Response of kernel growth of barley genotypes with different row type to climatic factors before and after inflection point of grain filling

2020 ◽  
Vol 255 ◽  
pp. 107864
Author(s):  
Dejan Dodig ◽  
Vesna Kandić ◽  
Miroslav Zorić ◽  
Emilija Nikolić-Ðorić ◽  
Sonja Tančić Živanov ◽  
...  
Nematology ◽  
2017 ◽  
Vol 19 (2) ◽  
pp. 185-195
Author(s):  
Nikola Grujić ◽  
Milan Radivojević

Annual decline rates of potato cyst nematode (PCN) populations have been extensively studied. They vary considerably due to many factors, including potato cultivar, initial PCN density and climatic factors. Information is needed on PCN decline in potato fields in the specific conditions of Western Serbia, which is the centre for most of the local potato production, especially seed potato. We investigated the decline of Globodera rostochiensis over 1 or 2 years under the influence of PCN-resistant potato cv. Agria in the field and microplots. Decline was compared with fallow in Ponikve, near the original record of G. rostochiensis. Population decline in the field after cv. Agria was approximately 80%. In two parts of the field where potato cv. Agria was cropped once or twice with fallow before and after, the viable PCN population declined over 9 years to about 1% of initial values. In a third part of the field, left fallow for 9 years, 15% of the initial population was still viable, after an annual decline rate of 9.4%. The influence of volunteer potatoes on maintaining PCN populations was also examined. In the microplots, with a higher density of volunteers compared to the field, PCN decline under resistant potato cv. Agria was 70%. At crop harvest a new generation was recorded, suggesting its possible formation on susceptible volunteer potato. The full cysts represented 1% of all cysts examined and 13% of total second-stage juveniles found in the samples. The information will be useful for improvement of management procedures.


Computation ◽  
2020 ◽  
Vol 8 (2) ◽  
pp. 59 ◽  
Author(s):  
Giovanni Delnevo ◽  
Silvia Mirri ◽  
Marco Roccetti

As we prepare to emerge from an extensive and unprecedented lockdown period, due to the COVID-19 virus infection that hit the Northern regions of Italy with the Europe’s highest death toll, it becomes clear that what has gone wrong rests upon a combination of demographic, healthcare, political, business, organizational, and climatic factors that are out of our scientific scope. Nonetheless, looking at this problem from a patient’s perspective, it is indisputable that risk factors, considered as associated with the development of the virus disease, include older age, history of smoking, hypertension and heart disease. While several studies have already shown that many of these diseases can also be favored by a protracted exposure to air pollution, there has been recently an insurgence of negative commentary against authors who have correlated the fatal consequences of COVID-19 (also) to the exposition of specific air pollutants. Well aware that understanding the real connection between the spread of this fatal virus and air pollutants would require many other investigations at a level appropriate to the scale of this phenomenon (e.g., biological, chemical, and physical), we propose the results of a study, where a series of the measures of the daily values of PM2.5, PM10, and NO2 were considered over time, while the Granger causality statistical hypothesis test was used for determining the presence of a possible correlation with the series of the new daily COVID19 infections, in the period February–April 2020, in Emilia-Romagna. Results taken both before and after the governmental lockdown decisions show a clear correlation, although strictly seen from a Granger causality perspective. Moving beyond the relevance of our results towards the real extent of such a correlation, our scientific efforts aim at reinvigorating the debate on a relevant case, that should not remain unsolved or no longer investigated.


1990 ◽  
Vol 62 (3) ◽  
pp. 227-236 ◽  
Author(s):  
Jari Peltonen ◽  
Tuomo Karvonen ◽  
Erkki Kivi

Interrelationships between climatic factors and spring wheat yield and quality were examined with 21 years field experiments. The formation of gluten was less at dry conditions (total precipitation under 50 mm) and total precipitation exceeded 130—140 mm. The optimum daily temperature for gluten production was some 15—17°C during grain filling. The gluten content decreased if daily minimum and maximum temperatures exceeded 11—12°C and 21—22°C, respectively. The effect of temperature and rainfall were not, however, significant in early maturing varieties. The climatic factors and grain yield did not correlate. Grain yield and protein yield had strong positive relationship, which was perhaps a consequence of supply and utilization of nitrogen. It is concluded that climatic factors affecting yield to quality ration in wheat may be excessive rains before heading and high temperature during grain filling. Interaction between weather and nitrogen are discussed to optimize correct timing of nitrogen fertilization for amount and quality of economic wheat yield.


1997 ◽  
Vol 6 (5-6) ◽  
pp. 399-408 ◽  
Author(s):  
Jonathan Robinson ◽  
Marja Jalli

Data on grain yield, and terminal severity of net blotch (Pyrenophora teres f. teres) and scald (Rhynchosporium secalis) from Finnish official barley (Hordeum vulgare) variety trials were analysed to indicate the pattern of disease incidence over six years and five sites for nineteen barley genotypes, and the effect of the diseases on yield and the genotype by environment interaction for yield. The effect of climatic factors on net blotch severity were also investigated. The genotype by site interaction for net blotch severity was not statistically significant, but that for yield was. Net blotch severity differed between years, but was similar across sites and there were statistically significant first order interactions between year, site and genotype. ‘Saana’ and ‘Thule’ had relatively low mean terminal net blotch scores and their reaction to the disease was less sensitive to the environment than was that of ‘Tyra’ for example. Analysis of yield data adjusted for net blotch severity indicated that the magnitude of the genotype by environment interaction terms were not accounted for to any significant degree by differences in relative net blotch resistances among the barley genotypes. Overall, mean scores for scald severity were lower than those for net blotch. Terminal net blotch severity was correlated with May rainfall and growing degree days.


2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Hui Zhang

Based on social network theory and dynamic capability theory, a theoretical model is constructed that specifies the process through which relational embeddedness affects enterprise value. The authors selected 612 Shenzhen and Shanghai A-share manufacturing enterprises in the CSMAR database as sample enterprises, and a multiple regression analysis method was used to test hypotheses. The results show that (1) there is an inverted “U” relationship between relational embeddedness and enterprise value; that is, the enterprises’ relational embeddedness has an “inflection point” effect on the enterprise value; (2) the enterprises’ resource integration capability plays an intermediate role in the impact of relational embeddedness on enterprise value; (3) the market environmental dynamics and technology environmental dynamics play negative regulatory roles in the inverted “U” relationship between relational embeddedness and enterprise value, and they play different regulatory roles before and after the enterprise relational embeddedness reaches the “inflection point”; that is, before the relational embeddedness reaches the inflection point, the technology environmental dynamics plays a major negative regulatory role, while after the relational embeddedness reaches the inflection point, the market environmental dynamics plays a major negative regulatory role. Compared with the market environmental dynamics, the impact of technology environmental dynamics on the relationship between relational embeddedness and enterprise value is more significant; that is, the effect of relational embeddedness on enterprises value is more sensitive to the technology environmental dynamics.


1995 ◽  
Vol 268 (2) ◽  
pp. H817-H827 ◽  
Author(s):  
C. Melot ◽  
M. Delcroix ◽  
J. Closset ◽  
P. Vanderhoeft ◽  
P. Lejeune ◽  
...  

We investigated whether the Starling resistor model (Mitzner et al. J. Appl. Physiol. 51: 1065–1071, 1981) or a distensible vessel model (Haworth et al. J. Appl. Physiol. 70: 15–26, 1991) best describes pulmonary vascular pressure-flow (Q) relationships in embolic pulmonary hypertension. Mean pulmonary arterial pressure (Ppa)-Q plots at constant left atrial pressure (Pla) and Ppa-Pla plots at constant Q were investigated in seven dogs before and after 500-micron glass bead pulmonary embolism. Embolization to a mean angiographic obstruction of 78% increased the slope and extrapolated pressure intercept (P(i)) of Ppa-Q plots and increased the inflection point of Ppa-Pla plots, above which an increase in Pla is transmitted to Ppa in a ratio of approximately 1:1. The Starling resistor and the distensible vessel model provided a reasonably good fit to the Ppa-Q and Ppa-Pla coordinates before and after embolism. However, contrary to the prediction of the Starling resistor model, no correlation was found between the inflection point of Ppa-Pla plots and P(i). We therefore conclude that an increased closing pressure is unlikely to contribute to embolic pulmonary hypertension.


2018 ◽  
Vol 69 (12) ◽  
pp. 1215 ◽  
Author(s):  
Dejan Dodig ◽  
Vesna Kandić ◽  
Miroslav Zorić ◽  
Emilija Nikolić-Đorić ◽  
Ana Nikolić ◽  
...  

Barley (Hordeum vulgare L.) is often grown in sites with low rainfall and high temperature during grain filling. Because spike architecture is one of basic footprints of barley domestication, the importance of spikes in adaptation to different environments or abiotic stresses can be hypothesised. In order to compare different barley spike types in terms of kernel growth and yield components, we tested 15 two-row and 10 six-row winter genotypes in eight environments where terminal drought was simulated by defoliation at 7 days after heading (7 DAH). Control plants were grown intact. On average, two-row genotypes outyielded six-row genotypes by 17% under control conditions and 33% under simulated late drought. Observations of kernel dry weights from 7 DAH through to harvest maturity at 5-day intervals were regressed onto a measure of thermal time. After preliminary evaluation of four nonlinear (S-shaped) models for kernel dry-weight accumulation, the ordinary logistic model was deemed the most appropriate in most cases and was finally applied to all plant-growth curves. Four parameters were estimated from the logistic model. Whereas two earliness estimators (inflection point and thermal time needed to reach maximum kernel weight) were similar for the two barley types, maximum kernel weight (Ymax) and mean rate of kernel growth (RG) were higher (P<0.05) in two-row than in six-row barleys. Differences in Ymax and RG among six-row barley genotypes were greater between control and defoliation treatments than between years, whereas among two-row barley genotypes, differences between years were greater, suggesting better stability of six-row types and better drought tolerance of two-row types in the tested barley set.


2003 ◽  
Vol 141 (2) ◽  
pp. 203-212 ◽  
Author(s):  
M. ZAHEDI ◽  
C. F. JENNER

Compared with growth at 20/15°C (day/night), exposure of wheat (Triticum aestivum L.) plants to moderately high temperature (30/25°C) significantly decreased grain weight through shortening the duration of grain filling, combined with small (or no) positive increases in the rate of grain filling. Several mathematical models of grain filling were assessed for their suitability as means of analysing these effects of temperature. The ordinary logistic model was found to be the most appropriate model and was used for the analysis of grain filling responses in four cultivars differing in their responses. Genotypic variation in response to temperature was observed for both rate and duration of grain filling, but the variation for the duration of grain filling among cultivars was small at the higher temperature. Significant correlation was found between single grain weight with the rate, but not with the duration, of grain filling at high temperature, which indicated an important role for synthetic processes involved in grain filling in the temperature sensitivity of wheat cultivars. As they are independent traits, both rate and duration are required selection criteria for the improvement of heat tolerance. Responses of one attribute estimated from the logistic model, the inflection point of the course of grain filling, may give insight into a temperature response that is distinguishable from that associated with the duration of grain filling. The inflection point appears to be worth including as a criterion in selecting for high temperature tolerance in wheat.


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