Prediction of growth and dry matter production of flue-cured Virginia tobacco (Nicotiana tabacum) using mathematical models in irrigated Alfisols of Andhra Pradesh

Abstract

Field experiments were conducted during 2005–07 on ’Kanchan’ flue-cured tobacco (Nicotiana tabacum L.) under irrigated condition to study the effect of planting dates on dry matter accumulation, leaf weight, growth parameters and to develop suitable mathematical models to predict the drymatter and leaf weight by using growth and weather parameters. Late planting showed reduction in cured leaf yields, leaf area, dry matter accumulation but specific leaf weight increased compared to early and normal planting. Maximum crop growth rate and net assimilation rate were recorded between 40 and 80 days after planting. Among various growth parameters, leaf area index and specific leaf weight had highest positive correlation with total dry matter production and leaf weight. Dry matter accumulation and leaf weight showed positive correlation with sunshine hours, evaporation, maximum temperature and difference of maximum and minimum temperatures. Leaf area index can alone predict the total dry matter (R2=0.96 * * ) and leaf weight (R2 =0.93 * * ) of fluecured virginia tobacco with high degree of accuracy. By including the specific leaf weight and weather parameters, viz temperatures, rainfall and sunshine hours the accuracy was further improved. Predicted values of total dry matter and leaf weight with the selected multiple regression equations, correlated significantly with actual values. These prediction equations will help in formulating the production and marketing regulation strategy of FCV tobacco in northern light soils of Andhra Pradesh.