ABSTRACT
The estimative of the leaf area using a nondestructive method is paramount for successive evaluations in the same plant with precision and speed, not requiring high-cost equipment. Thus, the objective of this work was to construct models to estimate leaf area using artificial neural network models (ANN) and regression and to compare which model is the most effective model for predicting leaf area in sesame culture. A total of 11,000 leaves of four sesame cultivars were collected. Then, the length (L) and leaf width (W), and the actual leaf area (LA) were quantified. For the ANN model, the parameters of the length and width of the leaf were used as input variables of the network, with hidden layers and leaf area as the desired output parameter. For the linear regression models, leaf dimensions were considered independent variables, and the actual leaf area was the dependent variable. The criteria for choosing the best models were: the lowest root of the mean squared error (RMSE), mean absolute error (MAE), and absolute mean percentage error (MAPE), and higher coefficients of determination (R2). Among the linear regression models, the equation yË=0.515+0.584*LW was considered the most indicated to estimate the leaf area of the sesame. In modeling with ANNs, the best results were found for model 2-3-1, with two input variables (L and W), three hidden variables, and an output variable (LA). The ANN model was more accurate than the regression models, recording the lowest errors and higher R2 in the training phase (RMSE: 0.0040; MAE: 0.0027; MAPE: 0.0587; and R2: 0.9834) and in the test phase (RMSE: 0.0106; MAE: 0.0029; MAPE: 0.0611; and R2: 0.9828). Thus, the ANN method is the most indicated and accurate for predicting the leaf area of the sesame.
ABSTRACT
ABSTRACT Salinity is one of the major problems of modern agriculture, affecting physiological, growth and plant production. Basil (Ocimum basilicum) is a plant widely used in cooking, and in the pharmaceutical and cosmetics industries. Salicylic acid can be a strategy to mitigate the harmful effects of saline stress on basil plant. The present study aimed to evaluate plants with, gas exchange, chlorophyll a fluorescence and chlorophyll indices of basil (cv. Cinnamon) plants under saline stress and salicylic acid. The experimental design was a randomized block design in a 5x5 incomplete factorial scheme generated through the central composite design. The factors we five electrical conductivities of irrigation water (ECw- 0.5, 1.3, 3.25, 5.2 and 6.0 dS m-1) and five doses of salicylic acid (SA- 0.0, 0.29, 1.0, 1.71 and 2.0 mM), with five replications and two plants per replicate. Growth, gas exchange, chlorophyll a fluorescence and chlorophyll indices of O. basilicum cv. Cinnamon were evaluated. Canonical variables analysis and confidence ellipses (p ≤ 0.01) were performed to study the interrelationship between variables and factors. Salicylic acid alleviated the deleterious effects of salt stress on growth, gas exchange, chlorophyll fluorescence and chlorophyll indices of basil.
RESUMEN La salinidad es uno de los mayores problemas de la agricultura moderna, afectando la fisiología, el crecimiento y la producción vegetal. La albahaca (Ocimum basilicum) es una planta muy utilizada en la cocina y en las industrias farmacéutica y cosmética. El ácido salicílico puede ser una estrategia para mitigar los efectos nocivos del estrés salino en las plantas de albahaca. El objetivo del presente estudio fue evaluar el crecimiento, intercambio de gases, fluorescencia de clorofila a e índices de clorofila de plantas de albahaca (cv. Cinnamon) bajo estrés salino y ácido salicílico. El diseño experimental fue un diseño de bloques al azar en un esquema factorial incompleto de 5x5 generado a través del diseño compuesto central. Los factores fueron cinco conductividades eléctricas del agua de riego (ECw- 0,5, 1,3, 3,25, 5.2 y 6,0 dS m-1) y cinco dosis de ácido salicílico (SA- 0,0, 0,29, 1,0, 1.71 y 2,0 mM), con cinco repeticiones y dos plantas por réplica. Crecimiento, intercambio de gases, fluorescencia de clorofila a e índices de clorofila de O. basilicum cv. Cinnamon fue evaluado. Se realizaron análisis de variables canónicas y elipses de confianza (p≤ 0.01) para estudiar la interrelación entre variables y factores. El ácido salicílico alivió los efectos nocivos del estrés salino sobre el crecimiento, el intercambio de gases, la fluorescencia de la clorofila y los índices de clorofila de la albahaca.