<i>In Vitro</i>Conservation Tactics for a Sweet Genotype of <i>Amygdalus scoparia</i>, an Endangered Medicinally Important Tree Species by Propagation Using Synthetic Seeds

Bud stems arisen from in vitro cultures of A. scoparia were encapsulated in calcium alginate pieces for short term stockpile and germplasm interchange. The maximum frequency (88.96%) of conversion of encapsulated nodal segments into plantlets and the highest node number (7.20) was performed on a murashige and Skoog’s medium (MS medium) containing 2.2 μM banzyl adenine (BA). The highest length of re-growing shoots was achieved when MS medium was supplied with 2.2 μM BA and 0.5 μM NAA. However, the number of shoots produced was higher (5.30 and 5.10) on MS medium supplemented with 2.2 μM BA and 0.5 μM NAA and MS medium with 2.2 μM BA, respectively than on the hormone-free media. Treatment with 19.6 μM IBA resulted in the highest conversion of encapsulated nodal segments into plantlets. The frequency of conversion (89.6% - 88.6%) was retained at 25?C for up to 2 weeks without significant change. The highest frequencies (61.1%) of plantlet formation from encapsulated nodal segments were obtained by transferring synthetic seeds onto peat mass and perlite (2:1) (v/v) mixture substrate. When transplanted into the peat mass and perlite (2:1) (v/v) mixture, these plantlets showed greater plantlet high, leaf number, shoot number and root number per plantlet than those of the other substrates. The synthetic seed technology offered a promising way for short term storage without refrigerating, germplasm conservation exchange for improvement and an alternative clonal propagation method for this endangered genotype of A. scoparia.

Banana Fusarium Wilt(Fusarium oxysporum f. sp. cubense)Control and Resistance, in the Context of Developing Wilt-resistant Bananas Within Sustainable Production Systems

Banana(Musa spp.) is seriously threatened by the soil-borne fungus Fusarium oxysporum f. sp. cubense(Foc), also known as Panama disease.Attempts to control Fusarium wilt with fungicides damage soil health and have limited efficiency due to pathogenic variability. Elucidating the mechanism of infection and molecular basis of host defense through banana genome sequencing, genome editing and proteomic profile analysis will help formulate strategies to develop resistant cultivars. This will include research to better understand the functions of Fusarium wilt-resistance proteins. Transgenic approaches and protoplast fusion could be employed as tools for transferring resistance genes from wild relatives to commercial banana varieties, and may serve as a new strategy in solving the problems faced by banana breeding programmes.Evaluation of banana germplasm for resistance to Fusarium wilt using in vitro mutation and selection, along with somaclonal variation and somatic hybridization, could improve banana breeding efficiency for resistance against Foc. Plant hormones could also play an important role in regulating plant growth and defense by mediating developmental processes and signaling networks involved in banana responses to Foc. A complementary approach for managing Fusarium wilt, such as exclusion, surveillance and biological control as important components of integrated disease management programs must be considered to prevent and contain contagion. This includes studies on banana plant-microbe interactions, embracing both plant growth promoting rhizobacteria(PGPR) to induce Foc resistance, and exploring Foc-derived elicitors for inducing defense-related enzymes in bananas. The role of Silicon and crop and livestock integration must also be included in the Fusarium control toolbox. The current review also gathers knowledge of the biotechnological approaches along with biological control of Fusarium wilt of banana that will provide researchers insights and criteria to develop future studies.