Enhancing the crop yield through capacity building programs: Application of double difference method for evaluation of drip capacity building program in Tamil Nadu State, India

A capacity building program on drip irrigation (TNDRIP) was undertaken in certain regions of the Indian State of Tamil Nadu during 2009-2010. An assessment of the impact of the program in terms of effective use of drip irrigation and increased crop yields was made in 2011 by applying double difference method (a combination of both with and without and before and after approaches). The results had indicated that the drip capacity building program resulted in a yield increase of 2.5 t/ha for Banana 1, 1.9 t/ha for Banana 2, 3.3 t/ha for sugarcane and 0.3 t/ha for turmeric. The conventional method using the before and after situations had shown a yield increase of 4.3 t/ha for Banana 1, 12.1 t/ha for Banana 2, 40.6 t/ha for sugarcane and 2.6 t/ha for turmeric. The conventional approach is highly upward biased in estimating the impact of the drip capacity building program and thus the double difference method will be an appropriate method to evaluate the impact of the programs that involve both with and without as well as before and after situations.

Combining ability and gene action studies for yield and fibre traits in Gossypium arboreum using Griffings numerical and Haymans graphical approach

Background For the purpose of utilising hybrid vigour to produce possible hybrids with a suitable level of stability,the knowledge of gene activity and combining ability is a crucial prerequisite before choosing desirable parents.The present study was carried out with six parents crossed in full diallel fashion and generated 30 F1 hybrids.These hybrids were evaluated in two replications in Randomized Block Design at Department of Cotton,TNAU for combining ability and gene action.Diallel analysis was carried out according to Griffing’s method-I(parents + F_(1) + reciprocals) and model-I and Hayman’s graphical approach by using INDOSTAT software.Results Analysis of variance for combining ability indicated that mean square values of GCA,SCA and reciprocals were highly significant for all the traits except for the uniformity index.RG763 and K12 showed highly positively significant GCA effects for most of the yield traits while PA838 and K12 for fibre quality traits,so they were found as best general combiners.PAIG379 × K12 and PDB29 × K12 for yield traits,and PDB29 × PA838,RG763 × PA838,and CNA1007 × RG763 cross combinations for fibre quality traits could be recommended for future breeding programms.Conclusion The results of both Griffing’s and Hayman’s approaches showed that non-additive gene action predominates as SCA variance was bigger than GCA variance,so heterosis breeding is thought to be a more fruitful option for enhancing GCA of many traits.

Diversity of Endophytic Fungi in Banana Cultivars of Assam India

Endophytic fungal isolates(139 no.)were obtained from 143(62 roots,18 fruits and 54 leaves)samples of 15 dif­ferent varieties of banana collected from 10 sites in Assam,India during 2018-2019.Overall isolation frequency from surface-sterilized tissue ranged from 10%-80%(as per site)and 6%-70%(as per variety of banana).All isolates were segregated into 40 different types on the basis of macromorphological and micro morphological characteristics.Forty different fungal taxa were isolated belonging to 14 genera including Absidia,Arthrinium,Aspergillus,Bipolaris,Cla­dosporium,Curvularia,Dendrophion,Fusarium,Humicola,Mortierella,Mucor,Penicillium,Paecilomyces,Verticilli­um and one mycelium sterile.Among them,Cladosporium cladosporioidies and Paecilomyces sp.frequently occurred in most of the sites surveyed whereas Cladospoirum cladosporioides and Aspergillus sp.8,Fusarium graminseram were most frequently isolated from different varieties.However,all sites differed in their fungal diversity.Banana samples from Narigoan and Jorhat have been found with maximum fungal species followed by marigoan samples so as to Banana varieties Amrit Sagar endowed 27 no.of fungi followed by Jehaji and Honda which were associated with a maximum 14 fungal sp.Isolation frequency and relative abundance of Cladosporium cladosporiodes(80%,4.6),Paecilomyces farinosus(80%,4.6)followed by Penicillium ruburm,Aspergillus sp.8&9(70%,4.02)were recorded as maximum comparatively in different sites.However,Aspergillus sp.8,Mortieralla sp.and Pacilomyces farinosus are isolated frequently from different banana varieties(73.33%,4.93).

Plant growth-promoting rhizobacteria(PGPR)and its mechanisms against plant diseases for sustainable agriculture and better productivity

Plant growth-promoting rhizobacteria(PGPR)are specialized bacterial communities inhabiting the root rhizosphere and the secretion of root exudates helps to,regulate the microbial dynamics and their interactions with the plants.These bacteria viz.,Agrobacterium,Arthobacter,Azospirillum,Bacillus,Burkholderia,Flavobacterium,Pseudomonas,Rhizobium,etc.,play important role in plant growth promotion.In addition,such symbiotic associations of PGPRs in the rhizospheric region also confer protection against several diseases caused by bacterial,fungal and viral pathogens.The biocontrol mechanism utilized by PGPR includes direct and indirect mechanisms direct PGPR mechanisms include the production of antibiotic,siderophore,and hydrolytic enzymes,competition for space and nutrients,and quorum sensing whereas,indirect mechanisms include rhizomicrobiome regulation via.secretion of root exudates,phytostimulation through the release of phytohormones viz.,auxin,cytokinin,gibberellic acid,1-aminocyclopropane-1-carboxylate and induction of systemic resistance through expression of antioxidant defense enzymes viz.,phenylalanine ammonia lyase(PAL),peroxidase(PO),polyphenyloxidases(PPO),superoxide dismutase(SOD),chitinase andβ-glucanases.For the suppression of plant diseases potent bio inoculants can be developed by modulating the rhizomicrobiome through rhizospheric engineering.In addition,understandings of different strategies to improve PGPR strains,their competence,colonization efficiency,persistence and its future implications should also be taken into consideration.

Maternal and burial environment determine the physical dormancy release in tropical Senna auriculata(Fabaceae) seeds

In tropical ecosystems,species with an impermeable seed coat,i.e.physical dormancy(PY),are large in number and their seed coat is considered to be an adaptive trait for species persistence and colonization.However,only little is known about their mechanisms for breaking dormancy.The objective of this study was to understand the importance of seed maturation site and burial location in determining the PY release of Senna auriculata.Freshly collected seeds of S.auriculata from Vellore and Coimbatore,Tamil Nadu,India,germinated to 11±1.5%and19±2.5%respectively and remaining seeds did not imbibe water,thus had PY.Germination of seeds from both sites following hot-water treatment for 30 s and mechanical scarification increased significantly and seeds were able to germinate at a wide-range of temperatures(5–35℃)both in light and darkness.When incubated at 15/60℃for 3 months,dormancy release for seeds collected from Coimbatore(72%)was greater than seeds matured in Vellore(53%).Following 1 year of burial at three different locations,seeds from Coimbatore germinated to higher percentage than Vellore seeds at all locations.In particular,the higher temperature sites released dormancy to greater extent than the lower temperature site.Our results suggest that summer temperatures(>60℃)prevailing in the tropics provide appropriate cues for breaking PY,but this could be greatly affected by the initial state of seeds and the burial environment.

Association and Heritability Studies for Drought Resistance under Varied Moisture Stress Regimes in Backcross Inbred Population of Rice

Drought stress is one of the major constraints affecting rice production and yield stability in the rainfed regions. To understand the physiological basis of drought resistance related component traits, we used a backcross inbred population of rice under three kinds of moisture regimes viz., non-stress, moderate （24.48%） and severe stress （73.97%） conditions which reflect the differential responses of the genotypes to varying stress intensities. The plot yield, 1000-grain weight, panicle exsertion and canopy air temperature difference exhibited high heritability under the control conditions, whereas spikelet sterility and single plant yield exhibited high heritability under the moderate stress conditions. Traits such as days to 50% flowering, plant height and osmotic potential showed high heritability under the severe stress conditions. Plot yield under stress was significantly and positively correlated with harvest index and 1000-grain weight, but negatively associated with leaf rolling score and days to 50% flowering. The drought susceptibility index and drought response index were negatively correlated between each other both under the moderate and severe stress conditions. The derived traits viz., difference in panicle length between the control and the severe stress was associated with osmotic adjustment measured under field conditions. Difference in plant height and panicle length was negatively associated with plot yield under stress.

New Temperature Sensitive Genic Male Sterile Lines with Better Outcrossing Ability for Production of Two-Line Hybrid Rice

An investigation was carried out with three newly developed temperature sensitive genic male sterile （TGMS） lines for their floral traits, seed production potential and outcrossing ability in ten cross combinations. In the TGMS lines, fertile pollens had an average diameter of 0.89 mm while the sterile pollens was with 0.02 mm diameter.TS-29-150GY produced the biggest fertile pollens with 0.92 mm and other two lines produced relatively smaller pollens with 0.91 and 0.85 ram. Pollen fertility during the fertility reversion period was an average of 60.7%. TS-29-150GY had the maximum of 66.9% spikelet fertility whereas other two lines （TNAU18S and TNAU60S） had relatively lower spikelet fertility of 27.8% and 26.7%, respectively. Average of 17.00 g of seed yield was obtained in the TGMS lines during the fertility reversion period. TS-29- 150GY had the highest value of 21.20 g of seed yield while TNAU18S and TNAU60S produced 16.6 g and 13.2 g of seed yield, respectively. The low seed production ability of these three TGMS lines was attributed only to the environmental conditions prevailing during the period. All three TGMS lines had considerable outcrossing potential of 41.2%, 24.6% and 25.0%, respectively. The cross combinations viz. TNAU18S/IET21508 （36 g/plant）, TNAU18S/IET21044 （13 g/plant）, TNAU18S/IET21009 （26.5 g/plant）, TNAU60S/CB-09-106 （26.2 g/plant）, TNAU60S/IET21009 （14 g/plant） and TS29-150-GY/DRR 3306 （39.2 g/plant） showed perfect synchronization with acceptable hybrid seed yield, indicating suitability of TGMS system under Indian condition. Based on the outcrossing related traits viz. panicle exertion, angle of glume opening, stigma length and pollen size, TNAU18S was identified as the best, followed by TS-29-150GY.

Evaluation and Bulked Segregant Analysis of Major Yield QTL qtl12.1 Introgressed into Indigenous Elite Line for Low Water Availability under Water Stress

Near isogenic lines carrying large-effect QTL （qtl2.1）, which has a consistent influence on grain yield under upland drought stress conditions in a wide range of environments, were evaluated under water stress in the fields. The line which gave higher yield under drought was crossed with a local elite line, PMK3, and forwarded to F2：3 generation. Significant variation was found among the F2：3 lines for agronomic traits under water stress in the fields. Low to high broad sense heritability （H） for investigated traits was also found. Water stress indicators such as leaf rolling and leaf drying were negatively correlated with plant height, biomass and grain yield under stress. Bulked segregant analysis （BSA） was performed with the markers in the vicinity of qUl2.1, and RM27933 was found to be segregated perfectly well in individual components of drought resistant and drought susceptible bulks which were bulked based on yield under water stress among F2：3 lines. Hence, this simple and breeder friendly marker, RM27933, may be useful as a potentially valuable candidate marker for the transfer of the QTL qtl12.1 in the regional breeding program. Bioinformatic analysis of the DNA sequence of the qtl12.1 region was also done to identify and analyze positional candidate genes associated with this QTL and to ascertain the putative molecular basis of qUl2.1.

Evaluation of New Formulation of Oxyfluorfen (23.5% EC) for Weed Control Efficacy and Bulb Yield in Onion

A field experiment were conducted for two years at Agricultural Research Station, Bhavanisagar of Tamil Nadu Agricultural University, during kharif season of 2009 and 2010 to evaluate the new formulation of oxyfluorfen (23.5% EC) on weed control in onion. Weeds constitute one of the biggest problems in agriculture that not only reduce the yield and quality of onion but also utilize essential nutrients. Hence, weed control is essential for increasing onion production. Based on two years field experimentation, it was found that pre-emergence application of oxyfluorfen (23.5% EC) at400 g.ha-1 gave significantly lower total weed density, weed dry weight and higher weed control efficiency at all the intervals. Application of new formulation of oxyfluorfen (23.5% EC) at200 g.ha-1 as pre-emergence herbicide can keep the weed density and dry weight below the economic threshold level and increase the bulb weight (42.56 and43.87 g) and yield (15940 and15610 kg.ha-1) in onion. Unweeded control accounted for lower bulb yield which inturn reflected through higher weed index of 60.6 and 56.1 per cent, respectively during both the years, due to heavy competition of weeds for nutrients, space and light.

Plant Ionomics: A Platform for Identifying Novel Gene Regulating Plant Mineral Nutrition

In the present era of genomics, ionomics is one of the major pillars for the structural and functional genomic study. The complete set of ions present in an organism is referred to as the ionome of the organism. Hence, the ionomics is defined as the, “study of quantitative complement of low molecular weight molecules present in cells in a particular physiological and developmental state of the plant” [1]. The complete ionomic profiling of the plants are done by using a number of analytical tools like ICP-MS, ICP-OES, X-Ray crystallography, Neutron Activation Analysis (NAA) etc. All these analytical tools gave complete profile of the ions present in the plants. These data are stored in a database called PiiMS (Purdue Ionomics Information Management System) [2]. The huge data available in the database helps in the forward and reverse genetic approach for studying the structural and functional genomics of the particular organism. This review describes the role of the ionomic study in crop plants like arabidopsis, rice and maize.

Influence of Post Emergence Application of Glyphosate on Weed Control Efficiency and Yield of Transgenic Maize

Field experiment was conducted during kharif 2009 and rabi 2009-2010 at Tamil Nadu Agricultural University, Coimbatore to evaluate the weed control efficiency and yield potential of glyphosate resistant transgenic maize. Treatments consisted of two transgenic maize hybrids named Hishell and 900 M gold with application of glyphosate as post emergence at 900, 1800 and 3600 g a.e/hathese were compared with non-transgenic counterpart maize hybrids with application of atrazine as pre-emergence at 0.5 kg/ha followed by one hand weeding at 40 Days After Sowing along with need based insect control practices. Post emergence application of glyphosate at 900, 1800 and 3600 g a.e/ha in transgenic maize hybrids was recorded with lower weed density and higher weed control efficiency compared to other treatments. Higher grain yield was recorded with post emergence application of glyphosate at 1800 g a.e/ha in transgenic hybrid 900 M Gold and 3600 g a.e/ha in transgenic hybrid Hishell during kharif 2009 and rabi 2009-2010 seasons, respectively.

The Tomato Hybrid Proline-rich Protein regulates the abscission zone competence to respond to ethylene signals

The Tomato Hybrid Proline-rich Protein(THyPRP)gene was specifically expressed in the tomato(Solanum lycopersicum)flower abscission zone(FAZ),and its stable antisense silencing under the control of an abscission zone(AZ)-specific promoter,Tomato Abscission Polygalacturonase4,significantly inhibited tomato pedicel abscission following flower removal.For understanding the THyPRP role in regulating pedicel abscission,a transcriptomic analysis of the FAZ of THyPRP-silenced plants was performed,using a newly developed AZ-specific tomato microarray chip.Decreased expression of THyPRP in the silenced plants was already observed before abscission induction,resulting in FAZ-specific altered gene expression of transcription factors,epigenetic modifiers,post-translational regulators,and transporters.Our data demonstrate that the effect of THyPRP silencing on pedicel abscission was not mediated by its effect on auxin balance,but by decreased ethylene biosynthesis and response.Additionally,THyPRP silencing revealed new players,which were demonstrated for the first time to be involved in regulating pedicel abscission processes.These include:gibberellin perception,Ca2+-Calmodulin signaling,Serpins and Small Ubiquitin-related Modifier proteins involved in post-translational modifications,Synthaxin and SNARE-like proteins,which participate in exocytosis,a process necessary for cell separation.These changes,occurring in the silenced plants early after flower removal,inhibited and/or delayed the acquisition of the competence of the FAZ cells to respond to ethylene signaling.Our results suggest that THyPRP acts as a master regulator of flower abscission in tomato,predominantly by playing a role in the regulation of the FAZ cell competence to respond to ethylene signals.

Fungal Microbes Associated with Agarwood Formation

Agarwood is studied as the resinous secondary metabolites produced by the natural microbial infection. The current study investigated the range of microbial infection in agarwood trees collected from various parts of India. A total of 17 isolates were collected and identified based on the morphological and molecular studies. The study revealed that the agarwood was naturally infected with Aspergillus, Lasiodiploidia, Chaetomium, Fusarium and Penicillium species. Further studies on enzyme activities involved in the pathogenesis process showed the higher cellulase, ligninolytic and laccase activities in Aspergillus isolate AR13 when compared to other isolates. The current study has offered a potential opportunity to further strengthen the research on possible development of microbial strains for artificial inoculation in agar trees to induce agarwood formation.

Intra-population genetic variance for grain iron and zinc contents and agronomic traits in pearl millet

Crop biofortification is a sustainable approach for fighting micronutrient malnutrition in the world. The estimation of variance components in genetically broad-based populations provides information about their genetic architecture, allowing the design of an appropriate biofortification breeding method for cross-pollinated crops such as pearl millet. The objective of this study was to estimate intra-population genetic variance using self(S1) and half-sib(HS) progenies in two populations, AIMP92901 and ICMR312. Field trials were evaluated in two contrasting seasons(2009 rainy and 2010 summer; otherwise called environments) in Alfisols at ICRISAT, Patancheru. Analyses of variance showed highly significant variation for S1 s and HS progenies, reflecting high within-population genetic variation for both micronutrients and other key traits. However, the HS showed narrow ranges and lower genetic variances than the S1 for all of the traits. The micronutrients were highly positively correlated in S1(r = 0.77 to 0.86; P < 0.01) and HS(r = 0.74 to 0.77; P < 0.01)progenies of both populations, implying concurrent genetic improvement for both micronutrients. The genetic variance component was different among populations for Fe and Zn contents across environments, with AIMP92901 showing a greater proportion of dominance and ICMR312 greater additive variance for these micronutrients. The estimates of variance(additive and dominance) were specific for each population, given their dependence on the additive and dominance effects of the segregating loci, which also differ among populations. The possible causes for such differences were discussed. The results showed that the expression of these micronutrients in pearl millet shows largely additive variance, so that breeding high-iron hybrids will require incorporation of these micronutrient traits into both parental lines.

Does heat accumulation alter crop phenology, fibre yield and fibre properties of sunnhemp(Crotalaria juncea L.) genotypes with changing seasons?

Field experiments were carried out in split plot design during the dry and wet seasons for two years(two seasons each in 2016–2017 and 2017–2018) with two genotypes(SH4 and SUIN053), two plant geometry(30×15 cm and 45×15 cm main plots) and three levels of NPK(20 kg N ha^(–1), 40 kg P ha^(–1) and 40 kg K ha^(–1);20 kg N ha^(–1), 60 kg P ha^(–1) and 60 kg K ha^(–1);20 kg N ha^(–1), 80 kg P ha^(–1) and 80 kg K ha^(–1)) with an objective to study the relationship between fibre yield of sunhmep and thermal indices. The results indicated that the thermal units such as cumulative heat unit(CHU), photo thermal unit(PTU) and helio thermal unit(HTU) were the highest during dry seasons, while relative temperature disparity(RTD) was the highest during wet seasons irrespective of the genotypes, plant geometry and fertilizer levels. The combined analysis of variance showed that the suitability of sunnhemp genotypes for obtaining fibre and seed yields varied with season. The results further indicated that sunnhemp grew during dry seasons with longer photoperiod and higher values of growing degree days(GDD), HTU and PTU resulted in a higher fibre yield, while a higher seed yield and relatively longer, finer and stronger fibres were obtained during wet seasons with higher RTD values. Regression analysis indicated that CHU was positively related to fibre yield, while RTD was positively related to seed yield. CHU beyond 2 000 °C d reduced seed yield and favoured fibre production. In contrary to CHU, RTD values were positively related to seed yield and negatively related to fibre yield. Similarly, HTU had an inverse relationship with fibre yield while PTU had a positive relationship with fibre yield. The genotype SH4 produced a seed yield of 1 361 kg ha^(–1) during wet seasons, which was significantly higher than SUIN053, while a fibre yield of 990 kg ha^(–1)(significantly higher than that of SH4) was obtained for SUIN053 that required less CHU to attain the phenological events during dry seasons. The per unit area yields of seed and fibre with the closer spacing(30 cm×15 cm) by virtue of higher plant density were 17.0 and 14.9% higher than those with the spacing of 45 cm×15 cm, respectively. Higher doses of P and K resulted in higher seed and fibre yields.

Tagging of Brown Planthopper Resistance Genes in F_2s of IR50 × Ptb33 of Rice by Using Bulked Segregant Analysis

Brown planthopper （Nilaparvata lugens Stal） is one of the most damaging pests causing hopper burn in rice, and thereby reducing the productivity and also the quality of the product. The effective management strategy to control this pest is the identification and transfer of desirable genes to local rice cultivars. The most important approach for developing resistant cultivars is the identification of markers, which can help in marker-assisted selection of more durable resistant genotype. The susceptible parent IR50 and the resistant parent Ptb33, and their F2 populations were used in bulked segregant analysis for identification of resistant genes with random amplified polymorphic DNA marker （RAPD） primers. The primers OPC7 and OPAG14 showed both dominant and susceptible specific banding pattern so called co-dominant markers. Moreover, OPC7697 and OPAG14680 showed resistant specific bands and thus being in coupling phase, whereas OPC7846 and OPAG14650 showed susceptible specific genotypic bands in bulked segregant analysis. Therefore, the coupling phase markers, OPC7697 and OPAG14680, are considered to be more useful in marker-assisted selection of rice genotypes in crop improvement.

Microsatellite Marker Based Assessment of Genetic Diversity among Cultivars, Landraces and Wild Relatives in Rice

India being the primary center of origin for rice had a very large treasure of local land races, most of which are out of cultivation today. The exact genetic potential and their differences from commercial varieties and

Management of cotton bollworms Helicoverpa armigera and Earias vittella by ento mopathogenic nematodes

Background: The bollworm complex consisting of Helicoverpa armigera and Earias vittella is a major threat in cotton production globally. The habit of developing resistance to many insecticides including Bt transgenic cotton necessitates the exploration of an alternate strategy to manage bollworms. The entomopathogenic nematodes(EPN) Steinernema carpocapsae strain APKS2 and Heterorhabditis bacteriophora strains KKMH1 and TRYH1 at different concentrations of 1 × 10^(9) infective juveniles(IJs)·hm^(-2), 2 × 10^(9)IJs.hm^(-2), and 3×10^(9)IJs·hm^(-2) in 500 L of water were evaluated as a foliar spray in fields naturally infested with H.armigera and F.vittella located at Eastern Block and and Cotton Research Farm of Tamil Nadu Agricultural University, Coimbaotre, India during October 2010–February 2011 and October 2011–February 2012, respectively.Results: In general, all three tested EPN strains reduced the larval population of H. armigera and E. vittella;reduced square and boll damage;and subsequently increased cotton yield compared with the untreated control. The S. carpocapsae APKS2 is most e ective against H. armigera whereas both S. carpocapsae APKS2 and H. bacteriophora KKMH1 were equally effective against E. vittella. The higher dose of 3×10^(9)IJs·hm^(-2) was highly significant in the reduction of H. armigera larvae. However, the doses 2×10^(9)IJs·hm^(-2)and 3×10^(9)IJs·hm^(-2) were equally effective for E. vittella control. The S. carpocapsae APKS2 at 3×10^(9)IJs·hm^(-2) caused a 62.2% reduction of H. armigera larvae, 34% reduction of square damage, 58.5% reduction of boll damage, and yielded 45.5% more seed cotton than the untreated control plots. In E. vittella infested field, S. carpocapsae strain APKS2 and H. bacteriophora strain KKMH1 at 2×10^(9)IJs·hm^(-2)resulted in 60.6%~62.4% larva reduction, 68.4%~70.7% square damage reduction, 66.6%~69.9% boll damage reduction and 45.9% yield increase over the untreated control. The effective EPN treatments were comparable to the chemical insecticide chlorpyriphos 20% emulsifiable concentrate spraying at 2 mL·L^(-1).Conclusions: This study has shown that EPN have great potential in the management of the bollworm complex in cotton. Foliar spraying EPN strain S. carpocapsae(APKS2) at 3×10^(9)IJs·hm^(-2) and S. carpocapsae(APKS2) or H. bacteriophora(KKMH1) at 2×10^(9)IJs·hm^(-2) five times at 10days intervals are the best for the management of H. armigera and E. vittella, respectively.

Evaluation of Weed Control Options for Herbicide Resistant Transgenic Stacked (TC 1507 X NK603) and Conventional Maize Hybrids for Higher Productivity

Weeds are posing a serious problem in maize. The congenial climatic conditions encourage more weed growth in the widely spaced crop like maize and cause yield reduction to the tune of 29 to 70 percent. A field experiment was conducted for two years at Tamil Nadu Agricultural University, Coimbatore during kharif seasons of 2010 and 2011 to evaluate the weed management options for transgenic stacked (TC 1507 & NK 603) and conventional maize hybrids. The experiments were conducted with the following objective to evaluate the weed control efficiency and crop productivity with K salt of glyphosate formulations under field conditions. Treatments consisted of two transgenic stacked hybrids named 30V92 and 30B11 applied with glyphosate as early post emergence at 900 and 1800 g a.e ha-1 during kharif, 2010 and conventional maize hybrids named 30V92 and 30B11 applied with glyphosate by controlled droplet application method at 900, 1350 and 1800 g a.e ha-1 during kharif, 2011 compared with non transgenic counterpart maize hybrids applied with pre emergence atrazine at 0.5 kg ha-1 followed by one hand weeding on 40 DAS with and without insect management. Based on the two years field experimentation, it was found that early post emergence application of glyphosate at 1800 g a.e ha-1 gave significantly lower weed density, weed dry weight and higher weed control efficiency at all the intervals. Higher grain yield was registered with post emergence application of glyphosate at 1800 g a.e ha-1 in transgenic and conventional maize hybrid of 30V92 (12.21 t ha-1 and 11.23 t ha-1 ) during both seasons of the study. Unweeded control accounted for grain yield which in turn reflected through higher weed

Root Characters of Maize as Influenced by Drip Fertigation Levels

The efficient use of water by modern irrigation systems is becoming increasingly important in arid and semi-arid regions with limited water resources. Field experiments were conducted during 2008-2010 to study the effect of drip fertigation with water soluble fertilizer on root growth of maize under maize based intercropping system. The experiment was laid out in strip plot design with three replications. The treatment consists of nine fertigation levels in main plots and four inter crops in sub plots. Root spread and root dry mass were increased under drip fertigation practices while rooting depth was more under surface irrigation. Drip fertigation with water soluble fertilizer improved the root system by inducing new secondary roots which are succulent and actively involved in physiological responses. Drip fertigation has pronounced effect on the root architecture especially in the production of highly fibrous root system.