PART OF A SPECIAL ISSUE ON GROWTH AND ARCHITECTURAL MODELLING Simulation of fruit-set and trophic competition and optimization of yield advantages in six Capsicum cultivars using functional-structural plant modelling

BACKGROUND AND AIMS Many indeterminate plants can have wide fluctuations in the pattern of fruit-set and harvest. Fruit-set in these types of plants depends largely on the balance between source (assimilate supply) and sink strength (assimilate demand) within the plant. This study aims to evaluate the ability of functional-structural plant models to simulate different fruit-set patterns among Capsicum cultivars through source-sink relationships. METHODS A greenhouse experiment of six Capsicum cultivars characterized with different fruit weight and fruit-set was conducted. Fruit-set patterns and potential fruit sink strength were determined through measurement. Source and sink strength of other organs were determined via the GREENLAB model, with a description of plant organ weight and dimensions according to plant topological structure established from the measured data as inputs. Parameter optimization was determined using a generalized least squares method for the entire growth cycle. KEY RESULTS AND CONCLUSIONS Fruit sink strength differed among cultivars. Vegetative sink strength was generally lower for large-fruited cultivars than for small-fruited ones. The larger the size of the fruit, the larger variation there was in fruit-set and fruit yield. Large-fruited cultivars need a higher source-sink ratio for fruit-set, which means higher demand for assimilates. Temporal heterogeneity of fruit-set affected both number and yield of fruit. The simulation study showed that reducing heterogeneity of fruit-set was obtained by different approaches: for example, increasing source strength; decreasing vegetative sink strength, source-sink ratio for fruit-set and flower appearance rate; and harvesting individual fruits earlier before full ripeness. Simulation results showed that, when we increased source strength or decreased vegetative sink strength, fruit-set and fruit weight increased. However, no significant differences were found between large-fruited and small-fruited groups of cultivars regarding the effects of source and vegetative sink strength on fruit-set and fruit weight. When the source-sink ratio at fruit-set decreased, the number of fruit retained on the plant increased competition for assimilates with vegetative organs. Therefore, total plant and vegetative dry weights decreased, especially for large-fruited cultivars. Optimization study showed that temporal heterogeneity of fruit-set and ripening was predicted to be reduced when fruits were harvested earlier. Furthermore, there was a 20 % increase in the number of extra fruit set.

[1]  E. Goldschmidt.  Carbohydrate Supply as a Critical Factor for Citrus Fruit Development and Productivity , 1999 .

[2]  PuechClaude,et al.  Plant models faithful to botanical structure and development , 1988 .

[3]  D. Barthélémy,et al.  Plant architecture: a dynamic, multilevel and comprehensive approach to plant form, structure and ontogeny. , 2007, Annals of botany.

[4]  P. de Reffye,et al.  Parameter optimization and field validation of the functional-structural model GREENLAB for maize. , 2006, Annals of botany.

[5]  P. de Reffye,et al.  A dynamic, architectural plant model simulating resource-dependent growth. , 2004, Annals of botany.

[6]  Bill Shipley,et al.  Trade‐offs between net assimilation rate and specific leaf area in determining relative growth rate: relationship with daily irradiance , 2002 .

[7]  L. Marcelis,et al.  A simulation model for dry matter partitioning in cucumber. , 1994, Annals of botany.

[8]  Yiping Zhang,et al.  Prevention of Flower Abscission in Bell Pepper , 1991 .

[9]  Ep Heuvelink,et al.  How to reduce yield fluctuations in sweet pepper , 2004 .

[10]  E. Heuvelink,et al.  Flower and fruit abortion in sweet pepper in relation to source and sink strength. , 2004, Journal of experimental botany.

[11]  M. Tollenaar,et al.  Source : sink ratio and leaf senescence in maize:: I. Dry matter accumulation and partitioning during grain filling , 1999 .

[12]  Jan Vos,et al.  Modelling of Spatial Light Distribution in the Greenhouse: Description of the Model , 2009, 2009 Third International Symposium on Plant Growth Modeling, Simulation, Visualization and Applications.

[13]  Parameter Estimation and Growth Variation Analysis in Six Capsicum Cultivars with the Functional-Structural Model GreenLab , 2009, 2009 Third International Symposium on Plant Growth Modeling, Simulation, Visualization and Applications.

[14]  Marc Jaeger,et al.  Plant models faithful to botanical structure and development , 1988, SIGGRAPH.

[15]  A. de Gelder,et al.  Toward an optimal control strategy for sweet pepper production 2. optimization of the yield pattern and energy efficiency , 2006 .

[16]  J. Ledent,et al.  Evolution of flowering, ripening and seed set in buckwheat (Fagopyrum esculentum Moench): quantitative analysis , 2005 .

[17]  T. Doré,et al.  The role of grain number, nitrogen nutrition and stem number in limiting pea crop (Pisum sativum) yields under agricultural conditions , 1998 .

[18]  E. Heuvelink.  Evaluation of a Dynamic Simulation Model for Tomato Crop Growth and Development , 1999 .

[19]  Leo F. M. Marcelis,et al.  The Dynamics of Growth and Dry Matter Distribution in Cucumber , 1992 .

[20]  Ep Heuvelink,et al.  Dry Matter Partitioning in Tomato: Validation of a Dynamic Simulation Model , 1996 .

[21]  C. de Vega,et al.  A multi-year study of factors affecting fruit production in Aristolochia paucinervis (Aristolochiaceae). , 2006, American journal of botany.

[22]  W. Bruening,et al.  Fruit development and reproductive survival in soybean: Position and age effects , 2006 .

[23]  L. Marcelis,et al.  Growth analysis of sweet pepper fruits (Capsicum annuum L.) , 1995 .

[24]  Paul-Henry Cournède,et al.  Rhythms and alternating patterns in plants as emergent properties of a model of interaction between development and functioning. , 2007, Annals of botany.

[25]  F. Tardieu,et al.  Heat Stress-induced Abortion of Buds and Flowers in Pea: Is Sensitivity Linked to Organ Age or to Relations between Reproductive Organs? , 1997 .

[26]  A. Lindenmayer,et al.  Developmental models of herbaceous plants , 1990 .

[27]  A. Schaffer,et al.  Changes of Carbohydrates in Pepper (Capsicum annuum L.) Flowers in Relation to Their Abscission Under Different Shading Regimes , 1996 .

[28]  B. Andrieu,et al.  Functional-structural plant modelling: a new versatile tool in crop science. , 2010, Journal of experimental botany.

[29]  H. Nilwik.  Growth Analysis of Sweet Pepper (Capsicum annuum L.)1. The Influence of Irradiance and Temperature under Glasshouse Conditions in Winter , 1981 .

[30]  N. Bertin,et al.  TOMATO FRUIT-SET : A CASE STUDY FOR VALIDATION OF THE MODEL TOMGRO , 1993 .

[31]  W. Pettigrew.  Source-to-Sink Manipulation Effects on Cotton Lint Yield and Yield Components , 1994 .

[32]  E. Heuvelink,et al.  Genetic differences in fruit-set patterns are determined by differences in fruit sink strength and a source : sink threshold for fruit set. , 2009, Annals of botany.

[33]  B. S. Jackson,et al.  Modeling Cotton Fruiting Form Abscission 1 , 1986 .

[34]  E. Heuvelink,et al.  Parthenocarpic Fruit Growth Reduces Yield Fluctuation and Blossom-end Rot in Sweet Pepper , 2001 .

[35]  Critical yield components and key loss factors of tropical cucumber crops , 2006 .

[36]  Yuntao Ma,et al.  Fruit Set and Yield Patterns in Six Capsicum Cultivars , 2009 .