Evaluation of tissue culture response from mature seeds ofPanicumspp.

Abstract

AbstractThe genusPanicumcontains important warm‐season forage grasses and species with potential as biomass crops. We selectedPanicumgenotypes with high response to tissue culture for genetic improvement. The highest frequency of callus induction from mature seed ofPanicum maximumcultivar Natsukaze was obtained on MS medium containing 4.0 mg L−12,4‐dichlorophenoxyacetic acid and solidified with 0.3% Gelrite. We compared germination frequencies and callus induction capacities among 24 genotypes of 11Panicumspecies on this medium. Callus induction frequencies varied among genotypes. Those with high germination frequencies generally had high callus induction frequencies. On the other hand, especially inP. maximum, the callus induction ratio (callus induction frequency/germination frequency) depended on the reproductive mode and ploidy. The callus induction ratio of three sexual accessions ofP. maximumwere very low compared to apomictic accessions, and besides, a tetraploid sexual accession Noh PL1 had very low germination and callus induction frequencies. Callus induction and regeneration capacities were independent of each other. For shoot regeneration, we transferred callus derived from the 24 genotypes onto MS medium supplemented with 1.0 mg L−1kinetin and 0.4% Gelrite. Six of the genotypes regenerated plantlets. Among them,Panicum meyerianumproduced the highest shoot regeneration frequency of 61.6% and the maximum number of shoots callus−1in the shortest time. The callus ofP. meyerianumalso showed vigorous proliferation. We thus selected high‐response genotypes ofP. meyerianum.