Abstract
Rapid clonal propagation of papaya (Carica papaya L.) was obtained by culturing apices of mature field-grown plants on a modified Murashige and Skoog formulation. Individual plantlets were first induced on a medium with 50 μ m kinetin and 10 μ m naphthaleneacetic acid (NAA). Plantlets were transferred after 2 months to a proliferation medium containing μ m benzyladenine (BA) and 1 μ m NAA, which caused a 7-fold increase in the total number of plants during each 3 week period. Rooting was induced by subculturing plantlets on media with 0.5 – 15 μ m indolebutyric acid (IBA) or 1–5 μ m NAA. Successful transfer of papayas to soil was accomplished.
Abstract
Seed of papaya stored at 10°C and 50% relative humidity in cloth bags, and at 5° in sealed, moistureproof packages, retained their viability reasonably well during 6 years' storage.
Abstract
Susceptibility to chilling injury in ‘Kapoho’ papayas (Carica papaya L.) was reduced by ripening the fruit before storage at 5°C. The relationship between the decrease in chilling injury (CI) and postharvest ripening time at 24° was found to follow first order kinetics, hence, the half-lives for reducing the symptoms of CI of scald and hard core are 14.8 and 33.5 hr, respectively.
Abstract
Body transmittance spectroscopy and analytical measurements of chlorophyll, carotenoids, and soluble solids concentrations were used to develop a nondestructive technique for estimating the maturity of papayas (Carica papaya L.). Optical measurements were taken between 500−900 nm with a scanning monochromator and a tilting-filter, abridged monochromator. Immature and mature-green fruit which were indistinguishable by visual examination could be separated by body transmittance spectroscopy into nonripening and ripening groups.
Abstract
‘Cariflora’ is a dioecious papaya (Carica papaya L.) cultivar, tolerant of infection by papaya ringspot virus (PRV), that has been developed for south Florida and the lowland Caribbean region. ‘Cariflora’ produces good quality, round fruit with sweet yellow flesh and an agreeable aroma. This papaya is particularly suitable for commercial plantings because of the small size of its fruit, but it also could be useful to home growers. ‘Cariflora’ is being released for grower trial by the Agricultural Experiment Stations of the Univ. of Florida.
Three exotic lines (Dwarf, L-45, and L-50) of precocious papaya (Carica papaya L.) from India, were grown in nursery rows at the Fort Valley State College Agricultural Research Farm during 1986-1990. Performance of these lines was evaluated for their adaptation and production feasibility under the growing conditions of Middle Georgia. Two lines (L-50 and Dwarf papaya) showed a less satisfactory overall performance than did L-45, which had the highest female to male ratio (7:3) and abundantly produced tree-ripened fruits under cold protection frames during 1989 and 1990. Tree growth and survival for L-45 were greater than those for L-50 and Dwarf papaya lines. Two-month-old greenhouse-grown seedlings when established in the field in April, flowered in 60 to 65 days following transplanting. Under Georgia conditions, fruits ripened on trees in approximately 150 days after fruit set. During 1989-90, the fruit size on L-45 trees varied from 574 g to 2,286 g (mean 1,530 g) with an average of 22.5 fruits per tree. Four years data suggest that papaya can be a successful annual crop if shelter is provided during late fall to protect ripening fruits and trees from frost/cold.
Abstract
Thiabendazole (TBZ) applied in a carnauba wax formulation provided effective control of postharvest diseases of papaya (Carica papaya L.) for up to 14 days at 10°C plus ripening at room temperature. Slightly greater control of disease was observed when TBZ was used immediately after a short hot water spray treatment (54°, 1.5 minute). A more severe hot water dip treatment (48°, 20 minutes) was not significantly more effective than TBZ alone. Sodium o-phenylphenate (SOPP) in wax did not reduce decay when used alone or in combination with TBZ.
Abstract
Nutrient analysis of harvested papaya fruits from trees grown at Waimanalo, Oahu, Hawaii and at Malama-Ki, Puna, Hawaii showed the following descending order of removal: K, N, Ca, Mg, P. Quantities of N and K removed by Malama-Ki fruits represented 38 and 56%, respectively, of the amounts applied as fertilizer.
Abstract
The cocultivation method for transforming plant tissues in vitro with A. tumefaciens strains has been simplified and extended for use with leaf disks, stems, and petioles of Carica papaya L. These tissues have been transformed successfully with either pTiB6S3:pMON200 or pTiB6S3 with very high efficiency. Transformants were identified either by growth in hormone-free medium or by resistance to 300 μg·ml−1 of kanamycin. Putative transformants were confirmed on the basis of nopaline production.
Ripe yellow papaya fruit in the markets frequently show green sunken areas called “green islands” (GI). This disorder seems to be caused by mechanical injury in a commercial postharvest handling system. Fruit at different stages of ripeness (5 to 50% yellow) were dropped from different heights (0 to 100 cm) onto a smooth steel plate to try to create GI. The injury sustained was not the same as GI seen in fruit from the handling system. Fruit (10 to 15% yellow) dropped on different grades of sandpaper (220 mesh to 36 mesh) from a height of 10 cm had injury symptoms similar to those seen on fruit from the handling system. These results suggest that abrasion damage was more important than impact damage in papaya fruit. Heating fruit at 48°C for -6 hours or until fruit core temperature (FCT) reached 47.5°C aggravated the severity of GI. Delaying the time of heating from the time of dropping did not significantly lower the severity of GI, except for fruit heated 24 hours after dropping. Waxing fruit alleviated the severity of GI. The results indicate that avoidance of abrasive surfaces such as the plywood walls of field bins is the best approach to avoiding the unsightly GI blemishes on papaya peel.