Deciphering the ethylene production capacity of pear fruit within two segregating populations

Pear is one of the largest cultivated and commercialized fruit worldwide highly appreciated by consumers for its quality features including melty-juicy texture and typical aroma. The desired pear flavor and texture commonly develops as the fruit ripen mainly due to the action of ethylene. In fact, and despite of their climacteric nature, pears can be divided into summer and winter types, depending on the capacity of the fruit to produce ethylene immediately after harvest. Summer pears are able to ripen, hence to produce autocatalytic ethylene, just after harvest while winter pears need distinct periods of cold storage to trigger the ethylene autocatalytic burst and thereby to ripen. Accordingly, deciphering the ability of pear fruit to produce ethylene with or without chilling requirements may be of paramount importance to attain fruit with an optimal quality as well as to design the best postharvest handling strategies. In this work, we investigated the ethylene production capacity in two bi-parental crossing populations connected by a common and shared pedigree structure. The dynamics of ethylene production were evaluated in duplicate (3 fruit per rep and 2 reps per each of the 100 individuals evaluated) from the time of harvest and up to 21 days of storage at 20°C. The initial analysis of the data indicated that the fruit ethylene production capacity was not strictly associated to the fruit maturity at harvest and showed a favourable segregation of the production of this hormone among the targeted individuals. The results from this study will be further exploited in a QTL-mapping survey addressed to identify the QTL regions associated to this trait and to design markers suitable to assist the selection of novel and improved accession of pears.