Genetic mapping of QTLs associated with drought tolerance in citrus

A population of 73 hybrids of 'Rangpur' lime (Citrus limonia) and 'Swingle' citrumelo (Citrus paradisi x Poncirustrifoliata), kept in plastic bags of 3.8 liters in a greenhouse, had water removed for 15 days. The gradient of drought stress symptoms, after irrigation suspension, was measured by scores on a scale [absence ofsymptoms (0), wilting of leaves (1), leaf rolling (2), complete drying of the leaf, characterized by the changefrom green to brown (3) and drop of leaves (4)]. The symptoms were evaluated in four periods, the scores werepooled and the 'Index of Intensity of Symptoms of Drought' (IISD, from 0 to 100) was created, adapted fromCzemainski (1999). Results of IISD were subsequently used to find QTLs to drought tolerance in an integratedgenetic map of 'Rangpur' lime and 'Swingle' citrumelo, previously constructed, allowing the identification ofseven QTLs in two linkage groups (LG) of the map. Financial Support: CAPES and INCT-Citrus