Spectral characteristics of Tomato (lycopersicon esculentum mill.) in different sowing dates
J. Mukherjee and C. V. S. Sastri Division of Agricultural Physics, Indian Agricultural Research Institute, New Delhi – 110 012 Field experiment was conducted in IARI farm during 1998-'99 and 1999-'00 spring summer for evaluation of spectral response of tomato crop. Six different spectral indices (IR/R, NDVI, hVI, hNDVI, BNI and GNI) were computed to characterize the spectral pattern of tomato crop. Spectral reflectance of crop canopy was taken by spectroradiometer (LICOR 1800) in ten days interval. To characterize plant growth LAI, dry biomass, and plant height were taken and CGR was calculated. In general, it was observed that value of all the indices was more incase of first sowing than second and third sowing due to higher biomass, LAI and plant height in first sowing compared to late sowing. Value of all the indices (except BNI) increased with days after transplanting (DAT) of crop up to 80-90 DAT after that it decreased. After attaining peak value of all indices a constant value was observed due to indeterminate growth of vegetables crop. Little decreasing trend was observed due to yellow colouration of leaves at the final harvest stage. Among the three cultivars, cultivar Pusa Sheetal recorded highest values in both the seasons. And first season's crop recorded highest value of all the indices than second season as first season' crop had higher biomass, LAI and plant height and higher fruit yield. Among the all six indices NDVI gave highest correlation with dry plant biomass, LAI and plant height. The peak values of NDVI recorded were 0.699 to 0.799 among all the three cultivars. Regression model was developed for prediction of both yield and dry biomass using spectral indices. | ||
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