scholarly journals Winter wheat in England and Wales, 1923–1995: what do indices of genetic diversity reveal?

2003 ◽  
Vol 1 (1) ◽  
pp. 43-57 ◽  
Author(s):  
C. S. Srinivasan ◽  
Colin Thirtle ◽  
Paolo Palladino
Keyword(s):  
Genetic Diversity ◽  
Winter Wheat ◽  
Plant Breeding ◽  
Genetic Resources ◽  
Wheat Crop ◽  
England And Wales ◽  
Genealogical Relationship ◽  
Breeding Programmes ◽  
Winter Wheat Crop ◽  
The Stability

AbstractGenealogical data have been used very widely to construct indices with which to examine the contribution of plant breeding programmes to the maintenance and enhancement of genetic resources. In this paper we use such indices to examine changes in the genetic diversity of the winter wheat crop in England and Wales between 1923 and 1995. We find that, except for one period characterized by the dominance of imported varieties, the genetic diversity of the winter wheat crop has been remarkably stable. This agrees with many studies of plant breeding programmes elsewhere. However, underlying the stability of the winter wheat crop is accelerating varietal turnover without any significant diversification of the genetic resources used. Moreover, the changes we observe are more directly attributable to changes in the varietal shares of the area under winter wheat than to the genealogical relationship between the varieties sown. We argue, therefore, that while genealogical indices reflect how well plant breeders have retained and exploited the resources with which they started, these indices suffer from a critical limitation. They do not reflect the proportion of the available range of genetic resources which has been effectively utilized in the breeding programme: complex crosses of a given set of varieties can yield high indices, and yet disguise the loss (or non-utilization) of a large proportion of the available genetic diversity.

Effect of Winter Wheat Crop Residue on No-Till Corn Growth and Development

2007 ◽  
Vol 99 (2) ◽  
pp. 549-555 ◽  
Author(s):  
Anatoliy G. Kravchenko ◽  
Kurt D. Thelen
Keyword(s):  
Winter Wheat ◽  
Growth And Development ◽  
Crop Residue ◽  
Wheat Crop ◽  
No Till ◽  
Winter Wheat Crop

scholarly journals Winter wheat crop water consumption and its effect on yields in southern Romania, in the very dry 2019-2020 agricultural year

2021 ◽  
Vol 49 (2) ◽  
pp. 12309
Author(s):  
Mihai BERCA ◽  
Valentina-Ofelia ROBESCU ◽  
Roxana HOROIAS
Keyword(s):  
Winter Wheat ◽  
Water Consumption ◽  
Soil Depth ◽  
Vegetation Period ◽  
Early Summer ◽  
Wheat Crop ◽  
Soil Drought ◽  
Crop Water ◽  
Winter Wheat Crop ◽  
Crop Water Consumption

Researches on winter wheat in the south part of Romanian Plain during the dry years 2019 and 2020 have been focused on the crop water consumption issue in excessive conditions of air and soil drought. The wheat crop water consumption in the research sites (Calarasi and Teleorman counties), for the entire vegetation period, autumn – spring – summer, is between 1000 and 1050 m3 of water for each ton of wheat produced. Only in the spring-summer period, the wheat extracts a quantity of about 5960 m3 ha-1, i.e. 851 m3 t-1. The useful water reserve is normally located at about 1500 m3/ha-1, at a soil depth of 0-150 cm. In the spring of 2020, it has been below 400 m3 ha-1, so that at the beginning of May the soil moisture had almost reached the wilting coefficient (WC). Wheat plants have been able to survive the thermal and water shock of late spring - early summer, due to enhanced thermal alternation between air and soil. For a period of about 34 days, this alternation brought the plants 1-1.5 mm water, i.e. approximately 442 m3 ha-1, which allowed the prolongation of the plant’s agony until the rains of the second half of May. Yields have been, depending on the variety, between 1500 and 3000 kg ha-1, in average, covering only 60% of the crop costs. Other measures to save water in the soil have also been proposed in the paper.

Аgroclimatic conditions for formation of the winter wheat crop in the territory of the south federal district

2021 ◽  
Author(s):  
I. F. Asaulyak ◽  
Keyword(s):  
Winter Wheat ◽  
Federal District ◽  
Meteorological Station ◽  
Wheat Crop ◽  
The South ◽  
Winter Wheat Crop

An assessment of the dynamics of the average regional yield and the climatic component of winter wheat yields in the territory of the Southern Federal District has been carried out. The dynamics of the duration of dry and dry periods was determined according to the data of the Krasnodar meteorological station.

scholarly journals Influence of Soil Background on Spectral Reflectance of Winter Wheat Crop Canopy

2019 ◽  
Vol 11 (16) ◽  
pp. 1932 ◽  
Author(s):  
Elena Prudnikova ◽  
Igor Savin ◽  
Gretelerika Vindeker ◽  
Praskovia Grubina ◽  
Ekaterina Shishkonakova ◽  
...  
Keyword(s):  
Winter Wheat ◽  
Soil Type ◽  
Spectral Reflectance ◽  
Vegetation Index ◽  
Vegetation Indices ◽  
Soil Surface ◽  
Wheat Crop ◽  
Crop Canopy ◽  
Winter Wheat Crop ◽  
Type Factor

The spectral reflectance of crop canopy is a spectral mixture, which includes soil background as one of the components. However, as soil is characterized by substantial spatial variability and temporal dynamics, its contribution to the spectral reflectance of crops will also vary. The aim of the research was to determine the impact of soil background on spectral reflectance of crop canopy in visible and near-infrared parts of the spectrum at different stages of crop development and how the soil type factor and the dynamics of soil surface affect vegetation indices calculated for crop assessment. The study was conducted on three test plots with winter wheat located in the Tula region of Russia and occupied by three contrasting types of soil. During field trips, information was collected on the spectral reflectance of winter wheat crop canopy, winter wheat leaves, weeds and open soil surface for three phenological phases (tillering, shooting stage, milky ripeness). The assessment of the soil contribution to the spectral reflectance of winter wheat crop canopy was based on a linear spectral mixture model constructed from field data. This showed that the soil background effect is most pronounced in the regions of 350–500 nm and 620–690 nm. In the shooting stage, the contribution of the soil prevails in the 620–690 nm range of the spectrum and the phase of milky ripeness in the region of 350–500 nm. The minimum contribution at all stages of winter wheat development was observed at wavelengths longer than 750 nm. The degree of soil influence varies with soil type. Analysis of variance showed that normalized difference vegetation index (NDVI) was least affected by soil type factor, the influence of which was about 30%–50%, depending on the stage of winter wheat development. The influence of soil type on soil-adjusted vegetation index (SAVI) and enhanced vegetation index (EVI2) was approximately equal and varied from 60% (shooting phase) to 80% (tillering phase). According to the discriminant analysis, the ability of vegetation indices calculated for winter wheat crop canopy to distinguish between winter wheat crops growing on different soil types changed from the classification accuracy of 94.1% (EVI2) in the tillering stage to 75% (EVI2 and SAVI) in the shooting stage to 82.6% in the milky ripeness stage (EVI2, SAVI, NDVI). The range of the sensitivity of the vegetation indices to the soil background depended on soil type. The indices showed the greatest sensitivity on gray forest soil when the wheat was in the phase of milky ripeness, and on leached chernozem when the wheat was in the tillering phase. The observed patterns can be used to develop vegetation indices, invariant to second-type soil variations caused by soil type factor, which can be applied for the remote assessment of the state of winter wheat crops.

Estimation of winter wheat crop growth parameters using time series Sentinel-1A SAR data

2017 ◽  
Vol 33 (9) ◽  
pp. 942-956 ◽  
Author(s):  
P. Kumar ◽  
R. Prasad ◽  
D. K. Gupta ◽  
V. N. Mishra ◽  
A. K. Vishwakarma ◽  
...  
Keyword(s):  
Time Series ◽  
Winter Wheat ◽  
Growth Parameters ◽  
Crop Growth ◽  
Wheat Crop ◽  
Winter Wheat Crop ◽  
Sar Data

Extrapolating gross primary productivity from leaf to canopy scale in a winter wheat crop

2008 ◽  
Vol 148 (4) ◽  
pp. 668-679 ◽  
Author(s):  
Julien Hoyaux ◽  
Christine Moureaux ◽  
Denis Tourneur ◽  
Bernard Bodson ◽  
Marc Aubinet
Keyword(s):  
Winter Wheat ◽  
Primary Productivity ◽  
Gross Primary Productivity ◽  
Wheat Crop ◽  
Winter Wheat Crop
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