A phenological model of winter oilseed rape according to the BBCH scale

2016 ◽  
Vol 67 (4) ◽  
pp. 345 ◽  
Author(s):  
Ulf Böttcher ◽  
Enrico Rampin ◽  
Karla Hartmann ◽  
Federica Zanetti ◽  
Francis Flenet ◽  
...  

Implementation of the BBCH coding system for winter oilseed rape (OSR) phenology simulation can allow detailed description of crop ontogeny necessary for crop management and crop growth modelling. We developed such a BBCH model using an existing approach (Habekotté 1997). The new model describes winter OSR development by a combination of differential and conversion equations based on the structure of the BRASNAP-PH model (Habekotté 1997). Six phenological phases were reproduced daily according to the BBCH codes (00–89): emergence (00–09), leaf development (10–19), stem elongation (30–39), inflorescence emergence (50–59), flowering (60–69) and pod development-maturation period (70–89). The model takes into account temperature (including vernalisation) and photoperiod as the main environmental forces affecting crop phenology. The macro stages of leaf development and shooting were reproduced considering the rates of leaf appearance and internode extension. Model calibration and validation were performed using an extensive database of phenological observations collected from several experimental sites across France (n = 144), Germany (n = 839) and Italy (n = 577). The stability of the parameterisation was checked by a cross-calibration procedure. Applied to the independent datasets used for validation and cross-validation, the model was able to predict the whole-crop cycle with a root mean square error (RMSE) of 2.8 and 3.2 BBCH stages, respectively. Particularly accurate predictions of winter OSR development were obtained with the Italian datasets (RMSE: 2.1 and 2.3 BBCH stages for validation and cross-validation, respectively). Considering the phenological phases separately, emergence, leaf development, flowering and the pod development–maturation period were simulated with RMSE of 1.0, 2.4, 2.9 and 3.2 BBCH stages, respectively (validation datasets). Slightly higher uncertainty emerged in the prediction of stem elongation and inflorescence emergence phases (RMSE: 3.5 and 4.1 BBCH stages, validation datasets). The model reproduced winter OSR development with a sufficient degree of accuracy for a wide range of years, locations, sowing dates and genotypes, resulting in an efficient and widely applicable prediction tool with relevant practical purposes in the crop management scheduling.

BioControl ◽  
2009 ◽  
Vol 54 (4) ◽  
pp. 505-514 ◽  
Author(s):  
Johann G. Zaller ◽  
Dietmar Moser ◽  
Thomas Drapela ◽  
Claudia Schmöger ◽  
Thomas Frank

2013 ◽  
Vol 64 (2) ◽  
pp. 115 ◽  
Author(s):  
A. N. Papantoniou ◽  
J. T. Tsialtas ◽  
D. K. Papakosta

For crops grown in Mediterranean environments, translocation of pre-anthesis assimilates to the fruit is of great importance, because hot and dry conditions during fruit ripening diminish net assimilation rate and nitrogen (N) uptake. This field study was conducted to assess the pattern of dry matter and N accumulation and the role of assimilate translocation in pod development of oilseed rape plants in a Mediterranean environment. Four cultivars of winter oilseed rape (Brassica napus L.), i.e. three hybrids (Royal, Exact, Excalibur) and an inbred line (Fortis), were grown for two growing seasons (2005–06 and 2006–07) in northern Greece. On average, 581, 1247, 1609, and 2749 growing degree-days (GDD) were required for six leaves, stem elongation, 50% anthesis in main stem, and physiological maturity in the first year, and 539, 1085, 1601, and 2728 GDD in the second year. The R2 of the modified Richards function indicated that aboveground biomass and N accumulation were described with high approximation efficacy. The across-cultivars genotype mean maximum predicted total aboveground dry matter and N content were 1368.8 and 21.4 g m–2 in 2006 and 1655.1 and 25.4 g m–2 in 2007. In 2007, dry matter and N translocation from vegetative tissues to pods were 464.4 and 21.0 g m–2, and significantly higher than the corresponding values recorded in 2006 (264.4 and 17.0 g m–2). These differences were due to greater amounts of dry matter and N accumulating at anthesis and the greater sink capacity of plants (pod number) in 2007. The fact that pod development occurred in a period when N accumulation by oilseed rape plants had stopped led to high values of contribution of pre-anthesis N accumulation to pod N content in both years (92.8% in 2006 and 96.6% in 2007). Results indicated that hot and dry weather post anthesis reduced dramatically the net assimilation rates; thus, translocation of pre-anthesis assimilates was crucial for pod development. The results demonstrate that variation in weather conditions between growing seasons is one of the main causes of seasonal variation in oilseed rape productivity under Mediterranean conditions.


2015 ◽  
Vol 154 (3) ◽  
pp. 425-437 ◽  
Author(s):  
T. REN ◽  
J. ZOU ◽  
Y. WANG ◽  
X. K. LI ◽  
R. H. CONG ◽  
...  

SUMMARYEstimating crop nutrient requirements for winter oilseed rape (Brassica napus L.) is a crucial step in optimizing fertilization to enhance seed yield and improve fertilizer use efficiency. In the present paper, a database composed of 1035 on-farm observations collected from 2005 to 2010 across the major winter oilseed rape production regions in China was used to evaluate internal nutrient efficiencies (kg seed per kg nutrient in plant dry matter); then the Quantitative Evaluation of the Fertility of Tropical Soils (QUEFTS) model for winter oilseed rape was developed to describe the nutrient uptake-yield relationship of oilseed rape over a wide range of environmental conditions and predict the nutrient requirements for a target yield. After excluding observations with low harvest index values, <0·20, and excluding 0·025 of the highest and lowest internal nutrient efficiencies, the minimum and maximum internal nutrient efficiencies were estimated as 13·1 and 31·6 kg seed/kg nitrogen (N), 68·9 and 200·3 kg seed/kg phosphorus (P) and 8·9 and 31·1 kg seed/kg potassium (K), respectively. On the basis of the data settings, the balanced N, P and K uptake at different yield potential levels was calculated using a linear–parabolic–plateau curve with the QUEFTS model. Crop nutrient requirements increased linearly until the yield reached approximately 0·60–0·70 of the potential yield, and 46·0 kg N, 8·0 kg P and 57·1 kg K were found to be needed to produce 1000 kg of seed. The corresponding internal nutrient efficiencies were 21·8, 125·1 and 17·5 kg seed/kg N, P and K, respectively. However, when the target yields approached the yield potential, a decrease in internal nutrient efficiencies was detected in the model. The predicted nutrient requirement values simulated by the QUEFTS model compared well with observed values across a range of conditions. To conclude, the QUEFTS model was shown to be a practical and robust tool for assessing the crop nutrient requirements of winter oilseed rape.


Agronomie ◽  
2003 ◽  
Vol 23 (8) ◽  
pp. 725-736 ◽  
Author(s):  
Jean-Fran�ois Dejoux ◽  
Jean-Marc Meynard ◽  
Raymond Reau ◽  
Romain Roche ◽  
Patrick Saulas

2021 ◽  
Vol 13 (15) ◽  
pp. 2951
Author(s):  
Johannes Löw ◽  
Tobias Ullmann ◽  
Christopher Conrad

This study explores the potential of Sentinel-1 Synthetic Aperture Radar (SAR) to identify phenological phases of wheat, sugar beet, and canola. Breakpoint and extreme value analyses were applied to a dense time series of interferometric (InSAR) and polarimetric (PolSAR) features recorded during the growing season of 2017 at the JECAM site DEMMIN (Germany). The analyses of breakpoints and extrema allowed for the distinction of vegetative and reproductive stages for wheat and canola. Certain phenological stages, measured in situ using the BBCH-scale, such as leaf development and rosette growth of sugar beet or stem elongation and ripening of wheat, were detectable by a combination of InSAR coherence, polarimetric Alpha and Entropy, and backscatter (VV/VH). Except for some fringe cases, the temporal difference between in situ observations and breakpoints or extrema ranged from zero to five days. Backscatter produced the signature that generated the most breakpoints and extrema. However, certain micro stadia, such as leaf development of BBCH 10 of sugar beet or flowering BBCH 69 of wheat, were only identifiable by the InSAR coherence and Alpha. Hence, it is concluded that combining PolSAR and InSAR features increases the number of detectable phenological events in the phenological cycles of crops.


Agronomy ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 645
Author(s):  
Agnieszka Łopatyńska ◽  
Jan Bocianowski ◽  
Adrian Cyplik ◽  
Joanna Wolko

Limited genetic variability is a major problem in rapeseed breeding, whose strict selection, limited geographical range and a short period of domestication has led to a reduction in genetic and phenotypic diversity. Assessing specific populations for the greatest genetic diversity for many traits simultaneously, requires the evaluation of multi-feature characteristics. The aim of this study was to estimate the variability of DH (doubled haploid) lines and two generations of winter oilseed rape hybrids. In addition, the relationship between the Mahalanobis distances of parental forms and the effect of heterosis in hybrids was investigated. The results of MANOVA showed that the genotypes and years as well as genotype × year interaction were significantly different (p < 0.001) for all eight observed traits. The first (V1) and the second (V2) canonical variate explained 38.57% and 27.55% of the total variation in 2015, and 50.19% and 31.84% in 2016, respectively Canonical variate analysis showed that the traits, flowering time and number of branches per plant had a very large influence on the differentiation of genotypes. Graphs demonstrated that the tested DH lines and hybrids are characterized by a similar, wide range of variability. It was observed, that when using a diverse population of DH lines for crossbreeding with only one CMS/Rfo line, there was no significant reduction of variation in hybrid generations and between these generations. The phenotypic distance values determined by the results of Mahalanobis analysis were similar in both years, but slightly wider in 2016. The observed minimum and maximum ranged from 1.324 to 22.356 in 2015, and from 1.105 to 27.792 in 2016, respectively. No significant correlation was observed between the hybrid heterosis effect and the Mahalanobis distance of the parental lines.


2011 ◽  
Vol 30 (1) ◽  
pp. 77-84 ◽  
Author(s):  
Jan Piekarczyk ◽  
Hanna Sulewska ◽  
Grażyna Szymańska

Winter Oilseed-Rape Yield Estimates from Hyperspectral Radiometer Measurements Spectral reflectance data can be used for estimation of plant biophysical parameters such as seed yield, related to the use of solar energy. A field experiment was conducted to investigate relationships between canopy reflectance and seed yield of winter oilseed rape sown on four different dates. Ground hyperspectral reflectance measurements were made using a hand-held radiometer and multispectral images were taken with a VIS-NIR camera. The different sowing dates generated a wide range of difference in crop spectral response and seed yields. The strongest relationships (R2=0.87) between the yield and spectral data recorded by both sensors occurred at early flowering stages. Later, the presence of flowers caused a decline in the relationship between yield and spectral data especially in the visible (VIS) range. In the full flowering stage the strongest correlation (R2=0.72) with the yield showed vegetation indices of the near-infrared (NIR) bands.


Sign in / Sign up

Export Citation Format

Share Document