Main Agricultural Research Station Research Articles

First report of Candidatus Phytoplasma australasia (16SrII- subgroup D) associated with virescence of Chia (Salvia hispanica L.) from India.

Chia (Salvia hispanica L., Lamiaceae) is an important commercial and medicinal crop recently popularized in India and widely cultivated in Karnataka (Joy et al., 2022). During the field survey of chia crop diseases, characteristic virescence like symptoms were observed at Main Agricultural Research Station, UAS, Raichur as well as at Mysuru and HD Kote region. The incidence was ranged from 2 - 4 per cent in an area of 30 hectares. Typical symptoms associated with chia are malformed shoot and/or inflorescence axis with reduced floral parts with greenish florets. The stem axis become thick, flattened, leaves are reduced towards terminal region. A total of five phytoplasma suspected samples and five suspected healthy samples were used for identification purpose. The Plant Genomic DNA Miniprep Kit (Sigma Aldrich, USA) was used to extract the DNA from five symptomatic and five asymptomatic samples and the DNA was used as template to amplify the phytoplasma-specific 16S rDNA gene using P1/P7 primers (Deng and Hiruki, 1991; Schneider et al., 1995) followed by nested PCR using R16F2n/R16R2 primers (Gundersen and Lee 1996). The expected 1.25-kb amplicon was detected from the suspected symptomatic samples. Nested PCR products were purified and sequenced from both the directions using ABIX370 Genetic Analyzer (Applied Biosystems, Waltham, MA). The analysis revealed that all five sequences shared 100 per cent identity with Candidatus Phytoplasma aurantifolia (OM649850, ON975012) and Tomato big bud phytoplasma (EF193359). The in-silico RFLP pattern of F2n/R2 primed region of 16S rDNA gene analyzed by using iPhyClassifier (Zhao et al. 2009) revealed that the sequence shared 98.72 per cent nucleotide sequence similarity with coefficient value of 1.00 to the reference strain RFLP pattern of 16Sr group II, subgroup D (witches'-broom disease of lime; U15442). Based on 16SrDNA sequences and in-silico RFLP analysis, the phytoplasma associated with the chia virescence was identified as a member of 16SrII-D group. Further, SecA gene was also amplified from the samples using SecAfor1/SecArev3 primer pair (Hodgetts et al., 2008). All samples produced ~400 bp products and sequenced as detailed above. Sequence analysis by nBLAST revealed 100 per cent similarity to Ca. P. australasia (MW020545) and Ca. P. aurantifolia isolate Idukki Kerala 1 (MK726369) both representing 16SrII-D group phytoplasma. The representative sequence (16Sr: PP359693, PP359694; secA:PP386558, PP386559) were deposited in GenBank. Chia virescence phytoplasma belonging to Ca. phytoplasma australasia has not been reported anywhere. The phytopathological studies associated with chia crop are very limited. Joy et al. (2022) reported the occurrence of foot rot disease caused by Athelia rolfsii. Several hosts are recorded to be associated with 16SrII D phytoplasma which includes china aster, eggplant and crotalaria (Mahadevakumar et al., 2017, Yadav et al., 2016a, b). Now the wide occurrence of the phytoplasma in the area might have transmitted by vectors. The occurrence of virescence is of great importance as it affects the overall yield which reduces the market value. To our knowledge, this is the first report of a group 16SrII-D phytoplasma associated with chia virescence in India.

Assessment of Genetic Variability and Character Associations in Sunflower (Helianthus annuus L.) Yield Related Traits

Aims: To investigate yield and yield related characteristics for variability and association studies in fifty-two powdery mildew differentials of sunflower.
 Study Design:  Augmented block design.
 Place and Duration of Study: Main agricultural Research station, University of Agricultural Science, Raichur, Karnataka between November 2022 and February 2023.
 Methodology: Study included 52 powdery mildew differentials of sunflower studied factors such as genetic variability, heritability, and genetic advance in characters such as head diameter, seed filling percent, test weight, number of seeds per head, volume weight, oil content and seed yield. Correlation and path analysis was also done.
 Results: Findings revealed significant differences among the traits, especially in seed yield per plant, head diameter, seed filling percent, test weight, and number of seeds per head which conclude that there is variability present in the studied character and there is scope for crop improvement. Correlation coefficients showed positive connections between seed yield per plant and traits like head diameter, test weight, seed filling percentage, and number of seeds per head. However, volume weight had a negative correlation. Path coefficient analysis helped us understand the direct and indirect impacts of these traits on seed yield per plant. Head diameter, seed filling percentage, test weight, and number of seeds per head had positive direct effects on seed yield per plant. In contrast, volume weight had a negative direct effect.
 Conclusion: The study contributes to the understanding of the genetic architecture of sunflower traits related to yield and provides a foundation for developing targeted breeding strategies. These insights can guide sunflower breeding programs in selecting traits for improved yield.

Sustainable intensification of climate-resilient maize–chickpea system in semi-arid tropics through assessing factor productivity

Global trends show that the rapid increase in maize production is associated more with the expansion of maize growing areas than with rapid increases in yield. This is possible through achieving possible higher productivity through maize production practices intensification to meet the sustainable production. Therefore, a field experiment on “Ecological intensification of climate-resilient maize–chickpea cropping system” was conducted during consecutive three years from 2017–2018 to 2019–2020 at Main Agricultural Research Station, Dharwad, Karnataka, India. Results of three years pooled data revealed that ecological intensification (EI) treatment which comprises of all best management practices resulted in higher grain yield (7560 kg/ha) and stover yield compared to farmers’ practice (FP) and all other treatments which were deficit in one or other crop management practices. Similarly, in the succeeding winter season, significantly higher chickpea yield (797 kg/ha) was recorded in EI. Further EI practice recorded significant amount of soil organic carbon, available nitrogen, phosphorus, potassium, zinc, and iron after completion of third cycle of experimentation (0.60%, 235.3 kg/ha,21.0 kg/ha,363.2 kg/ha,0.52 ppm and 5.2 ppm respectively). Soil enzymatic activity was also improved in EI practice over the years and improvement in each year was significant. Lower input energy use was in FP (17,855.2 MJ/ha). Whereas total output energy produced was the highest in EI practice (220,590 MJ ha−1) and lower output energy was recorded in EI–integrated nutrient management (INM) (149,255 MJ/ha). Lower energy productivity was noticed in EI-INM. Lower specific energy was recorded in FP and was followed by EI practice. Whereas higher specific energy was noticed is EI–INM. Each individual year and pooled data showed that EI practice recorded higher net return and benefit–cost ratio. The lower net returns were obtained in EI-integrated weed management (Rs. 51354.7/ha), EI-recommended irrigation management (Rs. 56,015.3/ha), integrated pest management (Rs. 59,569.7/ha) and farmers’ practice (Rs. 67,357.7/ha) which were on par with others.

Phyto-Extract-Based Weed Management in Organic Sweet Corn: A Comparative Analysis

A field experiment was conducted during kharif 2020 and 2021 to study the weed management in organic sweet corn through phyto-extracts at the Main Agricultural Research Station, University of Agriculture Sciences, Dharwad, Karnataka. The experiment with randomized complete block design (RCBD) was laid out with fifteen treatments, comprises of four Phyto extracts of 30% concentration (Parthenium hysterophorus, Cassia sericea, Lantana camara and Prosopis juliflora) in combinations with directed spray of respective extract at pre-emergence, 20, 40 DAS fb one inter cultivation at 40 DAS fb hand weeding and another three treatments namely T13: inter-cultivation at 20 and 40 DAS fb one hand weeding at 20 DAS, T14: weedy check and T15: weed free check.   The pooled data of the experiment indicated that, inter-cultivation at 20 and 40 DAS and one hand weeding at 20 DAS recorded significantly higher the fresh cob yield (180.26 q ha-1), fresh fodder yield (341.66 q ha-1), net returns (Rs. 2,45,049 ha-1) and B:C ratio (4.16) with higher WCE as compared to other treatments. Among different phyto-extract treatments with time of application, directed spray of Parthenium hysterophorus at 30% leaf extract at 20 DAS and one inter-cultivation at 40 DAS followed by hand weeding recorded significantly higher the fresh cob yield (159.15 q ha-1), fresh fodder yield (315.13 q ha-1), net returns (Rs. 2,07,914 ha-1) and B:C ratio (3.66) with the higher WCE 80.40 and 68.76 per cent at 60 DAS and at harvest, respectively as compared to other phyto-extract treatments.

Effect of Humic Acid from Vermicompost and Commercial Source on Growth, Yield and Quality of Groundnut (Arachis hypogea L.)

A pot culture experiment was conducted in the year 2017 at Main Agricultural Research Station, University of Agricultural Sciences, Dharwad to study the impact of soil and foliar application of humic acid from vermicompost and commercial source on growth, yield and quality parameters of groundnut variety GPBD-4 by adopting completely randomized block design with thirteen treatments and three replications. The highest plant height (36.83 cm), LAI (0.96) and relative chlorophyll content (34.82) was recorded in the treatment which received soil application of humic acid from vermicompost @ 20 kg ha-1 in combination with the foliar spray of 0.2% at 30 DAS. Similar trend was observed in yield and quality parameters of groundnut. Significantly highest number of pods plant-1 (24.00), pod yield plant-1 (14.80 g plant-1), oil content (46.12%) and crude protein content (25.38%) was also recorded in the same treatment. The results revealed that there is a statistical increase in the periodical observation, yield and quality of groundnut with the additional application of humic acid extracted from vermicompost over the recommended package of practice.

Status quo of insect pests – a decade of survey in Groundnut ecosystem

Groundnut, Arachis hypogea L. is an important oilseed crop and the insecticides to manage these pests increase the plant protection cost much if not taken at right time and also result in ecological imbalance. In order to minimize the cost of management and economic sustainability, real time management of the pests is the need of the hour. In this regard, monitoring of incidence of insect pests in groundnut ecosystem was carried out at Main Agricultural Research Station, University of Agricultural Sciences, Raichur, Karnataka for a period for over a decade (2012-2022). The pooled data showed that the maximum damage by Spodoptera litura Fab, and leaf miner was noticed during 45-75 days of crop growth wherein, spodoptera damage ranged from 10-25 percent while, the leafminer damage ranged from 5-20 percent. However, there was negligible damage by Helicoverpa armigera Hubner. Meanwhile, The leafhopper activity started from 35th standard week and the peak activity was noticed at the 43rd standard week with a foliage damage of 10-15 per cent which continued up to 45th standard week. Later on, the per cent foliage damage due to leafhopper gradually declined. Similarly, the peak activity of thrips was noticed during 40th standard week (4.0/ terminal bud) which continued till 43th standard week and thereafter the population declined.

Influence of Weather Parameters on the Incidence and Severity of Guava Scab Caused by Pestalotiopsis psidii (Pat.)

Guava (Psidium guajava) is an important tropical fruit crop of India and is known as “apple of the tropics”. It is grown and utilized as an important fruit in tropical countries like India, Indonesia, Pakistan, Bangladesh and South America. Among the biotic and abiotic diseases of guava, guava infected by scab disease [Pestalotiopsis psidii (Pat.) Mordue] is an economically important and reported average yield losses in the range of 12-18%. An experiment was conducted during 2023 at Horticulture garden, Main Agricultural Research Station, University of Agricultural Sciences, Raichur during 2023 to understand the influence of various weather parameters on the guava scab disease development. The results revealed that, irrespective of the varieties, interaction among maximum temperature, minimum temperature, maximum relative humidity, minimum relative humidity, rainy days and rainfall showed significant positive correlation with guava scab disease. And the incidence and severity of guava scab was found to be 23.21, 56.00 (Allahabad Safed), 32.45, 68.50 (Lucknow 49) and 85.00, 74.51 (Arka Kiran) respectively.

Assessment of Growth, Flowering, Yield and Quality Parameters of Different Okra (Abelmoschus esculentus L.) Genotypes

The present investigation was carried out at New Orchard, Main Agricultural Research Station, UAS, Raichur, during late Kharif 2021-22 using thirty-one genotypes and laid out in Randomized Block Design (RBD) with three replications. The result of the study revealed that, there was significant differences (p < 0.05) among the genotypes for all the traits studied. Genotype OPL-2127 recorded the highest plant height (130.69 cm), stem girth (20.45 mm), number of leaves per plant (27.29), leaf area index (3.62), number of nodes per plant (16.04), chlorophyll content (64.26 SPAD readings), fruit length (18.69 cm), number of fruits per plant (16.10), harvesting period (63.50 days), fruit yield per plant (293.53 g), fruit yield per hectare (16.4 t) and it is found to be superior over the other okra genotypes under the study. The highest fruit girth (41.36 mm) and ten fruits weight (230.10 g) was noted in the genotypes OPL-2108 and OPL-2125, respectively. The genotypes OPL-2102 and OPL-2119 recorded the minimum number of days for first flower appearance (34.50) and days to 50 per cent flowering (38.00), respectively which indicates the earliness of the genotypes. OPL-2023 recorded the highest shelf-life (5.50 days) and fibre content (16.09%).

Effect of Conservation Agriculture Practices on Growth Attributes and Yield of Pigeonpea

A two-year field experiment was conducted at Main Agricultural Research Station, Raichur in 2021 and 2022 was laid out in a Split-Split design with four main, two sub and two sub-sub treatments with three replications to evaluate effect of conservation agricultural practices on growth and yield of pigeonpea. The treatments with flat bed, Compartment bund, Ridge and furrow & Broad bed and furrow were takes on main, treatments with mulching and without mulching an sub treatment and FYM and RDF & FYM an sub-sub treatment. Among them ridges and furrow (M3) method along with mulching FYM and RDF was found to have positive influence of growth parameters viz., plant height, number of primary branches and total dry matter production at harvest stage. Adopting the ridge and furrow method can be an effective strategy for optimizing the grain yield (1555 kg ha-1 and 1599 kg ha-1) in 2021 and 2022 in pigeonpea crop respectively.

Development of Genotypes for Foliar Disease Resistance in Mungbean [Vigna radiata (L.) Wilczek] through Recombination and Mutation Breeding

Background: Despite the best efforts for improving the greengram varieties, the yield potential of this crop remains low owing to both biotic and abiotic factors. Yield losses caused due to various diseases were estimated to be 24-67 per cent in anthracnose, 80-100 per cent in mungbean yellow mosaic virus and 40 per cent due to powdery mildew So, the use of resistant cultivars is the most effective and eco-friendly method of managing the disease. Methods: A series of field experiments spanned over seven years (2014-2021) were conducted at Main Agricultural Research Station, University of Agricultural Sciences, Dharwad, Karnataka. In the first set of experiments, the material comprised of eight varieties of greengram which were treated with 20kR gamma radiation. M1was planted in Kharif 2014 and each variety was bulk harvested. M2 was planted in summer 2014 and individual plant selection was carried out. Mutant families were advanced to the further generation in Kharif 2015 and Rabi 2015. The M2 mutants were scored for their reaction to anthracnose, cercospora leaf spot and powdery mildew diseases with respective susceptible and resistant checks. In another set of experiments aimed at developing MYMV tolerant genotypes, an investigation was carried out with 168 F2 individuals derived from crossing Vigna trilobata and DGGV2. One row infector line of DGGV-2 was raised after every three test entries to study the reaction to MYMV. Three rows of susceptible check was planted all around the border to ensure enough inoculum load. Of the 168 F2 individuals, two lines showed resistance to MYMV. They were stabilized through a series of selfing generations. Result: Evaluation of advanced breeding lines for their reaction to various foliar diseases revealed that the advanced breeding lines DGG-203, DGG-206, DGG-208, DGG-21, DGG-80, DGG-273, DGG-274, DGG-275, DGG-262, DGG-263, DGG-264, DGG-82, DGG-200, TARM-1 (C), DGG-215-5, DGG-302, DGG-152, IPM-3-2, DGG-20, DGG-73, IPM-14-10, DGG-121, DGG-250, DGG-109, DGG-96 had seed yields ranging from 9.8 g to 12.4 g and moderately resistant to both anthracnose and CLS. The breeding lines DGG-203, DGG-206, DGG-21, DGG-273, IPM-3-2 (Check), DGG-96 have recorded combined resistance to anthracnose, cercospora leaf spot and powdery mildew diseases.

Pollination Potentiality of Honey Bee (Apis cerana Fab.) in Sunflower Hybrid (DRSH-1) Seed Production

The study was conducted at Main Agricultural Research Station, UAS, Raichur during rabi 2020-21 to utilize honey bees in sunflower hybrid seed production. Totally, thirty species of floral visitors were recorded on parental lines of sunflower hybrid (DRSH-1), among them 15 were hymenopterans, 7 lepidopterans, 5 coleopterans and 3 dipterans. Apis cerana was predominant pollinator (17.91±6.72 bees/ 5 capitula/ 5 min) on CMS parental line (ARM-243), followed by A. dorsata and least was A. florea. The peak foraging activity of A. dorsata was recorded at 0900-1000 hr with 24 bees, A. cerana recorded two peak foraging activity, one at 1100-1200 hr (29 bees) and another at 1600-1700 hr (18 bees) and A. florea recorded at 1000-1100 hr (10 bees). The maximum Shannon-Wiener index of diversity (H=1.32) of floral visitors on CMS line under open condition was recorded at 0800-0900 hr of the day and least (H=0.84) was at 1600-1700 hr. In case of fertility restorer line (6D-1) maximum Shannon-Wiener index was recorded at 1600-1700 hr (1.24). A. cerana under caged condition (three colonies per acre) without pollen load on CMS line were recorded highest mean number of nectar foragers (65±22.60 bees), followed by A. dorsata, A. cerana and A. florea foragers from natural colonies in open pollination condition. Whereas, highest mean number of nectar foragers (42.25±23.59) with pollen load in A. cerana under caged condition (three colonies per acre) were recorded, followed by A. dorsata, A. cerana and A. florea. Nectar foragers with pollen load on CMS line play an important role in transfer of pollen grains from restorer line to CMS line and carry out effective pollination. A. florea with and without pollen load spent more foraging duration (13.17 and 25.20 sec/capitulum respectively) on CMS line, followed by A. cerana and least in case of A. dorsata in open pollination. Bees without pollen load spent significantly greater nectar foraging duration as compared with bees with pollen load, both in caged and open pollination situations. Significantly highest seed yield per hectare (839.53 kg), per cent filled seeds (95.80 %), test weight (5.41 g), volume weight (46.41 g/100 ml), kernel percentage (66.09 %), highest kernel to husk ratio (1.94) and highest seed quality and associated parameters were recorded in hand + open pollinated plots, followed by the A. cerana @ 3 colonies per acre treated plots, hand pollination, open pollination and least seed quality parameters were recorded in control treatment.

Experimental Evaluation of Irrigation Methods on Soil Nutrient Status and Nutrient Uptake of Summer Groundnut

Aims: To study the nutrient uptake and status of available nutrients in soil after harvest of groundnut as affected by different irrigation levels and methods at Northern Transitional Zone of Karnataka.
 Study Design: The experiment was laid out in randomized block design with different irrigation levels and methods replicated thrice.
 Place and Duration of Study: AICRP on Groundnut, Main Agricultural Research Station, University of Agricultural Sciences, Dharwad during summer 2021.
 Methodology: We took 11 treatments involving different level and methods of irrigation using eight micro-sprinkler treatments, one drip fertigation treatment and two flood irrigation treatments. After harvesting soil nutrient status and nutrient uptake from the soil were analyzed.
 Results: Significantly higher total nitrogen, phosphorus and potassium uptake were recorded with drip irrigation applied at 0.6 ET0 at Seedling, 1.0 ET0 at Flowering, 1.25 ET0 at Pegging, 0.8 ET0 at Pod formation stages along with fertigation of N and P [3 splits at NF on 3rd, 4th and 5th week] and CaNO3 and S nutrients [3 splits at PGF on 7th, 8th and 9th week] (164.0, 27.6 and 129.3 kg ha-1, respectively) and was 40.0, 55.43 and 25.91 per cent higher compared to control (Flood FAO). Same treatment enhanced the soil chemical properties like pH, EC and organic carbon by 1.04, 16.12 and 7.40 per cent compared to control.
 Conclusion: Drip irrigation and fertigation enhanced nutrient uptake of groundnut and available soil nutrient status and also improved soil chemical properties as compared to control (Flood irrigation). So, this method can be proved beneficial in reducing the nutrient requirement of the crop under cultivation in the Northern Transitional Zone of Karnataka.

Field Screening of Garlic Genotypes for Identification of Resistant Sources against Purple Blotch Disease

Garlic (Allium sativum L.) is one of the oldest cultivated plants in the world and belongs to the family Amaryllidaceae. Purple blotch caused by Alternaria porri (Ellis) Ciferri is one such disease which causes a great deal of loss for farmers. The best method to manage purple blotch is to adopt resistant genotypes for cultivation, which is highly necessary in areas with a high incidence. In order to identify resistant sources, 37 genotypes were field screened under artificial epiphytotic conditions at AINRPOG (All India Network Research Project on Onion and Garlic), MARS (Main Agricultural Research Station), Dharwad during Rabi, 2019 and 2020. Results from two years showed that no genotype was immune to purple blotch. Among the genotypes tested, five genotypes viz., G50, Bhima Purple, DOGR426, DOGR543 and DOGR569 were resistant to infection (1-10%), 17 genotypes moderately resistant to infection (11-20%), while 4 genotypes were moderately susceptible to infection (21-40%). On a scale of 0 to 5, only one genotype (HRG Local) showed susceptible (41-75%) in reaction. Among the remaining genotypes, disease reactions differed between years. The genotypes that are resistant can be utilized by breeders to produce high yielding purple blotch resistant varieties.

Simulated drought stress unravels differential response and different mechanisms of drought tolerance in newly developed tropical field corn inbreds.

Corn is one of the most important cereal crops in the world with highest yield potential. Nevertheless, its potential productivity is constrained by the occurrences of drought stress worldwide. Besides, in the era of climate change, frequent occurrences of severe droughts are predicted. The present investigation was carried out at Main Agricultural Research Station, University of Agricultural Sciences, Dharwad in split plot design to study response of twenty-eight new corn inbreds under drought free (well-watered) conditions and drought simulated by withholding irrigation from 40 to 75 DAS to create water stress. Significant differences among the corn inbreds, moisture treatments and interaction between inbreds were observed for morpho-physiological, yield and yield components indicating differential response of corn inbreds. The inbreds CAL 1426-2 (higher RWC, SLW& wax and lower ASI), PDM 4641(higher SLW, proline, & wax, and lower ASI) and GPM 114 (higher proline & wax, and lower ASI) were drought tolerant. These inbreds are having higher production potential (>5.0 t/ha) under moisture stress condition with less per cent reduction (<24.4%) over non-moisture stress condition and hence are putative candidates for developing drought tolerant hybrids suitable for rainfed ecosystem besides using them in population improvement program to combine different drought tolerant mechanisms to evolve highly potent drought tolerant inbreds. The results of the study suggested that proline content, wax content, anthesis silking interval, relative water content can be better surrogate traits to identify drought tolerant inbreds in corn.

Quality of Bread Wheat (Triticum aestivum L.) as Influenced by Different Nutrient Management Approaches under Northern Transitional Zone of Karnataka

The field experiments were conducted at the Research Farm of AICW&amp;BIP, Main Agricultural Research Station, University of Agricultural Sciences, Dharwad during rabi 2020-21 and 2021-22 and was laid out in Randomized Complete Block Design with 15 treatments replicated thrice to evaluate the performance of wheat quality to various nutrient management approaches. The pooled data onto two years indicated that application of 275:40.33:135.2 kg of N:P2O5:K2O ha-1 for yield target of 55 q ha-1 under SSNM practices significantly increased the protein content  (13.43 %), wet gluten (34.7 %), dry gluten (11.9 %), gluten index (81.6 %), sedimentation value (46.3 ml) and yellow pigment (5.93 ppm) in wheat grain and it was found on par with yield targets at 50 and 45 q ha-1 under SSNM.

EVALUATION OF BIOPESTICIDES AGAINST FALL ARMYWORM, Spodoptera frugiperda IN MAIZE DURING KHARIF

With the basic principle of integrated pest management (IPM) and searching for effective and sustainable alternatives for the management of Spodoptera frugiperda, different biopesticides were evaluated at Main Agricultural Research Station (MARS), UAS Raichur, Karnataka during Kharif 2019 cropping season. The experiment was laid in a Randomized Complete Block Design (RCBD) with three replications and seven treatments. Biopesticides such as Metarhizium rileyi, SfNPV and Bacillus thuringiensis var. kurstaki were found to be the best treatments in reducing the larval population and per cent leaf damage compared to untreated control at five and seven days after two sprays. The yield and cost economics also showed that they were economically viable biopesticides.

Evaluation of different methods to estimate monthly reference evapotranspiration at Raichur region, India

The potential evapotranspiration (PET) is an important parameter to address water needs for growing crops. Estimation of potential evapotranspiration (PET) requires knowledge of the values of many climatic variables, some of which require special equipment and careful observations. Although potential evapotranspiration is an important component of water balance, the data required for its accurate estimation are commonly available only at widely spaced measurement stations. Numerous potential evapotranspiration models have been developed and are being used, depending upon the availability of weather data. For the proposed study, the daily data of all weather parameters viz., maximum and minimum air temperature, maximum and minimum relative humidity, wind speed, actual sunshine hours and rainfall for estimating potential evapotranspiration for the duration of 31 years (1991-2021) were collected from the weather station at Main Agricultural Research Station (MARS), Raichur. A number of empirical formulae or approaches have been used for the determination of potential evapotranspiration (PET) from meteorological data. Availability of climatic data and accurately converting them in terms of water requirement are of great constraints. Judging the accuracy of different PET estimation models is a difficult task. The FAO 56-Penman Monteith model was considered as a standard reference for PET estimation in this investigation over the study location. The objective was to compare various PET models with standard reference model (FAO 56 Penman-Monteith model) and choose the best suitable model for estimating PET for the study area.

Quality of Bread Wheat (Triticum aestivum L.) as Influenced by Different Nutrient Management Approaches under Northern Transitional Zone of Karnataka

The field experiments were conducted at the Research Farm of AICW&amp;BIP, Main Agricultural Research Station, University of Agricultural Sciences, Dharwad during rabi 2020-21 and 2021-22 and was laid out in Randomized Complete Block Design with 15 treatments replicated thrice to evaluate the performance of wheat quality to various nutrient management approaches. The pooled data onto two years indicated that application of 275:40.33:135.2 kg of N:P2O5:K2O ha-1 for yield target of 55 q ha-1 under SSNM practices significantly increased the protein content  (13.43 %), wet gluten (34.7 %), dry gluten (11.9 %), gluten index (81.6 %), sedimentation value (46.3 ml) and yellow pigment (5.93 ppm) in wheat grain and it was found on par with yield targets at 50 and 45 q ha-1 under SSNM.

Seasonal abundance of major insect pests of potato (Solanum tuberosum) and their natural enemies in Karnataka, India 

It is essential to know the seasonal occurrences of various pests of potato along with their natural enemies so that timely management practices could be advised to farmers to avoid losses. Therefore, field studies on seasonal incidence of major insect pests of potato and their natural enemies were carried out at the All India Co-ordinated Research Project on Potato, Main Agricultural Research Station, University of Agricultural Sciences, Dharwad, India during Kharif 2016 and 2017; and at Hangaraki, a village near Dharwad during Rabi 2016-17 and 2017-18. The observations on the seasonal abundance of potato insects, mites, and their natural enemies were recorded at weekly intervals starting from 20 days after the emergence of the plant till harvest. These observations were made under unprotected conditions. During Kharif season, the sucking pests were active from July second week and continued up to harvesting of the crop and the maximum pest population was observed during August second week to September first week. The peak activity of the shoot borer, Leucinodes orbonalis Guenee was noticed during the 35th Meteorological Standard Week (MSW) (i.e., August). The maximum population of defoliator, Spodoptera litura (Fab.) was noticed during 34th MSW. The higher populations of coccinellid beetles and spiders were recorded during 35th MSW while chrysopid activity was maximum during 36th MSW (September). During Rabi season, the sucking pests were active from October second week and attained peak during the second and third week of November. The maximum activity of aphids and leafhoppers was noticed during the 46th and 47th MSW (November), respectively. The highest incidence of thrips was recorded during the 48th MSW. The peak population of whiteflies and mites was recorded during the 46th and 45th MSW, respectively. The peak activity defoliator and shoot borer were noticed during the 45th and 46th MSW, respectively. The chrysopid activity was maximum during 46th and 47th MSW.

Management of Powdery Mildew in Cluster Bean using Fungicides, Botanicals and Bioagents

Background: Cluster bean crop is affected by various biotic and abiotic stresses which are responsible for its poor quality and low yield resulting in severe economic losses. Among the foliar diseases, powdery mildew caused by Leveillula taurica is an important disease causing the yield losses ranging from 50-55 per cent. So, there is a need to formulate suitable management practices against powdery mildew. Methods: Field experiment was laid-out in a randomized complete block design with three replications at Main Agricultural Research Station, University of Agricultural Sciences, Dharwad to determine the efficacy of economically viable and effective fungicides, botanical and bioagent against powdery mildew of cluster bean. Observation on intensity of disease was recorded using 0-9 scale. The per cent disease index and yield per hectare were taken into consideration for statistical analysis. Result: Among the thirteen combinations, two sprays of hexaconazole @ 0.1 per cent was found to be statistically significant in reducing the disease severity (11.75%) and enhancing pod yield (138.46%) upto 6.20 t ha-1 with C: B ratio of 1:3.23. The combined application of nimbecidine and Bacillus subtilis also showed significant impact on disease reduction as well as on yield of cluster bean. Relatively, the chemical, hexaconazole gave a higher benefit with minimum production cost and this approach is proposed to the cluster bean growing farmers to mitigate the powdery mildew.