Double sigmoidal models describing the growth of coffee berries
Double sigmoidal models describing the growth of coffee berries
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DOI：
10.1590/0103-8478cr20160646
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发表时间：
2017-01-01
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影响因子：
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通讯作者：
Muniz, Joel Augusto
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文献类型：
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作者：
Fernandes, Tales Jesus;Pereira, Adriele Aparecida;Muniz, Joel Augusto
本研究的目的是验证咖啡浆果的生长模式，考虑随着时间的推移，新鲜的质量积累，是双S形，并选择最合适的非线性模型来描述这种行为。所使用的数据包括14个纵向观察的平均新鲜质量的咖啡浆果在实验中获得的栽培品种Obata IAC 1669-20。Logistic和Gompertz模型提供的拟合在其单版本和双版本中进行了比较。使用R软件的nls功能中实现的Gauss-Newton算法，使用最小二乘法估计参数。可以得出结论，咖啡果实的生长模式，在新鲜质量积累，是双S形。双Gompertz模型和双Logistic模型均能较好地描述这一生长曲线，双Logistic模型具有一定的优越性。
This study aimed to verify if the growth pattern of coffee berries, considering fresh mass accumulation over time, is double sigmoid and to select the most suitable nonlinear model to describe such behavior. Data used consisted of fourteen longitudinal observations of average fresh mass of coffee berries obtained in an experiment with the cultivar Obata IAC 1669-20. The fits provided by the Logistic and Gompertz models were compared in their single and double versions. Parameters were estimated using the least squares method using the Gauss-Newton algorithm implemented in the nls function of the R software. It can be concluded that the growth pattern of the coffee fruit, in fresh mass accumulation, is double sigmoid. The double Gompertz and double Logistic models were adequate to describe such a growth curve, with a superiority of the double Logistic model.