RAJA RAJESWARI, VLAKSHMI PRASANNA, Y2019-05-022019-05-022018http://krishikosh.egranth.ac.in/handle/1/5810101653D5703The present investigation entitled “Influence of silicon solubilizers on blast tolerance, growth, development and yield in Rice (Oryza sativa L) Genotypes” was conducted at DRR farm (Indian Institute of Rice Research), Rajendranagar, Hyderabad, Telangana. The study conducted as two experiments and one experiment (Experiment I) was laid out during Kharif 2014 and 2015 in split plot design and replicated thrice with three main treatments control (T0), silixol @ 0.2% (T1), imidazole @ 0.05 % (T2) and eight sub treatments DRRH 3 (V1), PA 6129 (V2), PA 6201 (V3), PA 6444 (V4), PHB 71 (V5), BPT 5204 (V6), CO 39 (V7) and HR 12 (V8). An artificial blast screening nursery experiment (Experiment II) was conducted in Rabi 2014-2015, using blast susceptible genotype HR 12. Blast disease pressure was created by artificial inoculation. Pre infectional and post infectional spray of silicon solubilizers along with carbendazim were imposed. Another artificial blast screening nursery experiment (Experiment III) was laid out with eight rice genotypes during Rabi 2015-2016 and pre infectional and post infectional spray of silicon solubilizers were imposed. Crop response to silicon solubilizer treatments was measured in terms of morphological, physiological, biochemical, yield and its attributes and blast disease incidence. Among the silicon solubilizer treatments imidazole @ 0.05 % recorded significantly higher values for all these parameters except blast tolerance followed by silixol @ 0.2 % in both Kharif 2014 and Kharif 2015. xii Among the individual effects genotype PHB 71 showed significantly higher values for morphological, physiological, biochemical, yield and its attributes and lower blast disease incidence followed by PA 6129. PA 6201 and PA 6444 recorded moderate values for all these parameters and HR 12 and CO 39 recorded the lowest values for all these parameters. Data on different growth parameters viz., plant height, total dry matter revealed that imidazole @ 0.05 % recorded highest of all the above parameters compared to control and silixol @ 0.2 %. Among the genotypes HR 12 recorded highest plant height and total dry matter followed by PHB 71 and PA 6129. Data on tiller number, leaf area and leaf area index were significantly higher in the imidazole @ 0.05 % treatment compared to control. Among the genotypes PHB 71 and PA 6129 recorded highest tiller number and leaf area and lowest values were recorded for HR 12 followed by CO 39. Silicon solubilizer treatments significantly recorded the lowest no of days for 50 % flowering and maturity. The results indicated that the growth characteristics like CGR, RGR, NAR, SLA and LAD increased with the silicon solubilizers treatment due to increase in the leaf area and dry matter production. PHB 71 maintained higher CGR, SLA and LAD values followed by PA 6129 and PA 6201. The results of physiological parameters indicated that silicon solubilizers recorded high SCMR, total chlorophyll content and significantly increased the photosynthetic rate, stomatal conductance and maintained lower transpiration rate, leaf temperature. Imidazole @ 0.05 % treatment showed significantly higher values compared to silixol treatment @ 0.2 %. PHB 71 maintained higher photosynthetic values followed by PA 6129 and PA 6201 lowest values were recorded for HR 12 followed by CO 39. Data on the biochemical parameters indicated silicon solubilizers significantly increased the total chlorophyll content, silicilic acid content, total sugar content and phenol content. Imidazole @ 0.05 % treatment showed significantly higher values compared to silixol treatment @ 0.2%. PHB 71 maintained higher values followed by PA 6129 and PA 6201 lowest values were recorded for HR 12 followed by CO 39. Yield and its attributes i.e. number of panicles m-2, number of effective tillers hill-1, total grains panicle-1, filled grain panicle-1, grain yield kg ha-1, harvest index and test weight (g) were higher with Imidazole @ 0.05 % treatment followed by silixol treatment @ 0.2%. PHB 71 maintained higher yield attributes followed by PA 6129, PA 6201. Lowest values were recorded for HR 12, CO 39 recorded lowest values during both years of testing. xiii Highest incidence of blast disease in the field experiment (Experiment I) was observed in control which was 29.63 % followed by silixol @ 0.2 % treatment (23.61 %). The least Percentage disease index (PDI) was recorded in Imidazole treatment @ 0.05% (23.15 %). Among the genotypes HR 12 recorded highest PDI followed by CO 39 during both years of testing and lowest PDI was recorded for PA 6129, PHB 71 and PA 6201. Results of experiment II denotes that both the post infectional and pre infectional spray of different dosages of silicon solubilizers on HR 12 showed least PDI in carbendazim @ 0.2 % followed by silixol treatment @ 0.5 % and Imidazole @ 0.2 % treatment and highest PDI observed in control. Increased dosage of silicon solubilizers decreased the PDI for blast. Results of experiment III denotes that post infectional and pre infectional spray of silicon solubilizers on eight rice genotypes showed highest incidence of blast disease in control (T0) followed by silixol @ 0.2 % treatment and Imidazole treatment @ 0.05 %. Highest PDI was recorded in HR 12 followed by CO 39, BPT 5204, PA 6444 and DRRH 3 showed complete susceptibility to blast. PA 6201 and PA 6129 recorded lowest PDI and showed the resistance towards the blast disease and PHB 71 showed moderate resistance towards blast disease. More effectiveness of treatments was recorded in pre inoculation spray compared to post inoculational spray. Based on results obtained from the present study, it is evident that the Imidazole treatment @ 0.05 % proved effective among silicon solubilizer treatments in improving growth, physiological parameters. However significant effect in inducing blast tolerance in rice genotypes was not observed. Among the genotypes PHB 71 and PA 6129 were found effective for morphological, physiological efficiency, biochemical and yield attributes.en-USnullThesis