A major obstacle to native orchid production is difficulty in seed germination. Culture media and light effects on seed germination of Calopogon tuberosus var. tuberosus, a native orchid with horticultural potential, were studied. Culture media included Knudson C, Malmgren modified terrestrial orchid, and PhytoTechnology orchid seed sowing. Effects of 8 weeks continual darkness, 8 weeks 16-h photoperiod, 2 weeks dark followed by 6 weeks 16-h photoperiod, 4 weeks dark followed by 4 weeks 16-h photoperiod, and 6 weeks dark followed by 2 weeks 16-h photoperiod were examined. Percent seed germination was highest on Knudson C after 8 weeks culture; however, seedling development was enhanced on PhytoTechnology seed sowing medium during 8 weeks culture under a 16-h photoperiod. This suggests that while KC and darkness promoted seed germination, P723 and light enhanced further seedling development. Seedlings of C. tuberosus readily acclimated to greenhouse conditions. Abbreviations: KC -Knudson C; MM -Malmgren modified terrestrial orchid medium; NAD -nicotinamide adenine dinucleotide; NADP -nicotinamide adenine dinucleotide phosphate; P723 -Phyto Technology orchid seed sowing medium

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2016-12-24T18:05:51

Rapid germination and corm formation may be a survival mechanism in response to a compressed growing season in northern populations. Ecotypic differentiation may be occurring based on seed germination and corm formation data.

Jatropha curcas L. (jatropha) is a species identified for biofuel production because of the high quality of the oil produced by its seeds. However, jatropha is undomesticated and little information is available about its reproductive characteristics. Breeding and genetic improvement programs are much needed for the jatropha development as a bioenergy crop. Information about floral display and mode of reproduction are considered essential for breeding programs. In this study, the total number of female flowers, male to female flower ratio, fruit set, in vitro pollen germination, and the formation of fruits by apomixis, self-pollination, and natural pollination were evaluated in 17 jatropha accessions planted in South Florida. The total number of female flowers per inflorescence and male to female flower ration ranged from 2.8 to 9.1 and 9.9:1 to 55.4 : 1, respectively. During summer 2011, high fruit setting average was observed (75.5%). In vitro pollen germination varied from 64.6% during spring 2011 to 51.6% during fall 2011. The fruit set observed was from 10.1% to 64.0% through natural pollination and apomixes, respectively. Characteristics such as fruit fresh weight, number of seeds per fruit, seed dry weight, and oil content were influenced by mode of reproduction.

Yellow passion fruit (Passiflora edulis Sims) yield and longevity have been drastically reduced by bacterial spot (Xanthomonas axonopodis pv. passiflorae -Xap) and passion fruit woodiness disease (PWD) (Cowpea aphid-borne mosaic virus -CABMV). This study was aimed at evaluating the reaction of 11 genotypes of yellow passion fruit, based on the reaction of their progenies, to both mechanically inoculated Xap and CABMV, under greenhouse conditions. There was a progressive increase in bacterial spot and PWD severity with time. BRS Gigante Amarelo, MAR20#12, and MAR20#34 were selected as the progenies with lowest bacterial spot severity and disease progress over time. MAR20#2005, EC-L-7, UnB2015-1, and EC-3-0 presented the lowest PWD severity and disease progress over time. These progenies, along with individual plants from other progenies in which disease severity was significantly low until the last evaluation, will be cloned and tested again for Xap and CABMV, including other isolates.

Orchids are lush and highly valuable plants due to their diversity and the beauty of their flowers, which increases their commercialization. The family Orchidaceae comprises approximately 35,000 species, distributed among more than 1,000 distinct genera and 100,000 hybrids, totaling approximately 8% to 10% of all flowering plants. With the advance of agriculture and the constant destruction of their natural habitat, orchid species are collected in an indiscriminate manner by collectors and vendors, and this extractive activity threatens many species with extinction, drastically reducing their genetic variability in nature. Therefore, it is essential to seek alternatives that make the preservation of such species feasible using techniques with low maintenance costs that provide greater storage time and that enable good phytosanitary conditions for the plant material for commercial use. Cryopreservation involves the conservation of biological materials at ultra-low temperatures, generally in liquid nitrogen at -196 ºC or in its vapor phase at -150 ºC. This is the only technique currently available for the long-term preservation of the germplasm of plant species that are vegetatively propagated or that have unviable, recalcitrant or intermediate seeds. The objective of this bibliographic review is to report on the importance, methods and application of cryopreservation for orchids. According to the studies reviewed, this is an incipient, developing and relevant field that generates a lot of discussion and requires further research relative to the type of treatment to use for cryopreservation and the methodology to be applied according to the species. The types of methods that are used for cryopreservation and the large variation in the responses of orchids to the cryopreservation methods observed in this study emphasize the need for the development of more appropriate protocols for the preservation of orchids.Index terms: Preservation, Orchidaceae, ex situ conservation, freezing tolerance, extinction. RESUMOAs orquídeas são plantas exuberantes e apresentam alto valor agregado devido à diversidade e à beleza de suas flores, o que incrementa a sua comercialização. A família Orchidaceae compreende cerca de 35.000 espécies, distribuídas em mais de 1000 gêneros distintos e 100.000 híbridos, totalizando cerca de 8% a 10% de todas as plantas com flores. Com o avanço da agricultura e a constante degradação do seu habitat natural, as espécies de orquídeas são coletadas de maneira indiscriminada por colecionadores e comerciantes. Este extrativismo ameaça muitas espécies de extinção reduzindo drasticamente a sua variabilidade genética na natureza. Portanto, torna-se fundamental a busca de alternativas que viabilizem a preservação destas espécies, com a utilização de técnicas que apresentem baixo custo de manutenção, que proporcionem maior tempo de armazenamento, e que possibilite ao material vegetal boas condições fitossanitárias para utilização comercial. A criopreservação compreende a conservação de material biológi...