scholarly journals Heritability of hardseededness in mungbean [Vigna radiata (L.) Wilczek] under varying environments

2019 ◽  
Vol 79 (01S) ◽  
Author(s):  
Debashis Paul ◽  
S. K. Chakrabarty ◽  
H. K. Dikshit ◽  
S. K. Jha ◽  
G. Chawla ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Low Temperature ◽  
Seed Coat ◽  
Surface Deposition ◽  
Moisture Condition ◽  
Hard Seed ◽  
Average Temperature ◽  
High Soil Moisture ◽  
Hard Seeds ◽  
Mild Temperature

Presence of hard seeds in seed lots reduces the seedling emergence percentage in field leading to non-uniform, lowered plant population and uneven maturity. Seed hardness, characterized by no water imbibition, is controlled by both genetic and environmental conditions. To estimate the broad sense heritability (H2) of hardseededness, 20 mungbean genotypes with >22% hard seeds were grown in four different environments (Env.) viz., high average temperature and high soil moisture (Env. 1), mild temperature and low soil moisture (Env.2), mild temperature and high soil moisture (Env. 3) and low average temperature and low soil moisture (Env.4). The average per cent hard seed in seed lots was 5.42, 28.7, 19.4 and 33.9 under Env.1, Env.2, Env.3 and Env.4, respectively. The H2 estimate of hardseededness under Env.1, Env.2, Env.3 and Env.4 was 0.67, 0.97, 0.96 and 0.98, respectively. Decreasing soil moisture, low temperature and delayed harvest increased occurrence of per cent hard seed. The force required in Texture Analysis Machine to break seeds produced under Env.1 ranged from 9.23 to 33.31 Newton while the same ranged from 39.51 to 71.53 Newton in seeds produced under Env.4. The Scanning Electron Microscope images indicated that the seeds produced under low average temperature and soil moisture had a presence of compact outer cell layer with low surface deposition and depression on the seed coat of seeds produced in Env.1 and there is existence of loose cells and cracks in the seed coat with high depression and surface deposition in the seeds produced under Env.4. A lower heritability of 0.67 for hardseededness in high temperature and soil moisture condition suggested that the character is influenced by stress conditions. Growing of genotypes under low temperature and moisture condition is suggested for screening of genotypes for hardseededness in mungbean.

scholarly journals Procedures for evaluating the tolerance of cassava genotypes to postharvest physiological deterioration

2015 ◽  
Vol 50 (7) ◽  
pp. 562-570 ◽  
Author(s):  
Marcela Tonini Venturini ◽  
Vanderlei da Silva Santos ◽  
Eder Jorge de Oliveira
Keyword(s):  
Soil Moisture ◽  
High Temperature ◽  
Low Temperature ◽  
Environmental Conditions ◽  
Fungicide Treatment ◽  
High Soil Moisture ◽  
Root Position ◽  
Postharvest Physiological Deterioration ◽  
Significant Interference ◽  
Diagrammatic Scale

Abstract: The objective of this work was to define procedures to assess the tolerance of cassava genotypes to postharvest physiological deterioration (PPD) and to microbial deterioration (MD). Roots of six cassava genotypes were evaluated in two experiments, during storage under different environmental conditions: high temperature and low soil moisture; or low temperature and high soil moisture. Roots were treated or not with fungicide (carbendazim) before storage. Genotype reactions to MD and PPD were evaluated at 0, 2, 5, 10, 15, 20, and 30 days after harvest (DAH), in the proximal, medial, and distal parts of the roots. A diagrammatic scale was proposed to evaluate nonperipheral symptoms of PPD. Fungicide treatment and root position did not influence PPD expression; however, all factors had significant effect on MD severity. Genotypes differed as to their tolerance to PPD and MD. Both deterioration types were more pronounced during periods of higher humidity and lower temperatures. The fungicide treatment increased root shelf life by reducing MD severity up to 10 DAH. Whole roots showed low MD severity and high PPD expression up to 10 DAH, which enabled the assessment of PPD without significant interference of MD symptoms during this period.

Factors influencing the development of bacterial blight of peas.

1954 ◽  
Vol 5 (3) ◽  
pp. 365 ◽  
Author(s):  
DC Wark
Keyword(s):  
Soil Moisture ◽  
Low Temperature ◽  
Moisture Content ◽  
Bacterial Blight ◽  
Soil Moisture Content ◽  
Atmospheric Humidity ◽  
Disease Symptoms ◽  
High Soil Moisture ◽  
Factors Influencing ◽  
Number Of Bacteria

Garden peas commonly carry a nucleus of plants with bacterial blight (Pseudomonas pisi Sackett) in a masked form. When such plants were exposed to low temperature, either by natural frosting or by dipping the tops of the plants in cold liquids, the number of bacteria in the tissues increased rapidly and typical symptoms of the disease occurred in a few days. Soil type and soil moisture content also influenced the development of the disease, which was more marked in peas grown on a red loam from the Dickson Experiment Station than in peas grown on a prepared potting soil. Disease symptoms developed more rapidly a t high soil moisture content than at lower soil moisture content, following exposure to high atmospheric humidity.

AN IMPROVED METHOD FOR BREAKING DORMANCY IN SEEDS OF SESBANIA SESBAN

2008 ◽  
Vol 44 (2) ◽  
pp. 185-195 ◽  
Author(s):  
Y. R. WANG ◽  
J. HANSON
Keyword(s):  
Water Temperature ◽  
Seed Dormancy ◽  
Seed Coat ◽  
Phase 1 ◽  
Sesbania Sesban ◽  
Germination Test ◽  
Two Phase ◽  
Hard Seed ◽  
Hard Seeds ◽  
Breaking Seed Dormancy

SUMMARYDormancy in seeds of Sesbania sesban is caused by a water-impermeable seed coat (hard seeds or hardseededness). A two-phase pretreatment technique was developed for breaking seed dormancy and was validated using different accessions and seed lots. Seeds were first soaked in water at 80 °C for 8 min and prepared for the germination test. Ungerminated hard seeds at the first count (after four days incubation) during the germination test were then subjected to a second treatment by mechanically scarifying the seed coat. The effects of water temperature and variation in initial hardseededness and viability among and within accessions were also investigated. The optimum water temperature, allowing maximum seed germination without increasing the percentage of abnormal seedling/dead seeds was 80 °C. The mean percentage of hard seeds across 30 seed lots of six accessions was reduced to 26% after phase 1 and to 0% after phase 2. In addition, full germination occurred within only 10 days for treated seeds while germination in untreated seeds had reached only 48% after 14 days. Significant differences existed among the seed lots within the accessions (p > 0.05) for the percentage of initial hard seed and for the effects of treatments on breaking seed dormancy. The two-phase technique developed was validated using over 1000 seed lots of S. sesban, and it was found to be a rapid and cost-effective method for breaking hard seed dormancy with potential for wider use for hard-seeded legumes.

Factors Affecting Seed Germination and Emergence of Venice Mallow (Hibiscus trionum)

Weed Science ◽  
2008 ◽  
Vol 56 (4) ◽  
pp. 509-515 ◽  
Author(s):  
Demosthenis Chachalis ◽  
Nikolaos Korres ◽  
Embrahim M. Khah
Keyword(s):  
Seed Coat ◽  
Seedling Emergence ◽  
Management Strategies ◽  
Physical Dormancy ◽  
Factors Affecting ◽  
Hard Seed ◽  
Hibiscus Trionum ◽  
Hard Seeds ◽  
Hydrophilic Material ◽  
Secondary Information

Venice mallow is an emerging weed problem in many regions of the world in various crops. Studies on its hard seed coat were conducted by scanning electron, light, and fluorescence microscopy. The effects of environmental factors on germination and seedling emergence were examined in laboratory experiments. Seeds possessed physical dormancy (90%) that required immersion for 0.5 h in concentrated sulfuric acid to break without damaging the seed. After scarification, 29% of seeds exhibited primary embryo dormancy. Exposure of seeds to even short periods of 15 d of prechilling induced secondary dormancy (10% germination). The surface of hard seeds had a velvety appearance from numerous papillate structures and deposits (hydrophilic material). The location of the water barrier was very superficial in the outer seed coat. Although, in hard seeds, the hilar area appeared to have vertical ruptures and the hilum fissure appeared to be open, there was no water entry. It was observed that microruptures could be the region of structural weakness of hard seeds in relation to water permeability during prolonged burial (8 mo).The highest (60%) germination was recorded at a day/night temperature of 30/20 C with a 12-h photoperiod. No germination was measured at either 10 or 45 C constant temperature. Germination was recorded with a broad range of pH (3-11) and seeds were rather tolerant to low water potential (20% germination at –1.2 MPa). Seedling emergence was higher for seeds buried at 2 cm than for those placed on the surface (54 vs. 38%, respectively). These results showed that Venice mallow is a rather unique species that possesses a complex mechanism of dormancy (physical, primary, and secondary). Information gained in this study will be used in developing management strategies for this species.

Physical and chemical difference of seed coat between hard and soft seeds of Licorice (Glycyrrhiza Uralensis Fisch) 

2018 ◽  
Author(s):  
Qun Sun ◽  
Liwei Zhu ◽  
Wenjing Zhang and Jianhua Wang
Keyword(s):  
Seed Coat ◽  
Mineral Elements ◽  
Chemical Difference ◽  
X Ray ◽  
Hard Seed ◽  
Hard Seeds ◽  
Significant Enrichment ◽  
Physical Impact ◽  
Physical And Chemical ◽  
Hard Seed Coat

In this paper, the physical and chemical differences of seed coat between hard and soft seeds from the same Licorice lot were identified. Electron microscopy-based examination revealed that the cracks on hard seeds coat were much less obvious (shallower and narrower) than those of soft seeds, and that hilar fissure from hard seeds was considerably narrower. Endosperm of hard seeds was markedly thicker than that of soft seeds. Finally, X-ray fluorescence spectrometry revealed significant enrichment for 12 out of the 14 tested mineral elements in hard seed coat. It could be concluded that these above features of hard seeds would increase their resistance to physical impact and protect against cracks in seed coat surface, thus contributing to the impermeability of hard seeds.

Large Scale Basins With Small to Negligible Slopes

2000 ◽  
Vol 31 (1) ◽  
pp. 27-40 ◽  
Author(s):  
Luis Silveira
Keyword(s):  
Soil Moisture ◽  
Large Scale ◽  
Hydrological Model ◽  
Transport Processes ◽  
Moisture Condition ◽  
Soil Moisture Condition ◽  
Soil Moisture Storage ◽  
High Soil Moisture ◽  
Rio Negro ◽  
Moisture Storage

Large basins with small to negligible slopes are seldom considered in the hydrological literature. An example of such basins is the Río Negro catchment in Uruguay. The first of this two-paper series showed the following special features: a) the existence of strongly developed horizontal layers and an essentially impervious B-horizon, b) significantly high soil moisture storage in terms of normally expected rainfall during a storm and c) the importance of vertical water transport processes to establish the soil moisture condition prior to a storm and its role concerning basin runoff response. These observations and hypotheses were taken into account by the lumped conceptual hydrological model called Hidro-Urfing through the percolation function and the basin runoff response function. This second paper shows its application to the Laguna I basin, a sub-basin of the Río Negro catchment with a surface area of 13,945 km2, and its ability to model the major storm hydrographs without any subdivision into smaller sub-basins. Modelling of low flows requires disaggregation of spatial-scale issues. A hydrological model of the entire Río Negro catchment did not previously exist.

Evaluation of Presswheels and Seed Coverers for Direct Seeding of Brassica

HortScience ◽  
1997 ◽  
Vol 32 (4) ◽  
pp. 599E-600
Author(s):  
Regina P. Bracy ◽  
Richard L. Parish
Keyword(s):  
Soil Moisture ◽  
Sandy Loam ◽  
Visual Observation ◽  
Mustard Seed ◽  
High Soil Moisture ◽  
Loam Soil ◽  
Direct Seeded ◽  
Plant Emergence ◽  
Moisture Conditions ◽  
Determine Effect

Improved stand establishment of direct-seeded crops has usually involved seed treatment and/or seed covers. Planters have been evaluated for seed/plant spacing uniformity, singulation, furrow openers, and presswheel design; however, effects of presswheels and seed coverers on plant establishment have not been widely investigated. Five experiments were conducted in a fine sandy loam soil to determine effect of presswheels and seed coverers on emergence of direct-seeded cabbage and mustard. Seed were planted with Stanhay 870 seeder equipped with one of four presswheels and seed coverers. Presswheels included smooth, mesh, concave split, and flat split types. Seed coverers included standard drag, light drag, paired knives, and no coverer. Soil moisture at planting ranged from 8% to 19% in the top 5 cm of bed. Differences in plant counts taken 2 weeks after planting were minimal with any presswheel or seed coverer. Visual observation indicated the seed furrow was more completely closed with the knife coverer in high soil moisture conditions. All tests received at least 14 mm of precipitation within 6 days from planting, which may account for lack of differences in plant emergence.

scholarly journals Disturbances to the Ground and to the Stand in Beech Forests Due to Thinning Treatments Performed by Different Levels of Mechanization

2020 ◽  
Vol 3 (1) ◽  
pp. 58
Author(s):  
Rachele Venanzi ◽  
Loredana Barbona ◽  
Francesco Latterini ◽  
Rodolfo Picchio
Keyword(s):  
Soil Moisture ◽  
Forest Soil ◽  
Anthropogenic Impacts ◽  
Tree Canopy ◽  
Forest Operations ◽  
Beech Forests ◽  
High Soil Moisture ◽  
Forest Logging ◽  
Fagus Sylvatica L ◽  
Different Levels

The aim of this work was to assess the possible impacts on the forest soil and stand due to silvicultural treatment and forest operations in a beech high forest. Even aged beech forests (Fagus sylvatica L.) in the Municipality of Cappadocia (L’Aquila) and in the Municipality of Vallepietra (Roma) were analyzed. The analysis of the soil and stand were performed in order to assess the effects attributable to applied silviculture and forest logging. Two different logging methodologies (in particular for the extraction) were applied: mules were used in the areas with greater slopes and with obstacles, while for the areas with better accessibility, mechanical means were used, in this case tractors. In detail, the main objective was to assess the disturbance on the ground and on the stand, generated by the two different levels of mechanization. In addition, it was also interesting to understand the possible effect on the soil and specifically on the partial uncovering where part of the tree canopy was removed. Only through an accurate cross-analysis of the studied parameters and indices could the anthropogenic impacts on the soil and stand due to forest operations be highlighted according to the different logging methodologies applied. The main results showed that the disturbances caused to the soil and stand were essentially caused in the bunching and extraction operations. The importance of avoiding or limiting the continuous passage of vehicles and animals on forest soil clearly emerges, especially in conditions of high soil moisture. It is also important to use correct technologies that are adequate for the specific environmental characteristics and the work plan. Finally, it can be said that there was no difference in the disturbance caused by the two logging methods when compared. Substantial differences in terms of improvement can be defined when comparing the findings of this study with other research studies. This can be done by applying a different type of mechanization with a different logging system.

scholarly journals Climate Differently Impacts the Growth of Coexisting Trees and Shrubs under Semi-Arid Mediterranean Conditions

Forests ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 381
Author(s):  
J. Julio Camarero ◽  
Cristina Valeriano ◽  
Antonio Gazol ◽  
Michele Colangelo ◽  
Raúl Sánchez-Salguero
Keyword(s):  
Soil Moisture ◽  
Radial Growth ◽  
Pinus Halepensis ◽  
Growth Dynamics ◽  
Early Summer ◽  
Growth Responses ◽  
Shrub Species ◽  
High Soil Moisture ◽  
Semi Arid ◽  
Mediterranean Conditions

Background and Objectives—Coexisting tree and shrub species will have to withstand more arid conditions as temperatures keep rising in the Mediterranean Basin. However, we still lack reliable assessments on how climate and drought affect the radial growth of tree and shrub species at intra- and interannual time scales under semi-arid Mediterranean conditions. Materials and Methods—We investigated the growth responses to climate of four co-occurring gymnosperms inhabiting semi-arid Mediterranean sites in northeastern Spain: two tree species (Aleppo pine, Pinus halepensis Mill.; Spanish juniper, Juniperus thurifera L.) and two shrubs (Phoenicean juniper, Juniperus phoenicea L.; Ephedra nebrodensis Tineo ex Guss.). First, we quantified the intra-annual radial-growth rates of the four species by periodically sampling wood samples during one growing season. Second, we quantified the climate–growth relationships at an interannual scale at two sites with different soil water availability by using dendrochronology. Third, we simulated growth responses to temperature and soil moisture using the forward, process-based Vaganov‒Shashkin (VS-Lite) growth model to disentangle the main climatic drivers of growth. Results—The growth of all species peaked in spring to early summer (May–June). The pine and junipers grew after the dry summer, i.e., they showed a bimodal growth pattern. Prior wet winter conditions leading to high soil moisture before cambium reactivation in spring enhanced the growth of P. halepensis at dry sites, whereas the growth of both junipers and Ephedra depended more on high spring–summer soil moisture. The VS-Lite model identified these different influences of soil moisture on growth in tree and shrub species. Conclusions—Our approach (i) revealed contrasting growth dynamics of co-existing tree and shrub species under semi-arid Mediterranean conditions and (ii) provided novel insights on different responses as a function of growth habits in similar drought-prone regions.

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