Plant regeneration of Lotononis bainesii (Leguminosae) through cotyledon culture

MARÍA LAURA VIDOZ; KENNETH HAYS QUESENBERRY

Tampa, Florida, EEUU

Congreso; Soil and Crop Science Society of Florida Meeting; 2006

Soil and Crop Science Society of Florida

Lotononis bainesii Baker is a subtropical forage legume which prefers sandy soils and exhibits some frost tolerance. The objective of this research was to evaluate the effect of different plant growth regulators (PGRs) on the in vitro response of cotyledons of 50 genotypes of L. bainessi. Seeds were scarified with concentrated sulphuric acid for 5 minutes, rinsed with running water for 10 minutes, surface disinfected in 70% ethanol for 30 seconds followed by 0.6% NaOCl plus one drop Tween 20® for 10 minutes, and rinsed 3x with sterile distilled water. Disinfected seeds were placed onto half strength Murashige and Skoog (1962) basal medium (MS), with 1.5% sucrose and 0.7% agar for germination. Cotyledons from one-wk-old seedlings were cut longitudinally into 2 pieces, so that 4 pieces were obtained per genotype and placed onto MS without PGRs, MS + 1mg L-1 thidiazuron (TDZ), MS + 1mg L-1 2,4-dichlorophenoxyacetic acid (2,4-D), and MS + 1mg L-1 picloram (PIC), respectively. Cultures were incubated at 25±2 ºC, with 14 h photoperiod. After two weeks, 54% of the genotypes developed adventitious buds from small callus produced on explants on medium containing TDZ. Explants placed on the medium devoid of PGRs remained irresponsive, whereas those cultured on media containing either 2,4-D or PIC produced callus but no organogenesis. After 60 days, buds were transferred to MS + 0.01 mg/L benzyladenine + 0.01mg/L indolebutyric acid, where they elongated and rooted. Plants were placed onto MS without PGRs for further development. Regenerated plants were successfully acclimatized ex vitro.