Nomenclatural standards of raspberry cultivars bred in the Altai

This article is devoted to designing nomeclatural standars and herbarium vouchers of raspberry cultivars bred in the M.A. Lisavenko Research Institute of Horticulture for Siberia. The article presents nomeclatural standards of cultivars ‘Barnaul’skaya’, ‘Blesk’, ‘Dobraya’, ‘Zoren’ka Altaya’, ‘Illyuziya’, ‘Kredo’ and ‘Rubinovaya’. The work has been performed according to the rules and recommendations outlined in the International Code of Nomenclature for Cultivated Plants and guidelines developed for the vegetatively propagated plants. The material for nomenclatural standards should be collected with assistance of either the cultivar author, a representative of the institution owning the cultivar, or an expert in these cultivars. Therefore, material of the cultivars in question was picked with assistance of N.D. Yagovtseva, a representative of the Lisavenko Institute and author of two cultivars ‘Blesk’ and ‘Dobraya’. Nomenclatural standards contain two herbarium sheets with parts of one plant collected at the same time: the first sheet holds the middle third of a primocane and a leaf from this part, while the second one displays the middle third of a floricane and a lateral branch with fruits. Also, the specimens were supplied with photos of fruits taken before herbarization. The nomenclature standards have been deposited with the Herbarium of cultivated plants, their wild relatives, and weeds (WIR).

Application of Vacuum Infiltration in Cryopreservation of Isolated Grape Buds

Preserving the gene pool of grapes, referred to the vegetatively propagated plants is a complicated task, which can be also solved by cryopreservation of the buds. To saturate such bulk and heterogeneous samples with cryoprotectants the novel methods are required. The effectiveness of vacuum infiltration and 60 min standard passive saturation (soaking) of isolated grape buds of the Russian Concord variety with a cryoprotective solution PVS 2 were compared in this research. To saturate by vacuum infiltration the buds were incubated in cryoprotective solution for 15 min at 40 kPa, afterwards, the pressure was gradually increased to atmospheric level. The efficiency of bud saturation was evaluated with low-temperature differential scanning calorimetry by changing the enthalpies and temperatures of phase transitions as well as the intensity of heat capacity jump at glass transition. The use of vacuum in the saturation of isolated grape buds were found to lead to a strong rise in cryoprotectant concentration in them and a significant decrease in the amount of free water crystallized during cooling compared to passive soaking in a PVS 2 vitrification solution.

Adaptation of plants derived from cultivated yam of Dioscorea cayenensis–D. rotundata complex species seeds germination in two agroecological zones of Benin

Vegetative propagation of plants promotes the accumulation of viruses in plant material; this causes the loss of vigor and consequently the drop of vegetable yield. Keep up productivity level of vegetatively propagated plants; it is therefore important to regenerate genetic material by sexual reproduction to improve the biodiversity. The main objective of this study is to improve yam seeds by sexual way, specifically to assess the response of seedlings from yam seeds in two agroecological areas, area IV (Djougou), in Sudanese climate and area V (Bantè), in transition climate. Seedling were transplanted in this agroecological areas using a completely Randomized design with three replications. Data was analyzed using one way ANOVA at 5% level of significance and a mean comparison test. Seedling survival rate is significantly different, 55.41% in zone IV and 23.60% in zone V, but the rate of tuberization of the two areas is similar, 55.63%; of zone IV and 57.62%; of zone V. The average of the tubers length and their weight are respectively 13.21 cm and 24.87 ± 19.22 g in zone IV and 8.95 cm and 10.30 ± 9.91 g in zone V. This results show that microtubers produced from the seeds show a high degree of heterogeneity, and, varieties creation and improvement is possible from the seeds. This technique would promote the selection of varieties adapted to current climatic conditions.

Conservation in the wake of myrtle rust – a case study on two critically endangered Australian rainforest plants

We investigated ex situ conservation options for two Australian rainforest species severely affected by myrtle rust in the wild – Rhodamnia rubescens (Benth.) Miq. and Rhodomyrtus psidioides (G.Don) Benth. Both species were successfully initiated into tissue culture though the rate of contamination was high and not significantly improved by the disinfection techniques tested. Explants surviving initiation grew well on Murashige and Skoog medium (MS; pH 6.0) with 30gL−1 sucrose, 1 µm benzyl adenine and 0.2 µm indole-3-butyric acid. Culture of R. rubescens for eight weeks on MS with 0, 5, 10 or 20 µm indole-3-butyric acid resulted in root production for some plantlets, and successful transfer to potting mix; no significant differences in root production among treatments were detected. Both species were successfully propagated by semi-hardwood cuttings with strike rates of 0–67% for R. rubescens and 0–75% for R. psidioides. For R. rubescens, pretreatment of cuttings with Zaleton® and incubation in Preforma® plugs reduced the time to root development and significantly improved the strike rate (P=0.001). R. rubescens seed proved to be orthodox and suitable for standard seedbanking; R. psidioides seed proved to be freezing sensitive but suitable for storage at 4°C. As the two species now produce few viable seeds in the wild, however, conservation by seedbanking will first require the establishment of a seed orchard from vegetatively propagated plants. We recommend swift action to conserve species in the Pacific similarly affected by myrtle rust before their growth and reproductive capacity are seriously diminished.

Cryobiotechnology: A Double-Edged Sword for Obligate Plant Pathogens

Pathogen-free stock plants are required as propagation materials in nurseries and healthy materials are needed in germplasm exchange between countries or regions through quarantine programs. In addition, plant gene banks also prefer to maintain pathogen-free germplasm collections. Shoot tip cryotherapy is a novel biotechnology method whereby cryopreservation methods are used to eradicate obligate pathogens from vegetatively propagated plants. Long-term preservation of pathogens is necessary in all types of virus-related basic research and applications such as antigen preparation for virus detection by immunology-based methods, production of plant-based vaccines, genetic transformation to produce virus-derived resistant transgenic plants, and bionanotechnology to produce nano drugs. Obligate plant pathogens such as viruses and viroids are intracellular parasites that colonize only living cells of the hosts. Therefore, their long-term preservation is difficult. Cryotreatments cannot completely eradicate the obligate pathogens that do not infect meristematic cells and certain proportions of plants recovered from cryotreatments are still pathogen-infected. Furthermore, cryotreatments often fail to eradicate the obligate pathogens that infect meristematic cells. Cryopreservation can be used for the long-term cryopreservation of the obligate plant pathogens. Thus, cryobiotechnology functions as a double-edged sword for plant pathogen eradication and cryopreservation. This review provides updated a synthesis of advances in cryopreservation techniques for eradication and cryopreservation of obligate plant pathogens.

Transgene-Free Genome Editing in Tomato and Potato Plants Using Agrobacterium-Mediated Delivery of a CRISPR/Cas9 Cytidine Base Editor

Genome editing tools have rapidly been adopted by plant scientists for gene function discovery and crop improvement. The current technical challenge is to efficiently induce precise and predictable targeted point mutations valuable for crop breeding purposes. Cytidine base editors (CBEs) are CRISPR/Cas9 derived tools recently developed to direct a C-to-T base conversion. Stable genomic integration of CRISPR/Cas9 components through Agrobacterium-mediated transformation is the most widely used approach in dicotyledonous plants. However, elimination of foreign DNA may be difficult to achieve, especially in vegetatively propagated plants. In this study, we targeted the acetolactate synthase (ALS) gene in tomato and potato by a CBE using Agrobacterium-mediated transformation. We successfully and efficiently edited the targeted cytidine bases, leading to chlorsulfuron-resistant plants with precise base edition efficiency up to 71% in tomato. More importantly, we produced 12.9% and 10% edited but transgene-free plants in the first generation in tomato and potato, respectively. Such an approach is expected to decrease deleterious effects due to the random integration of transgene(s) into the host genome. Our successful approach opens up new perspectives for genome engineering by the co-edition of the ALS with other gene(s), leading to transgene-free plants harboring new traits of interest.

Growth Measurements of Invasive Plant Mikania micrantha Kunth (Mile a Minute Weed), A Threat of Biodiversity

This study attempts to measure the growth of invasive plant species Mikania micrantha Kunth, which is considered as one among the top hundred worst invasive weeds worldwide. Seedlings of Mikania micrantha were propagated through vegetative part as well as seed for the study. The juvenile plants were allowed to grow on different hosts such as poles (nonliving support) and a garden plant (living support) in a soil that contains minimum requirements for growth. Growth of the seedlings was recorded daily by measuring the length of the stem, a number of twines and number of leaves for a growth period of fourteen days. The plants thrived on both types of support. The growth rate was higher in vegetatively propagated plants. It ensures re-growth even from a single node and is responsible for successful invasion of the weed after mechanical weeding.

Molecular phylogeny and evolution of tropical vegetal genus Coccinia (Cucurbitaceae) using chloroplast barcode markers and its implications for speciation patterns

Evaluation of molecular phylogeny employing barcode markers for a population analysis has revealed the association between character evolution and diversification. The present research study endeavors to estimate the molecular phylogeny and evolution amongst 30 geographically distant land races of Coccinia grandis using chloroplast barcode markers. On the basis of sequences of ­C. grandis landraces and sister genera’s of Cucurbits; phylogeny and evolutionary distances were estimated using bootstrap method of UPGMA and ML with MEGA and DAMBE software. The rbcL appear to be evolving marginally amongst land races studied, while matK loci exhibited several parsimonically insignificant variations. The ycf5 locus resolved efficiently the phylogeny at both intraspecies and intergeneric levels. The values of Tajima’s relative rate test, Nei’s genetic distance and gamma distribution, within C. grandis accessions and among Cucurbits denoted plausibility of occurrences of random population expansion, slow ontogenic transitions and high consanguinity percentage among core barcode regions.The present study thus lays a platform for researchers working with vegetatively propagated plants to plan strategies for exchange of varieties, their maintenance, utilization and enhancement for further crop development and propagation.