Transferring the cultured anther to a medium without activated charcoal overcomes the recalcitrance in pepper genotypes

Anther culture is a relatively easy and high-efficiency technique; however, low efficiency in plant regeneration may restrict its use in crop breeding. Activated charcoal is often used in in vitro culture, and it may ameliorate or hinder in vitro growth depending on genotype and tissue used. Pepper is one of the main vegetable crops of the Solanaceae family, but some pepper genotypes are known to be recalcitrant to androgenesis and formation of haploid regenerants. Therefore, this study was aimed to explore the effect of activated charcoal on response to androgenesis in pepper genotypes. The plant material included 34 Long Green (LG), 13 Bell pepper (BP), 13 Charleston (Ch), 6 California Wonder (CW), and 23 Capia (CP) advanced breeding lines. Initially, anthers were cultured in a medium with activated charcoal (WAC) for 25, 35, or 45 d, and then they were transferred to the same medium without activated charcoal (NAC). In the WAC medium, 15 lines of LG genotype showed the highest recalcitrance while many lines of CW had the lowest recalcitrance to androgenesis; however, after transferring the 35-d-old anthers to a NAC medium, the androgenesis was observed in recalcitrant LG lines. The results indicated that transferring the cultured anthers from WAC medium, ideally after 35 d, to a NAC medium overcame the recalcitrance to androgenesis in pepper.