Tag: germination
Direct seeding of Sesbania sesban for green manure in agroforestry systems — a short communication
This study was based at the Agroforestry Research Centre, Maseno Kenya. The objective was to evaluate the effects of pre-treatment, seed rate and depth of sowing seed on direct seeding of Sesbania sesban. Direct seeding was shown to be feasible during the rainy season, provided a shallow seed bed was used. Direct seeding at 3 cm furrow depth led to significantly (P = 0.05) greater germination compared to 10 cm depth. There was no effect of pretreatment and seed rate on germination, early seedling growth and dry matter partitioning. Depth of sowing similarly had no effect on early growth and dry matter partitioning. Establishment by direct seeding is relatively non-labour intensive with a probable high adoption potential.
Genetic variability and divergence of seed traits and seed germination of five provenances of Faidherbia albida (Delile) A. Chev
Establishment of Faidherbia albida trees on farm is often difficult despite the plant survival adaptive mechanisms such as drought and disease resistance. Adoption of the tree to agroforestry systems is also limited due to lack of knowledge on genetic variation of its provenances. Morphological charac-terization of F. albida provenances is therefore necessary to screen for natural genetic variation in seeds traits for selection of germplasm for long term agroforestry, timber production, fodder, soil fertility increment and environmental sustainability. In this study, seed traits of five provenances of F. albida: Taveta Wangingombe, Lupaso, Kuiseb and Manapools were examined. Divergent studies were analyzed based on seed morphology and geo-climatic conditions of the provenances. Seed length, width, thickness and weight were analyzed to determine the extent of phenotypic and genotypic variance and heritability. This study revealed significant differences among provenances (P=0.05) for all the studied characters indicating substantial genetic variability. Genetic variance for all seed traits was higher than environmental variance suggesting that the expressions of these traits are under genetic control. This result was supported by high heritability values for seed length (0.92), width (0.99), thickness (0.99) and weight (0.99). Seed germination test involved 4 replicates of 25 randomly selected seeds per provenance. Mean germination percentage among provenances was 83.3% with the highest being 97% and the lowest 71%, P=0.05. Relationships among these variables were analyzed using principal component analysis and cluster analysis resulting in separation of provenances into three distinct clusters. Manapools (760 mm), Lupaso (1165 mm) and Wangingombe (628 mm) with high rainfall were placed in cluster one. Taveta (545 mm) cluster two and Kuiseb (0.5) for all traits suggests that selection based on morphological traits can be made with a high degree of confidence.
Seed germination and in vitro regeneration of the African medicinal and pesticidal plant, Bobgunnia Madagascariensis
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.
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.
Variation in Seedling Germinationand Growth in Five Populations Ofvitellariaparadoxa C.F. Gaertn.subsp. Nilotica: A Threatenedusefulfruit Tree Species in Uganda
We studied seedlings germination and growth performance in an economically and socially important fruit tree species of Vitellaria paradoxaC.F. Gaertn.subsp. nilotica (Kotschy) in Uganda. The study aimed at determining variability in germination of the five shea tree seed lots and seedlings growth performance based on their growth traits. Five populations were considered from four agroecological zones of Uganda and 180 candidates plus trees (16 ethnovarieties) selected as seed trees based on their traits for faster growth and high oil yield. A total of 1204 biological seeds were collected and sown in a general tree nursery at Ngetta Zonal Agricultural Research and Development Institute (NgeZARDI)during the month of June 2018 in a randomized incomplete block design with three replications. Significant variation (χ = 526; p < 0.01) was observed in seedling phenotypic traits within and between populations. Regression equation for height growth and leaf size index were given asy = 0.3787 + 12.671x and y = 0.6483 + 15.413x respectively. Root collar diameter was more correlated to leaf size index (0.425) than to height growth (0.30). Clustering of shea tree seedlings based on phenotypic growth traits revealed one aggregated cluster indicating that most of the seedlings from the five populations were similar (Jaccard index 0.92, p < 0.01). However, clustering based on SNP markers revealed three different populations. We recorded higher growth (χ = 708; p< 0.001) in Arua shea population (19.69 cm)compared to the population average (19.04 cm). Red seeded; thin pulped and hairy fruited shea tree ethnovarieties assumed faster growth than the rest. The phenotypic analysis of shea tree seedlings revealed some fast-growing genotypes from the five studied populations. Thesegenotypes can be selected for faster growth for shea tree breeding in Uganda.