Use of remote sensing for drought stress monitoring, yield prediction and varietal evaluation in castor beans (Ricinus communis L.)

摘要

The current study was taken up to investigate the utility of remote sensing tools like infrared thermometer and spectral radiometer for screening of germplasm, stress monitoring and yield prediction in castor beans (Ricinus communis L.). The study was carried out through field experiments conducted for six years (1994— 1999) at Hayatnagar Research Farm, Hyderabad, India. In each year, four cultivars of castor beans, viz. VP-1, 48-1, GCH-4 and Aruna, were planted on two different dates maintaining an interval of 6-8 weeks so as to expose the crop to different environments. The infrared thermometric observations like canopy-air temperature differential (T_c-T_a) explained 50-60% variation in soil moisture status and showed a significant relationship with soil moisture. Yield of castor beans exhibited significant inverse relationship with T_c-T_a, which explained 59% of variation in yield. The hybrid GCH-4, registering comparatively lesser mean T_c-T_a over the entire growing period, established itself as a better cultivar. The spectrometer observations also proved GCH-4 to be a superior genotype in view of its higher reflectance in near-infrared region of the spectrum. The significant negative relationship of T_c-T_a of GCH-4 with saturation vapour pressure deficit brought out its drought tolerance trait over the other genotypes studied. These findings at field level can be extended to wider spatial level using satellite imageries.