PG Thesis
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Item Evaluation of chilli (Capsicum spp.) genotypes for mite resistance(Department of Plant Breeding and Genetics, College of Agriculture, Vellanikkara, 2024-10-21) Akshaya, R; Asish, I EdakkalathurChilli is an important crop which finds its use as vegetable, spice, ethnic medicine, cosmetics and in industry. Biotic and abiotic stresses impair chilli production and its quality. Among the biotic stresses, bacterial wilt and sucking pests are the major causes of concern. In summer months, there is drastic reduction in quality and quantity of chilli due to combined attack of thrips and mites which are often referred to as sucking pest complex. Sustainable, environment-friendly and cost- effective pest management strategy to combat mite pests is the development of mite resistant varieties. To achieve this, it is essential to identify resistant genotypes from germplasm and understand the host plant resistance mechanisms. In the above perspective, present study was conducted during October, 2021 to December, 2022 at College of Agriculture, Vellanikkara with the objectives of evaluation of chilli genotypes for resistance to mite (Polyphagotarsonemus latus Banks) and identification of biochemical characters associated with the mite resistance. The study comprised of two experiments. First experiment was germplasm evaluation for mite resistance and economic parameters. Materials used for the study included 71 genotypes collected from Department of Plant Breeding and Genetics, CoA, Vellanikkara, ICAR-NBPGR-RS Hyderabad, Nicobar lines received from ICAR-NBPGR-RS Thrissur, and farmers of Kerala. Genotypes were raised in augmented block design with five check varieties viz., Anugraha, Vellayani Thejus, Vellayani Samrudhi, Keerthi, and Arka Meghana during October, 2021 to May, 2022. Mite susceptible landrace Byadgi kaddi was raised around the field to ensure mite population in the field. Observations were recorded on primary leaf colour, days to flowering, immature fruit colour, fruit length (cm), fruit diameter (cm), fruit weight (g), number of fruits per plant and yield per plant (g). Many genotypes surpassed the superior check variety in above economic characters. Majority of accessions had green primary leaf and immature fruit. Number of leaves showing downward curling symptoms were recorded at 45, 60, and 75 days after transplanting (DAT) and Per cent Leaf curl Index (PLI) was estimated. Genotypes were grouped as resistant, moderately resistant, susceptible and highly susceptible based on PLI. Two genotypes viz., PbCa 445 and PbCa 446 were recorded as resistant and 12 genotypes viz., were recorded as moderately resistant. Except Keerthi, all varieties used as checks were recorded as susceptible or highly susceptible. Resistant and moderately resistant genotypes were forwarded to the next season for validation of resistance inside polyhouse. Fourteen resistant genotypes identified in the previous season were raised in polyhouse during July to December, 2022 for validation of resistance. Five most susceptible genotypes identified in the previous season were also raised for comparative study. Artificial inoculation was carried out at 25 DAT through leaf clipping method. PLI was estimated at 45, 60, and 75 DAT as in the first experiment to confirm the resistance reaction of selected genotypes. Genotypes viz., PbCa 445, PbCa 451, PbCa 417 and PbCa 446 were noted as least susceptible with average PLI of 30.00 to 36.67. All other genotypes including Keerthi were grouped as highly susceptible with average of PLI ranging from 62.22 to 91.11. Number of eggs and active stages of mites were recorded at 45, 60 and 75 DAT. Total number of eggs and active stages averaged on above three stages ranged from 14.07 to 170 per six leaves. Genotypes PbCa 445 and PbCa 451 were recorded with lowest average PLI of 30, whereas genotypes PbCa 446 and PbCa 451 were recorded with lowest total number of eggs and active stages of mite with values of 14.07 and 27.04, respectively. Non- glandular and glandular trichome densities were recorded from both abaxial and adaxial surfaces of leaf. Number of mite eggs, active stages and total mite number were positively correlated with density of adaxial non-glandular trichomes. Adaxial non-glandular trichomes in moderately susceptible genotypes ranged from zero to 28 per cent per square centimetre, whereas it was in the range of 5.67 to 100 in highly susceptible genotypes. Other types of trichomes were not associated with number of eggs or active stages of mite. Protein, sugar and phenol content were estimated from selected genotypes of which sugar showed negative correlation with PLI. Four moderately susceptible genotypes validated in the present study could be used in the further breeding programme. Selected genotypes may be crossed in diallel mating design and resultant F1 generation may be evaluated to know genetics of mite resistance and to obtain desirable genetic combinations having mite resistance and yield.Item Impact of biofertilizers on iron homeostasis under elevated CO2 condition in rice, Oryza sativa(Department of Plant Physiology, College of Agriculture , Vellayani, 2023-01-25) Musti Sri Phani Bhavya; Manju, R VThe study entitled “Impact of biofertilizers on iron homeostasis under elevated CO2 condition in rice, Oryza sativa” was proposed with an objective of assessing the impact of biofertilizers on iron uptake, translocation and grain iron content in rice variety Uma, under CO2 enriched condition. The experiment was conducted using open top chamber (OTC) facility at the Department of Plant Physiology, College of Agriculture, Vellayani, during the period 2021-2022. In this experiment, growth, yield, quality and iron uptake characteristics of rice variety Uma under elevated CO2 condition as influenced by the application of different biofertilizers were evaluated. The experiment was laid out in CRD with 4 treatments [(KAU-POP (control), POP+Azolla, POP+PGPR and POP+AMF)] under 2 conditions [(Ambient CO2 (aCO2) and Elevated CO2 (eCO2)-500 ppm)] with 3 replications. The experiment results revealed that elevated CO2 had a significant positive influence on growth of the plants which was further enhanced by biofertilizer application. When yield parameters were considered, increased CO2 was found to have an adverse effect. There was 58 per cent and 39.28 per cent reduction in filled grains per panicle and grain yield when plants were grown under eCO2 condition. The increase in temperature associated with CO2 enhancement can affect the pollen viability resulting in increased grain chaffiness and yield reduction. Application of biofertilizers had significantly increased grain yield, among which AMF treatment had shown highest impact under both the CO2 conditions. Among the physiological parameters, total chlorophyll content, total reducing sugars and photosynthetic rate increased in the plants grown inside OTC. However, a reduction was noted in total soluble proteins and transpiration rate under elevated CO2 condition. In all these physiological parameters, the biofertilizers treated plants showed higher response when compared to control plants. Grain carbohydrate content was significantly increased by 10.6 per cent in control plants under eCO2 while protein and amylose contents of grains decreased by 14 per cent and 13 per cent indicating reduced grain quality under eCO2. Even under eCO2 condition, the protein content in PGPR treated plants increased by 7.1 per cent and amylose content in AMF treated plants increased by 4.86 per cent when compared to control plants (aCO2). 115 CO2 enrichment and biofertilizers application were found to influence iron uptake and translocation significantly. The pre-anthesis Fe uptake in control plants was dropped by 11.76 per cent and Fe-accumulation by 4.4 per cent under eCO2 condition. But application of PGPR could bring 57.89 per cent increase in iron uptake under ambient condition and 64.7 per cent increase under eCO2 condition. During post-anthesis stage, Fe-uptake was found to increase compared to pre-anthesis stage. Fe-accumulation in the shoot decreased during post-anthesis stage due to re-mobilization of accumulated Fe into grains. There was a drop in Fe-uptake in control plants under eCO2 by 12.5 per cent at post-anthesis stage. At pre-anthesis and post-anthesis stages, plants treated with PGPR (eCO2) have shown increase in Fe uptake by 47.36 per cent and 40.7 per cent, respectively, than control plants. All the biofertilizers including Azolla, PGPR and AMF had significant impact on grain Fe-content under both the CO2 conditions. The Fe content of grains in control plants was dropped by 21 per cent under eCO2 condition. Application of PGPR was found to be most effective resulting in 80.5per cent and by 72.8 per cent increase in Fe-content under eCO2 and aCO2 conditions, respectively. The Fe content in grains was partitioned more into bran than into the polished rice. Control plants when exposed to eCO2 reduced Fe-content in bran and polished rice by 12 per cent and 23.4 per cent, respectively. PGPR treatment increased the Fe-content by 28.6 per cent and 61.7 per cent in bran and polished rice under elevated CO2 condition and by 22.3 per cent and 46.2 per cent under ambient condition when compared to control plants. Diminishing quality of rice with the increasing concentration of CO2 is a global concern today. Elevated CO2 had a positive impact on growth but negatively influenced grain yield due to eCO2 associated high temperature. By the response of experimental plants to AMF and PGPR treatments, these bio-fertilizers can be recommended in overcoming the impacts of elevated CO2 associated high temperature and thereby improving the plant performance. In the present programme, iron uptake and translocation were found to be modified in an unfavourable manner under eCO2 which reflected in the lower iron content of rice grains. The response of iron homeostasis of the experimental plants to the application of biofertilizers, especially PGPR, under eCO2 strongly suggests the possibility of utilizing them for designing iron management strategies to achieve higher yield and quality in rice.Item Physiological and phenological responses of cardamom (Elettaria cardamomum Maton.) as influenced by varying altitudes(Department of Plant Physiology, College of Agriculture, Vellayani, 2022-07-08) Sudharani, T S; Roy StephenThe study entitled ―Physiological and phenological responses of cardamom (Elettaria cardamomum Maton.) as influenced by varying altitudes. This was carried out to evaluate the physiological changes that occur in the physiology and phenology of cardamom (Elettaria cardamomum (L.) Maton.) growing at different altitudinal locations in Idukki district of Kerala. The objective of the experiment was to study the physiological changes that occur in the physiology and phenology of small cardamom (Elettaria cardamomum Maton.) and to find out the optimum altitudes at which the cardamom plant can perform with maximum efficiency. The study was conducted at BL Ram Cardamom Hill Reserve near Pooppara of Idukki District of Kerala. Njallani (Green Gold) variety of small cardamom plants of 6 to 8 years age at three different locations: BL Ram (1246 MSL), Killippara (1312 MSL & 1402 MSL) and Koluthamppara (1524 MSL & 1603 MSL) were selected. The study was conducted during the period of October 2020 to March 2021. The biometric parameters measured were plant height, number of tillers per plant, number of leaves per tiller, number of panicles per tiller and number of berries per panicle. Physiological parameters like photosynthetic rate, transpiration rate, stomatal conductance and water use efficiency were analysed by using portable photosynthetic system (CIRAS-3 SW). Portable minimum maximum thermometer was set at each location to record daily temperatures. The treatments had significant effect on the plant canopy development. Plants at lower altitude tend to produce taller tillers compared to other treatments. Similarly the number of tillers were also higher at lower altitude, T1 (1200-1300 m above MSL). At the same time more number of leaves were produced by the plants grown at higher altitude T5 (1600-1700 m above MSL). This may be due to the difference in solar interception at different treatment locations. Plants at lower altitude tends to grow more taller to get more sunlight. Similarly the number of panicles produced and number of capsules produced per panicle were also higher at lower altitude and it showed a decreasing trend as altitude increased. Physiological parameters like photosynthetic rate, transpiration rate, stomatal conductance, specific leaf area, water use efficiency were analysed to study the trend in variation in the physiological performance of the plant. Small cardamom plants growing at higher altitudes had higher photosynthetic rate, transpiration rate, stomatal conductance and specific leaf area. The plants grown at higher altitude were more physiologically active compared with the treatments at lower altitudes. Small cardamom plants at T5 (1600 MSL) showed higher photosynthetic rate (3.771µmol CO2 m-2 s -1), transpiration rate (29.007 mmol H2O m-2 s -1), stomatal conductance (1504.00 mmol H2O m-2 s -1 ), specific leaf area (167.843 cm2g-1 ) and water use efficiency (15.37 kg m-3). T5(1600MSL) had the highest protein content, followed by T4 (1500 MSL) and the lowest was recorded for T1 (1200 MSL). The nutrient status in soil were also analysed. Highest nitrogen and phosphorus content were recorded for lower altitudes. The potassium content was higher at T2 (1300m above MSL). Similarly the NPK status in leaf canopy at both upper leaves and lower leaves were also analysed and highest nitrogen content was observed in T2 (1300 MSL) in the upper canopy. Phosphorous content was the highest in T3 (1400 MSL) in lower canopy. The potassium content was highest at T3 (1400 MSL) in both upper and lower canopies. Phenological study conducted in small cardamom has shown that maximum number of bunches was produced in T2(1300 MSL) and T4(1500MSL) had the minimum number of bunches produced per panicle. Both T1 (1200 MSL) and T5(1600MSL) had the highest number of spikelets per panicle and T3(1400MSL) and T4 (1500 MSL) had the lowest no. of spikelets per panicle. Number of berries per panicle was highest at T5(1600MSL). It is therefore concluded that, significant variation in physiological, biochemical and yield components was there among treatments. Small cardamom plants grown at higher altitude shows higher physiological activity such as photosynthetic rate, transpiration rate, stomatal conductance and specific leaf area compared with those at lower altitudes whereas plants at lower altitudes are more biologically active viz. plant height, number of tillers, number of panicles, number of capsules thus the overall yield is balanced.Item Physiological, biochemical and yield attributes of bell pepper (Capsicum annum var.grossum) as influenced by biochar amended with biofertilizers(Department of Plant Physiology, College of Agriculture, Vellayani, 2023-02-07) Simhi Samyukta S MThe programme entitled “Physiological, biochemical and yield attributes of bell pepper (Capsicum annuum var. grossum) as influenced by biochar amended with biofertilizers” was carried out at the Department of Plant Physiology, College of Agriculture, Vellayani during 2021-2022. The objective of the programme was to evaluate the physiological, biochemical and yield attributes of bell pepper as influenced by biochar amended with biofertilizers. A pot culture study was carried out with bell pepper variety “California Wonder” in completely randomized design (CRD). It involved a combination of eight treatments which is inclusive of a control also, with three replications in each. The different treatments were T1-control, T2-biochar, T3-Azospirillum, T4-VAM, T5-Piriformospora indica, T6-biochar + Azospirillum, T7-biochar + VAM and T8-biochar + P. indica. Different morphophysiological parameters like plant height, number of branches, photosynthetic rate, transpiration rate, chlorophyll content, leaf area index, root weight, root volume, shoot weight, root:shoot ratio, days to first flowering and days to first fruiting were studied. Of all the eight treatments that were studied, biochar + VAM (T7) was found to be the best treatment in increasing the morphophysiological parameters. Biochar + Azospirillum (T6) was observed to be on par with biochar + VAM (T7) in terms of photosynthetic rate, transpiration rate, leaf area index and shoot weight. Whereas, P. indica treated plants were found to be on par with biochar + VAM (T7) in terms of root characteristics. Also, P. indica proved to reduce the vegetative period and induce earliness of flowering in bell pepper plants. Considering the biochemical parameters, flavonoid content, total soluble proteins and ascorbic acid content were found to increase under the influence of Azospirillum. Polyphenol content was found to increase upon the treatment with VAM. However, with the application of biochar there was enhancement in all the biochemical parameters, viz. biochar + Azospirillum (T6) proving to be the best in terms of flavonoids (4.87 mg g-1), total soluble proteins (23.67 mg g-1) and ascorbic acid content (129.92 mg 100g-1) while biochar + VAM (T7) in terms of polyphenols (24.34 mg g-1). 104 VAM and Azospirillum were found to be on par with each other in terms of yield parameters, viz. number of fruits per plant, fruit weight and yield per plant. However, among all the treatments, biochar + VAM (T7) resulted in higher number of fruits per plant (7.33), fruit weight (76.42 g) and yield per plant (0.61 kg). Biochar + Azospirillum (T6) was found to be on par with biochar + VAM (T7) pertaining to fruit weight (74.72 g). Among the biofertilizer treatments, nitrogen uptake by the crop was found to be significantly higher in Azospirillum (T3) while phosphorous and potassium uptakes were found to be higher in VAM (T4). Of all the eight treatments, biochar + Azospirillum (T6) recorded the highest nitrogen uptake (131.47 kg ha-1). Biochar + VAM (T7) recorded the highest phosphorous uptake (30.97 kg ha-1) by the crop and was significantly on par with VAM (T4). Also, biochar + VAM (T7) recorded highest potassium uptake (121.60 kg ha-1) which was significantly on par with biochar + Azospirillum (T6). VAM was found to increase the organic carbon content of soil to a higher extent than other biofertilizers. Biochar amendment (T2) significantly recorded highest organic carbon content in the soil (2.99%). Microbial characteristics study also evidently proved that biochar increased the Azospirillum population (40-40.74%) in rhizosphere soil and VAM colonization percentage (5.88-7.5%) in root bits of bell pepper plants when compared to sole application of biofertilizers alone. Based on the present study, it can be concluded that combined application of biochar and VAM biofertilizer could increase the performance of bell pepper plants and improve its physiological, biochemical and yield attributes while also improving the soil organic carbon content and microbial deItem Bioecology and management of root-knot nematode Meloidogyne incognita chitwood in kacholam Kaempferia galanga Linn(Department of Entomology, College of Agriculture, Vellayani, 1998) Rajani, T S; Sheela, M SThe biology of root-knot nematode of kachlolam, its histopathological effects on roots and the effect of soil type on the pathogenicity of M. incognito infesting kacholam were studied under pot culture conditions. The effect of soil moisture and pH on the hatching of eggs and survival of larvae were studied in vitro in micro pots. Field trials were carried out to assess the crop loss and to find out a suitable management strategy for the root-knot nematode infesting kacholam. The root-knot nematode, Miincognita took 37 days for the completion of one life cycle in kacholam plants at room temperature of 27 + or - 3 0 C and the mean number of eggs observed per egg mass was 130. In kacholam roots, the nematode mainly infests the xylem vessels. The giant cells were quadrangular in shape and three in number and were observed adjacent to the head of the nematode. Field capacity was the most favourable soil moisture level for the hatching of eggs and survival of larvae of M.incognita. There weas no statistically significant variation in the hatching of eggs and survival of larvae under different soil pH levels ranging from 5 to 7.5. Sandy soil (Entisol) was found to be the best soil type for the multiplication of M. incognita infesting kacholam roots. The biometric characters and yield were reduced with the increase in inoculum levels and a maximum reduction was noticed at 10,000 12 level in all soil types under pot culture conditions. At field conditions, inoculation of 1000 12 per plant resulted in the reduction of number of leaves, rhizome length, root weight and yield per plant and per plot yield to the tune of 43.33,23.71,46.26,63.69 and 43.46 per cent respectively over control plants. Neem cake 200 g/m2, V AM (Glomus fasciculatumy 300 g/m2 inoculum per plant and cabofuran 3.33 g/ m2 were found effective for the management of root-knot nematode, M. incognita infesting kacholam.But neem cake treatment was found to be the best in reducing the soil and root population of nematodes and increasing the plant growth characters (number of leaves, length of rhizome and weight of roots) and yield (rhizome weight per plant and per plot) of kacholam.