Recent Advances of Biotechnological Tools on Diverse Species of Citrus: Current Applications and Future Prospects

Based on the long term conservation of several endangered and indigenous species of Citrus, significant impact of biotechnological tools particularly in terms of in-vitro micropropagation methods in addition to synthetic seed production using encapsulation of plant propagules including shoot tips, nodal segments, androgenic embryos, embryogenic callus, etc. in sodium alginate has been highlighted in this manuscript. When seed is not available in enough quantity for raising seedlings for rootstock or have low levels of polyembryony and do not produce adequate quantities of nucellar seedlings, then micropropagation techniques could quickly supply in vitro regenerated rootstock or budwood. Rapid, mass-production and cost-effective biotechnological tools for propagation of citrus rootstocks and budwood would be of great importance in this regard. Reports on another aspect of long term conservation particularly based on storage of cells, tissues and organs of drought tolerant species of Citrus at ultra-low temperature preferably at -196 ºC via applications of cryopreservation techniques using vitrification and encapsulation or dehydration methods has been highlighted in this manuscript. In addition, several research on techniques of in-vitro micrografting using superior scion and rootstocks of two different species of Citrus with an objective of eradication of virus infected citrus stocks for successful production of grafts have been reviewed. Furthermore, effects of explants either through direct and indirect regeneration and conversion into a complete disease free plantlet using suitable synthetic nutrient media along with plant growth regulators at various concentrations and combinations have been highlighted in this manuscript. Hence, the current review is primarily focused on the applications and its effects of superior biotechnological tools for long term conservation of diverse species of citrus for further increasing the potentiality of Citrus industries in addition to genetic improvement and genetic resource conservation.

Synthetic seeds and their role in agriculture: status and progress in sub-Saharan Africa

Dicot seeds are commonly characterised by the rapid loss of moisture, vigour and longevity that cause adverse physiological and biochemical effects. Such changes reduce seed viability, germinability and seedling vigour in most agronomic legume crops. Thus, this paper evaluates the potential role of synthetic seed production as an avenue to achieve genetic variability, avert recalcitrance and fleet seed viability challenges experienced in recalcitrant legume species. Synthetic seeds, also known as synseeds or artificial seeds produced via somatic embryogenesis are crucial for the successful establishment of plants, and serve as an important determinant of plant productivity, especially for crops such as soybean. The potential use of synseeds could serve a fundamental role in ensuring cheap and rapid supply of new genetic resources and seed propagules for both breeders and farmers. This approach will ultimately maximise crop yield and offer a tremendous potential for micropropagation and germplasm preservation of recalcitrant species in sub-Saharan Africa. This review reports on a variety of applications and benefits of plant biotechnology in the African context and highlights important advantages such as genetic uniformity, simplified handling, storage, efficient distribution etc. that could be of immeasurable benefit to the seed value chain in agriculture, particularly for rural communities in these developing countries.

Synthetic seed technology for encapsulation and regrowth of in vitro-derived shoot-tips and somatic embryos of Asparagus officinalis L

Apical buds obtained from Asparagus plant vitro culture and somatic embryos obtained from stem cultivation, explants in MS medium supplemented with mg¹ᶫ 1, 2, 4-D and mg¹ᶫ 1 and Kinetin have been used in this research to produce artificial seeds. We encapsulated apical buds and somatic embryo using 2% sodium alginate and calcium chloride to prepare the artificial seeds. We placed artificial seeds at room temperature (about 25 ° C), in the cold, the temperature of 4 ° C and -18 ° C for different times (15,30,60,90 days) and evaluated the growing power of these seeds in MS and ½MS mediums for further investigations about the viability of seeds. The highest conversion percentage of seedlings in encapsulated embryos (70.01) was related to seed harvested from embryos treated with BA and the highest conversion percentage of seedlings in apical buds (96.54) was obtained from cultivated untreated seeds in MS medium. Encapsulated arteries and buds maintained germination energy and viability with increasing storage time after 90 days of storage at 4 and 25 ° C despite viability reduction while un-capsulated embryos and buds completely lost viability after 60 days of storage at 4 and 25 ° C and seeds stored at -18 ° C completely lost viability after 15 days of storage. In general, the percentage of seed germination and conversion to seedling is higher in seeds cultivated in MS medium compared to seeds cultivated in ½MS medium.