Geethakumari, V. LSunilkumar, BKAU2019-05-282019-05-282000http://krishikosh.egranth.ac.in/handle/1/5810105054PGA field experiment was conducted at College of Agriculture, Vellayani) to assess the effect of varying levels of solar radiation and silica on the performance of upland rice cultivars. This study also aimed at computing the economics of upland rice cultivation and silica application. The treatments included three shade levels (0, 20 and 40 per cent), two levels of silica (no silica and 100 kg ha-' silica) and four varieties (Swarnaprabha, A4-4-2, A4-1- 3 and Matta Triveni). Shade was imposed by using shade nets of appropriate shade levels and silica was applied as sodium silicate. The experiment was laid out in split-split plot design. The results of the investigation are summarised below. Solar radiation influenced growth attributes significantly. A significant reduction was observed in tillering, LAD, proline content, SL W, LAI, culm strength, root weight, root length and root-shoot ratio as the shade advanced to 20 and 40 per cent levels. Among the growth attributes only plant height and chlorophyll content increased significantly with increase in shade level. Yield contributing characters were also significantly influenced by solar radiation. Maximum number of productive tillers, spikelets per panicle, thousand grain weight, length and weight of panicle was observed in the open situation. A significant reduction in grain yield was observed with increase in shade level. Maximum productivity was registered at 0 per cent shade level which was 68 and 387 per cent higher than 20 and 40 per cent shade levels. Same trend was observed in DMP. Maximum straw yield was recorded at 20 per cent shade which was on par with zero per cent shade. Application of silica increased total chlorophyll content, chlorophyll a/b ratio, root length and root weight significantly. Grain and straw yield increased significantly by 22 and 18 per cent with the application of silica. In the open situation A4-4-2 recorded maximum grain yield. At 20 per cent shade level A4-4-2 and Matta Triveni top seeded other cultivars. Swarnaprabha recorded maximum straw yield In the open situation. Compared to open situation at 20 per cent shade level straw yield increased significantly in A4-4-2 and Matta Triveni. Sodium silicate was found as an un-economical source of Si for upland nee. Silica nutrition can be made economical by substituting sodium silicate with a cheaper source of silica. B : C ratio reduced significantly with increase in shade level. The treatment LoS I V I registered maximum B : C ratio of 1.35.ennullThesis