Propagation of the medicinal and pesticidal tree, Bobgunnia madagascarensis is difficult due to poor and erratic germination of its seeds and slow growth of its seedlings. This study involved two separate experiments. The first evaluated the effect of pre-sowing treatments and growing medium on ex vitro seed germination and early seedling development. The second experiment involved in vitro germination, shoot initiation and rooting of shoots. Pre-sowing seed treatments involved soaking seeds in cold and hot water for 12 and 24 h and soaking in different concentrations (0, 100, 200, 400 and 800 mg/l) of gibberellic acid for 24 h. Soaking of seeds in cold or hot water for up to 24 h did not achieve more than 45% germination, while seeds treated with gibberellic acid achieved 76%) when seeds were sown in a growing medium without compost compared with a medium with compost (<43%). All shoot-tips isolated from the in vitro germinated seedlings on B5 media without plant growth regulators continued to grow as a single shoot, while shoot-tips cultured on B5 supplemented with 0.1 mg/l of naphthaleneacetic acid (NAA) and thidiazuron (TDZ) produced two shoots each after four weeks. It was concluded that B. madagascariensis seeds had very low ex vitro germination percentages. Although, in vitro cultures improved seed germination, axillary shoot multiplication and rooting were not satisfactory. Therefore, further studies are needed to develop an optimal in vitro multiplication protocol for B. madagascariensis.
Tag: seeds
Propagation of the African medicinal and pesticidal plant, Securidaca longepedunculata
Propagation methods do not exist for Securidaca longepedunculata. In this study, ex vitro and in vitro experiments were conducted to identify simple propagation methods for this species. Ex vitro germination rates did not exceed 43%, whereas in vitro procedures achieved 67 to 90% germination rates. In vitro germinated seedlings produced at least two re-sprouts and consistently showed vigorous growth. Explants cultured on B5 medium supplemented with indole-3-butyric acid (IBA) and 1- naphthalene-3-acetic acid (NAA) successfully produced roots within 4 weeks. It is concluded that germination of seeds, shoot multiplication and rooting of S. longepedunculata can be improved through appropriate in vitro procedures.
Tritrophic defenses as a central pivot of low-emission, pest-suppressive farming systems
The ongoing COVID-19 pandemic has spotlighted the intricate connections between human and planetary health. Given that pesticide-centered crop protection degrades ecological resilience and (in-)directly harms human health, the adoption of ecologically sound, biodiversity-driven alternatives is imperative. In this Synthesis paper, we illuminate how ecological forces can be manipulated to bolster ‘tritrophic defenses’ against crop pests, pathogens, and weeds. Three distinct, yet mutually compatible approaches (habitat-mediated, breeding-dependent, and epigenetic tactics) can be deployed at different organizational levels, that is, from an individual seed to entire farming landscapes. Biodiversity can be harnessed for crop protection through ecological infrastructures, diversification tactics, and reconstituted soil health. Crop diversification is ideally guided by interorganismal interplay and plant–soil feedbacks, entailing resistant cultivars, rotation schemes, or multicrop arrangements. Rewarding opportunities also exist to prime plants for enhanced immunity or indirect defenses. As tritrophic defenses spawn multiple societal cobenefits, they could become core features of healthy, climate-resilient, and low-carbon food systems.
Domestication Potential of Garcinia kola Heckel (Clusiaceae): Searching for Diversity in South Cameroon
Seeds and bark of Garcinia kola Heckel (Clusiaceae) are popular products in West and Central Africa. Despite the tree’s economic and cultural importance, little is known about its phenotypic and genotypic variation. This study characterised the morphological and genetic diversity of G. kola in South Cameroon, searching for traits and populations that might be used for domestication. Morphological assessment and amplified fragment length polymorphism (AFLP) markers were applied to characterise diversity among geographic populations from Central and South regions, and between managed and wild trees. AFLP-SURV and analysis of molecular variance results indicated that a major part of genetic diversity is harboured within populations rather than between them. Bayesian analysis, principal component analysis and t-SNE identified three clusters where Ebolowa emerged as the transition population combining features from both regions. Trees from the South demonstrated a higher incidence of domestication-related traits, showing higher genetic diversity compared to the Central region. This suggests that individuals from the South might be more suitable for selection as “elite trees” in future breeding strategies for the species. No significant differences in phenotype and genotype were revealed between wild and managed populations, suggesting G. kola is still in the early stages of its domestication process.
Consultancy Report on ‘Training in and support to adjustment, use and maintenance of equipment for seed processing and seed testing at the RTSCs and FRC, incl. assessment of seed testing standards and data management of seed testing and seed stock’
The consultant conducted a training course together with the PATSPO Tree Improvement Officer, Girma Eshete and Duncan Sanders covering the subject ‘Training in and support adjustment, use and maintaining of equipment for seed processing and seed testing at the RTSC and FRC, incl. assessment of seed testing standards and data management of seed testing and seed stock’ at one RTSC and at FRC. Furthermore, a short trip to RTSC Mekele in Tigray was organized to estimate the current situation at the seed center, after the region has been closed for 2 years due to conflicts in the Tigray region.
Genome-Wide Association Mapping of Oil Content and Seed-Related Traits in Shea Tree (Vitellaria paradoxa subsp. nilotica) Populations
Shea tree (Vitellaria paradoxa) is an important fruit tree crop because of its oil used for cooking and the industrial manufacture of cosmetics. Despite its essential benefits, quantitative trait loci linked to the economic traits have not yet been studied. In this study, we performed association mapping on a panel of 374 shea tree accessions using 7530 Single-Nucleotide Polymorphisms (SNPs) markers for oil yield and seed-related traits. Twenty-three SNP markers significantly (−log10 (p) = 4.87) associated with kernel oil content, kernel length, width, and weight were identified. The kernel oil content and kernel width had the most significant marker–trait associations (MTAs) on chromosomes 1 and 8, respectively. Sixteen candidate genes identified were linked to early induction of flower buds and somatic embryos, seed growth and development, substrate binding, transport, lipid biosynthesis, metabolic processes during seed germination, and disease resistance and abiotic stress adaptation. The presence of these genes suggests their role in promoting bioactive functions that condition high oil synthesis in shea seeds. This study provides insights into the important marker-linked seed traits and the genes controlling them, useful for molecular breeding for improving oil yield in the species.
Rainfall shocks and inequality have heterogeneous effects on farmers’ seed purchase decisions in East Africa
Weather shocks and poverty worsen seed and food insecurity in smallholder farming. Here we use rich and representative household-level data for Ethiopia, Malawi, and Tanzania, combined with historical monthly weather data to examine the effects of prior drought exposure and wealth (asset endowment) inequality on seed purchase decisions. We find that between a third and half of the farmers purchase seed, and among seed purchasers, more than half of the total seed volume used is purchased. We model seed purchasing decisions using Cragg double-hurdle models, which allow variables to have different effects on the probability and the intensity of purchase decisions. We find that drought shocks experienced in the past season encourage sourcing seed off-farm through purchase in the following season. On average, drought shock exposure increases seed purchasing for both improved and local seeds in Malawi and Tanzania while encouraging (discouraging) local (improved) seed purchases in Ethiopia. In all three countries, farmers better endowed with household assets increase seed purchasing, particularly for improved seeds, after a drought shock exposure. In addition, smaller farm sizes and low asset wealth endowments in all study countries are significant deterrents for buying seeds in the market, particularly improved seeds. Policies need to support both formal and informal seed systems and address inequalities in access to seed from formal seed channels to achieve seed and food security under elevated climate risk.
Seeds as Potential Sources of Phenolic Compounds and Minerals for the Indian Population
Seeds are major sources of nutrients and bioactive compounds for human beings. In this work, the chemical composition and physicochemical properties of 155 Indian seeds (belonging to 49 families) are reported. Moisture and ash were measured with reference protocols from AOAC; total polyphenols and flavonoids were measured with spectrophotometric methods after extraction with organic solvents, and mineral elements were determined by X-ray fluorescence spectrophotometry. Total phenolic compounds, flavonoids and mineral contents (Al, Ba, Ca, Cl, Co, Cr, Cu, Fe, K, Mg, Mn, Mo, Na, P, Rb, S, Sr, Ti, V and Zn) were found to vary in the ranges 182–5000, 110–4465 and 687–7904 mg/100 g (DW), respectively. Noticeably, polyphenol contents higher than 2750 mg/100 g were observed in 18 seeds. In addition, mineral contents >5000 mg/100 g were detected in the seeds from Cuminum cyminum, Foeniculum vulgare, Commiphora wightii, Parkia javanica, Putranjiva roxburghii, Santalum album and Strychnos potatorum. Botanical and taxonomical variations in the proximate characteristics of the examined seeds are also discussed.
A Guide to Practical Preparation of Training Courses
This Guide to Practical Preparation of Training Courses is developed by Provision of Adequate Tree Seed Portfolios II (PATSPO II) and is based on a similar guideline prepared for Indonesia Tree Seed Project in 2002.
A Guide to Preparation of Extension Materials
This Guide to Practical Preparation of Training Courses is developed by Provision of Adequate Tree Seed Portfolios II (PATSPO II) and is based on a similar guideline prepared for Indonesia Tree Seed Project in 2002.