakea) trees in Hawaii and determine when these vegetative flushes flower, trees were monitored for an entire year (1988), and shoots from these flushes were monitored for flowering during the 1988-89, 1989-90 and 1990-91 flowering seasons. Flushing occurred year-round but was most frequent during the spring-summer and fall months which coincided with the end of the flowering season and the period of fruit maturation. For all cultivars, sporadic flowering occurred in 1988-89 on shoots that were less than one year-old but was not always associated with the oldest shoots. Flowering in 1989-90 and 1990-91 was observed on a larger proportion of the shoots and occurred on shoots that had emerged throughout 1988. Flowering was most abundant on two year-old shoots (1990-91) and could occur on shoots that had flowered in the previous season (1989-90).
Uniconazole (0.2 g a.i. per cm trunk diameter) was applied as a soil drench to 2-year-old potted macadamia (Macadamia integrifolia Maiden & Betche) trees, and reapplied yearly for 4 additional years. Uniconazole significantly reduced tree height and trunk diameter 1 year after initial treatment, and suppressed shoot extension for the duration of the study. It significantly increased flowering the second year after initial treatment, the first year that both the control and treated trees flowered. Subsequently, no differences in flowering were observed until the fifth year, when flowering was significantly less in treated trees, probably due to reduced shoot and trunk growth and tip dieback. Chemical name used: E-1-(p-chlorophenyl)-4,-4-dimethyl-2-(1,2,4-triazole-1-penten-3-ol) (uniconazole).
Flowering of Macadamia integrifolia trees was monitored following application of 220 mg/liter gibberellic acid (GA3) at various times preceding the onset of the flowering season. In untreated trees, flowering extended over a 4-5 month period. When GA3 was applied at 2, 3 and 4 months before the onset of anthesis, raceme production during the entire flowering season was inhibited. A slight reduction in raceme production was observed when GA3 was applied at 1 month preceding anthesis. This application coincided with appearance of the earliest infloresceuces. GA3 application after the onset of anthesis did not alter the flowering pattern of trees during the remaining 4 months of the flowering season. Results suggest that GA3 inhibits flower initiation, but has no effect on raceme emergence after flower bud differentiation has occurred. The relationship between flower initiation and raceme emergence will be discussed.
Flowering of Macadamia integrifolia trees was monitored following application of 220 mg/liter gibberellic acid (GA3) at various times preceding the onset of the flowering season. In untreated trees, flowering extended over a 4-5 month period. When GA3 was applied at 2, 3 and 4 months before the onset of anthesis, raceme production during the entire flowering season was inhibited. A slight reduction in raceme production was observed when GA3 was applied at 1 month preceding anthesis. This application coincided with appearance of the earliest infloresceuces. GA3 application after the onset of anthesis did not alter the flowering pattern of trees during the remaining 4 months of the flowering season. Results suggest that GA3 inhibits flower initiation, but has no effect on raceme emergence after flower bud differentiation has occurred. The relationship between flower initiation and raceme emergence will be discussed.
Abstract
Scarification and pre-soak treatments with water or 1000 ppm gibberellic acid (GA) accelerated seed germination of Alexandra palm [Archontophoenix alexandrae (F. J. Muell.) H. Wendl. & Drude]. Macarthur palm [Ptychosperma macarthurii (H. Wendl.) Nichols] germination was accelerated following scarification or pre-soaking in 1000 ppm GA, however, in both species greatest acceleration was obtained when the scarification and GA treatments were combined. Germination time of Macarthur palm was also reduced by 6 weeks when sown in beds heated to 27° ± 1°C.
Longan (Dimocarpus longan) fruit production and global exports are rapidly expanding. Consumer acceptance of this high value crop requires that fruit arrive in excellent condition. Pericarp browning and fungal diseases are the main postharvest problems for longans. Research was conducted to establish optimum storage temperatures and packaging systems to retain fruit quality of ‘Biew Kiew’ longans. Average respiration rates for longans stored at 20 °C (61.6 mg CO2/kg/h) were about twice the rate as those stored at 10 °C (32.7 mg CO2/kg/h) and triple the rate for those stored at 5 °C (21.1 mg CO2/kg/h). Ethylene rates were below 0.4 μg·kg−1·h−1. Fruit quality and shelf life were greatest when stored at 10 °C. Longans held at 20 °C were unmarketable after 10 d, and fruit stored at 5 °C exhibited chilling injury (CI). After storage at 10 °C, longans packaged in microperforated (MP) bags, clamshell (CL) containers, or Peakfresh® film (PF) had the highest visual quality ratings, lowest disease incidences, and longest shelf life when compared with fruit in Lifespan® film (LS) or fiberboard boxes. The most promising packages (MP, CL, PF) were evaluated further under constant 10 °C or simulated shipping (SS) conditions with fluctuating temperatures (22 °C/10 °C/22 °C). Longans in CL containers had the highest visual quality and lowest disease incidence when stored at 10 °C, but there were no differences among package treatments under SS conditions. Also, sensory ratings were greatest for fruit packed in CL or PF when stored at 10 °C but all sensory scores decreased under SS temperatures. When longans were stored under fluctuating temperatures, aril texture and flavor ratings were highest for CL packages. CL, PF, and MP are suitable packages for longans stored under optimal temperatures. However, for longans stored under SS conditions, sensory quality was highest when packaged in CL containers.