Progress 09/15/01 to 09/30/04
Outputs
Low-chill subtropical peach varieties (150 chill units) developed in the University of Florida breeding program have been shown to be adaptable in in tropical Puerto Rico. Varieties evaluated were Flordaprince, Flordaglo, TropicBeauty, and UFGold. UFGold was found not to be adapted to tropical climates due to an inability of flowers to set fruit when the night temperatures during bloom exceeded 58 F degrees. A new variety, UFSun, was released to replace UFGold. UFSun is adapted and sets fruit in the presence of warm night temperatures. A model for determining chilling in low-chill peaches was evaluated. In Florida chilling is related to latitude from north to south in the state. In Puerto Rico chilling is related to altitude by gaining elevation in mountian areas. Fruiting was poor at 800 feet and adequate at 1500 feet. The chilling unit model using the January mean temperature was found superior to other models. Total Chilling Accumulation equals -1174 plus
27585/January mean (degrees C)-(-75466/January mean)squared. The major constraints to production of peaches in the tropics (Puerto Rico) was determined to be chilling and peach foliar leaf rust disease (Tranzschelia descolor) and endgenous diprepes root weevels. Research trials of fungicides for peach leaf rust identified chemicals that were effective and controlling the disease and a production applicaiton timing guide was developed. Genetic resistance to peach leaf rust has also been identified. Feeding studies using citrus determined that peach was not the preferred host for Diaprepes. No Diaprepes damge was observed on peach. White peach scale was identified as a possible insect host that was easily controlled. Caribbean fruit fly was also identified as a potential problem althouth limited occurance was observed due to the early ripe period of the low-chill varieties. This is currently under investigation.
Impacts
Low-chill peaches can be grown and fruited in Puerto Rico and other parts of the Caribbean. These would most likely be suited to local markets and dooryards. Peaches would be an alternative crop with economic value.
Publications
- Libran, Maria del Carmon, R.E. Rouse, E. Hernandez, L. Cardona. 2005. Melocotones Tropicalizados (Prunus persica L.) cultivo alterno para la zona montanosa de Puerto Rico. Proc. Interamerican Soc. Trop. Hort. 49:in press.
- Delgado-Sanchez, Alexandra, A.L. Gonzalez-Rodriguez, P.Stansly, M. del Carmon Libran, R.E. Rouse. 2004. Feeding and oviposition behavior of Diaprepes abbreviatus L. (Coleoptera curculionidae) on peach, Prunus persica L. in Puerto Rico. HortScience 39:747.
- Rouse, R.E., W.B. Sherman, and P.M. Lyree. 2004 UFSun peach. J. Amer. Pomological Soc. 58:108-110.
- Rouse, R.E., W.B. Sherman, and P.M. Lyree. 2004 UFSun peach released for subtropical central and south Florida. Proc. Fla. State Hort. Soc. 117:239-241.
- Rouse, Robert E. 2004 UFSun peach released for tropical and subtropical climates. Proc. Interamerican Soc. Trop. Hort. 48:137-139.
- Rouse, Bob. 2003. Peaches Adapted for the Subtropics and Tropical Highlands. Proc. Interamerican Soc. Trop. Hort. 47:255-258.
- Rouse, R.E., and W.B. Sherman. 2003. Effective chilling tempertures for low-chill subtropical peaches. Proc. Fla. State Hort. Soc. 116:42-43.
- Rouse, R.E., W.B. Sherman. 2002 Foliar rust resistance in low-chill peaches. Proc. Fla. State Hort. Soc. 115:98-100.
- Rouse, R.E., P.D. Roberts. 2000. Fungicidal suppression of peach leaf rust in low-chill subtropical grown peaches. Proc. Fla. State Hort. Soc. 113:37-40.
|
Progress 10/01/02 to 10/01/03
Outputs
Low-chill peach (Prunus persica L. Batsch) cultivars adapted for subtropical climates and tropical highlands have been developed by the University of Florida deciduous fruit breeding program. The recommended cultivars are high quality and suitable for commercial, u-pick, and home planting. The melting flesh cultivars Flordaprince, and TropicBeauty have yellow flesh, Flordaglo, and TropicSnow have white flesh. A 2003 release, UFSun has yellow non-melting flesh and can be harvested tree ripe. Cultivars requiring approximately 100 to 150 chill units have been evaluated in south Florida and Puerto Rico, and fruit with commercial crops in climates with mild winter temperatures. Fruit are 5 to 8 cm diameter and weigh 80 to 130 grams. Fruit mature in April and early May during an optimum market window when there are no other peaches available. Low-chill peach (Prunus persica) cultivars adapted to subtropical conditions of south Florida with commercial quality have been
developed and are available. These cultivars require from 100 to 200 chill units, ripen in April and May, and have fruit size greater than 2.0 to 2.5 inches in diameter. These cultivars have flowered profusely each year and fruited with acceptable crops over the past five years. During this period Florida has experienced some of the mildest winters of the past century. Weather records and chill unit models suggest that trees did not always experience the required chill units (hours of temperatures at or below the recognized requirement of 45 degrees F), yet they flowered and fruited. This would suggest that temperatures of 50 to 55 degrees or higher are effective at satisfying the chilling requirement of these low-chill subtropical cultivars.
Impacts
Low-chill peaches are being grown commercially in south Florida. Low chil peaches have been introduced into Puerto Rico and local growers are interested in growing peaches in tropical highlands.
Publications
- Rouse, Robert E. 2004. Peaches adapted for the subtropics and tropical highlands. Proc. IntAmer. Soc. Trop. Hort. 47:In press.
- Rouse, R.E. and W.B. Sheman. 2004. Chilling temperature models. Proc. Fla. State. Hort. Soc. 116:In press.
|
Progress 10/01/01 to 10/01/02
Outputs
This project was initited this year as a T-STAR project with cooperators in Puerto Rico. Six similar plantings of four peach cultivars were established, three in Florida and three in Puerto Rico. Differing climatic areas in florida were selected by latitude north to south and by elevation in Puerto Rico. Trees have grown vigerously with trees in Puerto Rico reaching heights of 12 feet in the first year. Work in Collier County Florida was initiated during fall 2000 in response to a peach grower's request for assistance controlling an infestation of Diaprepes abbreviatus that had caused loss of approximately 80 % of his trees. Affected trees were 3 to 4 years old and in decline due to severe root damage from larval feeding ascertained upon excavation. A survey of the 12-acre and surrounding pine/palmetto flatwoods in the fall of 2000 revealed large numbers of weevils feeding and ovipositing on the peach trees and also aggregating on Brazilian pepper ( Schinus
terebinthifolius) and winged sumac (Rhus copallina). The grower was advised to spray carbaryl to his peaches for control of the adult weevils and inject entomopathogenic nematodes to control the larva. Pyramidal Tedders traps and cone emergence traps were set up in the orchard and woods were checked weekly to monitor weevil emergence and foliage sampled by beating from Sep 01 to Dec 02. Mark recapture was used to track movement and estimate populations. Weevils were present year round with populations peaking late fall both in the woods and in the orchard. The ratio captures from cone traps and Tedder's traps was 1:30 compared to 1:10 in citrus, indicating that fewer weevils were emerging on site. Of 636 weevils marked and released in the woods less that 200 yards from the orchard perimeter, only 5 of 866 captured in the grove were marked. Recaptures in the woods went from 0 to 50% as the season progressed from fall to winter. The pattern of abundance contrasted with that seen in
irrigated citrus, which typically peaked in late spring. Weevil emergence in the woods could be delayed compared to the irrigated grove due to the dry condition of the soil in spring, suggesting the woods as the likely source of most weevils we saw in peaches. This conclusion was supported by the lack of evidence for emergence within the peach orchard. At the same time, the low rate of recapture pointed to considerable size and mobility of the weevil population during the warmer months. The ratio of cultivated to uncultivated land may be the principal factor determining the origin of most weevils in crops. Given the relatively small size of orchard land in Puerto Rico we are again likely to see migration from uncultivated habitats as the principal source of weevils there.
Impacts
Low-chill prunis species have been have been evaluated and shown to be adapted to conditions in south Florida. The low-chill peach varieties introduced into south and central Florida have resulted in commercial plantings being established by growers.
Publications
- Sherman, W.B. and R.E. Rouse. 2001. Characteristics of plums from the University of Florida breeding program. Fla. State Hort. Soc. 114:30-32.
|
|