Resistência à traça-do-tomateiro em plantas com altos teores de acilaçúcares nas folhas

Abstract

The South American tomato pinworm was first detected in Brazil in 1980 and today it is among the major pests of tomato in Brazil. The control of this pest has been done primarily with the use of insecticides, and three sprays per week may be necessary in extreme cases. Wild tomato accessions such as S. pennellii LA-716 possess high levels of insect resistance, mediated by high foliar contents of acylsugars. The objectives of this study were obtain improved tomato genotypes with high contents of leaf acylsugars, and to assess their levels of resistance to the South American tomato pinworm Tuta absoluta. These genotypes were obtained from segregating (F2) populations from the cross between AF-8665 (an elite low AS tomato line) and lines BPX370E-30-275-11-7, BPX370E-30-275-11-8, BPX370E-30-380-68-6 and BPX370E-30-380-68-8 (pre-commercial high AS inbreds derived from an original interspecific cross between S. lycopersicum x S. pennellii LA-716). F2 plants selected for high AS contents were cloned and subsequently tested for pinworm resistance. The high AS genotypes showed smaller ovoposition counts and lower plant damage levels than low AS genotypes (commercial or not). Even though high AS genotypes were generally more resistant to the South American tomato pinworm than low AS genotypes, their actual levels of resistance may be background-dependent: high AS clones with BPX-410H background had slightly higher levels of resistance than high AS clones with BPX-370G background. Clones BPX-410H-01pl#281, BPX-410H-04pl#348 and BPX-410H-04pl#481 had the highest levels of pinworm resistance, and were recommended for further use in breeding programs.