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  • Author or Editor: Wayne Bourgeois x
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Significant opportunities exist for expanding the marketing season of Louisiana-grown satsumas. De-greening of the early season fruit coupled with optimal storage conditions for the late season fruit may allow for 6 months of market availability. Consumer demand in the U.S. for specialty citrus, particularly easy peel seedless mandarins, has increased in recent years. South Louisiana is one of the principal satsuma production areas in the United States, with harvest beginning in late September. Although the sugar: acid ratio of early season satsumas may meet the state-mandated 10:1, peel color typically ranges from green to greenish-yellow. Most consumers prefer a darker yellow-orange peel color. Postharvest de-greening tests were conducted to determine the appropriate method(s) and protocol for enhancing peel coloration of early season harvested satsumas. Green peel satsuma fruit were exposed to 0, 3, 5, 10, and 50 ppm ethylene for 12, 24, 36, and 48 hours at 21 or 29 °C. An atmospheric ethylene concentration of ≥5 ppm for ≥24 hours at 29 °C provided optimal de-greening. However, peel darkening in the form of irregular dark brown areas was observed after several days in fruit exposed to ethylene concentrations of 50 ppm. Ethephon was also an effective de-greening agent. Submersion of the fruit in 500 ppm ethephon for 30 seconds provided optimal de-greening. Buffering of the submersion solution pH had no effect on de-greening effectiveness.

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During the 1989 freeze, a scaffold branch irrigation freeze protection system was in operation on five-year old `Washington' navel and `Owari' satsuma trees and several younger trees of various navel orange varieties, a cold tolerant satsuma selection and other navel orange trees. Temperature dipped to a low of -11.1C, with 20 consecutive hours of -6.7C or below and 80 consecutive hours of 0C or lower. Post freeze evaluations and ratings show that an average tree survival rate of 94.6% was obtained. An average of 84.6% survival of scaffold branches and an average of 11% canopy survival was also achieved through the use of scaffold branch irrigation for freeze protection. Trunk injury ratings averaged 8.8 (scale 0-10; 0 – dead, 10 – no injury) and shoot regrowth after pruning dead wood averaged 8.0 (scale 0-10; 0 – no shoot regrowth, 10 – excellent shoot regrowth. The average percentage of the regrowth was slightly above 80% of the original tree volume prior to the freeze. Nonprotected trees sustained 100% kill and necessitated removal and reestablishment.

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Abstract

Scaffold branch irrigation significantly enhanced tree survival and decreased the percentage of canopy that was killed on young Washington navel orange (Citrus sinensis) and Owari satsuma (Citrus unshiu) trees subjected to — 8.9°C during a 1985 freeze. Scaffold branch irrigation has shown considerable potential as a method of freeze protection for Louisiana citrus producers.

Open Access

Abstract

Low-volume sprinkler irrigation increased the mean trunk, mean scaffold limb, and mean canopy temperature 4.6°, 0.6°, and 0.8°C, respectively, higher than the nonirrigated trees of ‘Washington Navel’ orange (Citrus sinensis). Similar results were obtained with ‘Owari’ satsuma (Citrus unshiu) trees in that the mean trunk, mean scaffold limb, and mean canopy temperature was increased 3.9°, 1.7°, and 0.9°, respectively, higher than the nonirrigated trees. These results lend support that scaffold branch irrigation is effective as a method of freeze protection.

Open Access

The peach breeding program in Louisiana was initiated in the late 1940's to develop adapted cultivars for Louisiana. The objectives of the program have been to develop large fruited disease resistant fresh market cultivars for all areas of Louisiana. The state is divided into three climatic zones in reference to the breeding program (north, south, and coastal). Cultivars have been developed that are adapted specifically for each zone. A few cultivars produce marketable fruit in all three zones. The annual chill units vary from 350 to 1000+ over the three zones. Seventeen cultivars have been released since 1969 and these are used throughout the southeast U.S. in production areas. A primary breeding objective is to develop a sequence of cultivars to service the market from late April through September. Also equally important is development of genetic disease resistance to bacterial spot, Xanthamonas campestris pv pruni.

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