Rose of two cultivars (Samantha and Madame Delbard) were evaluated in response to two ethylene inhibitors; the aminooxiacetic acid (AOA) that inhibits ethylene synthesis and silver thiosulphate (STS) that inhibits its action. Data of fresh weight, water absorption, specific weight and petal aperture were taken periodically. Statistical differences were found for the varieties among treatments.   The best treatment was STS at a concentration of 4 mM Ag and 16 mM Na₂SO₃, which increased vase life compared with the control and with the AOA inhibitor. This last one at 0.5 mM improved petal aperture.

In order to determine the inhibitory affect that Paclobutrazol may had over chrysanthemum, under greenhouse conditions one or two foliar sprays, four dosages (25, 50, 100 or 200 ppm ai), were applied to tree potted cultivars, in other experiment, 0, 12, 0.25, 0.50, or 0.60 ppm ia, were root drenched once. Foliar sprays induced no differences among cultivars, but there were differential responses among dosages and number of sprays. A direct relationship was found between the amount of the product and the stern shortening. When drenched, the product slightly stimulated growth, although without difference with the control. The best conformation of the pots was obtained whan foliar sprayed once, 100 ppm al (25 ml·litro^-1 commercial product).

With the purpose of promoting flower aperture and reduce flower and bud abscission in cut flower stems of tuberosa (Polianthes tuberosa L.) several combinations of the following compounds were tested. Sucrose 3%, citric acid 200 mg·liter^-1, nitrato de plata 600 mg·liter^-1, hidroxiquinoleina citrate 200 mg·L^-1, triiodobenzoico acid 200 mg·liter^-1 and cycocel 30 mg·liter^-1. There were highly significative differences for water absorption and total fresh weight where the best treatments were Sucrose 3% + hydroxiquinoline citrate 200 mg·liter^-1 and the control. For wilted and necrotic flowers significant differences were only found after 12 days, for flower aperture only at 4 and 12 days. A 14 days after treatments there were highly significant differences for total dry weight, dry leaves in the upper portion, dry leaves in the intermediate portion and total fresh weight. For total fresh and dry weight the best treatment was the control.

Arborescent dahlias were collected in different areas near Chapingo, México, and their floral structures were studied Morphological differences were observed on the basis of the collected material as well as on the literature concluding that two species were present. D. excelsa has single, intermediate, and double flowers, with 14, 15 and 13 cm diameter, respectively, lilac in color, and with a flowering season from August to May, except in the winter. D. tenuicaulis has single and double flowers, 12 and 11 cm diameter, respectively, same lilac color, and flowering all the year around.

With the aim of increasing of the volume of production of roses on important dates, we selected roses stems of different diameters of Miss Paris, Royalty, Vivaldi and Sari cultivars. The daily temperature of the greenhouse was recorded, with a thermometer of maximum and minimum, to quantify the units of heat. The data were evaluated with correlation analysis. The flower stems were harvested in growing, without considering the diameter; we select healthy sterns. The variables evaluated were, longitude and diameter of the flower stern, days to harvest and heat units for each of the cultivars, which were considered treatments. The requirement of heat units for ‘Miss París’ was 1394.1, follow by ‘Vivaldi’ with 1362.4 ‘Royalty’ 1188.0 and ‘Sari’ 1159.5 in general, the heat units requeried for each cultivar depend on the estimation method. For stem diameter we concluded that as the diameter increased the temperature requeriments to produce a new flower stern in ‘Royalty’, ‘Miss París’ and ‘Vivaldi’ were less and therefore more precocious, except ‘Sari’, with a behavior differently; independent stem diameter required the same number of days to produce a flower.

En horticulture, le terme “Bulbe”recouvre des organes de réserves (géophytes) très divers: bulbes, cormus, tubercules etc… Ces organes se différencient par la nature de leurs tissus de réserves, leur morphologie et leur anatomie. Ces différences doivent être prises en compte dans la réalisation des opérations qui vont de la production a l’utilisation des bulbes: récolte, conditions de stockage, plantation…   Les plantes bulbeuses présentent également des origines géographiques trés diverses et ont développé des mecanismos (périodes de repos) leur permettant de survivre aux conditions climatiques défavorables. Elles présentent des développments périodiques qui peuvent être classés en deux groupes, les espéces á floraison printaniére qui presentent une période de repos en étre et exigent la séquence température élevée – température base – température élevée pour réaliser leur cycle, et les espéces á floraison estivale qui présentent une période de repos en hiver et exigent la séquence température base température élevée température base pour réaliser leur cycle.

Plant biotechnology, or “In vitro culture of higher plants”, is defined as the culture and manipulation of plants, embryos, organs, explants, tissues, cells and protoplasts on nutrient media under sterile conditions. Plant biotechnology has shown a spectacular development since 1975, resulting in the production and regeneration of viable individuals of many plant species. In addition, since 1980 there has been an explosion in the development of genetic manipulation techniques.   In vitro culture of higher plants has become an important tool, particularly in ornamental horticulture and plant breeding. The applications can be summarized as follows: embryo culture, germination of orchid seeds, cloning of orchids, production of disease free plants, micropropagation of many plant species, somaclonal variation, in vitro fertilization, induction of haploids, genetic manipulation, transformation, and a number of miscellaneous applications (e.g. mutation induction, separation of chimaeras, isolation of mutations, chromosome doubling, storage of plants at low temperatures biosynthesis of chemicals, etc.)

With the objective of determine the best culture media and intensity of light in the development in vitro of seedlings of the genus Cattleya, Eneyelia, Oncidium and Stanhopea; an experiment was established in factorial design 4x3² in arrangement of generalized random blocks desbalanced with subsamples, the blocks were considered as “light intensity” (500, 1,000 and 1,500 lux) and like treatments the combinations of the four genus and three culture media. Different response variables were restred to measure the development of roots and shoots.   The results indicate that significative statistically interactions exist between the studied factor, this the selection of a culture media must consider, appart of the orchid genus, the light intensity where the plants will be established. The best light intensity for the tested genus was 1,500 lux and the best culture media for the genus Cattleya, Eneyelia, Oncedium and Stanhopea was the Vacin and Went (1949) supplemented with 25 % of coconut water, for thegenus Stanhopea the culture media Knudson (1946) modified by Morel (1965, 1970) supplemented with 60 g·litro^-1 of banana pup (Arditti, 1977).

Dahlia plant propagation procedure through shoot tip or floral buds is described. Shoots can be obtained from floral buds in a Murashige and Skoog medium with IAA (0.1 mg·liter^-1) + BAP (0.25 mg·liter^-1, Shoot tips produce shoots in almost all combination of IAA (0, 0.05, 0.1, 0.2 mg·liter^-1). Roots are produced with IAA 0.5 mg·liter^-1 or without auxins, although variability of rooting is evident. Shoot tips cultured with BAP tend to produce pigmented reddish color shoots.

The gypsophila (Gipsophila paniculata L.) or “nube”, is used as cut flower both as fresh or dry flower in buquets. The propagation plant material for commercial production should be of high quality, shoot tip culture results in an invaluable tool in the production of healthy plant material.   Soot tip and leaf segments were cultured in a Murashige and Skoog Medium (MS) with the aim to determine the conditions for plant multiplication and callus production. Diferent growth regulators; 2,4-D, NAA, IBA, IAA, BAP alone or in combinations, were used in concentrations ranging from 0 to 3 mg·l^-1 NAA + 3.0 mg·l^-1 BAP produced the highest shoot number, 8 shoots per shoot tip within five weeks. Root production was obtained in al probed auxins, even without growth regulators, although IBA 0.75 mg·l^-1 produced better root development. Callus were obtained from leaves in all probed media but it was evident that leaves have a high rooting capacity that could not be reverted by growth regulators.

Gypsophila belongs to the family of Cariophylaceae. It is a small herbacecus and slender plant arised from Europe and Asia. It produces abundant little flowers useful for mist-like effects, in mixed borders in gardens and as trimming in bouquets. This genus includes more than 75 species having a very branched form with scant foliage when blooming. From all gypsophila species only the Gypsophila paniculata L. became a popular plant to use in trimming of fresh and dry bouquets. This species is strongly cultivated for cut flower. Nowadays the cultivars of this species with full flowers and white colour have a big economic value in the world market. Especially from this type, more than 16 cultivars have been developed. Nevertheless the cvs. Perfecta Extra and Bristol Fairy, are the most popular cultivars in several countries.

The use of aquatic ornamental vascular plants in the State of Morelos, Mexico, la described. Eighteen species with ornamental importance were registered total; 9 for aquariums, 5 for flower arrangements, two for fountains, and one for aquatic gardens. The part of the plant used is mentioned too. The dominant families were the Potamogetonaceae with three species, Haloragaceae and Typhaceae with two species each, and other families with one. On the basis of the dominant way of life, hydrophytes with emerged roots, and the hydrophytes with immersed roots include seven aquatic; ornamental species. Free floating hydrophytes are represented by three species, and the rooted hydrophytes with floating leaves just by one.

Eustoma grandiflorum Griseb. Var Heidi Pink Rin, an ornamental plant which was introduced to Mexico from Holand was found in the greenhause in Villa Guerrero, State of Mexico with the symptoms of wit and death of the plants. Specially the underside tissue of the leaves had a downy mildew growth of grey color. On the basis of form and ramification of the sporangiophores and sporangia the fungus was identiffied as Peronospora clorae, the only fungus reported in Europe causing this type of disease. This disease caused an alarm, because the plants had a 32 % of infection. Infected plants were destroyed in short time.

This work is the result of the management of carnation during several cycles (1987-1991) under greenhouse and open field conditions in three grower companies.  A background is given about the actual situation and problems of the culture in the zone. Data are shown on cultivars productivity and characterization; besides, bibliographic reviews on topics of the major concernment on the technical management and some aspects on the management of workers of this type of enterprises are included.

The production of crysanthemum (Crysanthemum morifolium Ramat.) in the east of Mexico State and its perspective in the face of the North American free trade agreement   SUMMARY. In the east region of Mexico State, the producer of chrysanthemum cut flowers, faces today an alternative the is being confronted to the implementation of the Free Trade Agreement, due to socio-political problems as well as technical-financial, first, within the scope of the social and political media atmosphere, the productive structure is made up of small surface and scarcely organized producers; technically and financially, there is scarcity of skilled personnel and a banking structure little interested in this activity, although there is an internal market well developed and with prices which are always higher to those of the external market.   This implementation of the Free Trade Agreement opens the possibility of developing this region by establishing groups of producers who can insert themselves in the external market; or the productive structure is at the risk of disappearing in the event that foreign interprises settle down in the region that can cause an unequal competition, taking intro account that when NAFTA is implemented, 61 percent of the agricultural products, among them flowers, will be free of taxes.

Thirty one species of ornamental trees used in Green areas of the Valley of Mexico are mentioned. They are notable for the beauty of their foliage, for the color and fragrance of their flowers, as well as for their old age for their rarity. Fourteen species are native to Mexico and seventeen are exotic.

Some species of spring bulb flowers are described, which are used in the tandscaping of European home gardens and public ardens (Green áreas, recreative centers and parks). Also, reference is made to Mexican wild bulb plants, which may be applied in the gardens during the whole year.

Information is included about the content of the flower exhibition and some reasons for the worldwide success of Holand’s flower industry and its worldwide leading role.

The potencial use of the vesicular-arbuscular mycorrhizal fungi in the production of ornamental culture (flower, trees and shrubs) is presented. Their use is especially beneficial in plants produced under nursery conditions using fumigated or sterilized soil and soilless growth media. The presence of the symbiosis produce benefits in plant nutrition and growth, tolerance to transplant and water stress and resistance to root-pathogens, among others.

The effect of the inoculation of five endomycorrizic, vesicular-arbuscular fungi (EFAF) on Anthurium andreanum was studied. All the EVAF increased the number of leaves, foliar area, dry weight, of the aerial part, and root volume. The best treatments were with Glomus sp. Zac-6 and Zac-15. The effects of the inoculations were evident four months after transplant, being more striking differences with respect to the controls after that time. Studies with the mycorrhizal technology in ornamentals is suggested, since, so far, most of this technology has been implemented to fruit crops.

Virus diseases are primary problems to flower crops in Mexico. Diseases have been mostly introduced from other countries through propagation material. Diseases found are Carnation Mottle (carnation), Tomato Aspenny (chrysanthemum), Tomato Spotied Wilt (chrysanthemum, gerbera, gladiolus, begonia), Bean Yellow Mosaic (gladiolus), and Rose Mosaic (rose. Diseases very in incidence and damage to the crop depending on the particular variely and climatic conditions. An additional disease was found in daisy-type chrysanthemums apparently caused by a Mycoplasma-Like Organism. Suggested approaches to manage viral diseases of flower crops are plant quality, vector management and cultural practices in an integrated manner.

The availability of disease-free cuttings and sterile media has allowed chrysanthemum (Chrysanthemum morifollum) to become one of the most important floral crops worldwide. Hyghly destructive diseases such as Verticillium and Fusarium witts and certain virus and viroid diseases, especially stunt, are held in check by commercial propagators through the use of culture and virus and viroid – indexing procedures. As a result, growers can obtain healthy cuttings and theraby, program their culture of chrysanthemums for flowering at any time throughout the year.

The satisfaction of man’s aesthetical and intellectual needs, although not the only one, it is the fundamental reason of our interest for ornamental horticulture. This interest is evident while observing works of art. The plants always have multiple functions, especially in home gardens and parks. The ornamental ones should present some general basic characteristics, like resistance to pathogens. Nowa a days besides the ornamental one looks for the ecological functions. This one requires a range of characters besides the aesthetical ones. These are the reasons of the role of ornamental horticulture and especially ambiental horticulture.

Vegetatively propagated plants are divided into 2 groups, obligate vegetatively propagated crops and facultative vegetatively propagated crops. For sterile cultivars, triploides and obligate apomicts are the only source of variation. The main advantage of mutation breeding in vegetatively propagated plants in the possibility of changing one or two characteristics of an oihenvise outstanding cultivar without changing the remaining part of the genotype. One of the important problems of mutation breeding of this group of plants is chimensm. This is a result of treating with mutagens buds with multicellular apices composed of a number autonomous call layers. One of the methods to overcome this problem is the adventitious bus technique. The most common mutagenic agents used for induction of mutations in vegetatively propagated plants is radiation; X or gamma rays. Generally doses range between 5 and 100 Gy, depending on the plant species, cultivar and kind of starting material. Until now about 480 mutant cultivars have been realesed.

Alstroemeria, as a cut flower is a very new plant. The first cultivar Walter Fleming (synonym ‘Orchid’) was bred in 1948. Today, alstroemeria is one of the most important cut flowers in Europe. The number of cultivars grows very fast now exceeds 200. They have been developed by conventional and mutational breeding. The main centers of breeding new cultivars are Holland and Poland. For the induction of mutations, X and gamma rays as well as fast neutrons are used. Mutations of flower colour, petal design, petal shape, change of flower size, plant vigour, productivity and season of bloom were recorded. The range of optimal does of gamma rays for induction of useful mutations was 3-7 Gy. In the case of triploid cvs. 50 Gy of gamma rays was a lethal dose. As the result of mutation breeding 7 new Polish cvs were registered to the end of 1993 and 4 from crossbreeding 3 of Butterfly type and one with yellow flowers with vanilla fragrance, blooming all the year round.

From open-pollinated population of Tagetes erecta L. with single inflorescence character were originated off springs highly variable in morphology as: leaf color, essential oil glands, plant height, branch position, number of individual flowers, color and shape of ligule flowers.

The group of species of Cosmos represents a wide oramental potential, according to its attractive morphologic characteristics and to its adaptation to diverse biotic conditions. In this study 33 species were detected, from south United States to Panama and Cuba. With the exception of C. gracilis and C. pilosus, all the species are present in one of several States of Mexico. Only in the States of Baja California and Campeche the genus is not reported. Most of the genetic diversity, and the possible center of origen, is at the central part towards the Pacific Ocean, spreading its presence lo the northern mountains and to the south of the country as well. Actually, there is a tendency to the reduction of the specimens collected in most of 50 % of the species it, could well be an indication of genetic erosion of these resourses.

The genetic resources of interest to ornamental horticulture are of native origin and/or introductions made as an outcome of the discovery of the American Continent.   The contribution or Mexico to world ornamental horticulture is expressed in an estimated number of 1,400 species or commercial interest. The selection and floricultural breeding programs allow for the increase of aesthetical values and for the continuous promotion of the new disease resistance cultivars. Due to the advances in the plant propagation techniques it is possible of offer to the public those plants that were once about to be extinguished (Dioon edule Lindley, Mammillaria sanangelensis, etc.).   The ornamental horticulture industry, exerts a high pressure on natural resources (explotation of the resources, search of new species and forms). Another source to be explored is the flora of natural minerals deposit and the vegetation of industrial conglomerations or urban zones. These plants have been little explored for their ornamental, environmental or adaptative values to distortioned places.   The objective is to reflect on the potential and the usage of genetic resources of Mexican ornamental plants. A bibliographical and field study were applied using the prospective method.

Cosmos is an ornamental plant native of the highlands of Mexico, late-flowering annual, the actual variation of this specie is not known and a lot of valuable genotypes are in the world form. Population from different states of Mexico were evaluated by morphological trails, leaves, stems, flowers, stomata. Some details of this variation are presented.

International intelectual property legislation has different Ways to protect plants and its application should depend of a specific country development. Mexico choose one of these ways of it’s intellectual property law Since 1991, it is possible to patent new varieties. In this document is analized all kind of plant varieties protection ways. Recently, the Mexican government has subimitted a new law related with plant protection and it has been sent to different research institution related with plant breeding. This law is according with 1991 UPOV Convention. The Mexican govemment proposai means a hard change from the patent system to plant variety protection certificates, and it is an opportunity to design a national strategy to develop our agriculture through of a narrow relationship among government research institutes, universities and industry.