Latest Research on Seedling Production : October 2021



Acorn predation and seedling production in a low-density population of cork oak (Quercus suber L.)


Prospects for cork oak recruitment were examined in a scrub-dominated area with low tree density in southern Spain by sowing acorns experimentally in a variety of sites. Seeds placed on the ground surface were invariably eaten within a few months by a variety of vertebrate herbivores (cattle, red deer, fallow deer, wild boar and rabbits). Predation reached 100% whether acorns were placed beneath trees or more than 100 m away from trees. Seeds placed under dense heath scrub were also rapidly removed, although their final fates could not be ascertained. Single acorns buried under open or dense scrub experienced the lowest predation (52% and 0%, respectively) and had relatively high emergence rates (38% and 60%, respectively). Heavy shoot browsing occurred in both scrub types, and out of the 49 buried acorns which produced a shoot, only two seedlings were alive 1 year after germination. None survived 2 years after sowing.[1]

Can current native tree seedling production and infrastructure meet an increasing forest restoration demand in Brazil?

Recent global commitments have placed forest and landscape restoration at the forefront of countries’ efforts to recover ecosystem services, conserve biodiversity, and mitigate the effects of climate change. However, it needs to be asked if current native tree seedling supply meets an increase in demand for forest restoration? This study assessed the current configuration, distribution, and production capacity of forest nurseries producing native trees in Brazil. Brazil provides an interesting example of how global agreements aligned with national policies can lead to the proliferation of native seedling nurseries, and the challenges faced to restore species-rich native forest ecosystems. We found that the nurseries in the Atlantic Forest region can still meet an increase in demand—both in terms of seedling quantity and diversity—because most of their production capacity is not currently used. However, not all Brazilian biomes have sufficient nurseries to meet restoration demands, thus there is a risk of using native species from a few biogeographical regions in a much spatially wider and ecologically diverse area. In addition, lack of seed supply and qualified labor can hamper the growth of the market. Barriers to seed supply may also lead to low levels of genetic variability and floristic representation in the populations and ecosystems to be restored. We conclude that restoration of high-diversity forest ecosystems requires policies and supportive programs, with emphasis on private nurseries, to guarantee adequate supply of native tree seedlings and provide the necessary incentives to develop the emergent economy of forest restoration. [2]

High Frequencies of Fertilization and Haploid Seedling Production in Crosses Between Commercial Hexaploid Wheat Varieties and Maize

Nineteen commercial hexaploid wheat varieties were crossed with the maize F1 hybrid ‘Seneca 60’. Fertilization frequencies ranged from 32.1 % to 47.5 % of pollinated florets (mean 39.5 %) in the 14 winter wheat varieties and from 40.7 % to 51.4 % (mean 47.8 %) in the five spring wheat varieties. In some cases only an endosperm was formed and the frequencies of embryo formation were therefore slightly lower, being 28.2 % to 45.9 % (mean 36.4 %) for winter wheats and 39.8 % to 48.6 % (mean 45.1 %) for spring wheats. Mean values were significantly higher in the spring wheats but no significant variation was found between varieties within the spring or winter categories. In the five spring wheats the mean yield of embryos, and hence the potential yield of haploid plants, was 3.4-fold higher than with the tetraploid Hordeum bulbosum clone PB179. For the 14 winter wheats the figure was 10.9-fold higher. These differences were highly significant (p < 0.001) in all varieties. A single 2,4-D treatment given to spikes one day after pollination with maize enabled embryos to be recovered from all 19 varieties. A total of 311 embryos were recovered from 950 florets (an average of 7.3 embryos per spike) of which 191 germinated, giving an average yield of one haploid plant for every 5.0 florets pollinated (4.4 haploid plants per spike). [3]


Organics to Enhance Emergence and Growth of Oil Bean (Pentaclethra macrophylla Benth) Seedlings

Insufficient seedlings supply caused by poor seed germination is one of the major problems in the propagation of tropical fruit tree crops. Pre-sowing seed treatment has been known to improve germination and seedling production under different environmental stressed conditions. Fortunately, organics plays an important role in regulation of many physiological and genetic processes. This study evaluated the effectiveness of pre- planting seed treatment in organics namely: banana sap, cassava effluent and fermented palm sap, soaked for 0, 2, 4, 6 and 8 hours to enhance seed germination and growth of oil bean (Pentaclethra macrophylla) seedling. The experimental design was a 3 x 5 factorial in completely randomized design with 6 replicates carried out in the screen house of the School of Agriculture and Agricultural Technology, Federal University of Technology, Owerri. Days to emergence, plant height and number of leaves were highly significant with the organic treatments. Generally, seed pre-treatment in organics improved the emergence, and growth of oil bean seedlings. Seeds soaked in banana sap recorded the highest percentage total emergence of 87.50 while six hours of soaking in cassava effluent significantly reduced the mean number of days to emergence to approximately 17 day. [4]

Different Substrates in Seedling Production of Caesalpinia pyramidalis Tul

The use of native species for the recovery of degraded areas has been of great relevance, however, there is a deficiency in studies aimed at the Northeast region of Brazil, which presents one of the largest areas under desertification in the South American continent. The region has a diverse native flora of high cultural and economic relevance such as Caesalpinia pyramidalis Tul, popularly known as catingueira that stands out for the rusticity and use in diverse areas medicinal, logging, cultural, animal feeding, among others. The objective of this work was to evaluate the effects of chemical fertilisation on different substrate sources on the emergence and initial growth of Caesalpinia pyramidalis seedlings. For the constitution of the substrates samples, Yellow Oxisol distrocoeso were collected at 0.50 m depth and superfine vermiculite. Also organic manure and organic compound were used. The emergence and morphological features (area and total dry mass, height, diameter, chlorophyll A and B) were evaluated. The seedlings of Caesalpinia pyramidalis placed on substrates consisting of organic compound in the ratio 1:1:1 (compound: soil: vermiculite) and 2:1:1 (compound: soil: vermiculite) and cattle manure 2:1:1 (manure: soil: vermiculite) generated satisfactory results for the development of the crop. There was no interaction (p> 0.05) between the addition of NPK and the types of substrates evaluated for the studied variables. [5]

Reference

[1] Herrera, J., 1995. Acorn predation and seedling production in a low-density population of cork oak (Quercus suber L.). Forest Ecology and Management76(1-3), pp.197-201.

[2] Moreira da Silva, A.P., Schweizer, D., Rodrigues Marques, H., Cordeiro Teixeira, A.M., Nascente dos Santos, T.V., Sambuichi, R.H., Badari, C.G., Gaudare, U. and Brancalion, P.H., 2017. Can current native tree seedling production and infrastructure meet an increasing forest restoration demand in Brazil?. Restoration Ecology25(4), pp.509-515.

[3] Laurie, D.A. and Reymondie, S., 1991. High frequencies of fertilization and haploid seedling production in crosses between commercial hexaploid wheat varieties and maize. Plant Breeding106(3), pp.182-189.

[4] Onwubiko, N.C., Uka, C.A., Ngwuta, A.A., Onyishi, G.C. and Keyagha, R.E., 2015. Organics to Enhance Emergence and Growth of Oil Bean (Pentaclethra macrophylla Benth) Seedlings. Journal of Advances in Biology & Biotechnology, pp.36-41.

[5] Dias, F.P.M., de Castro Paes, É., dos Santos Silva, F.T., Nóbrega, R.S.A. and Nóbrega, J.C.A., 2018. Different Substrates in Seedling Production of Caesalpinia pyramidalis Tul. Journal of Experimental Agriculture International, pp.1-7.

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