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Determination of Wheat Growth‐Environment Relationships 1
Author(s) -
Haun J. R.
Publication year - 1973
Publication title -
agronomy journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.752
H-Index - 131
eISSN - 1435-0645
pISSN - 0002-1962
DOI - 10.2134/agronj1973.00021962006500050042x
Subject(s) - regression analysis , environmental science , mathematics , variables , growth rate , regression , variable (mathematics) , moisture , current (fluid) , statistics , agronomy , soil science , geography , meteorology , biology , physics , mathematical analysis , geometry , thermodynamics
Wheat ( Triticum aestivum L. em. Thell.) growth data were obtained from field plantings in North Dakota by observing morphological development at intervals of 1 to several days. The system of observation was based on rate of production of leaves and other plant parts. The emergence of each leaf or other unit was subdivided into appropriate decimal divisions. The rate of development was determined by subtraction of the previous day's observation from the current observation of morphological development. Environmental data collected in the vicinity of the plants included solar radiation, maximum and minimum air temperature, maximum and minimum soil temperature, rainfall, soil moisture, and evaporation. The status of soil moisture was also estimated by the Thornthwaite‐Mather method. In subsequent statistical analyses, environmental data were evaluated with respect to their current effects as well as to the delayed or lagged effects for each of the 4 days prior to growth observations. These variables were used in their original form and also transformed into the square, cube, and selected cross products of important variables to account for curvilinear effects and interactions of various environmental factors. Daily growth rate was used as the dependent variable; age, cumulative development, and environmental data, with appropriate lags and transformations, were used as independent variables. Multiple regression analyses were conducted to determine the overall relationship of the various environmental factors to growth rate. A prediction equation was obtained. The objective of this research was to determine whether data from daily visual quantification of wheat development could be related to variations in the major environmental variables. Daily growth rates for 1966, predicted by the equation obtained from analysis of 1967 data, were in close agreement with observed growth rates. Due to the complex interrrlationships of environmental factors, the 13 independent variables of this equation are not necessarily an exclusive or unique expression of the environment. However, tests of significance and tests of the prediction equation on unrelated data indicated that quantitative morphological observations may provide a potent dependent variable for relating plant growth to environmental factors.