Evaluation of round and Roma-type tomato varieties and advanced breeding lines resistant to tomato yellow leaf curl virus in Florida

Abstract

Tomato yellow leaf curl virus (TYLCV) is considered to be the most damaging tomato (Solanumlycopersicum) virus worldwide. Management of TYLCV has relied primarily on insecticidal control targeting the vector sweet potato whitefly [SPW (Bemisia tabaci)]. However, resistance of the SPW to insecticides; increased length of the growing season, due in part to increased plantings of grape tomato; and asymptomatic hosts of TYLCV such as pepper (Capsicum annuum) have increased the need for wider use of TYLCV-resistant (TYLCV-R) varieties. The objective of this study was to evaluate horticultural characteristics of commercially available TYLCV-R varieties/advanced breeding lines of round and Roma-type tomato varieties in Florida. Sweet potato whitefly populations and incidence of TYLCV were greaterin2007 than 2008. Under high TYLCV pressure, most of the TYLCV-R varieties/advanced breeding lines produced higher yield than susceptible varieties. In contrast, no clear advantage was found by using TYLCV-R varieties under low TYLCV pressure. Additionally, TYLCV-R varieties produced a high percentage of unmarketable fruit due to rough blossom end scars (BES), zippering, cat facing, sunscald, yellow shoulders, off shapes, and radial or concentric cracking compared with susceptible varieties in both years. Visual assessment of TYLCV-R varieties/advanced breeding lines for horticultural traits showed that 'Security 28', Sak 5443, and 'Shanty' were the best overall varieties/ advanced breeding lines based on participants combined score rating, although 'Tygress' and Sak 5808 performed best based on empirical evaluation (numerical data) of total marketable yields and low unmarketable yield.