Regeneration of zoysia grass (Zoysia matrella L. Merr.) cv. Konhee from young inflorescences and stem nodes

Abstract

We have optimized conditions for efficient regeneration of the vegetatively propagated zoysia grass (Zoysia matrella L. Merr) cultivar "Konhee". Two explants, young inflorescences, and stem nodes, were used and they displayed different responses to combinations and concen- trations of plant growth regulators in callusing, embryo- genic callus formation, and regeneration. The highest callus initiation rate from young inflorescences was obtained on medium supplemented with 4.5 to 9.0 μM 2,4-dicholor- ophenoxy acetic acid (2,4-D) and 0.44 μM 6-benzyl amino purine (BA). When the BA concentration was lowered to 0.044 μM, the highest percent embryogenic callus induc- tion from young inflorescences was achieved. The highest callus initiation rate from stem nodes was obtained, when young inflorescences were cultured on MS medium supplemented with 4.5 to 9.0 μM 2,4-D, 0.44 μM BA, and 0.037 μM abscisic acid (ABA). But embryogenic callus formation from the stem node was highest in the presence of 4.5 to 9.0 μM 2,4-D, 0.044 μM BA, and 0.037 μM ABA. Addition of ABA significantly increased embryogenic callus formation from stem nodes, but not from young inflorescences. Regeneration percentage was variable in response to BA level, and inclusion of α- naphthalene acetic acid (NAA) and gibberellic acid (GA3) further increased the regeneration percentage. The highest regeneration percentages obtained from the young inflor- escences and stem nodes were 82% and 67%, respectively. This is the first report showing that plants can be regenerated from young inflorescences and stem nodes of vegetatively propagated zoysia grass.