In vitro plantlets regeneration in Bambara groundnut [Vigna subterranea (L.) Verdc. (Fabaceae)] through direct shoot bud differentiation on hypocotyl and epicotyl cuttings

In vitro regeneration system via direct organogenesis in Bambara groundnut (Vigna subterranea L.) using hypocotyl and epicotyl cuttings was studied. Basal Murashige and Skoog (MS) medium supplemented with 6-benzylaminopurine (BAP), 6-furfurylaminopurine (kinetin) or Thidiazuron (TDZ) with or without -naphthaleneacetic acid (NAA) were attempted. Multiple shoots were induced from both explants but regeneration efficiency was higher when epicotyl cuttings were used. The ability of hypocotyl and epicotyl cuttings to produce shoots varied depending on the culture medium. BAP (2 mg/l) gave the highest response (73.33 - 97.77%) with the regeneration of 3.7 shoots per explant with hypocotyl and 5.8 shoots per explant with epicotyl. Substitution of BAP at an equimolar concentration with kinetin and TDZ, and incorporation of NAA during shoot bud induction did not show anyimprovement over that obtained with BAP and promoted callusing to a different degree. The regenerated shoots were readily elongated on the same medium as used for induction and rooted on half-strength MS basal medium without any growth regulators. 62% of the plantlets were successfully acclimatized and potted plants were established in soil with 73% survival rate

In vitro-assisted compression of breeding cycles

Prod 2018-143 BAP GEAPSI CT1 BAPInternational audienceThe compression of breeding cycles to quickly progress segregating material to homozygosity has attracted substantial international research interest for some decades. Modified pedigree breeding methods such as single seed descent (SSD) have enabled faster generation turnover and commercialization of new crop cultivars. Since the latter part of the last century, doubled haploid technology has revolutionized the progression to genome fixation in responsive species. In unresponsive but economically important families, biotechnological tools are being developed to accelerate traditional SSD – either by completing the full plant life cycle in vitro or by coupling controlled environmental conditions in the soil to elicit rapid floral onset with germination of immature seed in vitro to truncate seed filling. Both techniques have resulted in step-change efficiencies in generation turnover with up to fourfold improvements in species such as grain legumes. Such enhanced SSD systems are also valuable for breeding complex traits across a range of species. In this chapter, we explore the recent advances in in vitro-assisted breeding cycle compression in crops, opportunities to combine rapid phenotyping for key traits and the benefits of in vitro life cycle completion when researching under restrictive regulatory frameworks and working with enfeebled or rare material