Induction of various types of chlorophyll and morphological mutations by three doses (250, 350 and 450 Gy) of gamma rays in two genotypes, developed from Gobindabhog and Tulaipanja was studied. Segregation of chlorophyll and morphological mutants in M2 generation from normal looking M1 plants indicated recessive nature of mutations. Frequency of different chlorophyll and morphological mutations was higher in Tulaipanja group. The highest frequency of chlorophyll and morphological mutations was observed in the genotype IET 14143, developed from Tulaipanja, at 450 Gy. Among different chlorophyll mutations albina was the most predominant group. In general, higher mutagenic effectiveness and mutagenic efficiency were found at 450 Gy. Various morphological mutants like grassy leaf, rolled leaf, striped leaf, and broom stick leaf and several other mutants like sterile, early flowering, late flowering, non-flowering, tall, dwarf, semi-dwarf and high yielding mutants were induced with variable frequencies in different genotypes by different doses of mutagen. The frequency of chlorophyll mutations increased with increase in dose of mutagen but no relationship between the doses of mutagen and mutation spectrum could be established in morphological mutation.

Combining ability study on grain yield, various yield components and selected grain quality traits of 9 x 9 diallel mating design (excluding reciprocals) indicated predominance of additive gene action for all the traits except plant height, net-assimilation rate, biological yield, harvest index and protein content (%). The parent HPR2047, VL93-3613, JD8, VL93-6052 and HPR1164 were good general combiners for grain yield, its components and grain quality characters. On the basis of specific combining ability effects, the cross combinations HPR2047x JD8, China 988 x VL91-1754, HPR1164xVLDhan221 and HPR1164x HPR2047 are having high grain yield plant-1 and grain quality traits. These crosses and are suggested for isolation of high yielding transgresive segregants through pedigree method.

Combining ability hispa resistance along with other yield attributing traits in rice was studied through Line x Tester analysis involving two lines and seven testers. The mean squares of combining ability for line x tester interaction were significant for all the characters. The Combining ability analysis revealed non-additive gene action for all the characters except for plant height. Among the lines IR-50, and among the testers AS-36 and Begonbisi were found to be the best general combiner. Two crosses viz; Mahsuri x Begonbisi and IR-50 x Govind showed desirable sca effects for grain yield and hispa resistance. Implications of these results were discussed for breeding high yielding varieties with hispa resistance.

Fifty-two traditional aromatic rice genotypes of India were studied for genetic variability, heritability and genetic advance with respect to grain yield and 14 related traits. Considerable diversity was observed among these aromatic rice cultivars. Based on per se performance, the cultivar Punjab Basmati appeared as a promising genotype for earliness, long grain size and length/breadth ratio. Highest GCV was observed for grain yield per plant followed by high-density grain index. Heritability estimates was highest for plant height. D2- analysis classified the fifty two genotypes into eight diverse clusters. The largest cluster included most of the indigenous aromatic fine-grained rice varieties of India. The maximum inter-cluster distance was observed between cluster VI and VII followed by clusters III and VIII. Characters namely grain maturity duration, plant height and panicle weight contributed maximum towards divergence. On the basis of D2- inter cluster distance the cross namely; Lalmati (cluster VI) X HUR-BL-6AR (cluster VII) exhibiting contrasting differences for a large number of traits is expected result in desirable segregants on hybridization.

The effect of environmental factors on certain grain quality traits of three notified rice hybrids viz., PA 6201, PA 6444 and KRH-2 and one high-yielding inbred variety IR 64 were studied during wet seasons of 2005 and 2006 at two locations i.e. Simbhaoli and Hyderabad. Milling recovery and head rice recovery increased with increase in ageing from one month to six months and with increase in number of seedlings planted hill-1 from 1 to 3. Further, these environmental factors like ageing and number of seedlings planted per hill had no or non-significant effect on chemical characters like amylose content, gelatinization temperature and aroma.

Five methods of rice establishment methods viz. zero tillage, row seeding in prepared bed, broadcast seeding of pre-sprouted seeds in puddle field, row seeding of pre-sprouted seeds with drum seeder and manual transplanting; 3 methods of wheat establishment viz. zero tillage, conventional tillage and bed planting were evaluated to assess the productivity and profitability of rice–wheat system to find out the suitable alternative to the standard transplanting method. Transplanted paddy resulted in significantly higher grain yield (3.98 tonnes ha-1) followed by drum seeding (3.37 tonnes ha-1), broadcast seeding of sprouted seeds (3.23 tonnes ha-1), row seeding in prepared bed (2.92 tonnes ha-1) and zero tilled rice (2.76 tonnes ha-1). Conventional tillage in wheat produced 10 and 18 per cent more grain yield as compared to zero tilled and bed planted wheat, respectively. Net returns (Rs 30,819 ha-1) and benefit: cost ratio (1.37) from rice-wheat cropping system were highest from broadcast seeding of pre-sprouted seeds in puddle field–zero tillage wheat, followed by Rs 30,069 ha-1net return from RM3 – conventional tillage wheat. Bed planting of wheat was least economical for all rice establishment methods except transplanting method. Transplanted method of rice can be profitably replaced with sowing of pre-sprouted seeds in puddle field with subsequent wheat established either by zero tillage or by conventional tillage.

A field experiment was carried out during wet season of 2003 in calcareous soil at RAU, Pusa, Samastipur to find out the yield, nutrient uptake and fertility buildup in upland transplanted rice as influenced by organic and inorganic fertilizers. Integrated use of chemical fertilizer with organic manure and crop residue could substitute 50 percent of the recommended dose of NPK. The grain yield of rice (33.4) with 150 percent NPK alone increased the grain yield to 42.3 q ha-1 with 150 percent NPK + compost + crop residue. Integrated effect of chemical fertilizers with organic manure and crop residue also augmented N, P and K uptake over control. Long-term application of compost and crop residues increased the organic content of soil. The combined use of compost, crop residues with chemical fertilizers significantly increased the availability of N, P and K in soil over chemical fertilizer alone.

Different N management strategies involving the use of leaf colour chart (critical value 4), were evaluated to refine the technique of the use of (LCC) in assessing the N requirement of rice in contingencies when aged seedlings were used for transplanting. Rice variety ADT 46 during Navarai and ADT 43 during wet season were tried as the test crops. The results indicated that basal application of 35 kg N ha-1 is necessary to avoid the yield loss (6.5 -14.9 %) in rice when more than 35 days old aged seedlings were used for transplanting. Use of 45 days old seedlings had resulted in a marked reduction in the productive tillers (9.1 to 15.7 %) in rice under the LCC based N management where the crop did not receive any basal N. Skipping the basal N for aged seedlings had also increased the percentage of unproductive tillers and inturn decreased the grain yield. A marked reduction (11.3-14.6 per cent) in the N uptake in rice under the LCC based N management was observed when the age of the seedlings exceeded 35 days and the same could be improved by the basal application of N.

Field experiments were conducted from 2003-04 to 2004-05 at Malipungar watershed, Koraput, Orissa to evaluate integrated nutrient management (INM) options involving Gliricidia/ Farm yard manure (FYM) , chemical fertilizers and bio-fertilizers for their effect on performance of upland rice and soil properties. It was observed that growth, yield and net returns from Gliricidia amended plots were better than the FYM amended plots. Soil moisture, bulk density, soil pH, organic carbon and P in Glricidia and FYM amended plots were at par. However, residual N and K contents were significantly higher in plots amended with Gliricidia green leaf manure. Combined use of 50% recommended dose of fertilizers, Gliricidia @ 2.5 t ha-1 and biofertilizers (Azotobactor and phosphate solubilising bacteria) with highest grain yield (2.01 t ha-1), net returns (Rs.4791 ha-1 and B:C ratio (1.6) was the best INM option. Moreover, soil moisture content, and available N, P and K status of soil recorded from plots having this treatment were also significantly higher than those with 100% Recommended dose of fertilizer.

Field experiments were conducted in dry and wet seasons in 2005 and 2006 at Directorate of Rice Research – Ramachandrapuram farm to assess the insect pest scenario in system of rice intensification (SRI) and conventional methods and also impact of SRI on arthropod diversity. Yellow stem borer damage was high at all stages of crop growth period and its damage (dead hearts) at maximum tillering stage was low in cv.Shanti grown under SRI (7.0%) as compared to conventional method (11.4%). At reproductive stage, the damage (white ear heads) was high in SRI (28.3%) than conventional method (21.2%). Total abundance 263.34 and species richness 20.34 was high in SRI as compared to conventional method. Among various guilds, natural enemies were found more in SRI than conventional method of rice cultivation.

Field trials were conducted for insect pest management in upland rice during wet seasons of 2007 and 2008 at Farm Science Centre, Santhapur, Cuttack, Orissa. Two varieties i.e. one high yielding variety (HYV), Anjali and a local check, Kolia and two management practice viz., schedule based protection (seed treatment with carbendazim (Bavistin) 2 gm/kg seed, herbicide pretilachlor (Rifit) 50EC @ 800 g a.i. ha-1 at 6 days after sowing and monocrotophos 36EC @ 500g a.i. ha-1 at 30 days after germination), need based protection(seed treatment with chlorpyriphos 20EC @ 3.75 lit 100kg-1 seed and application of monocrotophos 36EC @ 500 g a.i. ha-1 on pest infestation) and no protection (farmer practice as control) were compared for insect pest management and grain yield in upland rice ecosystem. During both the years, Anjali recorded the highest grain yield of 3.75 t ha-1 (2007) and 3.69 t ha-1 (2008) under need based protection. Similarly, Kolia under need based protection recorded higher grain yield of 2.36 t ha-1 (2007) and 2.76 t ha-1 (2008) than other treatments. Under all the protection, practices tested the variety, Anjali performed better than the check variety, Kolia in controlling pests like stem borer, termite and gundhi bug.

The diversity and community turn over of floodwater ASD 18, ADT 43, IR 50 and ADT 36arthropods in weeded and partially weeded conditon were studied in a rice field planted with four rice varieties at Madurai, Tamil Nadu. The study indicated that 23 species containing 12, 2, 6 and 3 species of Odonata, Ephemeroptera, Hemiptera and Coleoptera were recorded, respectively. Among them, Agriocnemis femina femina Brauer (damselfly), Dineutus sp., Crocothemis servilia (Drury), Pantala flavescens (Fabricius) and Diplocodes trivialis (Rambur) (dragonfly) were the dominant species under both the conditions but were significantly dominant in partially weeded rice plot. The other species viz., Agriocnemis pygmaea Rambur, Ishnura sp of damselflies, Neurothemis tullia (Drury), Traemea limbata (Desjardin) (dragonflies), Beatis sp. of mayfly, Laccotrephes ruber (Linnaeus) (water scorpion), Hydrometra freeni Kirkaldy (water measurer), Anisops cavifrons Brooks (back swimmer), Dytiscus sp. (diving beetle) and Hydrophilus sp. (water beetle) were less prevalent and observed under both the conditions. The dragonflies viz., Trithemis sp, Rhyothemis variegata (Linnaeus), Anax guttatus (Burmeister) and the giant water bug, Lethocerus indicus (Lepeletiller and Serville) were absent in weeded rice ecosystem and were present only in partially weeded rice ecosystem. The diversity of floodwater arthropods indicated that diving beetle, whirligig beetle, water beetle, water measurer, water scorpion and water strider expressed perfect similarity (1.00) throughout the season. The community turnover indicated that turn of taxa generally increased during tillering stage of rice crop. The succession rate of taxa in floodwater fauna was higher in partially weeded rice than in weeded rice plots. Partially weeded plots had the highest turnover of 70.96, 70.58, 72.22 and 71.05 per cent at 58days after transplanting (DAT), respectively. The turnover of flood water arthropods had a declining trend in weeded plots and the increasing trend in partially weeded plots through out the season.

Four summer rice cultivars, viz. Jyotiprasad, Bishnuprasad, Joymoti and Kolaboro were grown in the farmers field at Kohar Goan, Jorhat during 2004-05. Four different treatments given to 40 days old seedlings before transplanting were control, 40 C cold hardening treatment in light for 48 hours, GA3-10 ppm treatment five days before transplanting and ABA-10 ppm treatment five days before transplanting. Various morphological and physiological parameters, viz plant height, tiller number, leaf number, leaf area, relative leaf water content, leaf chlorophyll, nitrogen, phosphorus and potash content of shoot at harvest were significantly influenced by the treatments. Seedlings treated with GA3 exhibited better growth and plant vigour in comparison to control. Bio-chemical traits, viz leaf proline content, total soluble sugar in stem, grain yield and yield attributes such as panicle length, grains panicle-1, sterility percentage were also found to be influenced significantly due to GA3, ABA and 40 C hardening treatment. The adverse effect of low temperature on growth and development of summer rice can be reduced with suitable cold hardening treatments. Among the different treatments GA3 was found to be the most suitable treatment for improvement of cold tolerance in terms of growth and yield in summer rice.

Screening for submergence tolerance and aroma in selected rice varieties of Tripura and their segregants were done both phenotypically and using linked molecular markers. Allelic specific amplification using primers derived from putative BAD2 gene for aroma could identify parents and two heterozygous lines derived from Basmati 370 x Pyzum and three homozygous aromatic lines from Pyzum x Binni cross. SSR marker, RM219 linked to Sub-1, could identify one submergence tolerant line derived from Basmati 370 x Pyzum. Although no aromatic line was found submergence tolerant in the current investigation, but the consistency of this screening process, would help in selecting aromatic lines with submergence tolerance from hybridization program involving traditional varieties of Tripura.

Eleven traditional early duration varieties of rice, collected from four tribal dominated hilly districts of Orissa, were compared with the high yielding improved check in respect of yield and nine component characters. Among the traditional cultivars, Chheligudia produced highest grain yield of 429 gm-2 that was at par with that of the high yielding improved check variety Swarnaprabha. Significant variation was observed for leaf area index, specific leaf weight, tillers m- 2, total dry matter at flowering stage and panicles m - 2, spikelets m- 2, 1000-grain weight and yield at harvest.

Eighteen indica/indica hybrids produced by crossing three male sterile lines with six restorers were analyzed for various quality traits and mid parent heterosis and heterobeltiosis. For head rice recovery, IR 68886A x IR 21567 registered significant positive relative heterosis and heterobeltiosis. For kernel length only one cross viz., IR 58025A x IR 21567 possessed positive significant mid parent heterosis. Most of the indica/indica hybrids exhibited significant negative heterosis for water uptake and volume expansion ratio. Significant negative relative heterosis was recorded for gel consistency in all the hybrids except for IR 62829A x IR 29723. The relative heterosis and heterobeltiosis for amylose content were found to be negative indicating that the indica/indica hybrids in the present study had their amylose content less than their mid parent and better parent values

In farmers’ participatory trials carried out in five different villages of Brahmagiri Block in the Puri district of Orissa, the relative contribution of improved variety and integrated weed management practices to grain yield and economics of deepwater rice was evaluated. The yield was significantly improved due to adoption of improved variety. The improved variety, Durga produced 68% more yield than the traditional variety, Dhuia Bakui. In contrast, the adoption of integrated weed management practices alone enhanced the grain yield to the tune of 49% over traditional weed management practices. The overall yield enhancement due to adoption of improved variety combined with integrated weed management practices was 143% over cultivation of traditional variety with traditional weed management practices. The highest net monetary return (Rs. 5383 ha-1) and benefit:cost ratio (1.66) was recorded in the treatment where improved variety was grown with integrated weed management practices.