Commercial Cut Flower Production Research Articles

Foliar application of citric and malic acid to stock plants of rose alters the rooting of stem cuttings

BackgroundAs the world’s best-selling cut flower, there is a high demand for propagated rose plants. Auxins are the dominant growth regulator used to improve the rooting of cutting; however, their application remains a labor-intensive process, and on the other hand, side effects like poor shoot growth exist. Organic acid sprays have enhanced many physiological traits of plants which justified surveying their possible effect on the rooting process in the current study.MethodsDifferent concentrations of citric or malic acid were sprayed to stock plants of rose (Rosa x hybrida cv. ‘Sherbet’) prior to taking cuttings. Malic or citric acid (3, 6, or 9 mM) was applied five times on a 14-day interval in a commercial cut flower production greenhouse. Single-node cuttings were prepared and were rooted under mist. Data collected included rooting percentage, root count, root and shoot length and dry weight, and root-to-shoot ratio (R:S).Results and discussionThe rooting percentage was enhanced by all treatments. Citric acid enhanced root number at 6 mM level followed by 3 mM citric acid. Average root length was increased by all treatments except 3 and 6 mM malic acid. All CA treatments increased shoot length, while it remained unaffected by MA treatments. CA at 3 and 6 mM level and 6 mM MA increased shoot dry weight, but only 9 mM CA increased the root dry weight.ConclusionBoth organic acids had positive effects on rooting response of ‘Sherbet’ roses. However, the mechanism of observed responses to organic acids remains to be studied. While they enhance the physiological performance of stock plants, they can also simultaneously both enhance the rooting as well as the shoot growth of the new plantlets.

Physiological and phenological responses of Protea ‘Pink Ice’ to elevated temperatures

Rising temperatures associated with global climate change may alter the physiology and phenology of Protea species and cultivars. Protea species are assumed to be well adapted to warm summers characteristic of their natural Mediterranean-type habitat, but their plasticity in responding to higher growth temperatures is not known. Using infrared lamps, a greenhouse-based temperature gradient was constructed, with temperatures ranging from ambient to ambient+3.1°C. Potted plants of Protea ‘Pink Ice’ (P. compacta R. Br×P. susannae Phill.) were grown at five positions along this gradient for 12 months under irrigation. Simultaneously, a field verification experiment in a nearby commercial ‘Pink Ice’ orchard was conducted under ambient temperature and ambient+2.9°C. Increased sclerophylly (leaf dry weight per unit area) with increasing temperature indicated leaf structural changes. While leaf area based gas exchange (net CO2 assimilation rate, stomatal conductance and dark respiration rate) did not differ across the temperature gradient, leaf weight based CO2 assimilation rate and dark respiration rate decreased significantly towards the upper end of the temperature range. The optimum temperature for net CO2 assimilation rate (Topt) showed seasonal adjustments, but increased in response to experimental warming only in the field experiment. Significant temperature elevation resulted in an earlier onset of spring bud break, but warming extended inflorescence initiation from the spring flush to the summer flush, leading to delayed flowering. Aboveground biomass allocation shifted from inflorescences to leaves and to a lesser degree to stems, with elevated temperatures, whereas root growth was stimulated in the middle of the warming range. The results of this study suggest that elevated temperature may prolong the vegetative growth period in some Protea cultivars where water is not limiting, at the expense of flower production. This could have significant economic and marketing consequences for commercial cut flower production systems. The findings are also of significance to ecologists studying the responses of Proteaceae to climate change.

Genetic Relationship among Sweetpea Cultivars and Related Species by AFLP Analysis

Sweetpea (Lathyrus odoratus L.) is an important ornamental crop belonging to the Fabaceae family. In Japan, commercial cut flower production under forced culture has flourished, but few cultivars are bred exclusively for cut flower forced culture. In order to obtain knowledge for the selection of breeding materials, we elucidated the genetic relationships among eighty-seven sweetpea cultivars and two related species using the amplified fragment length polymorphisms (AFLP). Sweetpea cultivars were grouped into two clusters. Cluster I consisted of four cultivars, including a wild cultivar, ‘Cupani’ and cultivars established from spontaneous mutation or natural hybridization, such as ‘Cupid’ and ‘Painted Lady’. The biggest cluster, cluster II, consisted of eighty-three sweetpea cultivars. No distinct subcluster shared common morphological or ecological characteristics, such as tendril-less, plant type, or flowering habit in cluster II. The distinct genetic differentiation among cultivars highly seems to reflect sweetpea breeding history originating in the United Kingdom 300 years ago using limited genetic resources. Thus, hybridization with genetically distinct, exotic resources may contribute to the development of sweetpea cultivars.

Commercial Cut Flower Production in Nepal and Status of Four Important Cut Flowers

Commercial cut flower production in Nepal had its origin during late eighties of last century. This paper deals with history of commercial cut flowers production in Nepal and the current situation of cut flower production in Nepal with special reference to types of cut flowers grown, area under various cut flowers, production system (in-door or out-door) and location of production area in the country. Status of four most important cut flowers of Nepal is also described. This paper has revealed steady increase in the area of production and spread of growing area from within the Kathmandu valley to other parts of the country. The types of cut flowers grown in Nepal has also diversified and production changed for high value cut flowers from open field cultivation to semi to fully protected cultivation system. Keywords: Floriculture, inventory, production system, protective production J. Inst. Agric. Anim. Sci. 25:17-21 2004

Flowering of three species of Brodiaea in relation to bulb size and source

Flowering of Triteleia bridgseii Greene, Triteleia ixiodes Greene, and Dichelostemma Ida-maia Greene was investigated using corms of various sizes collected from the natural habitat as well as those from a cultivated field. Regardless of species, flowering percentage of all plants in the Brodiaea complex increased, the number of florets per scape increased, and the forcing time decreased as the size of the mother corm increased. The length of the flowering scape is species specific: 18–20 cm for T. ixiodes, 40–45 cm for T. bridgseii, and 40–50 cm for D. Ida-maia, and is unaffected by the size of the mother corm. Except for large corms, T. bridgseii and T. ixiodes generally produced only one replacement corm indicating that other means of propagation would be required prior to commercial cut flower production. In contrast, D. Ida-maia readily produced a replacement corm as well as many cormlets from each mother corm. The minimum corm size for 100% flowering varies with species and the source of the corms. All T. bridgseii corms >0.8 g flowered, whereas for D. Ida-maia, a minimum corm size of 3 g was required. In T. ixiodes, the source of the corms affected the flowering of the corms. All T. ixiodes corms from the natural habitat weighing >0.3 g flowered, whereas for those from the cultivated field, a minimum corm size of 3.6 g was required. Data for T. ixiodes, thus, suggest that environmental conditions during which the corms are produced may play a significant role in the flowering potential of a species.

Breeding vandaceous orchids for commercial cut-flowers in Singapore: an overview

Extensive artificial hybridisation among members of some 86 genera of vandaceous orchids within the subtribe Sarcanthinae in Singapore over the past five decades has created many thousands of exotic hybrids. A small number of these are selected for commercial cut-flower production, while others are cultivated as pot-plants. Two classes of intergeneric hybrids are of special commercial importance as export cut-flowers, the bigeneric Aranda (Arachnis x Vanda) and the trigeneric Mokara (Arachnis x Vanda x Ascocentrum) hybrids. Cytogenetic studies of these hybrids in recent years have provided information on the significance of ploidy levels and genomic constitutions on the horticultural performance of cut-flower cultivars, and also on the strategy for effective breeding in vandaceous orchids.

Breeding cut flower cultivars ofLeptospermumusing interspecific hybridisation

Abstract Leptospermum scoparium Forst. has an ideal form for a cut flower, but its use is limited by a short vase life. Flowers on cut stems typically wilt within 4–6 days of harvest. A breeding programme was initiated to develop cultivars with improved characteristics for commercial cut flower production, focusing on increasing postharvest life. A survey was conducted of 38 cultivars of L. scoparium as well as 16 other species of Leptospermum, 3 of the closely related genus Kunzea, and 1 intergeneric hybrid between L. scoparium and K. sinclairii. The vase lives of the L. scoparium cultivars studied varied from 1 to 6 days, with a modal value of 4 days. L. scoparium ’Crimson Glory’ has been successfully hybridised to L. rotundifolium ’Jervis Bay’. The Fl progeny of this cross lasted from 4 to 9 days in a vase with a modal value of 6.5 days. Other heritable characters included differences in leaf and flower dimensions and the accumulation of the blue anthocyanidin moiety delphinidin in the petals.