Regional Agricultural Research Station Research Articles

Effect of crop geometry and nitrogen levels on leaf chlorophyll content of cotton (Gossypium hirsutum) at different growth stages under rainfed Vertisols

A field experiment was conducted during the rainy (kharif) season of 2018–19 at the Regional Agricultural Research Station, Acharya N.G. Ranga Agricultural University, Lam, Gunter, Andhra Pradesh on Vertisols under rainfed conditions. To study the effect of crop geometry and nitrogen levels on compact cotton (Gossypium hirsutum L.). Leaf chlorophyll content was measured with the Soil Plant Analysis Development meter (SPAD 502 Plus Chlorophyll Meter) at different crop growth stages. Among the various crop geometry studied, maximum chlorophyll (SPAD index) content, functional leaves per square meter and leaf area index (LAI) were recorded with close crop geometry 60 cm × 10 cm. Among nitrogen levels application of 180 kg N/ha recorded maximum chlorophyll content, functional leaves per square meter and LAI. Combined effect on crop geometry and nitrogen levels on chlorophyll content was recorded significant with closer geometry 60cm x10cm along with an application of 180kg N ha-1 at 90 days after sowing. Dry matter accumulation (kg/ha) at 30 DAS, 60 DAS, 90 DAS and at harvest was significantly affected by crop geometry and levels of nitrogen but not by their interaction.

Effect of Kharif Paddy Straw Management Options on Nitrogen Requirement to Rabi Paddy

A study conducted during the rabi season of 2020-21 at the Regional Agricultural Research Station, Polasa, Jagtial, under the auspices of Professor Jayashankar Telangana State Agricultural University, yielded insightful findings. The investigation revealed that incorporating paddy straw with a C:N ratio of 71:1 led to the immobilization of soil mineral nitrogen. Specifically, during 7, 15, and 30 days after treatment (DAT), approximately 7.2, 9.3, and 7.03 kg ha-1 of available nitrogen respectively was immobilized without phosphorus, whereas with phosphorus addition, the figures rose to 10.94, 14.75, and 11.04 kg ha-1 during the same time frames. Notably, after harvest of rabi rice significantly higher soil available nitrogen levels were recorded under paddy straw incorporation with phosphorus (169.7 kg ha-1), followed by incorporation without phosphorus (161.2 kg ha-1), and paddy straw burning (151.9 kg ha-1). Moreover, the application of nitrogen at graded levels impacted soil available nitrogen. Based on these findings, it was recommended, to counteract the immobilization effect and maximize crop yield, it was advised to apply 15% excess of recommended dose of nitrogen (RDN), as basal application.

Cultural, Morphological and Pathogenic Variability in the Colletotrichum capsici Isolates, Inciting Anthracnose and Fruit rot of Chilli (Capsicum annuum L.) in different Agro-Climatic Zones of Kerala, India

Aims: To study the cultural, morphological and pathogenic variability existing among the pathogen isolates of Colletotrichum capsici, inciting anthracnose and fruit rot of chilli in Kerala. Study Design: Completely randomized design (CRD). Place and Duration of Study: Department of Plant Pathology, College of Agriculture (Kerala Agricultural University), Vellayani, Thiruvananthapuram during 2018-2019. Methodology: A survey was conducted in the five agro-climatic zones (ACZs) of Kerala viz., Northern zone, Central zone, Special problem zone, High range zone and Southern zone to assess the incidence and severity of anthracnose disease. The various symptoms in the surveyed locations were also noted. Pathogen isolates were grown in PDA medium in the laboratory and colony characters (colour and mycelial growth rate of pathogen colonies) were observed. Also, the morphological characters viz., mycelial width, shape and size of conidia, acervular diameter, number and size of setae, appressorial size were recorded. Results: Maximum anthracnose incidence of 90 per cent and severity of 52.60 per cent were noticed at Regional Agricultural Research Station (RARS), Pilicode (Northern zone). Characteristic leaf spot, fruit rot and die-back symptoms were observed in the survey locations. Pathogen colonies showed different shades of white, off-white to grey turning brown or black with regular or irregular margins and concentric rings of black acervuli in the potato dextrose agar (PDA) medium. The diameter of growth of C. capsici isolates ranged from 7.20 to 8.60 cm at 7 days after incubation. All the C. capsici isolates initiated hyaline mycelium having a width of 1.73 - 2.36 µm and produced numerous sickle shaped conidia with a size range of 19.42 - 20.46 µm × 2.16 - 3.09 µm. Black coloured, circular or ellipsoidal acervuli (122.14 - 189.08 µm dia.) had 20 – 46 setae of length 74.13 to 107.30 µm. Also, brown or black appressoria of size 8.64 - 12.64 µm × 5.54 - 7.84 µm were formed in slide culture. Cc3 from College of Agriculture, Vellanikkara was obtained as the most virulent isolate producing a lesion size of 1.13 cm and PDI of 45.33 in the artificially inoculated chilli fruits (var. Vellayani Athulya) at 5 days after inoculation. Conclusion: All the nine C. capsici isolates exhibited variability in their cultural, morphological and pathogenic characteristics. Variability in phytopathogenic fungi helps in identifying novel and sustainable control methods to tackle the diseases incited by them. Understanding pathogen variability provides new insights for developing effective disease management methods. This will help in promoting sustainable agriculture and preventing severe crop losses.

Native Liquid Biofertilizer Consortia of Staphylococcus equorum, Bacillus velezensis and Staphylococcus epidermidis Enhanced the Growth of Nutmeg Seedlings

Aims: The aim was to evaluate the three most distinct native liquid biofertilizer consortia on the growth of nutmeg seedlings under pot culture studies. Study Design: Completely Randomized Block Design. Place and Duration of Study: Department of Agricultural Microbiology, College of Agriculture, Vellanikkara, Thrissur, Kerala and Block 10, Regional Agricultural Research Station, Ambalavayal, Wayanad, Kerala. The pot culture experiment was conducted from February 2023 to August 2023. Methodology: The experiment was carried out in a completely randomized block design with three replications along with control. Each treatment was applied with a combination of NPK fertilizers (50% and 75% of recommended dose of fertilizer, based on soil test data). One treatment was composed of only organic fertilizers. Results: The biofertilizer inoculation had a positive impact on the population of soil microbes, which indicates good soil health. Application of Staphylococcus equorum + Bacillus velezensis + Staphylococcus epidermidis (consortium – 2) along with 50% of the recommended dose of NPK fertilizers, recorded the highest plant growth parameters viz., plant height, leaf length, leaf breadth, stem diameter, leaf area, shoot dry weight, and maximum number of secondary roots. In most of the treatments, nutmeg shoot growth was higher when compared to root growth. Conclusion: The present study indicated that inoculation of native liquid biofertilizer consortia enhanced the growth of nutmeg seedlings under pot culture studies in Wayanad. Hence liquid biofertilizer consortia can be utilized for earlier establishment of nutmeg seedlings and thereby reduce the dependency on the quantity of chemical fertilizers.

Potassium augments growth, yield, nutrient content, and drought tolerance in mung bean (Vigna radiata L. Wilczek.)

Uneven rainfall and high temperature cause drought in tropical and subtropical regions which is a major challenge to cultivating summer mung bean. Potassium (K), a major essential nutrient of plants can alleviate water stress (WS) tolerance in plants. A field trial was executed under a rainout shelter with additional K fertilization including recommended K fertilizer (RKF) for relieving the harmful impact of drought in response to water use efficiency (WUE), growth, yield attributes, nutrient content, and yield of mung bean at the Regional Agricultural Research Station, BARI, Ishwardi, Pabna in two successive summer season of 2018 and 2019. Drought-tolerant genotype BMX-08010-2 (G1) and drought-susceptible cultivar BARI Mung-1 (G2) were grown by applying seven K fertilizer levels (KL) using a split-plot design with three replications, where mung bean genotypes were allotted in the main plots, and KL were assigned randomly in the sub-plots. A considerable variation was observed in the measured variables. Depending on the different applied KL and seed yield of mung bean, the water use efficiency (WUE) varied from 4.73 to 8.14 kg ha−1 mm−1. The treatment applying 125% more K with RKF (KL7) under WS gave the maximum WUE (8.14 kg ha−1 mm−1) obtaining a seed yield of 1093.60 kg ha−1. The treatment receiving only RKF under WS (KL2) provided the minimum WUE (4.73 kg ha−1 mm−1) attaining a seed yield of 825.17 kg ha−1. Results showed that various characteristics including nutrients (N, P, K, and S) content in stover and seed, total dry matter (TDM) in different growth stages, leaf area index (LAI), crop growth rate (CGR), root volume (RV), root density (RD), plant height, pod plant−1, pod length, seeds pod−1, seed weight, and seed yield in all pickings increased with increasing K levels, particularly noted with KL7. The highest grain yield (32.52%) was also obtained from KL7 compared to lower K with RKF. Overall, yield varied from 1410.37 kg ha−1 using 281 mm water (KL1; well-watered condition with RKF) to 825.17 kg ha−1 using 175 mm water (KL2). The results exhibited that the application of additional K improves the performance of all traits under WS conditions. Therefore, mung beans cultivating under WS requires additional K to diminish the negative effect of drought, and adequate use of K contributes to accomplishing sustainable productivity.

Genetic Variability and Character Association among the Yield and Yield Attributing Traits in Niger [Guizotia abyssinica (L. f.) Cass.

Niger is a minor oil seed crop mostly cultivated in high altitude and tribal zones of India with relatively lower productivity. Development of varieties with higher yielding ability needs keen observations and scientific studies on the genetic variability and character association studies among the available germplasm or in the breeding material. The present investigation was carried out with a main objective to estimate the extent of genetic variability and character association with respect to yield and yield component traits. Thirty five genotypes of niger were collected from different niger stations and sown in rabi, 2022 in a randomized block design at Regional Agricultural Research Station, High Altitude and Tribal Zone, Chintapalle, ANGRAU. Observations were recorded on five plants in each line in each replication for plant height (cm), number of branches plant-1, number of capitula plant-1, test weight (g) and seed yield plant-1 (g). Days to 50 % flowering, days to maturity and seed yield ha-1 (kg/ha) were recorded on plot basis. Analysis of heritability(bs) and genetic advance as percent of mean revealed that four characters viz., plant height, number of branches plant-1, number of capitula plant-1 and seed yield plant-1 are governed by additive gene action, which can be improved further by simple selection methods. Majority of the characters under study are having a significant positive association with seed yield ha-1which helps in indirect selection for higher yield by using these character combinations. All the characters showed significant and positive association with seed yield plant-1which helps in indirect selection of genotypes for improved yielding ability.

Effect of Different kharif Paddy Straw Management Options and Nitrogen Levels on Soil Organic Carbon and Soil Total Carbon and Nitrogen

A field experiment was conducted during rabi 2020-21, at Regional Agricultural Research Station, Polasa, Jagtial, PJTSAU to study the effect of paddy straw burning and incorporation on soil organic carbon, total carbon and nitrogen and soil C:N ratio. The results of the investigation reported that incorporation of paddy straw whose C:N ratio was 71:1 showed that soil organic carbon was significantly higher under paddy straw incorporated treatments. Total carbon content of soil in paddy straw burnt treatments was 1.07 times higher than initial and in paddy straw incorporated treatments 1.51 times higher over initial was observed. Soil total nitrogen decreased with crop duration. At harvest soil total nitrogen was 2606 kg ha-1, 2693 kg ha-1 and 1931 kg ha-1 in paddy straw burning, paddy straw incorporation without phosphorus, paddy straw incorporation with phosphorus respectively. C:N ratio of soil is not influenced by paddy straw management options, nitrogen levels and the interaction between them.

ENHANCING THE PRODUCTIVITY OF CHICKPEA THROUGH FOLIAR NUTRITION UNDER RAINFED CONDITIONS

The study was carried out at Regional Agricultural Research Station, Lam for three years (2020-21, 2021-22, 2022-23) for assessing the productivity of chickpea using foliar nutrition under rainfed conditions of the Krishna Agro Climatic Zone of South Coastal Andhra Pradesh. The experiment was laid out in Randomized Block Design and was replicated thrice. The experiment consisting of eight treatments viz., control (RDF:N20:P50:K0 kg ha -1), application of water soluble NPK, Zn, Fe, soluble monophosphate and soluble potassium nitrate at different stages alone and in combinations. Pooled analysis (2020-2023) of the experimental results revealed that along with recommended dose of fertilizers (N20:P50:K0 kg ha-1) foliar application of Zn @ 0.2% at pre flowering, water soluble monophosphate @1% at flowering and water soluble potassium nitrate @1% at pod filling stage recorded significantly higher seed yield (1871 kg ha-1) and protein content (22.90%) which was on par with foliar application of Fe @ 0.5% at pre flowering, monophosphate@1% at flowering and potassium nitrate @ 1% at pod filling stage with seed yield (1821 kg ha -1) and (22.63%) protein content, both the treatments recorded BCR of 1.9.

Mineral and Labile Organic Nitrogen Fractions in Soil Profile and Their Response to FYM and Inorganic Fertilization in Different Growth Stages of Rice Crop

Nitrogen is the key element among the major nutrients in crop production. The mineralizable soil organic nitrogen is the main contributors of soil N supply. A better understanding of soil organic nitrogen dynamics in agro-ecosystems is needed to improve N management. The present investigation was conducted in Regional Agricultural Research Station (RARS), Assam Agricultural University, Titabar, Jorhat during 2017-18. In this study, the impact of Farmyard Manure (FYM) and inorganic fertilization on soil mineral nitrogen (NO3−-N and NH4+-N) dynamics and labile organic nitrogen fractions viz. microbial biomass N (MBN), particulate organic N (PON) and water-extractable organic N (WEON) at three growth stages of rice viz. active tillering, flowering and physiological maturity stages and nitrogen stock were assessed. Six treatments viz. control (no fertilization), 100% NPK, 100% NPK + FYM 5 t ha-1, 50% NPK, 50% NPK + 50% N through FYM and FYM 10 t ha-1 were tested in randomized block design with four replications. The results showed that NO3−-N and NH4+-N were found to be significantly higher in 100% NPK+FYM 5 t ha-1 at the three growth stages of rice. The labile organic nitrogen fractions were significantly higher in FYM 10 t ha-1. All these variables were decreased with increase in crop growth stages. Integrated use of inorganic fertilizer and FYM recorded the highest nitrogen stock. Stepwise regression analysis indicated that NH4+-N was the main contributor to nitrogen stocks at the three growth stages of rice of the studied soils.

Bio-efficacy of certain new insecticides against pod borer complex in pigeonpea (Cajanus cajan L.)

A study on evaluation of certain new insecticides against pod borer complex in pigeonpea was conducted at Regional Agricultural Research Station, Warangal for three consecutive years from Kharif 2019-20 to Kharif 2021 22 in medium maturity pigeonpea cultivar ‘Rudreswara’ (WRG-65). Seven treatments including untreated control were evaluated for their relative efficacy towards suppression of pod borer larval population and reduction of percent pod damage. The insecticide treatments along with untreated control were applied two times during the crop season viz., 50% flowering and pod formation stage. The results revealed that chlorantraniliprole 18.5 SC @ 0.3 ml/L followed by emamectin benzoate 5 SG proved significantly superior against gram pod borer (Helicoverpa armigera) and spotted pod borer (Maruca vitrata) with highest mean percent larval reduction and cumulative least percent pod damage (10.8 and 14.7%, respectively) over control. Further, chlorantraniliprole 18.5 SC followed by emamectin benzoate 5 SG @ 0.4 g/l recorded higher grain yields and best ICBR ratio (1:4.6; 1:4.5). Thus, the effective chemicals observed in the study could be used as basis for selection of label recommended insecticides for successful management of pod borers in pigeonpea.

Studies on the Effect of Water Stress on Root Traits in Redgram Genotypes

The experiment was conducted during July–November, 2019 at Regional Agriculture Research Station, Professor Jayashankar Telangana State Agricultural University, Palem, Nagarkurnool district, Telangana State, India. The main treatments had five red gram genotypes and water stress levels were taken as sub-treatment in 3 replications in factorial RBD using specialized root structure made with cement bricks. There was great variability in the yield performance of different Redgram genotypes under drought conditions. The experiment was conducted to select genotypes with efficient root architecture and associated traits under drought stress. Root studies were performed with the Delta T automatic root scanner. The SPAD chlorophyll meter was used to measure the SCMR value. The present study results revealed that genotype, Maruti showed significant superiority for character plant height and SCMR under non-stress, mild stress and severe stress conditions. The same genotype showed superior values for main root length under control and mild stress. Whereas, Laxmi recorded the highest plant height under severe stress and the same genotype also showed significant superiority for total plant dry weight, root dry weight and root area under severe stress. The genotype Laxmi showed significant character, root area and diameter superiority under mild stress. ICPL-20176 recorded significant superiority for main root length under severe stress and root tip for mild stress. The identified genotypes can be used as the parents in future drought-proof breeding useful for cultivating in water stress conditions.

Influence of Weather Parameters on the Development of Grey Mildew Disease in Cotton

A study was conducted at the Regional Agricultural Research Station in Warangal to investigate the impact of environmental factors on the development of grey mildew (Ramularia aerola Atk) in cotton. The research spanned from the Kharif season of 2019-20 to 2022-23 and focused on both Bt and non-Bt cotton genotypes grown in vertisols. Disease scores were recorded weekly on randomly selected labeled plants, and the percentage of disease intensity (PDI) was analyzed in relation to various weather parameters. Grey mildew was observed during the boll development stage up to the boll bursting stage, reaching its peak during the latter phase. Correlation analysis revealed significant negative associations between PDI and maximum temperature, minimum temperature, morning relative humidity, evening relative humidity, rainfall, and the number of rainy days. These findings indicate that these environmental factors influenced the development of the disease in both Bt and non-Bt genotypes. Furthermore, multiple linear regression analysis of PDI demonstrated that one percent increase in evening relative humidity led to a corresponding increase in the percent disease index of grey mildew. Specifically, in Bt (RCH 2 BG II) genotype, the increase was 0.38%, while in non-Bt (LRA-5166) genotype, it was 1.87%. Consequently, the study suggests the implementation of preventive and/or protective measures, such as the use of recommended fungicides like 0.3% wettable sulphur or 0.1% carbendazim.

Effect of Different Factors on the Soil Quality of Typic Ustipsamments of State Kerala, in India

Aims: Assessment of soil quality of selected panchayaths of sandy plains (Typic Ustipsamments ) of Kerala based on various soil attributes and to work out soil quality index (SQI).
 Study Design: A study was conducted in the selected panchayaths of sandy plains of Kerala (AEU 3) and 100 representative georeferenced surface soil samples were collected from various land uses. These soil samples were characterized for important physical, chemical, and biological properties.
 Place and Duration of Study: Onattukara Regional Agricultural Research Station, Kayamkulam between April 2021 and May 2022.
 Methodology: Hundred geo-referenced surface soil samples were collected from various land uses of selected panchayaths of sandy plains of Kerala and characterized for various physical (texture, bulk density, particle density, porosity, aggregate analysis, soil moisture, and WHC), chemical (pH, EC, organic carbon and available macro and micronutrients and biological attributes (acid phosphatase and dehydrogenase activity). Principal component analysis was used to set up the minimum data set of the indicators to compute the soil quality index. Seven principal components were extracted from which nine indicators that highly influenced the soil quality were identified. Scores and weights were assigned to each indicator, and they were aggregated to compute the soil quality index. The relative soil quality index of the soils was also found.
 Results: Increased soil acidity and low levels of nutrients like nitrogen, potassium, magnesium, sulfur, and boron were noticed in these soils. The available P content of the soil was high. Mg, S, and B were deficient in 100 percent of the samples, whereas, Fe and Mn remained sufficient. Ca, Zn, and Cu exhibited 72.9, 24.3, and 21.7 percent deficiency, respectively. The majority of the soils belonged to medium soil quality (78.6 percent), followed by poor (12.8 percent) and good (8.6 percent) quality.
 Conclusion: The majority of soils of selected panchayaths of sandy plains of Kerala fell into the medium soil quality class. However, there are several soil fertility issues in these soils. Hence site-specific and crop-specific management strategies have to be followed for the profitable cultivation of the crops and soil test-based fertilizer application has to be followed. It is mandatory to maintain the fertility of the soil for the sustainability of the environment.

Effect of Different Sowing Windows on Dry Matter Accumulation of Pigeonpea Genotypes

A field experiment was conducted to study the “Effect of different sowing windows on dry matter accumulation of pigeonpea genotypes” at Regional Agricultural Research Station, Vijayapura, during Kharif 2021. The experiment was laid out in a split-plot design assigning four sowing windows to main plots viz., first fortnight of June (23-24th SMW), second fortnight of June (25-26th SMW), first fortnight of July (27-28th SMW) and second fortnight of July (29-30th SMW), whereas genotypes to subplot viz.,TS-3R, GRG-152 and GRG-811 and replicated thrice. The results revealed that sowing in first fortnight of June accumulated more dry matter in leaves (18.47 g plant-1), stem (131.22 g plant-1) and reproductive parts (68.16 g plant-1). Among the genotype GRG-152 accumulated higher dry matter in leaves (17.34 g plant-1) and stem (123.01 g plant-1). However, dry matter accumulation in reproductive parts is higher in TS-3R (63.68 g plant-1). Similarly TDMP was higher in first fortnight of June sowing (217.85 g plant-1) than delayed sowing in second fortnight of July. TS-3R accumulated higher TDMP in the beginning growth stage when compared to GRG-152 and GRG-811. However, TDMP was higher in GRG-152 at later stage. This study revealed that pigeonpea sown in first fortnight of June recorded higher dry matter production and it’s partitioning in leaf, stem and reproductive parts and among the genotype TS-3R recorded significantly higher dry matter in pods due to more photosynthetic activity of the genotype which results in higher yield of the crop.

Correlation and path analysis of yield traits in B & R lines of rabi sorghum [Sorghum bicolor (L.) Moench

The present investigation was carried out for correlation and path coefficient analysis using 32 rabi sorghumhybrid parents including maintainers (B) and restorer (R) lines for grain yield and its attributes. The experimental materialwas evaluated during rabi season 2021-22 at Regional Agricultural Research Station, Vijayapur in randomized block designwith two replications. The character association studies revealed that grain yield per plant was found to be significantly andpositively correlated with days to 50% flowering, plant height, panicle breadth, panicle weight, harvest index, panicleharvest index, seed set percentage and grain number per plant both at genotypic and phenotypic level. Path analysisrevealed that characters such as panicle weight, panicle harvest index, harvest index, fodder yield per plant, days to 50%flowering and SPAD at physiological maturity showed a positive direct effect on grain yield per plant. These traits can beconsidered as principal yield determining components and it is suggested to use these as indirect selection criteria for B andR-line improvement.

Combining Ability Studies of Promising Restorer Lines for Yield and Yield Components in Rice (Oryza sativa L.)

Background: The present inquisition was carried out at Regional Agricultural Research Station, Maruteru with a set of 30 experimental hybrids developed by crossing three male sterile lines with 10 testers in Line ´ Tester mating design during Kharif, 2022. Methods:The resultant 30 hybrids were studied in randomized block design with two replications along with the parents and hybrid check, HRI-174 during Rabi, 2022-23. Predominant non-additive gene action was found in the analysis of combining ability for lines, testers and line testers for grain production per plant, days to 50% flowering, days to maturity, ear bearing tillers per plant, filled grains per panicle and 1000-grain weight. Result:The results revealed RGL 5613 and MTU 2055 to be effective combiners for grain yield per plant, filled grains per panicle, spikelet fertility percentage and grain weight of one thousand grains. For five hybrids, the sca effects on grain yield per plant were large and favourable. These hybrids had recorded significantly higher grain yield perplant, more than 30 per cent, compared to the check, HRI-174, in addition to significant desirable sca effects for grain yield per plant.

Berseem Clover (Trifolium Alexandrinum L.) Seed Yield and Seed Quality Response to Irrigation Frequency and Foliar Spray of Plant Bio-Regulators

The primary challenges in Berseem clover (Trifolium alexandrinum L.) seed production in Nepal are low productivity levels and substandard quality indicators. To address this issue, the experiments were conducted at the Regional Agricultural Research Station, Khajura, Banke, Nepal, and replicated in farmers' fields using a Randomized Complete Block Design from November 2018 to June 2019. Four irrigation schemes and three levels of foliar sprays of plant bio-regulators were used. The experiment result revealed that three and four irrigations were most suitable for achieving higher seed yield (p<0.05), resulting in 0.99 and 0.93 t ha-1 at on-station and 0.87 and 0.85 t ha-1 at on-farm, respectively. Similarly, two and three sprays of plant bio-regulators yielded better (p<0.05) seed yields of 0.89 and 0.94 t ha-1 at on-station and 0.79 and 0.85 t ha-1 at on-farm, respectively, without significant alteration on days taken to seed maturity and biological yield. The interactions between the levels of irrigation and plant bio-regulators spray were non-significant (p>0.05) for seed yield and biological yield. The experiments demonstrated that three irrigations @ 666.67 kiloliters of water ha-1 at 15-day intervals after one cut at 60 days after sowing, and three foliar sprays of plant bio-regulators (P2O5 @ 2 kg ha-1 + KNO3 @ 4 kg ha-1) at 7-day intervals in the pre-flowering stage, significantly enhanced the seed yield and quality of Berseem clover. SAARC J. Agric., 21(2): 131-143 (2023)

Genetic variability, correlation and path analysis for yield and its contributing traits in Barley (Hordeum vulgar L.)

In breeding programs, direct selection based on crop yields is paradoxical due to its complex polygenically inherited nature, that is impacted by its component traits. To determine the degree of relationship between yield and yield components and other traits in nine barley varieties, a field experiment was carried out at the Regional Agricultural Research Station, Jashore during Rabi 2021–2022. For plant height, disease and insect reaction, and grain yield, substantial heritability together with strong genetic progress as a percentage of mean were detected, indicating a prevalence of additive gene action in the expression of these traits. At both the genotypic and phenotypic levels, the correlation coefficient between grain yield was shown to be positively correlated with plant height and thousand grain weight, indicating that an increase in these traits will boost grain production. Both genotypic and phenotypic analysis of the path coefficient demonstrated that plant height and thousand grain weight had a direct positive impact on grain production, highlighting the significance of these parameters as the primary contributors to yield. For the purpose of genetically improving barley yield, a genotype with a higher extent of these qualities could be chosen as a parent from among genotypes that already exist. SAARC J. Agric., 21(2): 15-25 (2023)

Efficacy of Botanicals on Seed Quality Enhancement in Cowpea [Vigna unguiculata (L.) Walp.] on Yield and Yield Attributes

The field experiment was conducted at the Regional Agricultural Research Station, Pattambi of Kerala Agricultural University with the objective to understand the effect of seed treatment using different organic leaf extracts on the growth and yield of cowpea. The experimental design was used for the layout of the design in Randomized Block Design, with three replications and nine treatments. The experiment was conducted with 9 treatments viz., the 5% leaf extracts of Calotropis (T1), Pappaya (T2), Pongamia (T3), Castor (T4), Moringa (T5), Vitex (T6), Neem (T7), Tulsi (T8), Control with distilled water (T9). Different field observations revealed that the seed hardening significantly influenced the seed yield and yield contributing characters of cowpea. The highest yield was recorded due to seed hardening treatment with Pongamia 5% leaf extract (T3) for 4 hrs followed by Calotropis 5% leaf extract (T1) for 4 hrs. All the seed hardening treatments had significant effects on yield contributing characters like plant height at maturity, number of branches(primary and secondary) per plant, number of clusters per plant, number of seeds per pod, pod length, pod girth, pod weight, 100 seed weight, seed yield per plot(kg/ha) and dry matter production at harvest. The nodule count at flowering and total chlorophyll content at maturity were also found to be significantly different among the treatments. The seeds hardened with Pongamia leaf extract (5%) (T3) for 4 hrs recorded higher field emergence with maximum grain yield (716 Kg/ha), plant height at maturity (145.07 cm), number of primary branches per plant (3.60), seed yield per plant (g) (13.69 g), and seed yield (716 kg/ha) followed by Calotropis leaf extract (5%) (T1) for 4 hrs with a seed yield of 694 kg/ha.

Identification of resistant sources against wilt disease incastor (Ricinus communis L.)

An experiment was carried out under wilt sick plot at Regional Agricultural Research Station, Palem during kharif, 2019 to identify the potential sources of resistance against wilt disease in castor. A total of 99 germplasm accessions were screened under sick plot conditions. Observations were recorded as per cent wilt incidence periodically at thirty days interval up to 150 days in each germplasm accession. The national checks viz., JI-35 & 48-1 were used as susceptible and resistant checks respectively and were sown after every five test entries. Among the accessions, nine entries have shown immune reaction to wilt disease and 48 accessions were recorded less than 20% wilt incidence and the range of wilt incidence in the remaining accessions was 21.4 to 75 %. The wilt incidence in susceptible (JI-35) and resistant (48-1) checks were 100% and 0% respectively.