High-Efficiency Plant Regeneration from Immature Inflorescence Derived Callus Cultures of Two Phenotypically Distinct Accessions of Centipedegrass (Eremochloa ophiuroides)

Centipedegrass [Eremochloa ophiuroides(Munro) Hack] is an important warm-season (C-4 ) grass species widely used in lawn and forage industry. To achieve the purpose of improvement and innovation of centipedegrass germplasms, a high efficient plant regeneration system was established from immature inflorescence-derived callus cultures. Two centipedegrass accessions of E022 and E092-1 with different phenotypic characteristics were investigated for their performances in callus formation, development and as well plant regeneration. The optimum medium for initiation of callus induction was Murashige and Skoog (MS) medium supplied with 4.0 mg/L dichlorophenoxy acetic acid (2,4-D) and 0.2 mg/L N6-benzyl adenine (BAP), and the callus induction rate reached up to 53.4% and 80.0% in E092-1 and E022, respectively. Callus proliferation was best in the subculture medium consisting of a MS base medium supplemented with 2.0 mg/L2,4-D and 0.1 mg/L BAP, with enhanced osmotic pressure. Shoot organogenesis was brought about when the calli were shifted to MS media containing 2.0 mg/L Kinetin (KT) and 0.1 mg/La-Naphthalene acetic acid (NAA), or 2.0 mg/L BAP and 0.1 mg/L NAA or 2.0 mg/L N-(2-chloro-4-pyridyl)-N'-phenylurea (CPPU) and 0.1 mg/L NAA. Maximum organogenesis of E022 was obtained on medium containing BAP, but maximum organogenesis of E092-1 achieved on medium containing KT. Rooting of plantlets was achieved for both accessions under the rooting induction medium of MS plus 0.5 mg/L NAA. Plants with well-formed root system were hardened and transplanted to soil. Thus, a highly efficient, reproducible plant regeneration system was developed for two phenotypically distinct E. ophiuroides accessions by using immature inflorescence explants, which can effectively solve the problem of low percentage of embryogenic calli formation and meanwhile improve the regeneration frequency of plantlets in centipedegrass. (c) 2018 Friends Science Publishers