GROWTH AND REPRODUCTION OF NEW ZEALAND, MEDITERRANEAN, AND HYBRID DACTYLIS GLOMERATA AFTER SHORT DAY AND TEMPERATURE TREATMENTS

Abstract

Floral induction was studied in New Zealand and Mediterranean varieties of Dactylis glomerata L. and their hybrids. Treatments of 1 month vernalization, or 1 month of cold short days, or 2 months of warm short days, when followed by long days, induced almost complete heading in the field for most materials. Early dates of heading, many fertile tillers of increased height, and heads of a large and branched type also were induced by these treatments as compared with the untreated control material. Certain cold treatments produced, at early vegetative stages, more growth than the control. It is inferred that earlier attempts to vernalize New Zealand Dactylis plants were unsuccessful because of the restricted root growth in pots and flats. Plant breeding implications concerning heterosis, genotype–environment interactions, and reciprocal differences in hybrids were discussed.