PRABHAKARA REDDY, GVENKATARAVANA NAYAKA, G.V2020-02-132020-02-132019http://krishikosh.egranth.ac.in/handle/1/5810142993D5836A field experiment was conducted on a clay loam soil at Indian Institute of Rice Research (IIRR) formerly Directorate of Rice Research (DRR), Rajendranagar, Hyderabad during the kharif seasons of 2017 and 2018 to study the “Productivity and water use efficiency of rice (Oryza sativa L.) cultivars under different irrigation regimes and systems of cultivation”. The treatments consisted of two irrigation regimes viz., alternate wetting and drying (AWD) and saturation as main plot treatments, three systems of cultivation viz., system of rice intensification (SRI), drum seeding (DS) and normal transplanting (NTP) as sub plot treatments and four cultivars namely DRR Dhan 42, DRR Dhan 43, MTU-1010 and NLR-34449 as sub-sub plot treatments laid out in split-split plot design with three replications and comprises of 24 treatment combinations. Growth and physiological parameters were measured at periodical intervals and yield attributes were recorded at harvest. Quantity of irrigation water applied, effective rainfall, water productivity and water use efficiency were measured. Nutrient uptake at 30, 60, 90 DAS/DAT and at harvest (grain and straw) was estimated and expressed as total NPK uptake. N, P and K use efficiency was estimated. Soil available nutrient status (kg ha-1) after harvest of rice was also determined. Economics and energetics of rice cultivation were quantified. The data generated on different aspects in this study in response of crop to different irrigation regimes, systems of cultivation and rice cultivars were analyzed through standard statistical methods and logical conclusions were drawn. Between the irrigation regimes plant height (cm), number of tillers m-2, dry matter production (kg ha-1), root dry weight (g m-2), leaf area index were significantly higher in alternate wetting and drying method as compared to saturation at all the growth stages. AWD method took 2-3 days earlier to attain 50 per cent flowering. AWD recorded significantly higher SPAD xix chlorophyll meter readings, relative water content (%), specific leaf area (cm2 g-1) during both the years. Significantly higher CGR from 30-60 DAS/DAT, 60-90 DAS/DAT and 90 DAS/DAT- harvest was recorded in AWD during 2017 and 2018 as compared to saturation. Among the different systems of cultivation, SRI resulted in taller plants at all the crop growth stages. The number of tillers m-2 increased up to 60 DAS/DAT there after decreased up to harvest in all the establishment methods. Significantly higher DMP was noticed in system of rice intensification at 30, 60, 90 DAT and at harvest. SRI method noticed significantly superior LAI as compared to NTP and DS during 2017 and 2018 at 60, 90 DAS/DAT and at harvest, but not significantly different at 30 DAS/DAT. Significantly lower plant height, number of tillers, DMP and leaf area index were recorded in NTP at every crop growth stage. Days to 50 per cent flowering were early by 8 - 10 days in drum seeding method and 5 - 6 days early in SRI method as compared to NTP. SRI method recorded significantly superior SPAD chlorophyll meter readings, relative water content (%) and specific leaf area (cm2 g-1) as compared to normal transplanting and drum seeding during 2017 and 2018. Among the establishment methods higher CGR values were recorded in SRI than normal transplanting and drum seeding during 2017 and 2018. The RGR was not appreciably influenced by different systems of rice cultivation. Among the different rice cultivars, the highest plant height (cm), number of tillers m-2, DMP (kg ha-1), root dry weight (g m-2) and leaf area index were observed with DRR Dhan 43 throughout the study as compared to other cultivars. The cultivar NLR-34449 had taken higher number of days to attain 50 per cent flowering, whereas DRR Dhan 43 and MTU-1010 recorded lower number of days to attain 50 per cent of flowering. DRR Dhan 43 recorded significantly superior SPAD chlorophyll meter readings, relative water content (%) and specific leaf area during 2017 and 2018 over other cultivars. Significantly superior values of CGR was recorded by DRR Dhan 43 over other cultivars. All the cultivars recorded statistically similar values of RGR at all the growth stages except at 90 DAS/DAT - harvest. The number of panicles m-2, length of the panicle (cm), panicle dry weight (g), test weight (g), total number of grains panicle-1 and number of filled grains panicle-1 were significantly higher with alternate wetting and drying during both the years as compared to saturation. Significantly higher chaffy grain per cent and unfilled grains were observed with saturation. The number of panicles m-2, panicle dry weight (g), test weight (g), length of the panicle (cm), total number of grains panicle-1 and number of filled grains panicle-1 were significantly higher with SRI than other establishment methods. Number of unfilled grains panicle-1 and chaffy grain percentages were significantly higher with normal transplanting. Lower yield attributes were recorded with normal transplanting. xx Among the different rice cultivars, DRR Dhan 43 recorded significantly superior number of panicles m-2, panicle dry weight (g), test weight (g), length of the panicle (cm), total number of grains panicle-1 and number of filled grains panicle-1 than other cultivars. Number of unfilled grains panicle-1 and chaffy grain percentages were significantly higher with DRR Dhan 42. AWD irrigation practice registered enhanced grain and straw yields than saturation. SRI method registered significantly higher grain yield and straw yield than other systems of cultivation. DRR Dhan 43 noticed significantly higher grain and straw yields as compared to other cultivars during both the years of study. Among the irrigation regimes, the highest quantity of irrigation water was applied to saturation method and higher effective rainfall was recorded under AWD. Application of water through AWD method saved around 11-14 per cent of total water requirement during crop growth period. Irrigation by AWD recorded significantly superior irrigation water productivity and WUE. Among the irrigation regimes, AWD noticed significantly superior nitrogen, phosphorus, potassium uptake at 60, 90 DAS/DAT and at harvest during 2017 and 2018 as compared to saturation. Uptake of nitrogen and potassium at 30 DAS/DAT were found to be non-significant during both the years. Between irrigation regimes, AWD recorded significantly superior N, P and K use efficiency as compared to saturation. Among the systems of cultivation, SRI method required lowest amount of water (11.61 % and 13.21 % less of mean applied water than drum seeding and normal transplanting respectively). Higher effective rainfall was also recorded with SRI method. Significantly higher water productivity as well as WUE was recorded with SRI. Highest amount of water was applied under normal transplanting method. At 30 DAS/DAT, no significant differences were noticed in nitrogen and potassium uptake between SRI, NTP and DS methods during 2017 and 2018. Whereas at 60, 90 DAS/DAT and at harvest, SRI method recorded significantly superior N, P and K uptake as compared to NTP and DS during both the years. Higher NUE of nitrogen, phosphorus and potassium was observed with SRI than DS and NTP methods. DRR Dhan 43 recorded higher water productivity as well as WUE as compared to other cultivars during both the years of study. N, P and K uptake was significantly higher with DRR Dhan 43 at 60, 90 DAS and harvest during both the years of study followed by MTU-1010. Among the rice cultivars higher N, P and K use efficiency was recorded in DRR Dhan 43 over other cultivars. However lower N, P and K use efficiency was noticed in DRR Dhan 42 as compared to other cultivars. AWD method recorded significantly higher gross returns, net returns and B:C ratio as compared to saturation. While saturation recorded higher cost of cultivation and higher input energy. Gross output energy, net energy and energy use efficiency (EUE) recorded were higher with AWD as compared to saturation. xxi Among the systems of cultivation higher net returns and B:C ratio were recorded in drum seeding method followed by SRI method. Normal transplanting method required higher input energy. The gross energy output, net energy and EUE recorded were significantly superior in SRI than other establishment methods. Among different rice cultivars, DRR Dhan 43 recorded significantly higher gross returns, net returns and B:C ratio as compared to other cultivars followed by MTU-1010. Whereas inferior gross returns, net returns and B:C ratio ratio were observed in DRR Dhan 42. Different rice cultivars did not show any significant effect on input energy during both the years of study. The cultivar DRR Dhan 43 recorded higher gross output energy, net energy and EUE compared to other rice cultivars. Based on the results obtained in the present investigation it can be concluded that either DRR Dhan 43 (long and bold grain type) or NLR-34449 (fine grain type) cultivars of rice can be grown under SRI or drum seeding method of sowing with alternate wetting and drying irrigation system for higher yield and economic returns.en-USnullThesis