Corm Size Research Articles

EFFECT OF PLANT DISTANCE ON FLOWER YIELD AND QUALITATIVE AND QUANTITATIVE CHARACTERISTICS OF FORAGE PRODUCTION OF SAFFRON (CROCUS SATIVUS) IN MASHHAD CONDITIONS

EFFECT OF PLANT DISTANCE ON FLOWER YIELD AND QUALITATIVE AND QUANTITATIVE CHARACTERISTICS OF FORAGE PRODUCTION OF SAFFRON (CROCUS SATIVUS) IN MASHHAD CONDITIONS

THE EFFECT OF DURATION OF INCUBATION AND PHOTOPERIOD ON CORM AND SHOOT CHARACTERISTICS OF SAFFRON PLANT (CROCUS SATIVUS L.)

Although botanical characteristics of saffron are well documented in the literature, there is little evidence on physiological aspects of this plant. Four separate studies were conducted to evaluate effects of duration and condition of incubation period, weight of mother corm and different light / temperature regimes on aerial and corm criteria of saffron. Results showed that combination of 120 days incubation in growth chamber and bigger size of corms caused more rapid emergence of aerial parts and an increase in leaf area. Corm size had significant effect on days to emergence of aerial parts, leaf area, shoot dry weight (aerial biomass) and number of active buds on corms. Incubation of corms in growth chamber promoted emergence of aerial parts significantly. Length of planting to emergences period of aerial parts was longer with 120 days compared with 60 days incubation. However with application of water to corms, this period was shorter. Light / temperature regimes had a significant effect on length of emergence of aerial parts, aerial dry mater, leaf area and number of active buds on corms and increasing light period from 6.5 to 16 hours increased all these components. When corms were located under light regimes of 16/8 (light / dark), 33 % of corms initiated flower compared with 75 % for corms located under natural conditions. Corms located in light regimes of 6.5 / 5.5 did not initiated flower.

Effects of temperature on the growth of spring ephemerals: Crocus vernus

Spring ephemerals of deciduous forests appear shortly after snow melt and senesce shortly after the overstorey canopy has closed. During this short period, they take advantage of the high light conditions, but also of the low‐temperature regime that favours growth in these species. This better growth at cooler temperatures has been attributed to longer leaf life duration. The objective of this study was to test if temperature effect on growth in spring ephemerals can be explained solely by the leaf life duration, or if there is also a direct temperature effect on the underground organ growth. Crocus vernus (L.) Hill was exposed to two temperature regimes, 12/8 and 18/14°C (day/night), for sequential harvests and to four differential air to soil temperature regimes: 12/12, 12/18, 18/12 and 18/18°C (air/soil temperature). Dry mass, leaf nitrogen, starch concentration and cell size of the new corm were determined. Final dry mass and cell size were higher at the lower temperature regime while leaf lasted longer than at the higher temperature regime. Although both air and soil temperatures had an impact on the different growth parameters measured, the impact of soil temperatures was greater and it also influenced leaf life duration. At higher temperature, corm growth stopped before the first visual sign of leaf senescence, suggesting that corm growth controls leaf life duration in C. vernus rather than the opposite and that crocus growth becomes rapidly sink limited at higher temperatures.

Floating System Production of Liatris spicata (L.) Willd.

Liatris is an ornamental plant cultivated as a garden perennial for more than 70 years. Since the early 1970s, Liatris spicata has gained importance as a cut flower because of its long-lasting flowering and its peculiar downward flowering succession. This species is usually cultivated in beds both outdoors and in greenhouses. However, in order to improve yield and quality production, some research has been carried out on soilless cultivation. In particular, floating systems seem to provide the best performances, although only different nutrient solutions or their concentrations have been studied. In this research, in addition to two different concentrations of Hoagland solution [full-strength (H) and a half-strength (1/2H)], three corm circumferences (8/10, 10/12, and 12+) and three plant densities (36, 48, and 60 plants/m2) were also evaluated. The full-strength solution gave the best performance from both qualitative and quantitative standpoints. This nutrient solution also showed, at the end of the experiment, very high residual nitrate-N, which could induce environmental pollution during disposal. Furthermore, the management of the solution appeared more difficult and time-consuming. All these aspects should be taken into account by growers in making choices. Corm size also affected production. Increasing circumference from 8/10 to 12+ increased marketable stems per plant and their quality traits, but, because of the highest mortality of plants observed with the bigger corms, yield per square meter did not increase over corm size of 10/12. Finally, rising plant density from 36–60 plants/m2, the biomass of the single plant decreased. However, it resulted also in the enhancement of sellable production per square meter.

INFLUENCE OF CORM SIZE ON THE ORNAMENTAL USE OF WILD SPECIES OF GENUS GLADIOLUS

Gladiolus italicus and G. illyricus are two wild species that grow in SE Spain, whose botanical characteristics, it was thought, may allow them to be used as ornamental plants. If this is so, two objectives could be achieved: first, an increase and diversification in the offer of ornamental plants of genus Gladiolus, which is mainly based on large flowered hybrids, and, secondly, the recovery and maintenance of the regional germplasm by means of massive propagation methods. This is very important in the case of G. italicus, a species regarded as rare, since it could avoid the potential risk of its extinction. In order to adapt the above mentioned species to the ornamental industry, we cultivated them both in the open air and in an unheated greenhouse in an attempt to increase yield and flower quality, and also to improve marketing timing. The object of this work was to study the influence of the corm size of both species to determine their possible use as ornamental plants. The results show that G. italicus can be used as a cut flower, if large (8/9) and medium (6/7) corm sizes are used, while G. illyricus is suitable for use as a rockery plant, as a potted plant or as packaged cut flower in the ornamental industry if a 5/6 corm size is used.

EFFECT OF LOW TEMPERATURE AND CHITOSAN ON DORMANCY BREAKING AND GROWTH OF YOUNG CORMS OF THREE ARISAEMA SPECIES

EFFECT OF LOW TEMPERATURE AND CHITOSAN ON DORMANCY BREAKING AND GROWTH OF YOUNG CORMS OF THREE ARISAEMA SPECIES

Influence of Plant Growth Regulators on Growth, Flowering and Corm Yield of Gladiolus (Gladiolus grandiflorus L.) cv. Oscar

In a field experiment, uniform sized corms of gladiolus (Gladiolus grandiflorus L. cv. Oscar) were planted in last week of October at a distance of 30 cm. between rows and 20 cm. between plants. The effect of GA (50, 100 ppm), Cycocel (500, 1000) and NAA (50, 100 ppm) on gladiolus plants. It was concluded that foliar application of 100 ppm GA3 at 45 days after corm planting has shown superiority in all vegetative, floral characters and corm & cormel yield viz., plant height (128.53 cm), number of leaves (8.57) per plant, spike length (108.33 cm), spike weight (128.87 g), number of florets (17.60) per spike, size of second florets (15.07 cm), number of spikes (1.67) per plant, size of largest corm (7.52 cm), number of corms (1.80) per plant, number of cormels (11.53) per plant and weight of corms (79.33 g) per plant. Whereas, a highest longevity of florets opening or survival on spike (20.33 days) was recorded in 1000 ppm Cycocel.

Short-term preservation of maize landrace seed and taro propagules using indigenous storage methods

Some native subsistence farmers in South Africa store maize (Zea mays L.) cobs over a fireplace and subject the seeds to smoke and heat. Taro (Colocasia esculenta L. Schott.) propagules are maintained in dry pits for one month, in layers separated by grass straw, and water is prevented from contacting them. These methods have been used together with others to maintain landraces for centuries, but they have largely been abandoned with no modern technology replacements. The objective of this study was to examine the effects of the maize and taro storage methods on the quality of planting material. Experiments were conducted on three subsistence farms located in KwaZulu-Natal, and at the University of KwaZulu-Natal, South Africa. Two maize landraces, yellow and white, were subjected to the smoke-over-fire storage method for five months during the normal off-season period for maize production in the location. Control maize seeds were stored in unsealed containers away from fire and smoke. Taro propagules of different sizes (80−100 g corm − 1 , 40−60 g corm − 1 and 20−30 g corm − 1 ) were compared for storability in dry pits, in layers separated by grass straw, for one month. Subsequently, sprouted corms were stored in dry conditions to allow shoot development. During maize seed storage, water content was determined monthly. Maize seed quality was determined by viability, germination and seedling vigour. Sprouting and rooting during taro pit storage, and main shoot development during air storage were used to determine taro propagule performance in storage. Seeds that were stored over fire and smoke showed higher germination and vigour that non-smoked seed. Sprouting and shooting of taro propagules were better in large propagules and the optimum storage depth was 35 cm to 40 cm. α-amylase activity increased during pit storage and declined to almost the pre-storage levels during shoot growth period outside the pits, in all corm sizes. It is concluded that smoke and heat storage improve maize seed quality and pit storage enhances taro propagules by inducing sprouting. Data from this study can be used to investigate the physiological and biochemical basis of seed and propagule quality enhancement, and possibly contribute to technological inventions that are based on indigenous knowledge systems.

Foraging in the subterranean social Damaraland mole-rat,Cryptomys damarensis: an investigation into size-dependent geophyte utilization and foraging patterns

The foraging behaviour of captive colonies of the Damaraland mole-rat, Cryptomys damarensis, was investigated in an artificial soil-filled burrow system provided with three tray patches that varied in bulb and corm (i.e., geophyte) density and size. Members of two founder colonies (comprising three and four mole-rats) were exposed to resource patches that varied in food profitability (both size and density of geophytes). There was no preference for excavating any of the patches with different densities or sizes of geophytes. The larger geophytes were preferentially stored and the smaller ones preferentially eaten both on encounter and within the food store. The duration of handling and rate of consumption of geophytes by 15 animals of various body sizes from three colonies were recorded. Handling time was related to the size of the geophytes. Small geophytes were less profitable to consume. It was concluded that the mole-rats generally followed the qualitative predictions of optimal foraging theory but fell short of being energy maximizers.

ORNAMENTAL USE OF WILD SPECIES OF GENUS GLADIOLUS

ORNAMENTAL USE OF WILD SPECIES OF GENUS GLADIOLUS

Effect of Corm Size and Depth of Planting on the Growth and Flowering of Gladiolus

Effect of Corm Size and Depth of Planting on the Growth and Flowering of Gladiolus

Plant Growth Regulators Affect the Development of Both Corms and Cormels in Gladiolus

The effects of BA, ethephon, and GA3 on freshly harvested cormels of three cultivars of Gladiolus sp. were studied for 3 years. The treatment with 400 mg·L-1 ethephon significantly reduced the dormancy period by 17.5 days as compared to control, while BA and GA3 were found to be less effective. Among all treatments, ethepon at 400 mg·L-1 was found to be the most effective in altering the days to sprout, sprouting percentage, corm size and production and development of cormels. While GA3 at 100 mg·L-1 increased growth of corms and cormels, BA at 25 mg·L-1 increased growth of corms and cormels. BA at 25 mg·L-1 only influenced the sprouting percentage of cormels. Along with reducing the dormancy period, the plant growth regulators stimulated growth and development of corms and cormels. Chemical names used: benzyladenine (BA); 2-chloroethylphosphonic acid (ethephon); gibberellic acid (GA3).

GROWTH DYNAMICS AND DECORATIVE VALUE OF 'EASY POT' POTTED FREESIA DEPENDING ON THE GROWING CONDITIONS

GROWTH DYNAMICS AND DECORATIVE VALUE OF 'EASY POT' POTTED FREESIA DEPENDING ON THE GROWING CONDITIONS

Andromonecy in Colchicum stevenii C. Koch (Liliaceae)-- Frequency, phenology, and reserve allocation

Colchicum stevenii, an autumnal geophyte in Israel, was found to be andromonecious. Examination of the phenomenon in relation to the corm size, flowering rank, flower size, and habitat indicated that hermaphrodite flowers are larger and have a greater dry weight than male flowers. Within each individual, hemaphrodite flowers always appear at the beginning of the flowering sequence, whereas male flowers appear at the end. Smaller corms produce fewer and smaller flowers, but with a high percentage of male flowers. Populations in dry habitats have smaller corms and relatively more male flowers, and fewer and smaller flowers per individual plant, in comparison with populations of more humid habitats. The adaptive value of sequential andromonecy is discussed. The results are in accord with the hypothesis that under stressful conditions the individual plant allocates more reserve to male flowers.

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.

FUSARIUM RESISTANCE IN GLADIOLUS: EFFECTS OF PLANT MATERIAL AND TESTING CONDITIONS ON THE INFECTION OF CULTIVARS

Fusarium oxysporum f.sp. gladioli is the most important pathogen of Gladiolus. Cultivation of both corms and flowers is hampered by this fungus. Resistant cultivars are therefore much desired and partial resistance was found within the commercial gladiolus assortment. To assess the Fusarium resistance of cultivars for breeding purposes a standard assay is in use at CPRO-DLO. Genotypes are planted in infested soil. The resistance level is determined six to eight weeks after planting, by calculating the relative length (RL) of the shoots, i.e., length of shoots in infested soil divided by length of shoots in control soil. No information about effects of corm origin, corm size, corm cleaning, temperature or inoculum concentration is known. For Values for Cultivation and Use purposes (VCU) more information is needed about these conditions. Therefore this was investigated in the present study. The disease incidence of a number of cultivars with differing Fusarium resistance was assessed with various corm treatments. In all our experiments, a significant cultivar effect was found. No cultivar by treatment interactions were detected. A significant corm origin effect was also found. For VCU purposes, corms from different growers (mostly breeders), must be cultivated during one year under equal conditions. The corm size had no significant effect on the level of Fusarium infection. Significant corm cleaning effects were found. Dehusking and disinfection of the corm gave a significantly higher infection level. For further tests corm cleaning is not advised, since by damaging the corm secondary infections may occur. Significant temperature and inoculum concentration effects were found. A higher temperature and a higher inoculum concentration gave a higher disease incidence. Both parameters can be manipulated to influence the time course of an assay.

CARACTERIZAÇÃO E AVALIAÇÃO DE ARÁCEAS COMESTÍVEIS NO ESTADO DO AMAZONAS

Avaliaram-se os atributos morfológico, agronômicos e nutricionais em quatorze introduções de Aráceas comestíveis em Manaus-AM, nos anos de 1983 e 1984. Em geral os acessos de inhames (Colocasia sp.) apresentaram porte baixo, com folhas de tamanho médio ou pequeno, com rizomas secundários com maior valor para proteína, destacando-se 02/79 como o mais produtivo. Nas taiobas (Xanthosoma sp.) o porte variou muito entre os acessos e a produção total de rizomas o maior rendimento se deve ao rizoma principal onde se concentra também o maior valor nutricional.

Ontogenetic and demographic studies of Sparaxis grandiflora subspecies fimbriata (Iridaceae)

The seasonal ontogeny and phenology of Sparaxis grandiflora spp. fimbriata were examined along with various population parameters for this synanthous geophyte which possesses an annual storage organ. It was found that the majority of plants in the sample were less than seven years old with a maximum age determined at eighteen years. Age was successfully determined by examining subterranean markers (tunics) and it was found that the plants do not generally flower before they are four years old and have a ‘critical minimum corm biomass’ of 0.37 g dry matter. Corm size is related to depth of burial until reproductive maturity is reached, with over 80% of the corms found in the organic profile which extends to 3 cm below the soil surface. The seasonal allocation of dry matter to the various plant parts indicated the efficient mechanisms adopted by this species to cope with the mediterranean climatic conditions and the low soil nutrient levels.

Flowering and Corm Yield of Brodiaea in Response to Temperature, Photoperiod, Corm Size, and Planting Depth

Flowering of brodiaea (Triteleia laxa syn. Brodiaea laxa `Queen Fabiola') did not have an obligate requirement for manipulation of temperature or photoperiod. Vernalization of corms reduced the greenhouse forcing phase but did not alter the number of flowers per inflorescence or scape length. Long photoperiods hastened flowering but decreased flower quality and flowering percentage. Scape length, which was not affected by photoperiod or mother corm size, was increased when plants were grown at night temperatures < 10C. Diameter of the apical meristem in the dormant corm, flowering percentage, and flower quality were not affected by a 10-fold increase in corm size above a critical weight (0.6 g). In contrast, the weight and number of daughter corms were closely correlated with mother corm size. The optimum planting depth for brodiaea corms was 10 cm below the soil surface.

Costs of Flower and Fruit Production in Tipularia Discolor (Orchidaceae)

The cost of reproduction may be an important constraint on the evolution of life history traits, yet it has seldom been adequately measured in plants. To demonstrate a net cost of reproductive structures one must show that their production has a negative effect on future growth. Using a summer—deciduous orchid, we compared subsequent growth of plants with no inflorescence, no fruits, few fruits (<10), or many fruits (>10). Greater investment in reproduction led to increasingly negative effects on future corm size and leaf area. The cost of an inflorescence without fruits was about one—half the cost of an inflorescence with few fruits. Each fruit cost the plant °2% of its total leaf area the next year. Natural pollination resulted in a mean of seven fruits per plant. Hand—pollination led to a dramatic increase in fruit set (up to 25 fruits per plant), and a large decrease in subsequent growth. Plants with many fruits were less likely to propagate vegetatively than those with few fruits. Also, plants with many fruits were less likely to flower the following year, probably because they were smaller than those with few fruits. The potential benefits of greater pollinator visitation are unclear because larger "clutch size" may not result in greater lifetime fecundity.