Trifolium alexandrinum × T. resupinatum – Interspecific Hybrids Developed through Embryo Rescue

Abstract

This is the first report on the development of interspecific hybrids between T. alexandrinum and T. resupinatum, using embryo rescue. T. resupinatum is an important donor species for traits such as resistance to root and stem rot diseases, and tolerance to alkalinity for the potential improvement of T. alexandrinum. T. alexandrinum, as female parent, was crossed with T. resupinatum and embryos were excised 10–12 days after pollination and cultured in vitro on EC3 medium. Of the recovered embryos, 23.08% showed plumule emergence. For subculturing, shoot-induction medium LSP3 was used. Roots were induced on RL1 medium. Regenerants were hardened and inoculated with Rhizobium before transfer to the field. Morphological appearance of the hybrids was intermediate to both the parents. The hybrids were erect, leafy with short internodes and possessed distinct dwarf bushy compact appearance and were profusely branched. The plants were late flowering with pollen fertility more than 90%. Three out of five hybrid plants set seed following selfing. Hybridity of the plants was also confirmed through Est, PRX, SOD, GOT isozymes and protein banding patterns.