highly significantp < 0.01
All selected best two VIs showed a highly significant correlation with GSC, GPC, and GOC at the tasseling and grain-filling stages ( p < 0.01), with MERIS terrestrial chlorophyll index (MTCI) ( r = 0.69), MTCI ( r = 0.64), and NDWI ( r = 0.55) showing the best correlation with GSC, GPC, and GOC, respectively, at the tasseling stage.