Breeding for resistance becomes more and more important because we want to reduce the use of pesticides. A fast and cheap alternative can be to make use of morphological or chemical markers. In... Show moreBreeding for resistance becomes more and more important because we want to reduce the use of pesticides. A fast and cheap alternative can be to make use of morphological or chemical markers. In order to do so we first need to study resistance mechanism in plants and how they may change depending on environmental conditions or plant development. Based on these ideas we developed markers for thrips resistance in gladiolus. we showed that the density of papillae and chemical traits (triterpenoids and amino acids) are useful markers for breeding programs targeted at increased resistance in Gladiolus. Epicuticular papillae are easily detected since they are located at the leaves surface. The density of papillae is highly correlated with a number of metabolites that were associated with resistance. Concentrations of triterpenoid saponins, alanine and threonine were higher in resistant varieties. Therefore, papillae density and chemical compounds may provide an easy marker in Gladiolus breeding programs targeted at increased resistance against thrips. Concentrations of metabolites associated to thrips resistant remained constant during the ontogeny of the plant and under different growing conditions. These findings provide useful information for breeders because it implies that these markers can be determined in young plants and under different conditions. In dwarf gladiolus, Gladiolus nanus, also kaempferol was associated to resistance. However, it was only found in in plants grown in the climate chamber and not in plants grown under field conditions. Further studies will be needed to understand the mechanism of thrips resistance in Gladiolus in more detail. Show less
