Seedling Emergence In Field Research Articles

Physiological quality of cowpea seeds for different periods of storage

The aim of this study was to evaluate physiological quality in the seeds of four cowpea cultivars during nine months of storage. The cowpea cultivars used were BRS Mazagao, UFRR Grao Verde, Pretinho Precoce 1 and BRS Guariba, produced intercropped with cassava in the experimental area of the Centre for Agrarian Science of the Federal University of Roraima, in Boa Vista. After harvest, the seeds were dried, hand cleaned, placed in PET bottles and stored for nine months at a temperature of 23 oC and a relative humidity of 60% at the Seed Analysis Laboratory of Embrapa Roraima. Data analysis was carried out in a completely randomised design, in a 4 x 4 factorial scheme with eight replications. The physiological quality of the seeds was evaluated at the start of storage, and after 3, 6 and 9 months, for germination, first germination count, 1000-seed weight, moisture, electrical conductivity, speed of emergence, seedling field emergence and water gain. Physiological quality in the seeds of BRS Guariba is influenced by the storage period. Irrespective of storage period, seeds of the Mazagao cultivar show superior physiological quality in relation to the other cultivars. Seeds of the BRS Guariba and Grao Verde cultivars show a reduction in physiological quality after three months of storage.

Response of Digitaria insularis seed germination to environmental factors

Digitaria insularis (sourgrass) is a weed problem emerging in importance in agricultural fields from the north of Argentina and has recently been reported as resistant to glyphosate. Understanding the germination of local biotypes of D. insularis could help to reduce invasion and improve the long-term management strategies for this weed. The objective of this work was to study the effect of environmental factors on germination of D. insularis seeds from two different populations of Argentina. Three experiments were performed in germination chambers by using recently dispersed seeds. Seeds with or without pre-chilling treatments had 95% germination, suggesting the absence of dormancy in freshly harvested seed. Germination at constant temperature of 25°C was ~55% lower than germination at fluctuating temperature of 20°−35°C. At constant 25°C, germination was higher for seeds from Santiago del Estero than seeds from Córdoba, and as the number of hydration–dehydration cycles increased. Germination was reduced with exposure to far-red light for 1 h. Any crop management decision that reduces soil thermal fluctuations and/or far-red : red ratio (such as stubble or cover crops) could reduce seedling field emergence for this species.

Germinação e emergência de plântulas associadas ao tamanho e peletização de sementes de quinoa

This work has been performed with the aim of verifying the existing relation between the size of the quinoa seeds and their pelleting in lab germination and emergence of seedlings in field. First, the experiment has been conducted in laboratory, using completely randomized design (DIC) with incomplete factorial scheme 2 x (4 or 3). Then, it has been conducted to field, using randomized block design (DBC) with subdivided portions, in four repetitions and with scheme of 2 x (3 or 2). The statistical analyses have been calculated using the software R, followed by the analysis of variance followed by the Tukey average test in 5% of error probability. According to the performed tests, when put into lab environment, bigger quinoa seeds present higher germination performance than smaller seeds. When the seeds were put into field condition, no matter the size of the seed or its pelleting process, there was no meaningful difference in the index of emergence speed.

Germinação e Emergência de Plântulas Associadas ao Tamanho e Peletização de Sementes de Quinoa

This work has been performed with the aim of verifying the existing relation between the size of the quinoa seeds and their pelleting in lab germination and emergence of seedlings in field. First, the experiment has been conducted in laboratory, using completely randomized design (DIC) with incomplete factorial scheme 2 x (4 or 3). Then, it has been conducted to field, using randomized block design (DBC) with subdivided portions, in four repetitions and with scheme of 2 x (3 or 2). The statistical analyses have been calculated using the software R, followed by the analysis of variance followed by the Tukey average test in 5% of error probability. According to the performed tests, when put into lab environment, bigger quinoa seeds present higher germination performance than smaller seeds. When the seeds were put into field condition, no matter the size of the seed or its pelleting process, there was no meaningful difference in the index of emergence speed.

Laser Light Stimulation Effects on Scorzonera hispanica L. Seeds Germination, Field Emergence and Photosynthetic Pigments Content

Abstract The study presented herein concerns the effect of pre-sowing stimulation of scorzonera seeds with He–Ne laser on germination capacity, field emergence of seedlings and the content of chlorophylls and carotenoids. Seeds of scorzonera cv. ‘Duplex’, from harvests of various years, dis-played variable quality expressed by their germination capacity. They were subjected to pre-sowing stimulation with He–Ne laser light of the power of 40 mW and wavelength of 632.8 nm, surface power density of 5 mW·cm−2 and different exposure times. Germination capacity on Petri dish test increased only in one lot of seeds after exposure for 1 and 5 min. Increase in seedling emergence in the field experiment in the result of laser treatment occurred only in one seed lot. One-min laser treatment increased contents of chlorophylls and carotenoids in 8-day cotyledons (laboratory test) and in the second true leaves (field experiment).

Controlled deterioration test for evaluation of sunn hemp seed vigor

The controlled deterioration test is efficient for seed vigor evaluation of several species. However, the procedures conditions are incipient, especially in respect to tropical forages such as sunn hemp, which still does not have a standardized procedure. The objective of this research was to adjust the procedures for a controlled deterioration test in Crotalaria juncea L. seeds. For this, five commercial seed lots were evaluated for water content and initial physiological potential (germination test, first germination count, germination speed index, saturated salt accelerated aging with NaCl, electrical conductivity and seedling field emergence). For controlled deterioration test, the initial seed moisture content was adjusted to 18, 21 and 24% and, subsequently, the samples were exposed at 45 °C during 24 hours. Seed germination test was conducted with the use of sand as substrate. Evaluations were performed on the fourth, fifth and sixth day after sowing. The controlled deterioration test for sunn hemp seeds should be performed with 24% seed moisture content, at 45 °C during 24 hours, and the test evaluation on the fourth day after sowing.

Rising atmospheric CO2: Potential impacts on chickpea seed quality

Experiments on chickpea (Cicer arietinum L.) were performed in open-top chambers during 2010–11 and 2011–12 to assess effects of atmospheric CO2 enrichment on the quality of seeds. Although no physical modification was observed, an increase in seed water uptake was recorded in plants grown under enriched atmospheric CO2 condition. Germination of seeds reduced by 45–47%, while seed leachate conductivity increased by 10–17%. Seedling vigor decreased, although root and shoot lengths and seedling biomass showed negligible changes. Similarly, atmospheric CO2 enrichment reduced field emergence of seedlings with no change in root characteristics of the emerged seedlings. A decrease in protease activity supports the reduced seed viability, although no change in grain phosphatase and α-amylase activities were recorded. Increase in carbon content in germinating seed-cotyledon along with decrease in N in cotyledon resulted in large increase in C:N ratio for the plants grown under enriched CO2 condition. The starch content increased with no change in soluble sugar in germinating seed-cotyledons. This indicates more carbonaceous seeds from plants grown under enriched CO2 environment. Results suggest that rising atmospheric CO2 might have adverse impact on viability and germination of chickpea seeds, and cause nutritional imbalance through increase in C with dilution of N contents in germinating seed-cotyledons.

Understanding erratic seedling emergence in perennial grasses using physiological models and field experimentation

Year-to-year variability in field seedling emergence in arid rangelands poses questions about the viability of perennial grasses threatened by overgrazing. There are practical difficulties in estimating long-term seedling emergence for perennial species with erratic behavior (high temporal variability). We present a novel approach combining seed germination studies, modeling, and field experiments to estimate long-term germination probability using Poa ligularis as a perennial grass model. Additional objectives were to evaluate: (i) germination requirements of different P. ligularis populations, (ii) field emergence behavior at two extreme locations within the distributional range in the southern region, and (iii) the influence of microsite or local soil on field emergence. Germination parameters were obtained from 8 populations collected across a 12° latitude transect. Germination parameters were combined with a soil water model to estimate long-term germination (used as a proxy of field emergence) in the southernmost location. Germination requirements differed across populations and correlated with environmental conditions of collection sites, demonstrating ecological significance. Field experiments showed very low emergence. Simulations for the southern location indicated erratic emergence. Fifty percent of the years had nil simulated field emergence and the magnitude of the events, when occurred, was small. The magnitude of these events depended on the population, demonstrating an additional genetic constraint. Erratic field emergence arises from the mismatch between environmental conditions and germination requirements. Knowing favorable climatic conditions triggering seed germination (and thus emergence) events are key for opportunistic management of species with this erratic behavior.

Fire affects soil organic matter and the emergence of Pinus radiata seedlings

These results present great interest for the knowledge of fire effects and the regeneration capacity of the ecosystems, which is essential to minimise the long-term fire impacts. This study integrates thermal analysis of soil with tests of fire effects on Pinus radiata seeds germination and field seedling emergence in P. radiata plantations. The consequences of fire intensity P. radiata plantation regeneration can be predicted from the results. This study aims to identify the effects of fire on soil organic matter and emergence of P. radiata seedlings in a stand in NW Spain and to test the response of seeds from two provenances of P. radiata to smoke and heat. Burnt, unburnt and laboratory-heated samples of dry soil were analysed in a differential scanning calorimeter. Based on the comparison between heat released during the combustion of the organic matter of these samples, we estimated the fire severity. Early emergence of P. radiata seedlings was recorded in the field after fire. Finally, the effects of fire on seeds germination were tested in the laboratory. The limited loss of soil organic matter indicated that the fire had been of low severity and that the temperatures reached during the fire remained below the ignition temperatures of soil organic matter. The germination rate was high in controls and the lowest fire severities but decreased with fire intensity. The two provenances differed in their response to fire intensity. Seedling emergence was moderate and varied over time. The intensity of the investigated fire remained moderate, with a limited loss of soil organic matter. It limited seedling germination and emergence. Nevertheless, despite the scarce seedling emergence observed in the field, re-establishment of the population was possible.

Vigor evaluation of stored cotton seeds, including the Seed Vigor Imaging System (SVIS®)

This study aimed at evaluating efficiency of different tests to assess cotton seed vigor during storage, including the SVIS® software. Thereby, five cotton seed lots (cv. BRS 293) were stored under controlled environmental conditions of low temperature and relative humidity (10 ºC; 30% RH), and under non-controlled laboratory environmental conditions, for eight months. Evaluations of germination, first germination count, cool germination, accelerated aging test traditional and with saturated salt, field seedling emergence and seedling imaging automated analysis - SVIS® were performed before and after every two storage months. It was concluded that the cool germination, accelerated aging (traditional and with saturated salt), field seedling emergence and seedlings length (SVIS®) are adequate parameters for assessing vigor of cotton seeds during storage, and that both accelerated aging and SVIS® (vigor index and seedlings length) present enough sensitivity to identify changes on seed vigor during storage.

Condução do teste de condutividade elétrica utilizando partes de sementes de feijão

The aim of this work was identify the best conditions for bulk and individual electrical conductivity evaluation using bean seed parts at the less time for imbibition as possible. Beans seeds cultivar IAPAR 81 were used in this work, and represented by four lots. Physiological potential was evaluated by germination standard test, first count germination, seedling vigour classification, speed radicle protrusion, and field seedling emergence. Electrical conductivity test was done by bulk and individual procedures, with whole seeds, cotyledons and embryonic axis at different immersion periods. The bulk electrical conductivity test is able to identify vigour differences in bean seed lots after two hours of imbibition using exclusively cotyledons or with whole seeds after five hours of imbibition, and both methodologies are able to classify bean seed lots by vigor levels.

Foliar fungicide and environments on the physiological quality of oat seeds

The oat crop is of great economic importance and seed production depends on several factors (biotic and abiotic) that can alter its quality. Thus, the study aimed to evaluate the physiological quality of oat seeds produced with and without application of foliar fungicide in contrasting environments. The experimental design was a randomized block design in a factorial 6x2 (cultivar x fungicide) for each site, with four replications. The physiological quality of seeds was evaluated by grain yield, germination, first count, accelerated aging, moisture content after accelerated aging, seedling length, seedling dry weight, electrical conductivity and seedling emergence in field. Data were subjected to joint and individual analysis of variance, and means were compared by Tukey’s test at 5%. Grain yield in Mauá da Serra is superior to Londrina, Parana State - Brazil, but the seed quality is lower, although all cultivars have shown germination above 90% in the two cultivation sites. Cultivars FAEM 6 DILMASUL and UPFA OURO showed no disease, indicating possible resistance. The application of the product has a beneficial effect on seed germination and vigor, even in the absence of disease.

Growth and Yield Response of Mungbean (Vigna radiata L. Wilczek) Genotypes to Wet Puddling, Flooding and Saturated Soil Culture

Anoxia and hypoxia, caused by excessive rainfall and inadequate drainage are the most common environmental stresses in upland crops after wetland rice in many regions of Asia. Such stresses and/or puddling of soil in rice culture often reduce the growth and yield of post-rice upland crops. This study examined the growth and yield responses of three mungbean genotypes viz. VC3950-88, VC6173A and BARI Mung-5 to three different environmental stresses viz. wet puddling, soil flooding and saturated soil culture. Wet puddling significantly reduced the field emergence and vigor index of seedlings. Height of plants was also adversely affected due to the stresses, although recovery was comparatively better in flooded situation. Irrespective of growing conditions, leaf chlorophyll index reduced significantly and recovered almost completely. The extraordinary responses of plants to all the stresses were the damaging of roots and/or impairing of root and shoot growth. The subsequent recovery of root and shoot growth significantly varied depending on the types of stresses. The development of numerous adventitious roots and the production of greater amount of root nodules were the most important recovery mechanisms of plants to withstand flooding situation and saturated soil culture, respectively. As a result, seed production was less affected under these two conditions. In contrast, wet puddling situation performed the worst, showing depressed plant growth throughout the growing period and thus seed production was affected the most. Among the genotypes, VC6173A was best adapted under the three stresses, giving the highest seed yield by producing higher amount of pods, increased seed size and longer pod.

Produção e qualidade de sementes de feijão-caupi em função de sistemas de plantio e estresse hídrico

O feijão-caupi desempenha importante papel na produção agrícola brasileira, especialmente nas Regiões Norte e Nordeste, onde é amplamente cultivado por pequenos produtores. Neste sentido, este trabalho foi desenvolvido com o objetivo de avaliar a qualidade fisiológica de sementes de feijão-caupi produzidas em sistema plantio direto e convencional, sob diferentes períodos sem irrigação. Utilizou-se delineamento em blocos casualizados, em esquema de parcelas subdivididas, com quatro repetições. As parcelas foram constituídas por sistemas de plantio (direto e convencional) e as subparcelas por períodos sem irrigação (2, 6, 10, 14, 18 e 22 dias). Nas parcelas, as sementes foram colhidas e submetidas às seguintes avaliações: massa de sementes por planta, massa de mil sementes, massa hectolítrica, comprimento e largura da semente, grau de umidade, germinação, envelhecimento acelerado, emergência de plântulas em campo e índice de velocidade de emergência. Sementes de feijão-caupi provenientes de plantas submetidas ao estresse hídrico resultaram em menor qualidade fisiológica, contudo, fisicamente maiores e mais pesadas. O sistema plantio direto proporcionou sementes com melhor qualidade fisiológica. Plantas de feijão-caupi submetidas ao estresse hídrico após o florescimento produziram menor quantidade de sementes.

Estimation and Comparison of Base Temperatures for Germination of European Populations of Velvetleaf (Abutilon theophrasti) and Jimsonweed (Datura stramonium)

Weed emergence models require biological parameters such as base temperature for germination, determination of which is costly and time-consuming. Transferability of these parameters across different populations may therefore represent one of the main constraints for the development and practical use of emergence models at a large scale. A collaborative project was undertaken to assess the interpopulation variability of base temperature for germination in different European populations of velvetleaf and jimsonweed and evaluate possible applicative consequences in terms of weed control. Seeds were collected in Italy, Portugal, and Spain, and each population was then sown in every country, obtaining nine seed batches named as experimental lots. Base temperature for germination was estimated for each experimental lot to calculate lot-specific accumulation of growing degree days (GDD) under three dissimilar climatic scenarios. Threshold date (TD50) was calculated as the date when GDD accumulation of a given experimental lot surpassed the values corresponding to 50% of cumulative field emergence of seedlings. GDD accumulation and TD50were then used as indicators to identify differences among experimental lots within each climatic scenario. No significant differences were detected among base temperatures estimated for velvetleaf experimental lots or among their patterns of accumulation of GDD and TD50values within climatic scenarios. Each value of base temperature determined for a single experimental lot could therefore be adopted to model germination for all the lots regardless of the population of origin or cultivation site. In contrast, the population of origin affected the base temperature for jimsonweed, with significantly higher values for experimental lots of the Portuguese population. From an applicative perspective, differences among patterns of accumulation of GDD and TD50of several experimental lots within each climatic scenario suggest the need to use population-specific values as base temperature for germination and emergence modeling of jimsonweed.

Discrimination of soybean seed lots by multivariate exploratory techniques

Physiological potential characterization of seed lots is usually performed by germination and vigor tests; however, the choice of a single test does not reflect such potential, once each test assesses seeds of differentiated mode. Multivariate techniques allow understanding structural dependence contained in each variable, as well as characterize groups of seed lots according to specific standards. The study aimed at evaluating variability among soybean seed lots and discriminate these lots by multivariate exploratory techniques as function of seed vigor. Experiment was performed with 20 soybean seed lots (10 lots cv. BRS Valiosa RR and 10 lots cv. M-SOY 7908 RR). Seed physiological potential was assessed by testing for: germination (standard, and under different water availability); vigor (accelerated aging and electrical conductivity); and field seedling emergence. Cluster analysis of seed lots, as well as Principal Component Analysis was performed using data obtained on all tests. Multivariate techniques allowed stratifying seed lots into two distinct groups. Principal Component Analysis showed that values obtained for variables: field seedling emergence, accelerated aging, and germination under different water availability were linked to BRS Valiosa RR; while to variables germination and electrical conductivity, were linked to M-SOY 7908 RR.

Electrical conductivity of different common bean seeds genotypes

The electrical conductivity test is a fast and non-subjective method used to assess seed physiological potential. Thus, the objective of this study was adapting the methodology for conducting the electrical conductivity test in common bean seeds and investigate effects of genotype in results of the test, comparing cultivars of the two trade groups: Carioca and Black. The study was conducted in two phases: 1- tests with combinations of different temperatures (20, 25, 30, and 35 °C) and five different inhibition periods (4, 8, 16, 20 and 24 h); and 2- assessment of influence of genotype by comparing results obtained on the seeds of both groups. Tests of accelerated aging and seedling emergence in field were also performed. It was concluded that, for seeds of common beans, electrical conductivity test may be performed with samples of 50 seeds per replication, soaked into 75 mL deionized water, incubated at 25 °C, and performing reading of results after 20 or 24 h. It was also concluded that test efficiency is variable according to genotype, and that for the trade group Carioca, there is not genotype effect; although the same results have not occurred for results obtained for the trade group Black.

Improved assessment of wheat seeds vigor

The tetrazolium test is widely used for seed vigor assessment of various plant species. For wheat, however, there is no methodology specifically recommended. This study aimed at determining an efficient procedure to evaluate vigor of wheat seeds by this test; besides allowing the establishment of seed quality classes. Thus, four different wheat seed lots were assessed by determining the moisture content and through tests of germination, accelerated aging, and field seedling emergence. The following methodologies were assessed: 1) longitudinal bisection of seed, with subsequent placement of the two halves on filter paper moistened with a 1.0% tetrazolium solution, at 30º C, for 2 h; 2) longitudinal bisection, with subsequent immersion of one seed half into a 1.0% tetrazolium solution, at 30º C, for 3 h; and 3) longitudinal bisection, with subsequent immersion of one seed half into a 0.075% tetrazolium solution, at 40º C, for 2 h. It was concluded that the tetrazolium test is more efficient in evaluating wheat seed vigor when performed with immersion of one half of the seed into a 0.075% tetrazolium solution (40º C, for 2 h) or a 0.1% tetrazolium solution (30º C, during 3 h); allowing to sort seeds into four quality classes.

Deterioração controlada para avaliar o potencial fisiológico de sementes de beterraba

Sementes de hortaliças quase sempre apresentam elevado valor comercial, motivo pelo qual devem ter o potencial fisiológico eficientemente avaliado. O teste de deterioração controlada é um dos recomendados para avaliação do vigor de sementes pequenas, como as de beterraba. O objetivo do trabalho foi determinar o melhor procedimento para a condução de referido teste em sementes de beterraba e sua relação com a emergência de plântulas em campo. Foram utilizados sete lotes de sementes da cultivar Top Tall Early Wonder, adquiridos no comércio. Após lavagem em água corrente, as sementes foram submetidas aos testes de germinação, velocidade de germinação, envelhecimento acelerado, emergência de plântulas em campo, velocidade de emergência e deterioração controlada (temperaturas de 41 e 45ºC, teores de água de 22, 24 e 26% e períodos de exposição de 12, 24 e 36 horas). As combinações 41ºC/24%/12 h, 41ºC/24%/36 h, 41ºC/26%/36 h e 45ºC/24%/24 h apresentaram potencial para uso na avaliação do vigor de sementes de beterraba. No entanto, sob as combinações de 41°C/24%/12 h ou 45°C/24%/24 h reduziu-se o tempo de condução do teste.

Performance of lowland rice seeds coated with dolomitic limestone and aluminum silicate

The objective of this study was to evaluate the performance of seeds of two cultivars of lowland rice (Oryza sativa L.), coated with dolomitic limestone and aluminum silicate. It was used a completely randomized experimental design, with the treatments arranged in a 4 X 2 factorial scheme [4 treatments: dolomitic limestone; dolomitic limestone + aluminum silicate; aluminum silicate, at the dosages of 50 g/100 kg of seeds; and control (without the products) X 2 cultivars: IRGA424 and IRGA 422 CL], totaling eight treatments with four replications each. The variables analyzed were: fresh and dry weights of aerial biomass; plant height; leaf area at 10, 20, and 30 days after emergence (DAE). The physiological quality of seeds was also assessed using tests of: seed emergence; first count of germination; emergence speed index; and field emergence. It was concluded that the coating of rice seeds with dolomitic limestone and aluminum silicate does not affect seed germination and field seedling emergence. Aluminum silicate used via seed coating on cultivar IRGA 424 promoted greater leaf area, after 20 DAE. The dolomitic limestone and the aluminum silicate used via seed coating generated plants with larger dry biomass, after 20 DAE, for the cultivar IRGA 422 CL.