A Survey of Main Pepper Crop Viruses in Different Cultivation Systems for the Selection of the Most Appropriate Resistance Genes in Sensitive Local Cultivars in Northern Spain.

Mikel Ojinaga,Santiago Larregla,Pedro Guirao

doi:10.3390/plants11060719

Abstract

Viral diseases have become one of the main phytosanitary problems for pepper growers in the Basque Country (northern Spain). In 2014, a survey was carried out to determine the prevalence of the most common viruses found in Gernika pepper and Ibarra chili pepper landraces. A total of 97 plots were surveyed and classified according to the crop system. Within these plots, 1107 plants were sampled and tested for tobacco mosaic virus (TMV), tomato mosaic virus (ToMV), tobacco mild green mosaic virus (TMGMV), pepper mild mottle virus (PMMoV), paprika mild mottle virus (PaMMV), potato virus Y (PVY) and tomato spotted wilt virus (TSWV) applying a DAS-ELISA test. PaMMV was verified by the non-radioactive molecular hybridization technique and it was found to be negative. All viruses were detected, but the most prevalent viruses were PVY and TMGMV (19.8% and 10.6% of tested plants, respectively). Differences among cultivation systems were found for most of the tested viruses. PVY had a higher level of infection under open field conditions (27.3%) than under greenhouse conditions (12.3%). Inversely, the viruses belonging to the Tobamovirus genus and TSWV prevailed under greenhouse conditions (28.9% and 5.2%) when compared to open field (11.2% and 1.1%), respectively. Single (28%) and multiple infections (8.9%) were found. All PMMoV isolates were classified as pathotype P1.2. Survey results indicated that tobamovirus and PVY resistance genes would be the most appropriate to be included in breeding programs with these sensitive pepper landraces.

Highlights

Pepper is one of the main vegetable crops in the Basque Country, with a cultivated area of 250 ha in 2018
potato virus Y (PVY) had a higher level of infection under open field conditions (27.3%) than under greenhouse conditions (12.3%)
The viruses belonging to the Tobamovirus genus and tomato spotted wilt virus (TSWV) prevailed under greenhouse conditions (28.9% and 5.2%) when compared to open field

Summary

Introduction

Pepper is one of the main vegetable crops in the Basque Country (northern Spain), with a cultivated area of 250 ha in 2018. Pepper crops of this region are mainly concentrated in the Atlantic humid temperate climate zones [1]. The two main pepper landraces are Gernika type pepper and Ibarra yellow chili pepper (Figure S1). Roasting pepper landraces are cultivated but in fewer quantities. Several selected commercial cultivars have been obtained from the different varietal pepper types grown in this area, all of them are vulnerable to viral infections. The landrace of Gernika is mainly cultivated under greenhouse conditions from March to October. The landrace of chili pepper is mainly cultivated in open field conditions from May to October [2]

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Discussion

Conclusion