Forty five genotypes of Basmati rice (Oryza sativa L.) representing different regions of India were studied for genetic diversity on the basis of quality characteristics utilizing Mahalanobis D2 analysis. Based on the genetic distance (D2 values), the rice genotypes were grouped into eight clusters. Of the eight clusters formed, cluster I consisted of maximum 25 genotypes followed by cluster II accommodating five genotypes. The results indicated that there was some degree of similarity of genotypes clubbed together in a cluster on the basis of their origin. The highest genetic divergence was observed between cluster V and VI exhibiting wide diversity between the groups. The maximum intra-cluster divergence was observed for cluster VI and least for cluster VII and VIII. It was observed that all the minimum and maximum cluster mean values were distributed in relatively distant clusters. Among different traits, grain and kernel length, grain breadth and milling recovery had maximum contribution towards total divergence The genotypes from these clusters may be used as potential donors for future hybridizations programme to develop varieties with more grain as well as kernel length.

Key words: Basmati rice, genetic divergence, quality traits

Analysis of variance of forty upland genotypes indicated that all the genotypes were significantly different, with respect to most of the characters, except number of tillers plant-1, effective tiller plant-1 and grain yield panicle-1. Characters like grain yield plant-1, flag leaf area, grain yield panicle-1, plant height, 1000-grain weight and number of grains panicle-1 had recorded light to moderate PVC, GCV, heritability and genetic advance as per cent of mean. grain yield plant-1 had a significant and positive association with number of tillers plant-1, effective tillers plant-1, plant height, panicle length, number of grains panicle-1, grain yield panicle-1, flag leaf area and 1000-grain weight both at genotypic and phenotypic level. Path analysis revealed that all characters had positive direct effect on grain yield plant-1, except 1000-grain weight. Present study revealed that grain yield panicle-1, number of grains panicle-1, flag leaf area and plant height should be given more weightage during selection for increasing grain yield in upland rice.

Key words: Upland rice, variability, heritability, character association

Genetic diversity of 42 rain fed lowland rice varieties of different states of India were studied through Mahalanobis D2statistic.The genotypes were grouped in to 11clusters.The cluster II contained highest number of genotypes(9)followed by cluster III(7) ,cluster IV(7).The cluster VII to XI contained one genotype each. The intra cluster distance was highest in cluster VI(13.42),followed by cluster II(9.95),cluster I(7.13).and lowest was 0.00 from cluster VII to XI. Highest inter cluster distance was noticed in cluster VII and VI(D=40.07),followed by cluster XI and VI(D=37.020),cluster IX and VI(D=35.00)and cluster VI and III(D=33.74). The genotypes of the cluster II and VIII, cluster II and IX, and cluster VI and XI will exhibit high level of production as well as earliness. Plant height, Days to 50% flowering, 1000grain weight. together accounted for 87.11 percent to the total divergence indicating their importance in choice of parents for hybridization programme. The genotypes of these clusters should be selected for future breeding programme to enhance the yield in lowland.

Key words: Genetic diversity, D2 analysis, lowland rice

The assessment of genetic diversity among the rice varieties cultivated in Punjab was done using Mahalanobis D2 statistics based on eleven agro-morphological traits. Nineteen cultivars were grouped into four different clusters revealing sufficient amount of variability among the genotypes. The clustering pattern revealed non-correspondence of geographic diversity with genetic divergence. Days to 50% flowering and plant height contributed considerably, accounting for 61% of total divergence. The highest inter-cluster divergence (76.33) between clusters I and II maybe utilized in heterosis as well as in recombination breeding. Further, selection within cluster IV, having maximum intra-cluster distance (11.64), maybe exercised based on the highest mean for the desirable traits, which could be used for improvement through inter-varietal hybridization.

Key words: Genetic diversity, rice, clustering pattern, Punjab

Field experiments were conducted during the wet seasons of 2003-2005 to evaluate the performance of system of rice intensification with various aspects of nutrient management, soil water regime, varieties, and weed growth. Combined application of farm yard manure (FYM) at 5 tha-1 along with half the recommended nitrogen through chemical and gypsum at 1 t ha-1 registered highest yield (7.6 tha-1). Maximum grain yield (7.2 tha-1), root mass and root volume was recorded with Swarna in SRI method. All varieties exhibited their superior yields in SRI system. The highest grain yield and maximum water use efficiency (8.19 kg mm-1 ha-1) were registered under continuous submergence. The water requirement under saturation treatment was 40% lesser than continuous flooding at 5cm depth.

Key words: System of rice intensification, fertilizer technique, weed flora

The allelopathic potential ( E. colona (L.) Link. one of the most temportant weeds of rice, was evaluated by in vitro bioassay techniques. Rice variety ‘Kranti’ seeds were allowed to grow for 5-7 days in petri dishes with filter paper, soil or soil plus activated charcoal along with decomposing or decomposed leachates of the weed (obtained from 20, 30, and 40 or 60 days old plants). Observations of allelopathic effects on germination and root and shoot growth were recorded. The allelopathic effects of leachates increased with increasing concentrations (1, 2.5, 5, and 10% w/v). The decomposed leachates were found to be more toxic than the decomposing ones. Rice root growth was completely inhibited with 10% w/v leachates of 60 days old plant. The decomposing and decomposed leachates reduced rice shoot growth by 57% and 84% respectively. In soil medium the allelopathic effects were considerably reduced. Addition of activated charcoal to soil completely reduced the adverse effects on germination and seedling growth of rice.

Key words: Allelopathy, Echinochloa colona, Oryza sativa, germination

The phosphorus (P) concentration gradients at rice rhizosphere helps to study the root induced changes in the rice soil. For measurement of vertical concentration gradients rice seeds were sown in open ended plastic cylindrical pots consisting of two chambers. The upper chamber was filled with P free sand where the rice seeds were sown, while lower chamber was filled with 500 g soils. Soils and plant roots were separated by a horizontally placed stainless steel sieve (300 meshes) in such a way that only root hair could penetrate through the sieve. In another set to obtain the radial concentration gradient of P from plant roots, stainless steel mesh made cylinder was placed vertically in pot and plant was grown in soils placed inside the central cylinder. P concentration of rice rhizosphere was measured up to a distance of 45 mm from the vicinity of roots both in the vertical and radial directions. In Vertisol the P concentration was 5.48 mg kg-1 at 9 mm and attained 6.48 mg kg-1 at a distance of 27 mm from root surface in vertical direction. Where as, in Inceptisol P con centration was 33.78 mg kg-1 in first soil section and it was increased to 38.24 mg kg-1 at 27 mm away from root surface in radial direction. The concentration gradients were found up to a distance of 27 mm from root surface when the crop was 50 days old. This rhizosphere sampling technique could be effectively used under flooded rice condition considering no inter-root competition. But it has to be validated in field condition considering inter-root competition.

Key words: Phosphorus concentration gradient, technique rice, rhizosphere, vertisol, inceptisol

The effect of time of application (10 and 30 Days after sowing) and doses of common salt viz.,50, 100 and150 kg ha -1 and 2,4-D Na salt @1.5 kg ha-1 application on weed growth and yield of direct seeded upland rice was evaluated during wet seasons of 2003 and 2004. Application of 2, 4-D @1.5 kg ha-1 applied at 10 and 30 days after sowing significantly reduced weed population and dry matter accumulation, and was at par with common salt @150 kg ha-1 applied at 10 and 30 DAS. 2,4-D Na salt @1.5 kg ha-1 applied at 10 and 30 DAS recorded better growth ,yield attributes and yield viz., plant height ,number of tillers hill-1, dry matter accumulation, number of panicles m-2 number of effective grains panicle-1 and grain yield in comparison to common salt @50 kg ha-1 applied at 10 and 30 DAS. The highest benefit cost ratio was recorded with 2, 4-D Na salt @1.5 kg ha-1 applied at 10 days after sowing (2.47) followed by common salt @150 kg ha-1 applied at 10 days after sowing. Early application of common salt and 2, 4-D (10days after sowing) recorded more grain yield and benefit cost ratio in comparison of latter application(30DAS) of these treatments. Common salt application was not economical in comparison to 2, 4-D application.

Key words: Direct seeded rice, 2, 4-D Na salt, common salt, weed management

Experiment conducted at I.G.A.U., Raipur during wet season to find out the combined effect of planting times and nitrogen levels on hybrid rice indicated that planting of hybrid rice on 20th July and 5th August were at par to produce significantly higher crop growth rate (CGR), net assimilation rate (NAR), leaf area index (LAI), leaf production rate (LPR) and grain yield than that of planting on 20th August. The application of nitrogen up to 150 kg ha-1 significantly increased LPR, LAI and N concentration in third leaf as compared to other levels of nitrogen (50 and 100 kg ha-1). The grain yield increased significantly with the application of 100 kg N ha-1.

Key words: Hybrid rice, planting time, nitrogen level, yield

Management of Fusarium species associated with seed discolouration of rice was attempted through pathogen derived resistance (PDR). Twenty Fusarium isolates associated with rice varieties Lunishree, Pooja and Sarala were classified into six colour groups on the basis of their colour on Potato Dextrose Agar media. The variability in cultural, molecular characters and virulence were observed among the cultures, associated with the samples of a cultivar drawn from the same seed lot. The vigour index of seedlings of rice cultivar Utkalprabha and Savitri, treated with isolate F14A was considerably more than the untreated control. RAPD-PCR of twelve isolates was done using two primers, AP12h and R-108. The isolate F14A was found to be a fast growing isolate, distinctly different from other isolates and may be suitable for management of this devastating disease by Pathogen Derived Resistance.

Key words: Fusarium, discolouration, rice, pathogen derived resistance

Seedlings of rice var. IR-36 when exposed to mercury contaminated waste soil from a chlor-alkali factory containing 0.95 g of mercury, 30 days after transplanting, mercury accumulation increased from 3.70 ± 0.22 mg in 2.5 per cent waste soil combination (WSC) to 11.11 ± 0.14 mg in 17.5 per cent waste soil combination WSC per g fresh weight of shoot. In root mercury accumulation increased from 9.43 ± 0.38 mg g-1 in 2.5 percent WSC to 24.26 + 0.26 mg g-1 fresh weight in 17.5 per cent WSC. The accumulation depended both on soil contamination and time. The root length and shoot length decreased with increase in waste soil contamination. The content of chlorophyll, nucleic acid and protein decreased with increasing soil contamination and time. The percentage decrease of root length is 57.02, shoot length is 52.60,Chl-a is 62.00,chl-b is 62.12, total chl is 61.70,carotenoid is 67.34, DNA is 68.61, RNA is 63.15 and that of protein is 77.29.Changes in these variables were significantly correlated with waste soil combination and mercury uptake.

Key words: Solid waste, chlor-alkali factory, mercury, rice plant

Most of the seeds used by farmers for rice cultivation are farm saved and during seed production some selected seed production techniques are used. In this study attempt was made to examine the farmers’ knowledge level on recommended farming techniques and its relation with socio-personal variables like age, education, caste, occupation, contact with extension agencies, utilization of information from mass media and land owning status of farmers. Knowledge of seed growers was significantly associated with age, caste and utilization of mass media sources. Farmers of higher age group had acquired higher level of knowledge on seed production techniques. School and college education had no significant impact on this knowledge level. Out of the nineteen methods included in the study, majority of the farmers had adopted 17 methods with varying intensity except registering the crop for certification and maintaining isolation distance. The reasons for least adoption of these methods may be due to high cost involved in the methods, inadequate facilities, non availability of production materials and inadequate knowledge and skill.

Key words: Rice, seed production, farmers' knowledge

Thirty five genotypes of tall indica aman rice were evaluated for nine panicle characters under two environments to find out the extent of genetic variability present in the population. The experimental study indicated existence of considerable amount of genetic variability for all the characters studied. Genotypic and phenotypic coefficient of variation were high for unfilled florets panicle-1, grain yield plant-1, panicle number plant-1, grains panicle-1, panicle weight and 1000-grain weight. High estimates of heritability, genotypic coefficient of variation and genetic advance were observed for unfilled florets panicle-1, grain yield plant-1, panicle number plant-1, grains panicle-1, panicle weight and 1000-grain weight. These characters can be effectively improved through selection.

Key words: Genetic variability, tall, indica, aman rice

An incubation experiment on potassium fixation in some mineralogically different rice soils of West Bengal was studied at varying levels of added K. About 6.2 to 42 % of added K was fixed in these soils. Potassium fixation increased with increasing amounts of applied K, however, the percentage of added K fixed decreased gradually. Addition of 15 to 240 mg K kg-1 soil, illite and smectite dominant Inceptisols with high available and reserve K resutted in a relatively lower K fixation (4.9 to 39.6 mg kg-1 soil) as compared to illite , smectite and chlorite dominant Entisols (5.5 to 41.0 mg kg-1 soil) containing moderate available and reserve K. Conversely, kaolinite dominant Alfisol with low available and reserve K registered the lowest amount of K fixation (2.5 to 14.9 mg kg-1 soil).

Key words: Potassium fixation, available and reserve K, mineralogy, rice soils

Two fungicides viz., tricyclazole (Sivic 75 WP) and iprobenphos (Kitazin 48 EC) @ 0.06 % and 0.2%, respectively and two insecticides viz., indoxacarb (Indoxacarb 15 EC) and cartap hydrochloride (Caldan 50 SP) @ 0.006%l and 0.08%, respectively were evaluated as separate treatments as well as in all fungicide – insecticide combinations for their efficacy against blast and whorl maggot and to investigate their compatibility as tank mix application for the purpose of reducing the application cost in the event of simultaneous occurrence of blast and whorl maggot. Insecticides viz., cartap hydrochloride (Caldan 50 SP) and indoxacarb (Indoxacarb 15 EC) were effective against whorl maggot and fungicides viz., tricyclazole (Sivic 75 WP) and iprobenphos (Kitazin 48 EC) were effective against rice blast. There was no reduction in the efficacy of these insecticides and fungicides when used as tank mix combination and phytotoxicity symptoms were not observed in any of the treatments. Thus all the insecticides and fungicides used in the present investigation are compatible with each other and can be safely used as tank mix combinations for the control of rice pests.

Key words: Insecticidess, fungicides, compatibility, whorl maggot, rice blast

Ninety five rice genotypes along with resistant and susceptible check varieties Ptb33 and TN1, respectively were evaluated against Sogatella furcifera Horvath under net house condition at CRRI Cuttack during 2006. The result of the experiment revealed that only Ptb33 and IRGC 10118 were resistant and recorded damage score ‘0’. The genotype IRGC 13753 was found to be moderately resistant recording damage score ‘1’. Five genotypes viz., IRGC 10035, IRGC 44967, IRGC 45653, IRGC 45696 and IRGC 46021 were less susceptible to the pest with damage score ‘3’, three genotypes viz., IRGC 45242, IRGC 45152 and IRGC 45938, were recorded damage score ‘5’,eight genotypes were found moderately susceptible with score ‘7’ and the rest seventy eight were highly susceptible with score ‘9’.The genotype IRGC 10118 was again evaluated against the pest in 2007 and was found resistant.

Key words: Resistance, rice germplasm, WBPH

Field experiments were conducted to study the effect of plant nutrients on the incidence of YSB and grain yield of rice. It was observed that the incidence of borer was enhanced with application of increased doses of NPK fertilizers. But the supplementation of Zn (ZnSO4) with NPK nutrients recorded low incidence of borer both at vegetative (dead heart) and heading stage (white ear head).

Key words: Plant nutrients, Scirpophaga incertulas, incidence

Influence of different weather parameters on the incidence of sheath blight in the rice variety ‘Tapaswini’ was studied under field condition. Significant role of maximum and minimum temperature and rate of evaporation were observed to contribute 9.03, 23.03 and 61.05 per cent, respectively. for sheath blight incidence.

Key words: Weather parameters, Rhizoctonia solani, incidence

Seven insecticides viz., ethiprole 10 SC, clothianidin 50 WDG, cartap hydrochloride 50 SP, phosphamidon 40 SL, triazophos 40 EC, diazinon 20 EC and a-cypermethrin 10 EC @ 50, 25, 500, 400, 400, 200 and 25g a.i. ha-1, respectively were evaluated against the white backed planthopper, Sogatella furcifera Horvath (WBPH) of rice. The results revealed that out of seven insecticides tested the newer insecticides clothianidin belonging to neonicotinoid group and ethiprole belonging to phenyl pyrazole group were superior to other insecticides in suppressing WBPH population to the tune of 73.33-77.78% over control at 20 days after spraying during both the seasons of evaluation. Other insecticides registered below 50% control of the planthopper at 20 days after treatment with insecticides. Alpha-cypermethrin showed resurgence condition of the WBPH with 5.18-9.33% increase in population over control.

Key words: Sogatella furcifera, control, insecticides