DEVELOPMENT OF A NEW RACE OF EEREETUAL FLOWERING CARNATIONS A. D. Boikov Experimental Horticultural Station, Negovan, Sofia, Bulgaria Abstract As the result of 10 years breeding with the species Dianthus caryophyllus L. a new race of perpetual flowering carnations has been developed. The varieties of the new race may be distinguished from the Sim varieties by the following distinct characteristics: larger flowers, stronger perfume, wider colour range, larger, heavily serratted petals, thicker and stronger stems of normal length. Unlike Sim types, the new varieties are fertile, producing many stamens. The data of the comparative yield trials indicate that the new varieties are more vigorous and more productive both under field and greenhouse conditions. In the greenhouse preliminary trials of certain varieties have produced yields in excess of 50 % over Sim types. Introduction The most important development in breeding carnations throughout the world (Holley, 1965; Ivlehlquist et al., 1962; Morgan, 1956; Sparnaaij, 1975; Stohr, 1975) have come about not so much by gradual improvement of existing types but by the development of completely new races of the species. This is typified by the introduction of the Sim race for greenhouse cultivation and the Chabaud and Remontant races for field cultivation. The need to develop new races comes from essential hereditary defects within existing races which are almost impossible to overcome. Squally important is the stimulation of intemation customer interest in the carnation through new and desirable flower characteristics. Acta Hort iculturae 71, 1977 Carnations 279
Accordingly we set ourselves the objective of creating a new race of perpetual flowering carnations which would be an improvement over existing varieties in certain essential characteristics. Materials and methods The initial breeding material used included selected races of Dianthus caryopbyllus L. species together with species of Dianthus genus. The resulting seedlings were subjected to biochemical, cytological and morphological analyses and were evaluated on the basis of their productive and decorative characteristics. The most promising hybrids were further examined in comparative yield trials. This research was carried out both in the greenhouse and under field conditions. Results Data obtained from investigation 1975-1976 suggest that the flowers of the new race show improvements over existing types in several aspects. These include flower size which is generally larger and fuller. Under greenhouse conditions the open flower has an average diameter of 9.0-10.0 cm, 5.6-6.0 cm deep, with 80-120 petals. Under field conditions the flower size is almost double of that of the Chabaud and Remontant types (table 1). In addition, the flowers have a strong clove perfume and are highly male fertile. The petals are large - the expose are being 4.5-5.0 cm wide and 4.0-4.5 deep, with heavy serrations. The colour range is wide, including as well existing colours, many new hues and tones. Flower stems are similar to Sim types, being long and straight, but are thicker overall, giving extra strength. Under field conditions they are longer and thicker than the Chabaud and Remontant types. The leaves are generally broad and long and silvery grey in colour. Under greenhouse conditions it is at present difficult 280
to make an accurate comparison of the productive performance of the new varieties with Sim varieties, due to the differing cultural and environment requirements of the two races. Nevertheless in preliminary trials certain varieties of the new race have yielded in excess of 50 % over Sim varieties. Under field conditions the yield is four times higher than Chabaud varieties (table 2). From a planting under glass in early June flowering commenced at the end of September and was in full production by the first half of October and produced continuously until the plants were removed in May the following year. Planting in the open during early April in the region around Sofia, flowering extended from early July till the end of October. In Southern Bulgaria, from a late March planting flowering extended from June till the end of November. The new varieties have been investigated to determine their resistance (or otherwise) to Fusarium wilt and preliminary results suggest that certain varieties have a greater degree of resistance than Sim types. From cytological analysis it appears that the majority of the new varieties are diploid. Discussion An analysis of the results from the comparative trials of the new varieties reveals that they possess a combination of unique decorative and productive characteristics which suggest they must be considered as a new race of the species Dianthus caryophyllus L. As it can be seen from figure 1, the curves of the undimensional values of the indices characteristic for the qualities of the new race varieties have similar coordinates and are clearly differentiated in an ascending line from those of the Chabaud varieties. The increased size of the flowers of the new race re- 281
suits from the greater number of petals of the flower and from the increased size of the petals themselves. The size of the calyx is also larger in proportion with, the size and fullness of the flower, thereby providing greater stability against splitting which might otherwise occur with the increased number of petals. The decorative effect of the flowers of the new race is enhanced by the combination of unique characteristics: new colours, heavy serration and strong perfume which are not to be found in the other large-flowering types. The greater stem diameter is of particular benefit during the period of low light intensity in winter, in providing a strong support for the larger flowers. The improvement in flower quality is matched by a considerable improvement in yield. This increase is the result of the improvement in vigour of the new varieties. This allows the flower stems to develop more quickly and for more flowers to be produced in a given period. At the same time, the average number of flowers per plant is also higher. Once the specific growing requirements of the new race are known in more detail, it is expected that yield will be further increased. The male fertility of the new varieties will greatly assist the further improvement of its decorative and productive characteristics. References Holley, W.D., and Baker, R., 1963. Carnation production. Dubuque, Iowa: 1-22. Hehlquist, G.A.L., and Sagawa, Y., 1962. The effect of gamma radiation on carnations. Proc.16th int.hort. Congr. Brussels, 1962, 1:293. Morgan, A., 1956. M selection of perpetual-flowering cajv nations. Gard.Chron., 139, 15:390-391. 282
Spaxnaaij, L.D., and Beeger, G.., 1973» The improvement of seed production for breeding purposes in the glasshouse carnation (Dianthus caryopbyllus L.). Euriphytica, 22:274-278. Stohr, D., 1973. Die Edelnelke. Berlin: 11-22. Table 1 - Comparative quality indices of cut flowers of the Bulgarian, Chabaud and Remontant races of carnations under field cultivation Index- Flower Stem Dia- Petal Fresh Length Thickness in mm meter count weight in cm Races in cm in g Base Middle Top Bulgarian 8.3 74.2 7.6 55.9 5.6 4.3 3.1 Chabaud 3.2 35.4 3.2 48.8 3.8 3.0 2.2 Remontant 4.6 42.7 3.3 41.7 3.9 3.1 2.4 Table 2 - Cut flower yield from the Bulgarian and Chabaud races of carnations under field cultivation Types Cut flower Difference in relation yield, in to the control Signinumber per fide care lumber/de care % cance Bulgarian 31 716 24 490 338.9 +++ (P=0.1%) Chabaud (control) 7 226 283
Figure 1. Curves of the undimensional values of the qualitative indices of the varieties of the Bulgarian race (1 - Zornitsa, 2 - Zora, 3 - Ognen Char, and 4 - Yela) and of Chabaud race (5 - Etincelant, 6 - Heine Rose, 7 - Jeanne Dionis, and 8 - Nero). 1 - Flower diameter; 2 - Petal count; 3 - Fresh weight per flower; 4-6 - Stem thickness at the base, at the middle and at the top; 7 - Stem length. 284