Variation between genotypes of carnation (Dianthus caryophyllus cultivars and interspecific hybrids) in time of flowering and response to long days. I. Variation in yield distribution

Abstract

Early flowering carnation cultivars, responding to artificial long days, can assist the grower to plan the onset of flowering and achieve a better distribution of flower production over the year . A comparative trial is described of 20 carnation genotypes (cultivars and backcrosses of interspecific hybrids), representing a wide variation in flowering time and response to long days . The trial was planted in September in a phytotron under a winter light intensity of 15 W/mz for eight hours per day . In one half of the trial, daylength was increased to 24 hours for 25 days in December-January . At the end of February the plants were transferred to a glasshouse where they were observed until all primary shoots had flowered . The main purpose of the experiment was to analyse the genetic factors responsible for the large differences in flowering behaviour between genotypes . Average flowering dates varied from 132 days from pinching in a Dianthus chinensis hybrid to 181 days in the mediterranean cultivar `Raggio di Sole' . LD response was most pronounced in the earliest flowering Diantini selections and least in the traditional commercial cultivars . In the former the LD effect was evident in all shoots of a plant, but mostly so in the lower (older) shoots ; in the traditional cultivars only the higher placed shoots responded to LD . As a result, the proportion of the shoots actually responding to LD varied from 28% in the traditional cultivars to 54% in the Diantini X D .'Allwoodii' cv 'Doris' group of genotypes .

Selection of Carnation Line 806-46b with Both Ultra-long Vase Life and Ethylene Resistance

“…Although we primarily selected 8 lines with a longer response time among the progeny of the crosses between ethyleneresistant lines (Table 2), we were not able to select lines with an extremely long vase life despite a replicated test in the second year (data not shown). Another problem is that the progeny of this cross tend to show late flowering (in other words, tend to delay flower bud differen- tiation), which is generally unsuitable for practical cultivation compared with early-flowering cultivars of carnation (Sparnaaij et al, 1990). Therefore, we finally concluded that crosses between ethylene-resistant lines were ineffective to produce lines with both ethylene resistance and an extremely long vase life.…”

Variation between genotypes of carnation (Dianthus caryophyllus cultivars and interspecific hybrids) in time of flowering and response to long days. II. Variation in shoot development

“…In Part I of this paper (Sparnaaij et al ., 1990), genetic variation in average flowering date and response to a mid-winter LD treatment (dusk to dawn lighting) was studied in a phytotron experiment comparing a wide range of genotypes, partly derived from interspecific breeding programs . That study revealed a considerable potential for early flowering and a strong response to LD in several types of interspecific hybrids .…”