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Acharya N G Ranga Agricultural University, Guntur

The Andhra Pradesh Agricultural University (APAU) was established on 12th June 1964 at Hyderabad. The University was formally inaugurated on 20th March 1965 by Late Shri. Lal Bahadur Shastri, the then Hon`ble Prime Minister of India. Another significant milestone was the inauguration of the building programme of the university by Late Smt. Indira Gandhi,the then Hon`ble Prime Minister of India on 23rd June 1966. The University was renamed as Acharya N. G. Ranga Agricultural University on 7th November 1996 in honour and memory of an outstanding parliamentarian Acharya Nayukulu Gogineni Ranga, who rendered remarkable selfless service for the cause of farmers and is regarded as an outstanding educationist, kisan leader and freedom fighter. HISTORICAL MILESTONE Acharya N. G. Ranga Agricultural University (ANGRAU) was established under the name of Andhra Pradesh Agricultural University (APAU) on the 12th of June 1964 through the APAU Act 1963. Later, it was renamed as Acharya N. G. Ranga Agricultural University on the 7th of November, 1996 in honour and memory of the noted Parliamentarian and Kisan Leader, Acharya N. G. Ranga. At the verge of completion of Golden Jubilee Year of the ANGRAU, it has given birth to a new State Agricultural University namely Prof. Jayashankar Telangana State Agricultural University with the bifurcation of the state of Andhra Pradesh as per the Andhra Pradesh Reorganization Act 2014. The ANGRAU at LAM, Guntur is serving the students and the farmers of 13 districts of new State of Andhra Pradesh with renewed interest and dedication. Genesis of ANGRAU in service of the farmers 1926: The Royal Commission emphasized the need for a strong research base for agricultural development in the country... 1949: The Radhakrishnan Commission (1949) on University Education led to the establishment of Rural Universities for the overall development of agriculture and rural life in the country... 1955: First Joint Indo-American Team studied the status and future needs of agricultural education in the country... 1960: Second Joint Indo-American Team (1960) headed by Dr. M. S. Randhawa, the then Vice-President of Indian Council of Agricultural Research recommended specifically the establishment of Farm Universities and spelt out the basic objectives of these Universities as Institutional Autonomy, inclusion of Agriculture, Veterinary / Animal Husbandry and Home Science, Integration of Teaching, Research and Extension... 1963: The Andhra Pradesh Agricultural University (APAU) Act enacted... June 12th 1964: Andhra Pradesh Agricultural University (APAU) was established at Hyderabad with Shri. O. Pulla Reddi, I.C.S. (Retired) was the first founder Vice-Chancellor of the University... June 1964: Re-affilitation of Colleges of Agriculture and Veterinary Science, Hyderabad (estt. in 1961, affiliated to Osmania University), Agricultural College, Bapatla (estt. in 1945, affiliated to Andhra University), Sri Venkateswara Agricultural College, Tirupati and Andhra Veterinary College, Tirupati (estt. in 1961, affiliated to Sri Venkateswara University)... 20th March 1965: Formal inauguration of APAU by Late Shri. Lal Bahadur Shastri, the then Hon`ble Prime Minister of India... 1964-66: The report of the Second National Education Commission headed by Dr. D.S. Kothari, Chairman of the University Grants Commission stressed the need for establishing at least one Agricultural University in each Indian State... 23, June 1966: Inauguration of the Administrative building of the university by Late Smt. Indira Gandhi, the then Hon`ble Prime Minister of India... July, 1966: Transfer of 41 Agricultural Research Stations, functioning under the Department of Agriculture... May, 1967: Transfer of Four Research Stations of the Animal Husbandry Department... 7th November 1996: Renaming of University as Acharya N. G. Ranga Agricultural University in honour and memory of an outstanding parliamentarian Acharya Nayukulu Gogineni Ranga... 15th July 2005: Establishment of Sri Venkateswara Veterinary University (SVVU) bifurcating ANGRAU by Act 18 of 2005... 26th June 2007: Establishment of Andhra Pradesh Horticultural University (APHU) bifurcating ANGRAU by the Act 30 of 2007... 2nd June 2014 As per the Andhra Pradesh Reorganization Act 2014, ANGRAU is now... serving the students and the farmers of 13 districts of new State of Andhra Pradesh with renewed interest and dedication...

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    ThesisItemOpen Access
    VARIATION IN NUTRIENT UPTAKE, PHOTOSYNTHESIS AND YIELD OF MAIZE (Zea mays L.) AS INFLUENCED BY HEAT STRESS AND BIO-INOCULANTS
    (Acharya N G Ranga Agricultural University, 2023-11-30) MOHAMMED ANWAR ALI; K. JAYALALITHA
    The present investigation entitled “Variation in nutrient uptake, photosynthesis and yield of maize (Zea mays L.) as influenced by heat stress and bio-inoculants” was undertaken at the Agricultural College Farm, Bapatla during two consecutive years of rabi 2017-18 and 2018-19. The experiment was laid out in split plot design, replicated thrice. There are four main treatments i.e. normal sowing (sown on December 20th - M1), and subsequent sowings at 20 days interval i.e. (moderately delayed sowing - M2) sown on January 10th, (delayed sowing - M3) sown on January 30th, and (extremely delayed sowing - M4) sown on February 20th, to expose the crop to delayed sowings induced heat stress and five sub-treatments with bio-inoculants i.e. (control/ no application of bio-inoculant (S1), Arbuscular Mycorrhizal Fungi - AMF (S2), Phosphate Solubilizing Bacteria - PSB (S3), Potassium Releasing Bacteria - KRB (S4), and combination of AMF+PSB+KRB (S5)). The results of the study revealed, significant differences among the main treatments, sub-treatments and their interactions. Accumulated Growing Degree Days (GDD) at maturity decreased in delayed sown crops as the crop experiences heat stress and tires to completes its life cycle early. Soil temperatures increased in delayed sowings, however application of bio-inoculants helped in maintaining the soil temperatures. Plant height decreased significantly under delayed sown conditions, and the decrease was 40 and 44 per cent in extremely delayed sown maize crop during 2017-18 and 2018-19, respectively. Application of AMF+PSB+KRB in combination increased the plant height by 8.80 and 10.15 per cent, over the control plants in both the years. The extremely delayed sown maize crop that was applied xxi with AMF+PSB+KRB (M4S5) increased the plant height by 15.10 per cent, over no bio-inoculant application (M4S1). Leaf area was reduced drastically during both the years, due to heat stress (delayed sowings) and leaf, stem, reproductive parts and total drymatter were decreased by 31.82 and 44.10; 54.92 and 73.70; 75.99 and 94.51 and 77.51 and 107.80 per cent in extremely delayed sown crop during 2017-18 and 2018-19, respectively, over the normal sown crop. Among the bio-inoculant treatments, combined application of AMF+PSB+KRB increased the leaf, stem, reproductive parts and total drymatter by 20.17 and 22.18; 22.83 and 22.91; 29.94 and 24.88; 31.56 and 27.28 per cent over control plants during 2017-18 and 2018-19, respectively. AMF application was next to best treatment in increasing the leaf area and leaf, stem, reproductive parts and total drymatter over control plants. Normal sown maize crop that was applied with AMF+PSB+KRB in combination (M1S5) recorded the highest values of above parameters and the lowest values were recorded by the extremely delayed sown crop without bio-inoculant application (M4S1). Under extremely delayed sown conditions, the maize crop that was applied with AMF+PSB+KRB in combination (M1S5) increased the leaf area and leaf, stem, reproductive parts and total drymater over the extremely delayed sown crop without bio-inoculant application (M4S1). Thermotolerance parameters such as MII, CSI, RLWC and canopy temperature varied significantly by heat stress. Higher MII was recorded by the extremely delayed sown crop compared to the normal sown crop, indicating increased lipid peroxidation under heat stress (delayed sowing) conditions. Application of AMF+PSB+KRB in combination decreased the MII and canopy temperature and improved the CSI and RLWC under extremely delayed sown conditions (heat stress conditions), application of AMF+PSB+KRB in combination under extremely delayed sown condition (M4S5) helped in minimizing the damage to the cellular membranes by recording lesser MII values and canopy temperatures, higher CSI and RLWC compared to the extremely delayed sown crop without bio-inocualnt application (M4S1), indicating the role of bio-inoculants in amelioration of heat stress especially under extremely delayed sown conditions. Net photosynthetic rate, stomatal conductance and transpiration rate were decreased in the extremely delayed sown maize crop by 86.47 and 95.09; 64.66 and 70.60; 24.82 and 29.20 per cent, during 2017-18 and 2018-19, respectively over the normal sown crop. Application of AMF+PSB+KRB exhibited superior performance in enhancing net photosynthetic rate, stomatal conductance and transpiration rate by 35.60 and 32.28, 18.76 and 17.22; 67.50 and 70.67 per cent, respectively over control plants. Maize crop applied with AMF+PSB+KRB in combination under extremely delayed sown condition (M4S5) increased the net photosynthetic rate, stomatal conductance and transpiration rate over untreated plants (M4S1). SOD and CAT activity were increased in maize due to extremely delayed sowing as compared to normal sowing. Protein content was reduced in the extremely delayed sown maize crop. Application of AMF+PSB+KRB in xxii combination under extremely delayed sown condition (M4S5) significantly increased the SOD and CAT activity, and protein contents as compared to the untreated plants (M4S1). Nutrient uptake (macro and micro nutrients) in maize crop decreased with the increase in heat stress due to extremely delayed sowing of maize which decreased macro nutrient (N, P and K) and, the micro nutrients uptake (Fe, Mn, Cu and Zn) over normal sown maize crop. Application of bio-inoculants increased both the macro and micro nutrient uptake in maize under normal and delayed sowings. The application of AMF+PSB+KRB in combination under delayed sown conditions of maize crop increased the macro nutrient (N, P and K) and the micro nutrient uptake (Fe, Mn, Cu and Zn) over extremely delayed sown crop without application of bio-inoculants during both the years. In extremely delayed sown maize crop, the number of kernels cob-1, test weight and kernel yield were decreased over the normal sown crop. Among the bio-inoculant treatments, application of AMF+PSB+KRB in combination increased the kernels per cob, test weight and kernel yield over the untreated plants. Under normal sown conditions, the maize crop that was applied with AMF+PSB+KRB (M1S5) recorded increase in seed yield over the crop without bio-inoculant application (M1S1), and the extremely delayed sown crop with bio-inoculant application (M4S5). Under extremely delayed sown conditions, application of AMF+PSB+KRB in combination (M4S5) increased the kernel yield over the extremely delayed sown crop without bio-inoculant application (M4S1). Application of AMF+PSB+KRB in combination under extremely delayed sown condition sown maize crop recorded higher harvest index compared to the crop without bio-inoculant application. According to the results obtained in this study, it can be concluded that the morpho- physiological, thermotolerance, photosynthetic parameters, nutrient uptake levels and yield and its components and quality parameters were drastically reduced in the extremely delayed sown maize crop, indicating the determinantal effect of heat stress under extremely delayed sown conditions. Application of AMF+PSB+KRB in combination could improve the growth, nutrient uptake, photosynthesis and yield and its components of maize both under normal sown as well as in delayed sowings. AMF came in the second order in improving the above parameters. The use of AMF+PSB+KRB in combination especially under extremely delayed sown conditions, could alleviate the negative effects of heat stress on nutrient uptake (macro and micro), photosynthesis and yield of maize by improving the nutrient availability, thermotolerance capacity of the crop in terms of maintaining lesser MII, higher CSI, RLWC and lower canopy temperatures and higher activity of SOD and CAT which helped the maize crop to perform better under heat stress, due to delayed sowings.
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    ThesisItemOpen Access
    EVALUATION OF PIGEON PEA (Cajanus cajan (L.) Millsp) GENOTYPES FOR HIGH ROOT MINING, MORPHO-PHYSIOLOGICAL AND YIELD PARAMETERS UNDER RAINFED SITUATION
    (Acharya N G Ranga Agricultural University, 2023-11-30) R. PAVANI; K. JAYALALITHA
    Root study and the field experiment were conducted for the “Evaluation of pigeonpea [Cajanus cajan (L.) Millsp] genotypes for high root mining, morpho-physiological and yield parameters under rainfed situation” during kharif 2019 and 2020 at RARS farm and Dryland farm, S.V. Agricultural college, Tirupati. Ten treatments consisting of ten genotypes out of which four were mid-early duration genotypes (V1- PRG-176, V2- CO-6, V3- AKTE 12-04, V4- ICPL 8863), four were medium duration genotypes (V5- MPV 106, V6-RVSA 16-1, V7-LRG 133-33, V8-LRG-52) and remaining two were long duration genotypes (V9-ICPL 15062, V10- ICPL 17103) were selected for the study purpose. Root Mining studies were carried out under specially raised rectangular soil beds of size i.e; 15m x 2m x 1.5m (Lx B x H) in completely randomized block design and replicated twice, whereas the field study was carried out in randomized block design and replicated thrice. Significant genotypic variation was observed among the mid-early, medium and late duration genotypes with respect to root traits, growth, photosynthesis, WUE traits, heat tolerance traits, crop weather relations, biochemical and yield parameters. In the root study, the mid-early duration genotype, CO-6 and the medium duration genotype, LRG-52 exhibited superior performance by recording 66.0 and 57.0 per cent increase in root length over the late duration genotype, ICPL 15062. LRG-52 increased the number of primary and secondary roots by 64.0 and 57.0 per cent, and CO-6 by 50.0 and 45.6 per cent, respectively, over the late duration genotype, ICPL 17103. Higher root: shoot ratio was recorded in the genotype LRG 52 (0.41) and the lesser root: shoot ratio was recorded in ICPL 8863 (0.23) at 65 DAS in simulated raised soil bed conditions. Among the ten genotypes evaluated under field study, the maximum total plant drymatter production was recorded significantly in the genotypes LRG-52 and CO-6 and the increase was 1.5 folds over the late duration genotype ICPL 17103. These two genotypes recorded 1.6 and 1.4 folds increase in pod drymatter, xvii respectively, over ICPL 15062 at harvest. Hence these two genotypes were considered as efficient total dry matter partitioning ones under rainfed conditions. LRG-52 and CO-6 exhibited less leakage of solutes and increased the membrane thermo stability index by 27.4 and 24.6 per cent, respectively over ICPL 15062 and decreased the canopy temperature by 20.7 and 17.2 percent, respectively, over ICPL 17103 and by 18.7 and 15.1 per cent, respectively over ICPL 15062. CO-6 and LRG-52 recorded higher heat use efficiency and increased by 107.0 and 96.5 per cent, respectively over ICPL 17103. Hence these two genotypes with higher MSI and lesser canopy temperature were considered as heat tolerant genotypes compared with the late duration genotypes under rainfed situation. The maximum SCMR was recorded in LRG-52 and CO-6 genotypes and increased the value by 42.1 and 41.0 per cent, respectively, over ICPL 17103 and 41.8 and 40.6 per cent, respectively, over ICPL 15062. These two genotypes recorded 31.3 and 26.6 per cent increase in RWC over ICPL 15062. LRG-52 and CO-6 recorded 15.4 and 20.0 per cent decrease in SLA over the late duration genotype ICPL 15062 at flowering and pod formation stage of the crop (120 DAS). Hence these two genotypes with high RWC, SCMR and lesser SLA were considered as higher WUE genotypes under rainfed conditions. In the current investigation, genotypic variation was observed with respect to photosynthetic attributes. The genotypes LRG-52 and CO-6 recorded 49.6 and 42.4 per cent increase in photosynthetic rate over ICPL 17103. With respect to crop weather relations under rainfed conditions, at maturity, the late duration genotypes recorded the highest GDD of 3389.8 oC day followed by the medium duration genotypes, recorded the GDD value of 3076.6 oC day. The lowest GDD of 2724.0 oC day was recorded by the mid-early duration genotypes. At harvest, LRG-52, a medium duration genotype recorded maximum number of pods per plant and increased by 70.1 per cent and CO-6 by 64.5 per cent over ICPL 17103. This might be due to increase in number of branches plant-1 where balance was maintained between vegetative and reproductive phase. LRG-52 recorded the maximum 100 seed weight of 12.93 g which was at par with CO-6 (11.48 g). The minimum 100 seed weight of 9.53 g was recorded in ICPL 17103 which was at par with ICPL 15062 (10.11 g). LRG 52, a medium duration genotype exhibited superior performance and increased the seed and stalk yield by 74.3 and 18.8 per cent, respectively, and CO-6 by 63.0 and 23.1 per cent, respectively over the long duration genotype ICPL 17103. LRG-52 recorded higher HI of 28.44 % and the lesser HI was recorded in ICPL 17103 (21.16%). Correlation studies revealed that there is high positive correlation between growth and yield attributes. Medium and late duration genotypes exposed to terminal moisture stress (i.e., 2 to 3 continuous dry spells) during flowering and pod formation stages in both the years of study. The medium duration genotype LRG-52, eventhough faced with moisture stress, performed better over other maturing groups (i.e., late duration genotypes) in the present study. However, the mid-early duration genotype CO-6 was also comparable with that of medium duration genotype LRG-52 with regards to seed yield due to its early maturing character, and it is considered to use where early maturity of the crop is required, especially under rainfed conditions to escape the terminal moisture stress. The genotypes ICPL 15062 and ICPL 17103 were xviii late maturing and encountered moisture stress during flowering and pod formation stages during both the years of study that resulted in lesser seed yield and its components in the present study. Based on the results obtained, it can be concluded that the medium duration genotype LRG-52 has the capacity to withstand terminal drought situations and can be recommended as a drought tolerant one especially under rainfed conditions. Along with this, the mid-early duration genotype CO-6 can also be recommended to rainfed areas as it possess drought escape nature because of its earliness character. Hence these two genotypes may be popularized due to their noteworthy performance under rainfed conditions in Southern zone of Andhra Pradesh.
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    ThesisItemOpen Access
    PHYSIOLOGICAL AND BIOCHEMICAL RESPONSES OF SEED PRIMING IN MAIZE (Zea mays L.) UNDER SALINITY STRESS
    (Acharya N G Ranga Agricultural University, 2023-11-30) G. SRAVANTHI; M. RAVI BABU
    The present investigation entitled “Physiological and biochemical responses of seed priming in maize (Zea mays L.) under salinity stress” was undertaken in pot culture at Net house, Department of Crop Physiology, Agricultural college, Bapatla and field study at Farmer field, Cherukuru village, Bapatla, respectively during rabi season of 2021-22 to understand the impact of different priming treatments on physiological and biochemical components under salinity stress which in turn influence the productivity of maize. The pot culture and field experiment were taken up in completely randomized design (CRD) and randomized block design (RBD) with 7 treatments and replicated thrice. The treatments comprised of T1: Normal water irrigated (control), T2: 100 mmol L-1 of NaCl, T3: 200 mmol L-1 of NaCl, T4: 100 mmol L-1 of KCl, T5: 200 mmol L-1 of KCl, T6: 100 mmol L-1 1 of CaCl2.2H2O and T7: 200 mmol L-1 of CaCl2.2H2O. The data on morpho-physiological parameters viz., germination percentage root-shoot length and seedling vigor were recorded at 15 and 30 days in pot culture study and germination percentage, number of days to emerge, plant height, drymatter production, leaf area and relative water content were recorded at 30, 60 and 90 days in field experiment. Biochemical parameters viz., proline and superoxide dismutase activity and chemical constituents viz., Na+, K+ and Ca+2 were estimated at vegetative and reproductive stages. The data on yield and yield components were recorded at harvest. Under pot culture study, seed priming with CaCl2. 2H2O 200 mmol L-1 (T7) and CaCl2. 2H2O 100 mmol L-1 (T6) resulted in an increased germination percentage (14.2 and 10.6%), seedling vigor (27.3 and 29 %), root and shoot length (25, 24.5 and 20, 19.8 %) over control. xiii Under field conditions, seed priming with CaCl2. 2H2O 200 mmol L-1 (T7) and CaCl2. 2H2O 100 mmol L-1 (T6) resulted in an increase in germination percentage (20.7 and 19.2 %), days to emergence, plant height (21.3 and 18.36 %), maintained higher leaf area and higher RWC in leaves (17.91 and 16.93 %) with higher drymatter partitioning (30.01 and 27.60 %) than the control (T1). Higher drymatter partitioning at 90 days after sowing indicated the positive impact of seed priming with these chemicals in accumulating drymatter. Biochemical parameters like proline content and superoxide dismutase activity in leaf increased with seed priming treatment of CaCl2. 2H2O 200 mmol L-1 (T7) and CaCl2. 2H2O 100 mmol L-1 (T6). Seed priming with CaCl2. 2H2O 200 mmol L-1 (T7) recorded the lowest Na+/K+ ratio and Na+/Ca+2 ratio than the remaining treatments. All these biochemical parameters and lower Na+/K+ and Na+/Ca2+ ratio contributes for alleviating salinity stress in maize cultivated in coastal regions, where the salinity is the major problem. Seed priming significantly increased the yield and yield attributes. Among all the treatments, seed priming with CaCl2. 2H2O 200 mmol L-1 (T7) and CaCl2. 2H2O 100 mmol L-1 (T6) produced higher yield and it is associated with more number of rows per cob, test weight, cob length. Overall, it is concluded from the study that seed priming with CaCl2. 2H2O 200 mmol L-1 (T7) and CaCl2. 2H2O 100 mmol L-1 (T6) has shown good performance in rice fallow maize in enhancing the productivity by altering the physiological and biochemical constituents of the plant under salinity stress conditions.
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    ThesisItemOpen Access
    PHYSIOLOGICAL ROLE OF SILICON NUTRITION IN THE REPRODUCTIVE STAGE ON YIELD OF HYDROPONIC RICE (Oryza sativa L.)
    (Acharya N G Ranga Agricultural University, 2023-11-29) SHAIK SAFIYA; B. SREEKANTH
    A net house experiment entitled “Physiological role of silicon nutrition in the reproductive stage on yield of hydroponic rice (Oryza sativa L.).” was carried out at net house of Department of Crop Physiology Agricultural College, Bapatla during 2019- 2020 to study the effect of silicon nutrition on mobility of photosynthetic assimilates, leaf photosynthetic parameters, yield attributes and silicon uptake by rice at different time intervals during reproductive stage. Cv. BPT-5204 was used for the investigation. The experiment was laid out in three factorial completely randomized design with nineteen treatments viz., control (No silicon), foliar application of silicon with 50 mM, 100 mM, 150 mM concentration and through root application with 1.5 mM, 2.0 mM and 2.5 mM concentration of silicon. The treatments were applied at P.I (P1), 10 d. after P.I (P2) and 20 d. after P.I (P3). Observations were noted after 10 days of silicon application on physiological and biochemical parameters. Data on yield and yield attributes were recorded at harvest. From the above investigation, at all the three sampling stages silicon application increased the photosynthetic rate, stomatal conductance and SPAD value of rice leaves either through foliar or root application. But transpiration rate of rice leaves was decreased with silicon application either through root or foliar modes and this decrease was more through root mode with 2.0 mM concentration of silicon. Silicon application through root system with 2.0 mM concentration of sodium silicate at three different times during reproductive stage increased the total sugar and silicon contents of rice leaf and culm. Foliar application with 50 mM concentration of sodium silicate increased the parameters like starch content and starch phosphorylase activity of rice leaf and culm. The increasing effect of biochemical parameters of leaf and culm were reached to maximum at heading stage and then decreased, irrespective of time and form of silicon application. During all the three different sampling times, the uptake of silicon by the rice plant from nutrient solution was increased with the application of silicon @2.0 mM concentration among 1.5 mM and 2.5 mM concentration of silicon. Grain constituents like total sugar and silicon contents were increased with root application of silicon. But foliar application of silicon, increased the grain parameters like starch content and starch phosphorylase activity and this increasing effect was more at 10 d. after P.I with silicon application than at P.I and 20 d. after P.I stages, either through soil or foliar modes. Yield and yield attributing characters like panicle length, filled spikelet percentage, test weight, harvest index and grain yield per panicle were increased by root application of silicon, while spikelet length, number of primary and secondary branches of panicle were increased by foliar application of silicon and this increase was more at 10 d. after P.I than other times of application, irrespective of mode of silicon nutrition.
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    ThesisItemOpen Access
    INFLUENCE OF ARBUSCULAR MYCORRHIZAL SPECIES (AM) ON DROUGHT TOLERANCE, NUTRIENT UPTAKE AND YIELD OF GROUNDNUT (Arachis hypogaea L.) UNDER WATER STRESS
    (Acharya N G Ranga Agricultural University, 2023-11-29) Y. BHARGAVI; K. JAYALALITHA
    The present investigation entitled “Influence of arbuscular mycorrhizal species (AM) on drought tolerance, nutrient uptake and yield of groundnut (Arachis hypogaea L.) under water stress” was undertaken at Agricultural College Farm, Bapatla during two consecutive years of rabi 2019-20 and 2020-21. The experiment was laid out in split plot design replicated thrice. There are two main treatments i.e., no stress (M0- irrigation is given as per irrigation schedule), and moisture stress at pegging and pod formation stages i.e., 40-60 DAS (M1) and seven sub treatments viz., no application of mycorrhiza (S0), soil application of Glomus fasciculatum (S1), Glomus aggergatum (S2), Glomus mosseae (S3), Glomus intraradices (S4), Gigaspora sps. (S5) and Acaulospora sps. (S6) each @12.5 kg ha-1 The results of the study revealed that significant differences were observed between main plot, sub plot treatments and their interactions. Soil moisture content of the plots subjected to drought stress was depleted from 15.65 to 7.41 per cent during 2019-20 and 14.12 to 6.83 per cent during 2020-21 upon imposition of water stress from 40 to 60 DAS. Lower soil moisture content was observed in the treatments that received the soil application of Glomus mosseae and Gigaspora sps. @ 12.5 kg ha-1 which was 20.0 and 19.4 per cent lower, during 2019-20, and 19.5 and 19.2 per cent lower, respectively, during 2020-21, compared to control which indicates the enhanced the water uptake of plants by the extensive hyphal network of these mycorrhiza, whereas higher soil water content was recorded in plots without mycorrhizal application, Acaulospora sps. and Glomus aggregatum. In the present study, water stress reduced the leaf area by 15.3 and 17.0 per cent, relative water content (RWC) by 21.1 and 19.0 per cent, leaf water potential (LWP) by 54.6 and 92.5 per cent and, total dry matter accumulation by 32.8 and 32.6 per cent, and increased the cellular leakage of solutes (MII) by 61.1 and 50.3 per cent and specific leaf weight (SLW) by 13.3 and 21.2 per cent compared to the irrigated groundnut plants during 2019-20 and 2020-21, respectively. xxi Groundnut plants inoculated with Glomus mosseae and Gigaspora sps. @ 12.5 kg ha-1 exhibited superior performance by improving physiological parameters viz., leaf area by 25.5 and 19.4 per cent, relative water content by 12.7 and 12.2 per cent, leaf water potential by 26.1 and 25.6 per cent, specific leaf weight by 16.8 and 13.8 per cent and total dry matter accumulation by 56.0 and 53.4 per cent, and reduced the cellular leakage of solutes by 14.3 and 13.7 per cent respectively during 2019-20 and during 2020-21, leaf area (17.4 and 18.4 %), relative water content (15.0 and 13.8 %), leaf water potential (27.7 and 27.1 %), specific leaf weight (12.2 and 11.8 %) and total dry matter accumulation (39.5 and 38.4 %) were increased and MII (13.6 and 11.8 %) was reduced in the present study. Under water stress conditions, soil application of Glomus mosseae @ 12.5 kg ha-1 enhanced the leaf area (21.3 and 17.9 %), relative water content (12.1 and 19.8 %), leaf water potential (29.1 and 24.8 %) and total dry matter accumulation (96.2 and 68.7 %) compared to non-mycorrhizal plants under water stress conditions during 2019-20 and 2020-21, respectively and the soil application of Gigaspora sps. @ 12.5 kg ha-1 increased the leaf area by 14.2 and 12.6 per cent, relative water content by 8.1 and 16.9 per cent, leaf water potential by 25.6 and 22.7 per cent and total dry matter accumulation by 75.7 and 57.6 per cent in both the years, respectively. While, Acaulospora sps. @ 12.5 kg ha-1 recorded poor performance in improving the physiological parameters (leaf area, SLW, RWC, LWP, total dry matter accumulation and partitioning) of the plants both under irrigated and water stress conditions. Groundnut plants subjected to water stress recorded 43.3, 28.5 and 40.4 per cent reduction in net photosynthetic rate, stomatal conductance and transpiration rate of groundnut during 2019-20 and 40.7, 29.7 and 46.2 per cent reduction during 2020-21, respectively, compared to the irrigation treatment. Soil application of Glomus mosseae @ 12.5 kg ha-1 recorded 51.9 and 46.2 per cent higher net photosynthetic rate followed by Gigaspora sps. @ 12.5 kg ha-1 which recorded 50.5 and 45.0 per cent higher net photosynthetic rate during 2019-20 and 2020-21, respectively, over control. While, higher stomatal conductance was recorded with Gigaspora sps. @ 12.5 kg ha-1 (45.6 and 37.4 per cent higher) followed by Glomus mosseae @ 12.5 kg ha-1 (41.8 and 32.3 per cent) in both the years, respectively. Under water stress, net photosynthetic rate and stomatal conductance of the treatment that received the soil application of Glomus mosseae was 66.9 and 53.1 per cent higher during 2019-20 and 46.2 and 69.1 per cent higher during 2020-21, respectively, and the soil application of Gigaspora sps. @ 12.5 kg ha-1 recorded 58.5 and 52.0 per cent and 45.0 and 67.6 per cent increase in net photosynthetic rate and stomatal conductance, respectively, in both the years. The total leaf chlorophyll and carotenoid contents of water stressed groundnut plants were declined by 20.4 and 18.5 per cent, respectively, during 2019-20 and 17.8 and 20.7 per cent, respectively, during 2020-21. Soil application of Glomus mosseae enhanced the total chlorophyll and carotenoid contents in leaves by 42.9 and 65.9 per cent, respectively during 2019-20 and 27.1 and 41.9 per cent, respectively during 2020-21. Whereas, Gigaspora sps. @ 12.5 kg ha-1 increased the total chlorophyll and carotenoid contents in leaves by 38.6 and 61.4 per cent, respectively, during 2019-20 and by 26.4 and 39.5 per cent, respectively during 2020-21. Under drought stress, the leaf chlorophyll content of the treatment that received the soil application of Glomus mosseae and Gigaspora sps. @ 12.5 kg ha-1 was 73.0 and 46.8 per cent higher, during 2019-20 and 32.5 and 23.8 per cent higher, respectively, during 2020-21 than the control plants under drought stress. The xxii increase in leaf carotenoid content of the treatment that received the soil application of Glomus mosseae and Gigaspora sps. @ 12.5 kg ha-1 was 91.9 and 37.6 per cent, during 2019-20 and 52.6 and 34.2 per cent, respectively, during 2020-21, over non-AM plants under drought stress. A significant increase in antioxidant metabolites such as ascorbate (80.2 and 79.0 per cent) and proline contents (74.0 and 118.0 per cent) were noticed in the groundnut plants subjected to water stress over irrigated plants. Enhancement of ascorbate content with the soil application of Glomus mosseae and Gigaspora sps. @ 12.5 kg ha-1 was 40.4 and 28.4 per cent during 2019-20 and 32.0 and 30.9 per cent during 2020-21, respectively, and proline content was 25.4 and 19.3 per cent during 2019-20 and, 23.2 and 18.1 per cent during 2020-21, respectively. Especially under water stress, the treatment that received the Glomus mosseae @ 12.5 kg ha-1 exhibited superior performance and increased the ascorbate and proline contents by 38.1 and 37.5 per cent during 2019-20 and 56.0 and 31.2 per cent during 2020-21, respectively. While, the treatment that received Gigaspora sps. @ 12.5 kg ha-1 increased the ascorbate and proline contents by 46.7 and 27.4 per cent during 2019-20 and 50.0 and 23.9 per cent during 2020-21, respectively. Both under irrigated and water stress conditions, Acaulospora sps. @ 12.5 kg ha-1 exhibited poor performance and recorded lesser increase in antioxidant metabolites compared to all other mycorrhizae. Antioxidant enzymes i.e., superoxide dismutase and catalase activities were significantly increased in the groundnut plants under water stress by 130.0 and 59.9 per cent during 2019-20 and 102.5 and 53.0 per cent during 2020-21, respectively compared to those under irrigated condition. Soil application of Glomus mosseae and Gigaspora sps. @ 12.5 kg ha-1 recorded higher SOD and catalase activities both under irrigated as well as drought stress conditions. Especially under water stress, Glomus mosseae exhibited superior performance by increasing SOD and catalase activities by 134.1 and 28.3 per cent during 2019-20 and 93.7 and 36.4 per cent during 2020-21, respectively. While, Gigaspora sps. enhanced the SOD and catalase activities by 126.1 and 25.1 per cent, and 87.4 and 22.9 per cent in both the years, respectively. The uptake of macro and micro nutrients was declined under water stress. Nitrogen and phosphorus uptake of groundnut crop grown under water stress was reduced by 41.0 and 29.9 per cent during 2019-20, and 46.2 and 35.9 per cent during 2020-21 compared to control without stress at 60 DAS. Among the sub treatments, groundnut plants inoculated with Glomus mosseae increased the nitrogen uptake by 59.9 and 71.4 per cent, phosphorus uptake by 41.3 and 70.8 per cent and potassium uptake by 40.6 and 19.1 per cent during 2019-20 and 2020-21, respectively. While, Gigaspora sps. inoculation increased the nitrogen, phosphorus and potassium uptake by 50.0, 27.6 and 22.3 per cent during 2019-20, and 62.8, 49.0 and 16.4 per cent during 2020-21. Nitrogen uptake of groundnut plants inoculated with Glomus mosseae (68.3 and 94.4 %) and Gigaspora sps. (47.2 and 82.2 %) was significantly higher than control under stress. Similarly, phosphorus uptake was significantly increased with Glomus mosseae (33.9 and 57.1 %) and Gigaspora sps. (26.8 and 55.5 %) under water stress. Similarly, soil application of Glomus mosseae and Gigaspora sps. @ 12.5 kg ha-1 enhanced the potassium, calcium, magnesium, sulphur, iron, copper, manganese and zinc uptake compared to other mycorrhizal treatments under irrigated and water stress conditions in both the years. Non-mycorrhizal plants recorded lower nutrient xxiii uptake and the groundnut plants inoculated with Acaulospora sps. and Glomus aggregatum @ 12.5 kg ha-1 recorded poor performance in enhancing nutrient uptake of groundnut. Water stress reduced the yield attributes viz., number of pods per plant by 37.2 and 39.5 per cent, peg to pod ratio by 39.7 and 32.8 per cent, pod yield of groundnut by 32.0 and 33.5 per cent, and harvest index by 5.2 and 11.2 per cent during 2019-20 and 2020-21, respectively. Among the sub treatments, soil application of Glomus mosseae and Gigaspora sps. @ 12.5 kg ha-1 enhanced the yield and yield attributes significantly compared to other treatments. Number of pods per plant were enhanced by 23.0 and 22.9 per cent during 2019-20 and 33.4 and 29.7 per cent during 2020-21 by the inoculation of Glomus mosseae and Gigaspora sps. @ 12.5 kg ha-1, respectively, compared to non-mycorrhizal plants. While, the pod yield was enhanced by 26.4 and 25.2 per cent during 2019-20 and 28.9 and 25.5 per cent during 2020-21 by the inoculation of Glomus mosseae and Gigaspora sps. @ 12.5 kg ha-1, respectively. Irrigated groundnut plants inoculated with Glomus mosseae @ 12.5 kg ha-1 increased the pod yield by 15.8 and 21.4 per cent during 2019-20 and 2020-21, respectively, while, Gigaspora sps. @ 12.5 kg ha-1 enhanced the pod yield by 17.2 and 23.2 per cent, respectively compared to control under irrigation in both the years. Glomus mosseae and Gigaspora sps. exhibited superior performance under water stress also by increasing the number of pods per plant by 47.5 and 46.4 per cent and 38.5 and 29.4 per cent during 2019-20 and 2020-21, respectively, and the pod yield by 44.3 and 38.9 per cent during 2019-20, and 40.9 and 29.2 per cent during 2020-21. Soil application of Acaulospora sps. was recorded with lower number of pods per plant, peg to pod ratio and pod yield under irrigated and water stress condition. The VAM colonization per cent of the groundnut roots subjected to water stress was 32.7 and 34.8 per cent lower than the plants under irrigated condition. The higher root colonization was observed in treatments that received the soil application of Glomus mosseae and Gigaspora sps. @ 12.5 kg ha-1 which recorded 69.00 and 68.33 per cent, respectively, during 2019-20 and 66.50 and 66.00 per cent, respectively, during 2020-21 at 60 DAS. Under drought stress, higher root colonization was noticed with the soil application of Glomus mosseae @ 12.5 kg ha-1 (57.00 and 52.33 %) followed by Gigaspora sps. (54.33 and 49.67 %) during 2019-20 and 2020-21, respectively, while, control under drought stress was recorded with the lowest root colonization (7.33 and 7.33 %) in both the years, respectively. With regards to available soil nutrient content, except nitrogen and phosphorus no significant differences were observed with the application of mycorrhiza. The higher available soil nitrogen content after harvest was recorded in the treatment without mycorrhizal inoculation while, lower nutrient content was observed in the treatment that received Glomus mosseae @ 12.5 kg ha-1 during 2019-20 and in the treatment that received Gigaspora sps. @ 12.5 kg ha-1 during 2020-21. It was found to be on a par with all other mycorrhizal treatments except control i.e., no mycorrhizal application, and the available soil phosphorus content after harvest was higher in non-mycorrhizal plants and lower in the treatment that received the soil application of Glomus fasciculatum @ 12.5 kg ha-1 during 2019-20 and 2020-21 and it was found to be on a par with other mycorrhizal treatments except control. It is evident from the present study, water stress during pegging and pod formation stages had harmful effect on growth, pod yield, nutrient uptake and water status of groundnut plants. AM colonization improved the drought resistance and xxiv nutrient uptake of groundnut plants as a consequence of enhanced water and nutritional status (both macro and micro nutrients) of the plants. Our results clearly illustrate that Glomus mosseae and Gigaspora sps. were the most effective AM species which improved the growth and yield of groundnut plants both under irrigated as well as water stress conditions. Especially under water stress condition, inoculation of groundnut plants with Glomus mosseae and Gigaspora sps. @ 12.5 kg ha-1 improved the growth and yield of the plants due to the improvement of water relations, nutrient content, gas exchange status, photosynthetic pigments and antioxidant defense system which could protect the groundnut plants against the deleterious effects of drought stress.
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    PHYSIOLOGICAL STUDIES ON NITROGEN ASSIMILATION DURING REPRODUCTIVE STAGE OF GROUNDNUT (Arachis hypogaea L.)
    (Acharya N G Ranga Agricultural University, 2023-11-29) RAHUL CHANDRA; B. SREEKANTH
    The present investigation entitled “Physiological studies on nitrogen assimilation during reproductive stage of ground nut (Arachis hypogaea L.)” was undertaken at Agricultural College Farm, Bapatla during Rabi, 2020. As treatment, 10 kg N ha-1 was applied during four different reproductive growth stages of groundnut viz., at flowering (30 DAS, 50% plants have open flowers), at peg initiation (50 DAS, 50% plants have at least one elongated peg), at pod initiation (60 DAS, 50% plants have an elongated peg with ovary tip beginning to swell to at least twice peg diameter) and at mid pod development stage (72 DAS, a day at the middle of crop maturity and pod initiation) along with an untreated control with only recommended basal application of nitrogen. These treatments were imposed on groundnut cv TAG-24 in a randomized block design. The observations and samples required were collected from 5 random plants from each treatment plots in 4 replications 2 days before every treatment application, starting from flowering stage followed by observations which were made at different reproductive stages and after harvest. Different parameters, both biochemical and physical, were estimated, which are known markers for N uptake and assimilation as well as nodule and root activity in groundnut. At harvest, yield parameters such as number of pods plant-1, pod yield plant-1, seed yield plant-1 and oil content were estimated. Standard methodology was followed in the measurement of all the parameters. From the above investigation, N supplementation was found to positively regulate leaf and shoot dry weights, N supplemented during pod initiation stage was found to maximize shoot and root dry weight, while a negative effect was observed with N supplementation at later reproductive stages particularly on root dry weight. Increment in leaf area, photosynthetic rate and chlorophyll content was observed with N supplementation at different reproductive stages, early reproductive xii stage showed significant response to N supplementation. Maximum increment in leaf area and photosynthetic rate was noticed when N was supplemented at pod initiation stage and significantly higher chlorophyll content was produced by supplementation at pegging stage. No significant effect was observed in nodulation parameters such as nodule dry weight and proportion by mass of active to senescing nodules with N supplementation at any stage, but significantly higher numbers of active nodules were produced when N was supplemented at early reproductive stage (pegging). Ratio by mass of new to old roots were found to be higher when N supplementation was provided at early reproductive stage than when supplementation was done at a later stage. N supplementation positively regulated nitrate reductase content in leaves while leg haemoglobin content was observed to decrease progressively with N application at later growth stages. Significantly higher N content was observed in leaves, shoots, shells, roots and kernels when N was supplemented at early reproductive stages such as pegging and flowering. No effect was observed from N supplementation in peg N content. Yield parameters such as number of pods plant-1, pod yield plant1, seed yield plant-1 and oil content, N supplemented at an early reproductive growing period of plant was found to contribute maximum towards their increment. Maximum response to N supplementation produced by the plant, through increment of yield parameters was from N supplemented at flowering and pegging stage. Correlation analysis performed between root and shoot N assimilation indicators and N content in different plant parts yielded positive correlations between leaf, stem and root N content with NR activity at early reproductive stages. Significant positive correlation was obtained from correlation between root N content and nodule leg haemoglobin content. Correlation performed between the yield parameters (kernel yield and kernel oil yield) and nitrogen assimilation indicators of root nodules and leaves revealed that kernel yield and seed oil content showed a non significant positive correlation when correlated with leaf NR activity, while a non significant negative correlation existed between kernel yield and leg haemoglobin at later stages of reproductive growth. No specific pattern was observed between seed oil content and nodule leg haemoglobin from correlation.
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    ThesisItemOpen Access
    PHYSIOLOGICAL AND BIOCHEMICAL EFFECT OF PLANT GROWTH REGULATORS AND BORON ON POLLEN FERTILITY AND YIELD OF RICE (Oryza sativa L.) UNDER WATER STRESS
    (guntur, 2022-08-10) SAI ALEKHYA, M.; RAVI BABU, M.
    The present investigation entitled “Physiological and Biochemical Effect of Plant Growth Regulators and Boron on pollen fertility and yield of rice (Oryza sativa L.) under water stress” was undertaken at Agricultural College Farm, Bapatla during late kharif, 2020-21. The experiment was laid out in a split plot design with two main treatments i.e., M0 - no water stress and M1 – water stress and eight sub treatments viz., no spray (S0), 25 ppm of GA foliar spray (S1), 0.01 mg of Brassinosteroids foliar spray (S2), 2.5 ppm of Boron foliar spray (S3), 25 ppm of GA + 0.01 mg of Brassinosteroids foliar spray (S4), 25 ppm of GA + 2.5 ppm Boron foliar spray (S5), 0.01 mg of Brassinosteroids + 2.5 ppm of Boron foliar spray (S6), 25 ppm of GA + 0.01 mg Brassinosteroids + 2.5 ppm of Boron foliar spray (S7) with three replications. The results of the study revealed that, significant differences were observed among the main treatments, sub treatments and their interactions. Plant height decreased under water stress conditions, and the decrease was 11.4 per cent over the irrigated conditions. Foliar spray of 25 ppm of GA + 0.01 mg Brassinosteroids + 2.5 ppm of Boron at flowering stage increased the plant height by 17.3 per cent over the control plants. Leaf water potential was decreased by two folds over the irrigated rice crop. Foliar spray of 25 ppm of GA + 0.01 mg Brassinosteroids + 2.5 ppm of Boron helped to increase the leaf water potential of the rice crop. Higher membrane injury index was recorded by the water stress compared to irrigated conditions, indicating increased lipid peroxidation under water stress conditions. Foliar spray of 25 ppm of GA + 0.01 mg Brassinosteroids + 2.5 ppm of Boron helped in minimizing the damage to cellular membranes by recording lesser membrane injury index values. In the present study, pollen characters viz., pollen fertility, percent pollen germination, protein content in pollen, total soluble sugars in pollen were adversely affected under water stress. Percent pollen germination, protein content in pollen, total xiii soluble sugars in pollen were reduced by 8.1, 48.8 and 69.6 per cent over the irrigated rice crop. Foliar spray of 25 ppm of GA + 0.01 mg Brassinosteroids + 2.5 ppm of Boron exhibited superior performance in enhancing the pollen characters under water stress conditions. Proline content in leaves was increased by 91 per cent under water stress conditions over the irrigated crop. Foliar spray of 25 ppm of GA + 0.01 mg Brassinosteroids + 2.5 ppm of Boron significantly increased the proline content in leaves by 28.6 per cent compared to untreated control plants. In the present study, the yield parameters viz., number of panicles m-2, length of the panicle, number of filled spikelets per panicle, sterility percentage, test weight and yield were decreased by 17.0, 8.5, 21.8, 36.3, 16.0 and 13.7 per cent, respectively, under water stress conditions over irrigated crop. Foliar spray of 25 ppm of GA + 0.01mg of Brassinosteroids +2.5 ppm of Boron increased the number of panicles m-2, length of the panicle, number of filled spikelets per panicle, sterility percentage, test weight and yield increased by 6.3, 14.7, 17.3, 50.8, 18.9 and 21.2 per cent respectively over the control under water stress conditions. Based on the results obtained in the present investigation, it can be concluded that the morpho-physiological, pollen characters, seed yield and its components were drastically reduced when the rice crop was exposed to water stress during flowering and anthesis stages, that reflected the reduction on the above parameters. Foliar spray of 25ppm of GA + 0.01mg of Brassinosteroids +2.5 ppm of Boron improves the pollen characters, growth, yield and its components of rice crop under normal as well as water stress conditions. The use of 25 ppm of GA + 0.01mg of Brassinosteroids +2.5 ppm of Boron at flowering and anthesis stages especially under water stress conditions could alleviate the negative effects of water stress on growth and yield of rice crop by improving the pollen characteristics of the crop and maintaining less membrane injury index, higher pollen germination percentage, protein content in pollen, total soluble sugars in pollen, proline content in leaves which helped the rice crop to ameliorate the adverse effects of water stress at flowering and anthesis stages. Hence, foliar spray of 25 ppm of GA + 0.01mg of Brassinosteroids + 2.5 ppm of Boron at 100 DAS at flowering stage in late sown rice crop to ameliorate the adverse effects of water stress.
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    ThesisItemOpen Access
    Influence of zinc nutrition on growth, thermotolerance and yield of chickpea (Cicer arietinum L.)
    (guntur, 2022-08-10) KARTHIK, MAMIDALA; JAYALALITHA, K.
    The present investigation entitled “Influence of zinc nutrition on growth, thermotolerance and yield of chickpea (Cicer arietinum L.)” was undertaken at Agricultural College Farm, Bapatla during rabi, 2020 – 21. The experiment was laid out in split plot design with three main treatments i.e., three dates of chickpea sowing viz., normal sowing (sown on November 10th - (M1)), moderately delayed sowing (sown on November 30th - (M2)) and late sowing (December 20th - (M3)) to expose the crop to late sowing induced heat stress during flowering and pod formation stages, and four sub treatments viz., no zinc application (control – S0), foliar spray of ZnSO4. H2O @ 0.2 % (S1), Zn-EDTA @ 0.3 % (S2) and ZnSO4. 7H2O @ 0.5 % (S3) at pre flowering and pod formation stages in three replications. The results of the study revealed that, significant differences were observed among the main treatments, sub treatments and their interactions. Plant height decreased significantly under late sown conditions, and the decrease was 12.5 and 10.0 per cent in late sown and moderately delayed sown chickpea crops, respectively. Foliar spray of ZnSO4. 7H2O @ 0.5 % at pre flowering and pod formation stages increased the plant height by 10.0 per cent, over the control plants. The late sown chickpea crop that was sprayed with ZnSO4. 7H2O @ 0.5 % at pre flowering and pod formation stages (M3S3) increased the plant height by 10.6 per cent, over no zinc application (M3S0). Late sown chickpea crop attained 50 % flowering and maturity by 9 days early over the normal sown crop, indicating accelerated flowering and maturity under heat stress condition in the present study. Foliar spray of ZnSO4. 7H2O @ 0.5 % at pre flowering and pod formation stages took significantly more number of days to 50 % maturity compared to control plants. Leaf area was reduced by 14.2 and 7.1 per cent, and leaf, stem, reproductive parts and total dry matter was decreased by 30.0 and 21.8 per cent; 18.0 and 11.3 per cent; 27.0 and 18.6 per cent and 26.5 and 18.4 per cent in late sown and moderately delayed sown crops, respectively, over the normal sown crop. Among the zinc treatments, foliar spray of ZnSO4. 7H2O @ 0.5 % at pre flowering and pod formation stages increased the leaf area by 14.0 per cent; leaf, stem, reproductive parts and total xiv dry matter by 15.8, 17.6, 26.3 and 21.8 per cent, over control plants. Zn-EDTA @ 0.3 % spray came in the second order in increasing the leaf area and leaf, stem, reproductive parts and total dry matter by 9.1, 10.4, 11.8, 16.7 and 14.3 per cent, respectively, over control plants. Normal sown chickpea crop that was sprayed with ZnSO4. 7H2O @ 0.5 % at pre flowering and pod formation stages (M1S3) recorded the highest values of above parameters and the lowest values were recorded by the late sown crop without zinc application (M3S0). Under late sown conditions, the chickpea crop that was sprayed with ZnSO4. 7H2O @ 0.5 % at pre flowering and pod formation stages (M3S3) increased the leaf area and leaf, stem, reproductive parts and total dry mater by 17.5, 12.2, 23.4, 22.0 and 21.5 per cent, respectively, over the late sown crop without zinc application (M3S0). Thermotolerance parameters such as MII, CSI, RWC and CTD varied significantly by different dates of sowing. Higher MII was recorded by the late sown crop compared to the normal sown crop, indicating increased lipid peroxidation under heat stress (late sown) conditions. Lesser CSI, RWC and CTD were recorded by the late sown chickpea crop compared to the normal sown crop. Foliar spray of ZnSO4. 7H2O @ 0.5 % at pre flowering and pod formation stages decreased the MII values and improved the CSI, RWC and CTD. under late sown conditions (heat stress conditions), foliar spray of ZnSO4. 7H2O @ 0.5 % at pre flowering and pod formation stages (M3S3) helped in minimizing the damage to the cellular membranes by recording lesser MII values, higher CSI, RWC and CTD compared to the late sown crop without zinc application (M3S0), indicating the role of zinc in amelioration of heat stress especially under late sown conditions. Net photosynthetic rate, stomatal conductance and transpiration rate were decreased in the late sown chickpea crop by 12.3, 7.0 and 24.8 per cent, respectively, over the normal sown crop. ZnSO4. 7H2O @ 0.5 % foliar spray exhibited superior performance in enhancing net photosynthetic rate, stomatal conductance and transpiration rate by 22.2, 12.3 and 40.7 per cent, respectively, over control plants. Late sown chickpea crop sprayed with ZnSO4. 7H2O @ 0.5 % at pre flowering and pod formation stages (M3S3) increased the net photosynthetic rate, stomatal conductance and transpiration rate by 20.2, 9.7 and 40.0 per cent respectively, over untreated plants (M3S0). SOD activity was increased by 35.4 and 14.0 per cent in chickpea due to late sowing and moderately delayed sowing compared to normal sowing. Protein and zinc contents in seed were also reduced in the late sown chickpea crop. Foliar spray of ZnSO4. 7H2O @ 0.5 % at pre flowering and pod formation stages significantly increased the SOD activity, and protein and zinc contents in seed compared to the untreated plants. Late sown chickpea crop that was sprayed with ZnSO4. 7H2O @ 0.5 % (M3S3) recorded higher SOD activity, higher protein and zinc content in seed, over the crop without zinc application (M3S0). In late sown chickpea crop, the number of pods plant-1, number of seeds plant-1, test weight and seed yield were decreased by 14.1, 12.6, 5.5 and 17.6 per cent, respectively, over the normal sown crop. Among the zinc treatments, foliar spray of ZnSO4. 7H2O @ 0.5 % at pre flowering and pod formation stages increased the pods per plant, seeds per plant, test weight and seed yield by 17.3, 26.0, 3.4 and 42.6 per cent, over the untreated plants. Under normal sown conditions, the chickpea crop that was sprayed with ZnSO4. 7H2O @ 0.5 % at pre flowering and pod formation stages (M1S3) recorded 21.1 per cent increase in seed yield over the crop without zinc xv application (M1S0), and 21.1 per cent increase over the late sown crop with zinc application (M3S3). Under late sown conditions, ZnSO4. 7H2O foliar spray @ 0.5 % (M3S3) increased the seed yield by 41.2 per cent, over the late sown crop without zinc application (M3S0). ZnSO4. 7H2O @ 0.5 % foliar spray to the late sown chickpea crop recorded higher harvest index compared to the crop without zinc application. According to the results obtained above, it can be concluded that the morpho- physiological, thermotolerance and photosynthetic parameters; seed yield and its components and quality parameters were drastically reduced in the late sown chickpea crop in the present study, indicating the exposure of the crop to heat stress under late sown conditions during flowering and pod formation stages, that reflected reduction on the above parameters. Foliar spray of ZnSO4. 7H2O @ 0.5 % could improve the growth, yield and its components of chickpea both under normal sown as well as late sown conditions. Zn-EDTA @ 0.3 % came in the second order in improving the above parameters. The use of ZnSO4. 7H2O @ 0.5 % foliar spray at pre flowering and pod formation stages especially under late sown conditions, could alleviate the negative effects of heat stress on growth and yield of chickpea by improving the thermotolerance capacity of the crop in terms of maintaining lesser MII; higher CSI, RWC and CTD and higher activity of SOD, which helped the late sown chickpea crop from the adverse effects of heat stress from flowering to maturity.
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    ThesisItemOpen Access
    EFFECT OF PACLOBUTRAZOL AND MEPIQUAT CHLORIDE ON LODGING RESISTANCE, GROWTH AND YIELD IN RICE (Oryza sativa L.)
    (guntur, 2022-08-08) VENKATESH REDDY, K.; RAVI BABU, M.
    An investigation entitled “Effect of paclobutrazol and mepiquat chloride on lodging resistance, growth, and yield in rice (Oryza sativa L.)” was conducted at college farm, Agricultural college, Bapatla. The experiment was laid in Randomized Block Design which was replicated thrice to find out the effect of different concentrations of paclobutrazol and mepiquat chloride on morpho-physiological characters, growth, lodging, yield, and yield attributing characters. The nine treatments in each replication consisting of two different concentrations of paclobutrazol and mepiquat chloride at two different stages of crop growth (100 and 200 ppm paclobutrazol and mepiquat chloride at 35 DAT and panicle initiation stage) and a control. Results indicated a significant difference in morpho-physiological characteristics viz., plant height, culm thickness, culm strength, lodging percentage and number of effective tillers hill-1. A significant difference in biochemical parameter viz., the lignin content of the stem was observed. A significant difference was observed in yield and yield attributes viz., number of panicles m-2, number of filled spikelet panicle-1 and grain yield under different concentrations of paclobutrazol and mepiquat chloride. Data on different parameters were collected at 30 days interval. Significantly higher morpho-physiological parameters, yield and yield attributes and lower lodging percentage were recorded with foliar application of 100 ppm mepiquat chloride spray at panicle initiation stage (T7) when compared to other treatments.