Modulating the fruit morphology of traditional melon varieties: insights into IL × genetic background interactions

Abstract Traditional melon varieties with high value in local markets are grown in the Iberian Peninsula. However, their cultivation is declining, being replaced by modern varieties. Five high quality traditional were selected (‘Piel de Sapo’, ‘Amarillo’, ‘Rochet’, ‘Tendral’ and ‘Blanco’) to modify their fruit morphology in order to make them more appealing for consumer using a set of introgression lines (IL) from the accessions ‘Vedrantais’ (VED, cantaloupe, France), PI 273438 (DUD, Dudaim, Iraq), Ames 24,297 (TRI, wild melon, Pakistan), and PI 124112 (CALC, acidulus, India) in the genetic background of two ‘Piel de Sapo’ cultivars. The ILs contained QTLs that induced round fruits (CALC8-1, DUD4-2, VED11-2), large fruits (TRI05-2), and small fruits (TRI08-2, DUD1-2, DUD4-2). Hybrids between ILs and traditional varieties were studied to verify the effect of ILs in the traditional genetic backgrounds and IL × genetic background (IL × GB) interactions. The ILs with more stable effects were TRI08-2 (reducing fruit weight), TRI05-2 (increasing fruit weight), and CALC8-1 (round shape). ILxGB interactions were also found, mainly in VED11-2 and DUD4-2 for fruit weight. These results allowed us to identify the best ILs to modify fruit morphology in the traditional varieties by breeding programs. Additionally, the identification of IL × GB interactions for some ILs, such as VED11-2 and DUD4-2 for fruit weight provides an experimental system to shed insights into the genetic basis of QTLxGB interactions.