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

Abstract

Interspecific hybridization between canker-tolerant Konkan Seedless lemon (C. limon Burm) and commercially grown Kagzi lime (C. aurantifolia Swingle) is significantly impeded by the occurrence of nucellar embryony. Hence, our work aimed to enhance hybrid seedlings’ recovery and confirm their hybridity through polymorphic SSR markers. Results revealed quite a satisfactory germination (< 58%) from all the stages of embryos and media used, but younger and oldest embryos produced more than 87% germination on all three media tested. MS medium supplemented with 500 mg l-1 malt extract plus 1.5 mg l-1 GA3 and 20µl l-1NAA proved better for the survival of plantlets obtained from the culture of either aged or younger embryos. However, it was highest in plantlets obtained from the culture of 80-90 days old embryos. The seedlings obtained from culture 80-90 old embryos (DAP or days after pollination) on MS medium supplemented with 500 mg l-1 malt 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 distinguish the hybrids of Konkan Seedless (lemon) × Kagzi lime (acid lime).