Ecological Classification of Spring-flowering Gladiolus

Abstract

Ecological characteristics of spring-flowering gladiolus were studied, using 5 cultivars with different 5 pedigrees (‘Comet’ of Herald, ‘Charm’ of Tubergenii, ‘Elvira’of Herald×Nanus, ‘Robinetta’ of Ramosus and‘Albus’of Colvillei) and compared with summer-flowering gladiolus.
‘Comet’and‘Traveler’of summer-flowering gladiolus flowered earlier when grown at 30-25°C (day-night) than at 20°C (whole day), whereas‘Charm’flowered earlier when grown at 20°C.‘Robinetta’and‘Albus’flowered normally only when grown at 20°C.
The effect of day length on flowering was small.‘Elvira’flowered a little earlier when grown under short day than under long day, whereas‘Comet’, ‘Charm’, ‘Robinetta’and‘Albus’flowered a little earlier when grown under long day.
Flowering of‘Comet’was severely affected by low light intensity, resulting in 100% blasting. Flowering of‘Elvira’and‘Charm’were appreciably affected whereas flowering of‘Robinetta’was not affected at all.
Flower bud initiation and development of‘Charm’, ‘Robinetta’and ‘Albus’ were promoted by low temperature treatment on the corms, whereas those of ‘Elvira’and‘Comet’were not.
For breaking corm dormancy, high temperature storage (30°C) was more effective than low temperature storage (5°C) for all the cultivars.
Cold hardiness was strongest in‘Robinetta’, intermediate in‘Charm’, ‘Albus’ and‘Comet’, and weakest in‘Elvira’.
Drought resistance was strongest in‘Robinetta’, intermediate in‘Albus’and ‘Charm’, and weakest in‘Elvira’and‘Comet’.
Thus, spring-flowering gladiolus, which has been regarded as one group, could be ecologically classified into 3 groups: a typical spring-flowering gladiolus type, ‘Albus’and‘Robinetta’, an intermediate type, ‘Charm’, and a summer-flowering type, ‘Comet’and‘Elvira’. Ecological characteristics of these groups well reflected those of their parental species.