Editor's note: This is the Immokalee Report, a regular column written by researchers at the University of Florida's Southwest Florida Research and Education Center in Immokalee. This column appeared in the September-October 2011 issue of Citrus + Vegetable Magazine.
In tomatoes, variety trials have being conducted since 2006 on varieties resistant to tomato yellow leaf curl virus (TYLCV) and since 2009 on varieties resistant to Fusarium crown rot (FCR). The trials also included grafted varieties.
The testing program provided recommendation under low and high TYLCV pressure.
Although the trials demonstrated that TYLCV can be managed with resistant varieties, the lack of consistent fruit quality s was a big reason why the many of the state’s tomato growers didn’t adopt the TYCLV-resistant varieties.
On the other hand, the industry has widely adopted Fusarium crown rot-resistant varieties. But testing continues, since new varieties continue to be released annually.
A growing interest in grafted tomatoes stems from continuing disease problems, lack of land for ideal crop rotation periods, increasing markets for specialty varieties that do not have disease resistance, imperfection of soil fumigation and the pending loss of methyl bromide.
Testing grafted rootstocks will continue, thanks to a $2.2 million U.S. Department of Agriculture Specialty Crop Research Initiative Grant designed to improve the sustainability and competitive of the U.S. fruiting vegetable industry.
Several states in addition to Florida are participating in the research.
Pepper varieties resist bacterial spot
Bell pepper yields have been increased dramatically recently due to continued introduction of new varieties resistant to bacterial spot. Losses from this disease can be attributed to both defoliation and spotting or rotting of fruit.
Ten races of Xanthomonas euvesicatoria, the scientific name for bacterial spot, have been identified worldwide. A race (identified by numbers 1, 2, 3, etc.) is defined by how it can survive and grow on varieties with or without specific genes for resistance.
Over the years, genes resistant to various races of X. euvesicatoria have been identified and introduced into commercial bell pepper vareities. That’s why variety trials are conducted over multiple years, locations and seasons.