scholarly journals Effects of Mixed Coating of Oxygen Generating Chemicals and Several Kinds of Clay on Seedling Emergence in Direct Sowing of Paddy Rice.

1996 ◽  
Vol 65 (3) ◽  
pp. 430-436 ◽  
Author(s):  
Yasunori NAKAJIMA ◽  
Minoru SEKI ◽  
Shigenori TAKAHASHI
2018 ◽  
Vol 16 (4) ◽  
pp. 352-358 ◽  
Author(s):  
Junichi Kashiwagi ◽  
Koji Hamada ◽  
Yutaka Jitsuyama

AbstractDirect sowing of rice in a flooded paddy field is a beneficial cultivation practice for water use and labour efficiency, compared to the transplanted cultivation. However, a drastic reduction in seedling emergence under flooded paddy fields is a serious constraint especially when the seeds fell at deeper soil layers. Suitable rice germplasm for the direct sowing in flooded paddy fields could ensure the success of this cultivation practice. Instead of laborious field-based screening systems, a pot-based screening method was adopted for simplicity and efficient evaluation of seedling emergence of a subset of world rice germplasm (n = 75) at different sowing depths. As a result, two rice genotypes, ‘Vary Futsi’ (landrace from Madagascar, non-glutinous, subspecies Indica) and ‘Dahonggu’ (landrace from China, non-glutinous, subspecies Indica), with consistently better seedling emergence were identified from a wide range of rice germplasm. These genotypes could serve as excellent parents for the breeding program in developing new rice cultivars with the improved seedling emergence in flooded paddy fields. There were no significant differences in the seedling emergence rate in flooded paddy conditions among the groups from various agro-geographical regions.


2000 ◽  
Vol 78 (10) ◽  
pp. 1309-1318 ◽  
Author(s):  
Angélica Camacho-Cruz ◽  
Mario González-Espinosa ◽  
Jan H.D Wolf ◽  
Bernardus HJ De Jong

Germination and seedling survival of native tree species were studied in nursery (June-November 1998) and forest stands with varying dominance by pines in the central highlands of Chiapas (Mexico; June 1998 - November 1999). Species used are regarded as typical of mid- and late-successional habitats: Cornus disciflora Sessé & Mociño ex DC., Cornus excelsa H.B.K., Drimys granadensis L.f. var. mexicana (DC.) A.C. Smith, Liquidambar styraciflua L., Persea americana L., Quercus laurina H. & B., and Ternstroemia lineata (DC.) ssp. chalicophyla (Loesener) Bartholomew. Nursery treatments included presence and composition of litter collected from replicated plots of three forest types: old-growth forest, mixed pine-oak forest, and pine-dominated forest. Germination and seedling emergence of P. americana in the nursery were complete for all factor combinations. Cornus disciflora and L. styraciflua showed highest germination (p < 0.05) when sown in soil from old-growth forest and covered with litter of oak-broad-leaved species. In the field, differences (p < 0.05) among forest types (degree of pine dominance) were observed for C. disciflora (lowest germination in pinelands, 17%), D. granadensis (highest survival in old-growth forest, 23%), and Q. laurina (higher survival in pinelands, 54%). Natural recruitment and survival of seedlings were higher in old-growth forests. We conclude that oak litter may favor germination and early establishment of the studied species. However, the reintroduction of some of the studied species (C. excelsa, Q. laurina, and T. lineata) may be attempted with direct sowing on the forest floor of severely disturbed and species-poor pinelands.Key words: Cornus, Liquidambar, litter, Persea, Pinus, Quercus, seedling establishment, seeds.


2020 ◽  
Vol 42 ◽  
Author(s):  
Alexandre Carneiro da Silva ◽  
Maiara Pilar Palmeira da Silva ◽  
Rayssa Zamith ◽  
Gustavo Galetti ◽  
Fatima Conceição Márquez Piña-Rodrigues

Abstract: Direct seeding is a technology that reduces the costs of forest restoration projects and favors species which are difficult to establish for seedlings. The seeds osmotic treatment to accelerate and standardize germination and induce tolerance to environmental stresses may favor seedling establishment in field through direct sowing and contribute to the greater efficiency of this technique. With the purpose of favor seed germination and seedling establishment under direct seeding conditions in the field, Tabebuia roseoalba osmoprimed seeds in polyethylene glycol (PEG) solution and unconditioned seeds were treated with isolated and/or combined solutions of plant growth regulators (PGR) and rooting (RTG). These seeds were submitted to germination test and evaluated for percentage germination rate, germination speed index and normal seedlings, and to seedling emergence test by direct field seeding. RTG had a toxic effect on T. roseoalba seeds. Osmoconditioning induced stress tolerance by RTG during germination and on seedling establishment. PGR treatment favors seedling emergence in field conditions and alleviates the toxicity effect caused by RTG. These treatments have great potential for use in direct sowing of T. roseoalba seeds.


2018 ◽  
Vol 5 (4) ◽  
pp. 20-25
Author(s):  
Rogério Costa da Silva ◽  
Ana Paula Leite de Lima ◽  
Sebastião Ferreira de Lima ◽  
Guilherme Marchesini Trevizani ◽  
João Batista Leite Junior

The objective of this study was to evaluate the influence of using physical protectors on the emergence and initial growth of Baru seedlings in a direct sowing system. The experiment was installed in a randomized complete block design, testing the use of physical protectors (no protection, P0; plastic cup (500 mL) without the bottom, P1; laminated wood, P2), with 12 repetitions. Weekly soil temperature monitoring was carried out in the morning and in the afternoon in the period between 14 and 56 days after sowing (DAS). Daily emergence follow-up was also performed, and the stem diameter, total height and number of leaves were measured at 81 DAS. The use of physical protectors in the direct seeding of Baru interfered in the soil surface temperature on the sowing point, on the seedling emergence speed index, seedling survival, stem diameter and seedling height. Implementing protectors slowed the seedling emergence speed, however it provided higher percentages of emergence, survival and greater growth in diameter and height.


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