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

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.

Genetika ◽  
2012 ◽  
Vol 44 (3) ◽  
pp. 499-512 ◽  
Author(s):  
Novo Przulj ◽  
Vojislava Momcilovic

Environmental conditions in the Pannonian zone can be characterized with moderate high temperature and partially water deficit during grain filling of spring barley, although low temperature and water deficit are possible also in period till anthesis. This study was conducted to evaluate the variation of the duration of the period from emergence to anthesis (VP), duration of grain filling period (GFP), plant height (PH), spikes number m-2 (SN), grains number spike-1 (GN), thousand grains weight (GW) and yield (YIL) in spring two-rowed barley in conditions of the Pannonian zone. All three factors; genotype, environment and the interaction GxY affected the studied traits. Average VP was 777 GDD, GFP 782 GDD, PH 78 cm, SN 523, GN 28.2, GW 43.2 g and YIL 6.26 t ha-1. Variation across varieties was higher than across growing seasons. Heritability varied from 0.66 for YIL to 0.94 for VP and GFP. This study confirmed that a sufficiently large genetic variability must be base for selecting appropriate varieties for the Pannonian zone conditions. In order to determine high yielding and quality barley extensive research in relation to breeding, variety choice for production and growing practice must be done.


1954 ◽  
Vol 5 (3) ◽  
pp. 365 ◽  
Author(s):  
DC Wark

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.


HortScience ◽  
1995 ◽  
Vol 30 (4) ◽  
pp. 750E-750
Author(s):  
William J. Bramlage ◽  
Sarah A. Weis

Preharvest environmental conditions apparently determine susceptibility of apples to postharvest scald development. Cool temperature, as hours below 10C, can greatly reduce susceptibility, but greater than 30C appears to enhance it. These effects appear to interact, because a high-temperature episode can cause loss of some low-temperature benefit. Shading of fruit increases their scald susceptibility and preharvest light conditions, along with preharvest rainfall, appear to be factors in scald susceptibility in New England. Fruit maturation reduces scald susceptibility. We are constructing models of contributions of these variables to scald susceptibility of fruit grown under different environmental conditions, and in this the relative importance of these variables is being evaluated.


2019 ◽  
Vol 79 (01S) ◽  
Author(s):  
Debashis Paul ◽  
S. K. Chakrabarty ◽  
H. K. Dikshit ◽  
S. K. Jha ◽  
G. Chawla ◽  
...  

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.


2004 ◽  
Vol 261-263 ◽  
pp. 1301-1306 ◽  
Author(s):  
S.C. Kwon ◽  
P.K. Dutta ◽  
Yun Hae Kim ◽  
Soo Hyun Eum ◽  
Dong Hyuk Shin ◽  
...  

A summary of the experimental fatigue characterization of FRP composite bridge decks at two extreme temperatures [-30 ° C (-22 ° F) and 50 ° C (122 ° F)] is presented. Each deck was initially subjected to one million wheel load cycles at low temperature and another one million cycles at high temperature [1,2]. The results presented in this paper correspond to the fatigue response of each deck for four million load cycles at low temperature and another four million cycles at high temperature. Thus, the each deck was subjected to a total of ten million cycles. Progressive degradation in stiffness with cycling was noted for each deck. Comparisons of responses were made between the different FRP composite deck configurations and materials.


1994 ◽  
Vol 119 (6) ◽  
pp. 1234-1242 ◽  
Author(s):  
John P. Navazio ◽  
Jack E. Staub

Two experiments (1989 and 1990) were designed to characterize the response of cucumber (Cucumis sativus L.) plants with different leaf types [normal leaf (LL) vs. little leaf (ll)] to high soil moisture tension (SMT) and to determine whether hydrocooling would reduce the severity of pillowy fruit disorder (PFD). Comparisons were made among nine cultivars (7 LL and 2 ll) for aboveground vegetative and fruit response, and between two irrigation regimes. High SMT generally caused increased wilt ratings and stomatal conductance and decreased plant dry weight. PFD severity of fruit from watered plots was less [61% (Expt. 1, 1989) and 26% (Expt. 1, 1990)] than of fruit harvested from plots in which water was withheld. The response of the two ll cultivars to moisture stress differed depending on environmental conditions. Increased PFD severity was associated with increased temperature, lower relative humidity (RH), and excluding hydrocooling during postharvest handling. Of the four storage treatments examined, hydrocooling to ≈8.5C then storage at 15C and 85% RH for 4 days produced fruit with the least PFD symptoms. Fruit of `Carolina' (LL) exhibited the highest PFD ratings, while those of `Calypso' (LL) were consistently low compared to other cultivars. Processors can lower PFD incidence and severity by ensuring that adequate moisture is available to plants during fruit enlargement and that harvested fruit are hydrocooled before shipping and storage.


Author(s):  
P.P.K. Smith

Grains of pigeonite, a calcium-poor silicate mineral of the pyroxene group, from the Whin Sill dolerite have been ion-thinned and examined by TEM. The pigeonite is strongly zoned chemically from the composition Wo8En64FS28 in the core to Wo13En34FS53 at the rim. Two phase transformations have occurred during the cooling of this pigeonite:- exsolution of augite, a more calcic pyroxene, and inversion of the pigeonite from the high- temperature C face-centred form to the low-temperature primitive form, with the formation of antiphase boundaries (APB's). Different sequences of these exsolution and inversion reactions, together with different nucleation mechanisms of the augite, have created three distinct microstructures depending on the position in the grain.In the core of the grains small platelets of augite about 0.02μm thick have farmed parallel to the (001) plane (Fig. 1). These are thought to have exsolved by homogeneous nucleation. Subsequently the inversion of the pigeonite has led to the creation of APB's.


2020 ◽  
Vol 10 (10) ◽  
pp. 59-67
Author(s):  
Victor N. ANTIPOV ◽  
◽  
Andrey D. GROZOV ◽  
Anna V. IVANOVA ◽  
◽  
...  

The overall dimensions and mass of wind power units with capacities larger than 10 MW can be improved and their cost can be decreased by developing and constructing superconducting synchronous generators. The article analyzes foreign conceptual designs of superconducting synchronous generators based on different principles: with the use of high- and low-temperature superconductivity, fully superconducting or only with a superconducting excitation system, and with the use of different materials (MgB2, Bi2223, YBCO). A high cost of superconducting materials is the main factor impeding commercial application of superconducting generators. In view of the state of the art in the technology for manufacturing superconductors and their cost, a conclusion is drawn, according to which a synchronous gearless superconducting wind generator with a capacity of 10 MW with the field winding made of a high-temperature superconducting material (MgB2, Bi-2223 or YBCO) with the «ferromagnetic stator — ferromagnetic rotor» topology, with the stator diameter equal to 7—9 m, and with the number of poles equal to 32—40 has prospects for its practical use in the nearest future.


Alloy Digest ◽  
1980 ◽  
Vol 29 (12) ◽  

Abstract SOMERS LTA Copper is a wrought copper foil that can be annealed at 350 F in 15 minutes to the full-soft condition; its use simplifies the manufacture of printed circuits (LTA = Low-Temperature Annealable). LTA Copper is especially useful for foil weights up to and including one ounce per square foot (0.0014-inch thick) for laminating to high-temperature dielectric substrates. This datasheet provides information on composition, physical properties, and elasticity as well as fatigue. It also includes information on forming, heat treating, and machining. Filing Code: Cu-407. Producer or source: Olin Corporation.


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