Production and verification of lemon × acid lime hybrid populations via embryo rescue

Abstract

Interspecific hybridization between canker-tolerant Konkan Seedless lemon (C. limon Burm) andcommercially grown Kagzi lime (C. aurantifolia Swingle) is significantly impeded by the occurrence of nucellarembryony. Hence, the objective of our work was to enhance hybrid seedlings’ recovery and to confirm theirhybridity through polymorphic SSR markers. Results revealed quite a satisfactory germination (< 58%) from allthe stages of embryos and media used, but younger and oldest embryos produced more than 87% germinationon all three media tested. MS medium supplemented with 500 mg l-1 malt extract plus 1.5 mg l-1 GA3 and 20μll-1NAA proved better for the survival of plantlets, obtained from the culture of either aged or younger embryos,though it was highest in plantlets, obtained from the culture of 80-90 days old embryos. The seedlings obtainedfrom culture 80-90 old embryos (DAP or days after pollination) on MS medium supplemented with 500 mg l-1malt extract plus 1.5 mg l-1 GA3 and 20μl l-1 NAA had the highest root and shoot length at 30 days after culture(DAC). SSR loci CCSM4 and CAC-33 expressed the highest polymorphism, showing their ability to distinguishthe hybrids of Konkan Seedless (lemon) × Kagzi lime (acid lime) .