1. KAUTIR (Kerala Agricultural University Theses Information and Retrieval)
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Item Screening early segregating generation of brinjal (Solanum melongena L.) for resistance against shoot and fruit borer(Department of Plant Breeding and Genetics, College of Agriculture Vellanikkara, 2024-01-31) Ankit Kumar Upadhyay; Jiji JosephBrinjal, known as eggplant or guinea squash (Solanum melongena L.), belongs to the Solanaceae family. The fruit from the genus Solanum is also called “The King of vegetables”. It is an important solanaceous crop cultivated worldwide and is native to the Hindustan-China center, where it still grows in the wild. The brinjal crop is highly vulnerable to several pests and diseases. Among these, the production and productivity of the crop are severely affected by brinjal shoot and fruit borer (BSFB; Leucinodes orbonalis G.) reducing its market value. The loss caused by the pest may reach up to 70 - 92 per cent. The inadequacy of reliable biological control for the management of BSFB leaves farmers to resort to insecticides. This underscores the critical necessity for extensive research and the development of varieties resistant to shoot and fruit borer. Such resistant varieties have the potential to emerge as the most environment friendly, cost-effective, and sustainable method for pest control. In this context, the present study entitled “Screening early segregating generations of brinjal (Solanum melongena L.) for resistance against shoot and fruit borer” was conducted to investigate and select the superior lines with resistance to shoot and fruit borer from early segregating generations. Segregating generations of two crosses i.e., Ponni × Vengeri (F3 and F4 generations) and Ponni × IC624241 (F2 generation) were evaluated along with the parents and check varieties. Segregation with wide variation was observed in all the generations viz—F2, F3, and F4 of the respective crosses. Regarding fruit colour, both the segregating generations of Ponni (green) × Vengeri (purple-green) showed wide variation in the colouring pattern. The segregating generations had both oblong and long-shaped fruits similar to parental types i.e., Ponni (oblong) and Vengeri (long). Besides, elongated fruits were also observed in both generations. All the fruits in the F2 generation of Ponni × IC624241, exhibited green colour similar to the parent Ponni whereas, the fruit shape was round as in IC624241. Range, mean, variance, genotypic coefficient of variance (GCV) (%), phenotypic coefficient of variance (PCV) (%), heritability (H2), genetic advance (GA), genetic advance as percentage over mean (%) (GAM), skewness, kurtosis, and correlation between growth and yield traits were estimated in F2, F3, and F4 75 generations of the respective crosses. PCV was higher than GCV for all the traits in all the generations. The observed variability across all studied populations remained consistently high for various traits. This variability persisted in the subsequent generations, as indicated by the range, GCV, PCV, H2, GA, GAM, skewness, and kurtosis. This suggests that a single seed descent (SSD) method was employed throughout the generations without any selection process. For pedigree selection BSFB scoring according to Mishra et al., (1988) at the fruiting and shooting stage was performed and all the lines were categorized as susceptible to highly susceptible in accordance with their scale. The selection criteria for identifying the best-performing lines were based on percentage of fruit infestation, marketable yield, fruit yield per plant, and percentage of shoot infestation. Based on the selection criteria lines 1.2.18, 1.2.10, and 1.3.10 were identified from the F3 generation of the cross between Ponni × Vengeri and were forwarded as F4 lines. In the F2 generation of the cross between Ponni × IC624241, five F2 plants showed 50 per cent of fruit resistance but, due to susceptibility to bacterial wilt and low population size, further studies were not conducted. Correlation data from F3 (Ponni × Vengeri) and F2 (Ponni × IC624241) generation of the crosses revealed a positive association between the number of flowers, number of shoots, fruits per plant, and length of fruit with shoot and fruit infestation. However, in the F4 generation of Ponni × Vengeri the length and diameter of the fruit showed a negative correlation with the shoot and fruit infestation by BSFB. Fruit yield per plant was positively associated with the number of flowers, shoots, fruits, length of fruit, and average fruit weight in all the studied populations. The diameter of the fruit also showed a positive association with yield in the F2 (Ponni × IC624241) and F4 (Ponni × Vengeri) populations of the crosses. Superior lines selected through the pedigree method in terms of marketable yield and resistance to BSFB were identified from the F3 forwarded F4 generation of Ponni × Vengeri, the lines were 1.2.18.8, 1.2.10.7, and 1.3.10.7 (in descending order of their performance). The superior lines with resistance for fruit infestation from F4 generation developed through SSD were 1.3.11.2 (0 %), 1.4.13.2 (50 %), and 1.10.16.4 (0 %). The identified lines from the F4 generation of cross Ponni × Vengeri may be forwarded further to develop resistant varieties and other studies.Item Morphological and biochemical characterization of Brinjal (Solanum melongena L.) ge(Department of Plant Breeding and Genetics, College of Agriculture, Padannakkad, 2022-05-21) Alan Thomas.The study entitled “Morphological and biochemical characterization of brinjal (Solanum melongena L.) genotypes” was carried out in the Department of Plant Breeding and Genetics, College of Agriculture, Padannakkad during 2019-2021. The study was conducted in two experiments and the objectives were to characterize the brinjal genotypes based on morphological, biochemical and quality characters; analyze the genetic variability in collected accessions and to identify best genotypes having high yield, superior quality as well as resistance/ tolerance to fruit and shoot borer. The experimental material consisted of two wild species (S. insanum and S. incanum) and twenty eight S. melongena accessions including collections from North Kerala (Kannur-5, Kasaragod-4, Malappuram-1), accessions from NBPGR regional station, Thrissur as well as KAU released varieties (Ponny, Haritha and Surya). The first experiment was laid out in a randomized block design with 30 genotypes in three replications and observations were recorded for 12 qualitative, 18 quantitative and 8 fruit quality and biochemical characters. The analysis of qualitative characters showed wide variation for corolla colour and fruit characters such as curvature, shape, apex shape, pedicel and calyx prickles, flesh density, fruiting pattern and colour. The results of analysis of variance revealed significant differences for all the quantitative characters indicating presence of high genetic variability. The brinjal genotypes SM-1, SM-5 and SM-11 showed superiority for percent medium and long styled flowers (67.59%, 42.78%, 61.75%), fruit setting percentage (63.89%, 37.59%, 55.45%), days to first harvest (61.33, 63.67, 61.67), fruit weight (111.18g, 115.28g, 106.87g) and marketable fruit yield (1874.67g, 1619.67g 1673.33g). The variance component analysis revealed high heritability coupled with high genetic advance as per cent of mean for all the fruit and yield characters as well as pericarp thickness, anthocyanin in fruit peel and vitamin C indicating that most likely the heritability is due to additive effects making selection effective based on these characters. Correlation and path analysis revealed that fruit setting percentage, days to first harvest, fruit weight and number of fruits per plant showed significant genotypic correlation and direct effect depicting true association of these characters with fruit yield. Selection based on these characters will help to achieve efficient improvement in fruit yield. The UPGMA clustering of 30 eggplant accessions for qualitative traits revealed six groups based on fruit curvature, corolla colour, fruit shape, fruit apex shape, fruit flesh density, fruit colour. The genetic diversity analysis based on Mahalanobis D2 statistics for 18 quantitative characters grouped 30 accessions into thirteen clusters. The character fruit weight contributed maximum towards diversity. The maximum intra-cluster distance was reported in cluster V followed by cluster IV. The highest inter-cluster distance was recorded between cluster VII and XII followed by clusters VII and VIII indicating a wide range of diversity between these clusters providing scope for hybridization between superior genotypes of these highly divergent clusters. The accessions SM-1, SM-2, SM-5, SM-9, SM-10 and SM-11 showed superior ranking in their respective clusters based on three yield attributes viz., fruit weight, fruit setting percentage and marketable fruit yield identified in association and divergence analysis. In the second experiment brinjal accessions were screened for resistance to fruit and shoot borer in a completely randomized design in three replications. The observations were recorded for percentage of shoots infested and percentage of fruits infested at ten days intervals and the accessions were grouped into six categories based on severity of damage on fruits. Wild accessions SM-26 (S. incanum) and SM-27 (S. insanum) were found to be immune, as none of these plants showed symptoms of infestation. SM-6 and SM-7 were rated as highly resistant accessions. SM-1, SM-2, SM-3, SM-4, SM-5, SM-8, SM-9, SM-11, SM-14 and Haritha were found to be moderately resistant. SM-10, SM-13, SM-20, SM-22, Ponny and Surya were grouped as tolerant. All the remaining accessions were susceptible. Correlation studies between fruit infestation by fruit and shoot borer with biochemical characters revealed a positive significant correlation of fruit infestation with total sugars and protein content while a negative correlation of fruit infestation was obtained with solasodine content as well as phenol content. The present study resulted in identification of a fair number of high yielding resistant lines amongst the wide collection of indigenous brinjal germplasm used. The wild relatives from highly divergent clusters like cluster I (SM-26), cluster VIII (SM-27) and S. melongena accessions SM-6 and SM-7 can be exploited for their shoot and fruit borer resistance. Accessions SM-1, SM-2, SM-5, SM-9, SM-10 and SM-11 with higher nutrients (protein >1.22 g/100g and vitamin C >5.03 mg/100g), a balance of biochemical content (solasodine and phenol) in addition to high fruit yield (~1300g to ~2100g) and comparatively lesser infestation of fruit and shoot borer can be considered as the promising parents in future crop improvement programsItem Evaluation of brinjal (Solanum melongena L.) genotypes for resistance to bacterial wilt (Ralstonia solanacearum)(Department of Plant Breeding and Genetics , College of Agriculture, Padannakkad, 2023-12-11) Muslepally Niharika; Namboodiri Raji VasudevanThe current study entitled “Evaluation of brinjal genotypes for resistance to bacterial wilt (Ralstonia solanacearum)” was carried out in the Department of Plant Breeding and Genetics, College of Agriculture, Padannakkad during 2020-2023. The main objectives of the study were to evaluate brinjal genotypes for resistance to Bacterial wilt (BW) and examination of the mechanism of resistance through anatomical and biochemical parameters as well as estimation of yield characters in resistant lines. The experimental material consisted of thirty-one accessions which included eleven accessions (SM-1, SM-2, SM-3, SM-4, SM-5, SM- 8, SM-9, SM10, SM-31, SM-32, SM-33) collected from North Kerala, seventeen accessions (SM-11 to SM-27) from NBPGR. It also included three released varieties and hybrid of KAU (Haritha, Surya, Ponny and Neelima) as resistant checks and two susceptible checks (SM-26[S.incanum] and SM-27[S.insanum]). In experiment I, three weeks old seedlings of all brinjal genotypes were screened for resistance to BW in a completely randomized design with three replications. Based on percentage disease incidence (PDI), two accessions SM-15 and SM-25 were rated as highly resistant (HR: 0 PDI) and accessions SM-1 was rated as resistant (R: 1-10 PDI). Accessions SM-1, SM-2, SM-5, SM-11, SM-17, SM-24 and KAU hybrid Neelima were rated as moderately resistant (MR: 11-20 PDI). Accessions SM-4, SM-8, SM-14 and SM-19 were rated as susceptible (S: 21-30 PDI). Moderately susceptible (MS: 31-40 PDI) accessions were SM-3, SM-32, SM-33, SM-13 and SM-16. Accessions SM-9, SM-10, SM-12, SM 18, SM-20, SM-21, SM-22, SM-23, SM-26 and SM-27 were rated as highly susceptible (HS: >40 PDI). Biochemical parameters viz., Polyphenol oxidase (PPO) enzyme activity, total phenols, and total sugars (both reducing and non-reducing) were assessed at 12 and 24 hours post inoculation (hpi).In this analysis using twenty two accessions consisting of eight genotypes from resistant categories (HR, MR, R) and eight from HS group along with four RC ( Ponny, Haritha, Surya and Neelima) as well as two SC (SM-26, SM-27) were used. A control group with mock inoculation was also part of the analysis. Two factor ANOVA demonstrated significant differences in these biochemical parameters among all tested brinjal genotypes. At 12 and 24 hpi, the most significant rise in PPO activity was observed in the RC followed by the R group, HR germplasm and MR group compared to their respective control samples. Moreover at 24 hpi the resistant (R) genotypes exhibited a significant 3.5-fold increase in PPO activity compared to the control group. Resistant checks exhibited the highest phenolic content followed by the HR, R and MR germplasm at 12 and 24 hpi. The highest amount of total sugars, which includes both reducing and non-reducing sugars, was observed in RC followed by HR germplasm, R germplasm, and MR germplasm after 24 hpi. Correlation analysis revealed a significant negative correlation between biochemical parameters viz., PPO enzyme activity, total phenol content, total sugars including non-reducing sugars (12 and 24 hpi) and disease incidence. A positive correlation was observed between disease incidence and reducing sugars at 12 hpi whereas, negative correlation was observed between the same at 24hpi. The biochemical analysis indicated that PPO and phenols played a positive role in the resistance against R. solanacearum in brinjal. However, the role of sugar content in plant defense is still unclear and requires further studies for a better understanding of sugar metabolism. In the current study different aspects of the stem vascular anatomy viz., number of small and large vessels, total number of vessels, ratio of large to small vessels and average vascular area in the eggplant germplasm and correlation of these characters with disease incidence were analysed. A significant variation for anatomical characters was observed among all the genotypes. Among the germplasm HR accessions SM-15, SM-25 and R accession SM 1 showed highest number of large vessels, higher ratio of large vessels to small vessels and higher average vascular area compared to all other accessions. These anatomical parameters are found to play a significant role in the temporal and spatial distribution of the pathogen within the vascular vessels. After analyzing the response of various brinjal genotypes to disease incidence, as well as considering biochemical and anatomical parameters, it was observed that eight genotypes (SM-1, SM-2, SM-5, SM-11, SM-15, SM-17, SM-24, and SM-25) exhibited resistance against BW. These genotypes along with four KAU released resistant checks were further evaluated in the field in experiment II. Field evaluation was carried out in a randomized block design with three replications for sixteen quantitative and two qualitative characters. Per se performance of all genotypes revealed significant variation for all the quantitative characters indicating presence of high genetic variability. Association analysis revealed that leaf area, root dry weight and average fruit weight showed significant positive genotypic correlation and direct effect depicting true association of these characters with fruit yield. Selection based on these characters will help achieve efficient improvement in fruit yield. Among the local accessions, resistant accession SM-1 exhibited the maximum early fruit yield of 972.68 g followed by the Moderately resistant accession SM-11 (965.77 g). Accession SM-1 was also superior for plant height, earliness, average fruit weight and SM-11 for number of fruits per plant. Therefore, resistant accession SM-1 could be regarded as a promising genotype for potential release as a new variety. Highly resistant accessions SM-15 (oval green fruits with intermediate calyx prickles) and SM-25 (oval purple fruits and no prickles on the calyx), displayed excellent plant and flower characteristics like stem girth, branching, days to first and 50 per cent flowering but reported lower early yields. These can be used in hybridization programs either as parents to develop F1 hybrid or as recombinants in recombination breeding for resistance to bacterial wilt.Item Development of botanical soap formulation fortified with essential oils for the management of the pests of brinjal(Department of Entomology, College of Agriculture ,Vellayani, 2024-01-24) Neeraja, S R.; Narayana, RThe present study entitled “Development of botanical soap formulations fortified with essential oils for the management of pests of brinjal” was conducted at the Department of Entomology, College of Agriculture, Vellayani, with the objective of assessing the bioactivity of a botanical soap formulation against the pests of brinjal. The present study was carried out as four different experiments including preparation of botanical soap formulations, laboratory bioassay of soap formulations against fourth instar grubs of epilachna beetle, field assessment of soap formulations against major pests of brinjal and evaluation of its shelf life. Leaf dip bioassay were conducted to evaluate the efficacy of botanical soap formulations against epilachna beetle grubs, Henosepilachna vigintioctopunctata. After 24 hours of treatment, the highest percentage mortality (54.42) was observed in neem oil+ citronella oil soap @ 2%. The treatments, neem oil +basil oil soap @ 2% (38.61%), pongamia oil + citronella oil soap @ 2% (37.56%) and pongamia oil +basil oil soap @ 2% (40.80%) were found to be on par with neem oil+ citronella oil soap @ 2%. After 48 hours of treatment, the highest percentage mortality was recorded for neem oil + citronella oil soap @ 2% (80.44) and were found to be on par with neem oil +basil oil soap @ 2% (70.16), pongamia oil + citronella oil soap @ 2% (62.02), pongamia oil +basil oil soap @ 2% (61.42). Based on the results obtained from the bioassay, six treatments were selected for further experiments. The treatment involving neem oil + citronella oil soap @ 2% recorded the highest repellent effect (80 %). This was found to be statistically on par with pongamia oil+citronella oil soap @ 2% (73.33) and neem oil + citronella oil soap @ 1% (65.00%) 30 minutes after treatment. Sixty minutes after treatment (MAT), neem oil + citronella oil soap @ 2% accorded 85% repellence and was found to be on par with pongamia oil + citronella oil soap @ 2% (76.67%). Field trials were conducted to ascertain the efficacy of botanical soap formulations against major pests of brinjal. Among the different treatments, the treatment involving neem oil + citronella oil soap @ 2% exhibited the highest percent reduction in the population (59.66) of aphids after fourteen days of first spray. The same trend was observed in the second spray schedule (57.05). Against whiteflies, pongamia oil + citronella oil soap @ 2% recorded highest percent reduction in the population (71.38) after fourteen days of first spray. The same trend was observed in the second spray schedule (76.45). Neem oil soap @ 2% exhibited highest percent reduction in the population (75.92) of leafhopper after fourteen days of first spray. The same trend was observed in the second spray schedule (70.06). The highest percent reduction of damaged leaves by epilachna beetle was exhibited by neem oil+ citronella oil soap @ 2% (39.98) after fourteen days of first spray. The same trend was observed in the second spray schedule (40.84). The highest percent reduction of damaged fruits by fruit and shoot borer was exhibited by neem oil+ citronella oil soap @ 2% (69.53) after fourteen days of first spray. The same trend was observed in the second spray schedule (43.98). The highest fruit yield wasrecorded for the treatment, neem oil + citronella oil soap @ 2% (1556.66 g/plant). The shelf life studies revealed that after the first month, neem oil + citronella oil soap @ 2% recorded 46.71 and 65.09 percentage mortality of grubs after 24 and 48 hours of treatment, respectively when stored under refrigerated conditions. Neem oil + citronella oil @ 2% exhibited 43.03 and 61.25 percent mortality of grubs after 24 and 48 hours of treatment, respectively under room conditions. The treatments, neem oil +basil oil soap @ 2% and pongamia oil + citronella oil soap @ 2% were found to be on par with neem oil + citronella oil soap @ 2%. This study investigated the efficacy of botanical soap formulations under laboratory and field conditions. The results obtained from the laboratory and field evaluation proved the potential of neem oil + citronella oil soap @ 2%, and it can be recommended for controlling the pest population. Evaluation of shelf life of these formulations revealed that their effectiveness remained for three months.Item Magnetized irrigation water for enhancing production of brinjal (Solanum melongena L.)(Department of Agronomy, College of Agriculture, Vellayani, 2022-11-05) Vijayakumar, Pullagura; Sajitha Rani, TThe investigation entitled “Magnetized irrigation water for enhancing production of brinjal (Solanum melongena L.)” was carried out as two experiments at the Instructional Farm, College of Agriculture, Vellayani during 2018-2021, to study the effect of magnetization on quality of irrigation water, to assess the impact of magnetized water on growth, yield and quality of brinjal, to evaluate the effect of magnetized irrigation water on soil properties and to work out the economics. The present investigation revealed that employing magnetic strength of 2000G was effective for getting good quality irrigation water, and scheduling of irrigation with this water at IW/CPE ratio of 0.8 along with 75 per cent RDF could be recommended for obtaining higher growth, yield and monetary returns from both plant and ratoon crop of brinjal.Item Mechanisms of resistance in Brinjal Shoot and fruit broer, Leucinodes orbonalis (Guenee) (Lepidoptera:Crambidae) to diamide insecticides(Department of Agricultural Entomology, College of Agriculture ,Vellanikkara, 2024-10-18) Anu ThomasThe development of insecticide resistance among insect pests is a major concern in pest management. Generating data on the baseline susceptibility of field populations to insecticides facilitates to track the resistance development in insects. This helps in designing suitable insecticide resistance management (IRM) strategies; thereby, to delay the development of resistance and extend the useful life of an insecticide.Understanding the mechanisms of resistance, the possibilities of developing cross- and multiple-resistance, and the fitness costs involved in resistance are also crucial to maintain the sustainability of an insecticide. In this context, the present investigation entitled “Mechanisms of resistance in brinjal shoot and fruit borer, Leucinodes orbonalis (Guenee) (Lepidoptera: Crambidae) to diamide insecticides” was undertaken during 2019-2024 with the objectives to study the baseline susceptibility of brinjal shoot and fruit borer to diamide insecticides, to assess the possible mechanisms of resistance development, to investigate the potential of developing cross and multiple resistance in diamide-resistant populations and to analyze the fitness costs associated with resistance. Field populations of brinjal shoot and fruit borer were collected from brinjal fields of Kerala, Kullarayanpalayam (Palakkad) and Anchal (Kollam); Tamil Nadu, Devarayapuram (Coimbatore) and Trichy (Tiruchirappalli); and Karnataka, Heggadadevankote (Mysore) and Doddaballapur (Banglore Rural). A laboratory susceptible population, maintained without any insecticide exposure since 2012, was procured from NBAIR, Bangalore. The collected populations were assigned unique accession codes such as PKD, KLM, CMB, TRY, MYS, BAN, and Lo-S, respectively, and maintained separately in the laboratory. Information on insecticide usage pattern in brinjal cultivation obtained from farmers at collecting sites revealed the usage of insecticides of different modes of action and application above recommended dosages. An intensive application of various insecticdes including diamides was practiced in Bangalore Rural, Tiruchirappalli, Coimbatore, and Palakkad. In Kollam, on the other hand, a need-based application in recommended doses was followed. In Mysore, the farmers did not use any diamide insecticide; instead, they relied on organophosphates and neonicotinoids applied at frequent intervals. The laboratory bioassay of field populations of L. orbonalis was performed against flubendiamide (Fame 39.35% SC) and chlorantraniliprole (Coragen18.5% SC) to determine the median lethal concentration (LC50). The resistance ratio (RR) was assessed by comparing the LC50 values with that of the Lo-S population. All field populations of L. orbonalis except MYS displayed a significant shift in LC50 value compared to the Lo-S population and were considered resistant to flubendiamide and chlorantraniliprole based on the hypothesis of equality. Among the resistant populations, the BAN and TRY were resistant homozygotes according to the hypothesis of parallelism. The LC50 value of field populations ranged from 0.83 ppm in MYS to 544.07 ppm in TRY for flubendiamide compared to 0.50 ppm recorded with the Lo-S population. The TRY population showed the highest resistance ratio (RR) of 1079.5- fold to flubendiamide, followed by the BAN (845.85-fold), CMB (532.56-fold), and PKD (218.84-fold) populations. However, the KLM population showed comparatively less RR with 47.59-fold resistance, while the MYS population was considered susceptible to flubendiamide. The LC50 value for chlorantraniliprole ranged from 0.169 ppm in MYS to 116.80 ppm in BAN in contrast to 0.119 ppm recorded with the Lo-S population. Concerning chlorantraniliprole, the highest RR of 979.22-fold was recorded with the BAN population followed by 788.18-fold in TRY, 480.30-fold in the CMB, 244.75-fold in PKD, and 18.22-fold in KLM populations. The lowest RR of 1.41-fold was observed with MYS population and was considered susceptible to chlorantraniliprole based on the hypothesis of equality. The activity of detoxifying enzymes in the field populations of L. orbonalis was quantified and compared with the Lo-S population to examine the role of detoxifying enzymes in diamide resistance. The field populations, BAN, PKD, CMB, TRY, MYS, and KLM showed 1.66-, 1.47-, 1.24-, 1.21-, 1.21-, and 1.17-fold increase in carboxylesterase (CarE) activity, respectively. Significantly higher titers of cytochrome P450 (Cyt P450) activity were displayed by all the field populations with a 5.54- fold increase in the TRY population, followed by BAN (5.38-fold), CMB (5.26- fold), PKD (5.13-fold), MYS (4.56-fold), and KLM (3.12-fold). The relative activity of glutathione S-transferase (GST) was >4-fold in PKD, CMB, TRY, and BAN populations displaying 4.31, 4.33, 4.34, and 4.44-fold variations, respectively, compared to the Lo-S population. Meanwhile, KLM and MYS populations exhibited only 1.5-fold and 1.25-fold increases, respectively. To assess the potential for developing cross-resistance, a laboratory bioassay was carried out against cyantraniliprole, a less commonly used diamide insecticide. The field populations displaying resistance to flubendiamide and chlorantraniliprole also exhibited resistance to cyantraniliprole, even though the population had no previous exposure to the chemical. However, the populations that were not previously exposed to emamectin benzoate and spinosad did not show resistance to these insecticides, and thereby the possibility of developing multiple resistance in diamide-resistant populations was rejected. Fitness costs associated with diamide resistance were ascertained by comparing the life table parameters of different field populations of L. orbonalis with the Lo-S population. In the study, diamide-resistant populations, TRY, BAN, PKD, and CMB displayed significantly longer larval and pupal duration, and less oviposition period and female adult longevity than the Lo-S population. Male adult longevity in the TRY and BAN populations was also notably shortened compared to the Lo-S population. The survival of egg, larva, and pupa as well as fecundity of the diamide-resistant populations except KLM were significantly less compared to the Lo-S population. The BAN and TRY populations exhibited a relative fitness of 0.62, suggesting a higher fitness cost associated with diamide resistance. The CMB population displayed a relative fitness of 0.68 followed by PKD (0.74) and the lowest was in KLM (0.82). These results indicated a survival disadvantage with the resistant populations compared to the Lo-S population. In investigating the molecular basis of resistance in L. orbonalis, a partial sequence of the ryanodine receptor (RyR) gene involved in diamide resistance was analyzed. Thymine (T) was found to be substituted with cytosine (C) in the sequences of the BAN and TRY samples that were tested, but the Lo-S sample did not exhibit this substitution, which is consistent with the reference sequence (Acc. No. PQWD01009585.1) of L. orbonalis. Alignment of the protein sequences revealed a non-synonymous amino acid alteration from isoleucine to methionine (I to M) in the RyR of BAN and TRY, which was not observed in the Lo-S gene sequence, indicating the crucial role of point mutation for higher diamide resistance in TRY and BAN populations. The study revealed a shift in susceptibility status and the development of higher folds of resistance to diamide insecticides among the field populations of L. orbonalis. The possible role of detoxifying enzymes and target site mutations in the development of diamide resistance was also established. The study on cross- and multiple-resistance provided valuable information for the selection of insecticides in IRM programs. The involvement of fitness costs in the diamide-resistant populations indicated a negative impact of resistance on pest fitness and the chance of resistance reversion in the absence of insecticides.Item Molecular characterization of brinjal (Solanum melongena L.) genotypes and their performance assessment in summer(Department of Genetics and Plant Breeding, College of Agriculture, Padanakkad, 2023-05-31) Chakravaram, Alekhya; Namboodiri Raji VasudevanItem Mealybugs of vegetable ecosystems and tritrophic interactions of brinjal mealybugs(Department of Agricultural Entomology, College of Agriculture ,Vellayani, 2022) Mithra Mohan; Anitha, NThe study on “Mealybugs of vegetable ecosystems and tritrophic interactions of brinjal mealybugs” was conducted at College of Agriculture, Vellayani during 2017 to 2020 with the objectives to identify mealybugs and their natural enemy fauna in solanaceous and cucurbitaceous vegetables, to carry out the molecular characterization of mealy bugs in solanaceous and cucurbitaceous vegetables and to find out the tritrophic interactions of mealybugs infesting brinjal. An investigation on mealybug diversity in solanaceous and cucurbitaceous crops of Kerala revealed a total of six mealybug species viz., Coccidohystrix insolita, Ferrisia virgata, Paracoccus marginatus, Phenacoccus solenopsis, Planococcus citri and Pseudococcus jackbeardsleyi. Besides, four mealybugs viz., Crisicoccus hirsutus, Maconellicoccus hirsutus, Planococcus lilacinus and Rastrococcus iceryoides infesting other vegetable crops were also recorded from Kerala. The study also revealed that the population of mealybug, C. insolita collected from different regions of Kerala exhibited significant morphological variation. The molecular characterization studies proved that the population belongs to C. insolita and the variations may be environmental induced. An exploration of the host range of mealybugs infesting solanaceous and cucurbitaceous vegetables in Kerala revealed a total of 113 plants under 73 genera belonging to 31 families, out of which 14 plants were recorded as new host reports. A rich natural enemy fauna on mealybugs belongs to five orders viz., Coleoptera, Lepidoptera, Diptera, Neuroptera and Hymenoptera were documented from Kerala. Twenty species of mealybug predators from five different families were recorded, among which the predominant family was Coccinellidae with 16 species under six genera. Among the various predators collected, Cacoxenus sp. was recorded for the first time as a predator of P. jackbeardsleyi. Eleven hymenopteran parasitoids belonging to five families were documented from mealybugs, of which the majority belongs to the family Encyrtidae. Four new host-parasitoid associations were also recorded for the first 288 time. The study also identified six hyperparasitoids under the family Encyrtidae, of which two species were recorded as new report which includes Cheiloneurus sp. and Prochilonerus sp. associated with the mealybug P. solenopsis. The ants associated with mealybugs in different agroecosystems were also investigated and a total of 14 species of ants belonging to nine genera under three subfamilies were recorded, of which the most dominant subfamily was Formicinae followed by Myrmicinae and Dolichoderinae. The present study also revealed 15 new ant-mealybug associations for the first time. The molecular characterization of eight mealybug species was carried out that complemented the morphological identification of species. A total of eight nucleotide sequences were submitted to NCBI GenBank and accession numbers were generated. The sequences were also submitted to BOLD and illustrative barcodes were generated. The barcodes of C. insolita, C. hirsutus and P. jackbeardsleyi were generated for the first time. The diversity of endosymbionts of the mealybug C. insolita was carried out for the first time. The study revealed a total of 15 phyla of endosymbionts on C. insolita, of which Proteobacteria was the predominant one. An experiment was conducted at Instructional Farm, Vellayani to identify the tritrophic interaction in brinjal, C. insolita and its natural enemies. The study revealed that out of the ten brinjal cultivars evaluated, the lowest mean population of mealybugs was observed in Pusa Uttam whereas the hybrid cultivar, Udit recorded the highest number of mealybugs. The lowest mean per cent leaf infestation was recorded in Pusa Purple Long which was statistically on par with Pusa Uttam whereas the hybrid cultivar, Udit was severely damaged by the mealybugs. Among the tested cultivars, Pusa Purple Long was recorded under the group resistant whereas Udit and Haritha were included under the highly susceptible group based on the mean per cent leaf infestation caused by C. insolita. The cultivar Haritha attracted the highest number of predators whereas the maximum mean population of spiders were observed in Pusa Purple Long. 289 The correlation analysis on the mean population of mealy bugs with biophysical parameters revealed that trichome density, length width ratio of leaf and number of branches exhibited a significant positive correlation with mean population of mealybugs. Correlation studies on the mean population of natural enemies with biophysical parameters revealed that plant height exhibited a significant negative correlation whereas leaf thickness and number of branches revealed a non-significant negative correlation with the mean population of natural enemies. Among the biochemical parameters of brinjal cultivars, total phenol content exhibited a significant negative correlation with the mean population of mealybugs whereas total chlorophyll content showed a significant positive correlation. The correlation between biochemical parameters of brinjal cultivars with the mean population of natural enemies revealed that total phenol and carotenoid content exhibited a non-significant negative correlation whereas total protein content, reducing sugar and total chlorophyll content showed a nonsignificant positive correlation. The info-chemical mediated interactions in brinjal cultivars, mealybug and its natural enemies were studied using a multi-armed olfactometer and Y-shaped olfactometer assay. The results revealed that the cultivar Udit attracted the highest number of natural enemy Chrysoperla zastrowii sillemi while the cultivar Pusa Uttam attracted the lowest number. The variation in preference shown by the natural enemies may be related to the difference in volatile compounds emanating from the host cultivar. The GC-MS analysis of the synomonal compounds of the cultivar, Udit revealed a total of eleven compounds whereas the cultivar Pusa Uttam was recorded with a total of five compounds. The Y shaped olfactometer studies revealed that C. zastrowi sillemi adults showed more preference towards the synomonal compounds of mealybug infested plants than that of healthy plant synomonal extracts. On comparing the volatile profile of synomones of mealybug infested and healthy plants revealed that the synomonal extracts of the mealybug infested cultivar Udit comprised of 11 compounds whereas healthy plant synomonal extracts contained nine compounds. 290 The relative response of C. zastrowi sillemi towards the kairomonal compounds of C. insolita was evaluated in a Y tube olfactometer and the results revealed that the highest mean number of adult lacewings were attracted to the kairomonal compounds of mealybug compared to control. The kairomonal extracts of the mealybug comprised of seven compounds and the composition of these hydrocarbons may determine the selectivity of natural enemies towards the preferred host. The present study recorded a total of six mealybug species infesting solanaceous and cucurbitaceous vegetables and its host range, natural enemies and associated ants in different agro ecological regions of Kerala. The molecular characterization studies supported the morphological taxonomy and the sequences were submitted to NCBI Genbank and BOLD. The study also elucidated the interactions mediated by plant traits and info-chemicals in brinjal-mealybugnatural enemy tritrophic systems. The study recorded Pusa Purple Long as resistant cultivar and Udit and Haritha as highly susceptible cultivar to C. insolita. The plant traits viz., trichome density, length width ratio of leaf, number of branches, total phenol content and total chlorophyll content exhibited significant correlation with mean population of mealybugs whereas plant height exhibited significant correlation with mean population of natural enemies. The study on info-chemical mediated tritrophic interactions revealed that the concentration and composition of volatile compounds determine the differential selectivity of natural enemies. The volatile compounds identified in this study can also be used as a cue in moderating the behavior of natural enemies in the ecosystems. So a thorough knowledge on the tritrophic relations in the ecosystem will aid in manipulating these interactions to devise a better pest management strategy.Item Bioactivity of essential oils against insect pests of brinjal(Department of Agricultural Entomology, College of Agriculture, Vellayani, 2022) Manoj, K; Thania Sara VargheseThe study entitled “Bioactivity of essential oils against insect pests of brinjal” was undertaken in the Department of Agricultural Entomology at College of Agriculture, Vellayani during the period 2019-2021 with an objective of evaluating the bioactivity of essential oils viz., basil oil, citronella oil, eucalyptus oil and orange oil against insect pests of brinjal and characterization of the most effective essential oils. Laboratory screening of essential oils viz., basil oil, eucalyptus oil, citronella oil and orange oil was conducted against one sucking pest (mealy bug, Coccidohystrix insolita (Green)) and one chewing pest (Hadda beetle, Henosepilachna vigintioctopunctata (Fabricius)) in brinjal. Acute toxicity of the essential oils against the test insects was determined by leaf dip bioassay. Preliminary test dose range causing 10 to 100 per cent mortality was fixed and based on these 6 doses including a control treatment was taken. Based on the results of leaf dip bioassay of essential oils against mealy bug, LC50 and LC90 of basil oil, eucalyptus oil, citronella oil and orange oil were (0.49 and 1.33), (1.86 and 4.28), (0.64 and 2.39) and (1.54 and 3.53) per cent respectively at 24 hours after treatment (HAT). The corresponding LC50 and LC90 values of the above four oils at 48 HAT were (0.29 and 0.89), (0.72 and 1.92), (0.28 and 1.22) and (1.06 and 2.17) per cent respectively. Against hadda beetle the LC50 and LC90 values of basil oil, eucalyptus oil, citronella oil and orange oil were (1.25 and 2.85), (3.35 and 5.09), (0.93 and 1.52) and (3.48 and 9.11) per cent respectively at 24 HAT. While the corresponding LC50 and LC90 values at 48 HAT were (0.85 and 1.70), (2.09 and 3.51), (0.63 and 1.14) and (2.02 and 4.05) per cent respectively. Based on toxicity bioassays, basil and citronella oil had lower LC50 and LC90 values than eucalyptus and orange oil against both mealy bug and hadda beetle at both 24 and 48 HAT and these two were selected for further lab and field evaluation. Repellent and antifeedant effect of the selected essential oils from the first experiments viz., basil oil, citronella oil were evaluated against hadda beetle by modified preference method and no choice method respectively. At 0.5 to 1 per cent 76 concentration, both basil and citronella oil showed 90-100 per cent repellence at 30 and 60 minutes of treatment. On other hand, 0.5 to 1 per cent concentration of basil and citronella oil showed antifeedant effect of 100 per cent after 24 hours of treatment. Before conducting field evaluation of essential oils, bloom test and phytotoxicity evaluation on brinjal plants were done. Bloom test was conducted to check the emulsification of essential oil and surfactant formulation in distilled water. Results were showing “Good” bloom rating for basil oil and “Excellent” bloom rating for citronella oil. Phytotoxicity evaluation of basil and citronella oil was carried on brinjal plant as per the protocols of CIBRC (Central Insecticide Board and Registration Committee). Basil oil and citronella oil at 0 to 0.7% were not showing any phytotoxic symptoms on brinjal plants while the higher doses of 1%, 1.5% and 2% were showing slight moderate and severe phytotoxic symptoms. Based on the laboratory and phytotoxicity evaluation, two doses of basil oil and citronella oil (0.5% and 0.7%) were selected for the pot culture experiment along with two chemical checks and an untreated control. The experiments were laid in completely Randomized design with three replications. In field study, spraying of basil oil and citronella oil at 0.7% showed significant reduction in aphid population and it was statistically on par with thiamethoxam 25% WG even at 14 DAT. The leaf webber population was also significantly reduced for basil and citronella oil at 0.7% and it was statistically on par with chlorantraniliprole 18.5% SC even at 14 DAT. Basil oil and citronella oil at 0.7% showed significant reduction in the shoot and fruit borer damage after 14 days of treatment and it was statistically on par with chlorantraniliprole 18.5% WG at 14 days after treatment. Basil oil and citronella oil at 0.7 per cent showed significant reduction in the lady bird beetle population. There was no statistical difference among the different treatments with regard to the biometric observations viz., total number of leaves, damaged leaves, plant 77 height after the field spraying, however the fruit yield was recorded significantly higher in chlorantraniliprole 18.5% WG. GC-FID/GC-MS studies on basil and citronella oil revealed that the predominant component of basil oil is Methyl chavicol (75.73%), followed by Linalool (18.21%) and (8) Cuprenene (1.58%). In citronella oil, Geranial (64.77%) was the most abundant component followed by Citronellyl acetate (7.92%), Geraniol (7.08%), (Z) Iso citral (5.29%) and Neral (3.60%).Item Characterisation of brinjal (solanum melongena L.) and its wild relatives(Department of plant breeding and genetics, College of Agriculture, Padannakkad, 2021) Lintu, P; Namboodiri Raji VasudevanThe study entitled “Characterization of brinjal (Solanum melongena L.) and its wild relatives” was carried out at the Department of Plant Breeding and Genetics, College of Agriculture, Padannakkad during 2018-2020. The main objectives of the study was to characterize the brinjal genotypes and its wild relatives based on morphological characters; analyze the genetic variability in collected accessions and to develop selection index for cultivated types. The experimental meterial consisted of 25 S. melongena accessions and five wild relatives (S. mammosum, S. macrocarpon, S. insanum, S. incanum and S. gilo) collected from North Kerala (Malappuram-11, Kozhikode-5, Kannur-4, Kasaragod- 3, Wayanad-1) and Regional station, NBPGR, Thrissur (6). The passport data of thirty accessions were prepared and these were evaluated for 17 qualitative and 22 quantitative characters based on IPGRI descriptor in field experiment laid out in Randomized Block Design with three replications. The morphological characterization based on qualitative characters showed wide variation for stem colour, leaf lobing, fruit shape and fruit colour. The results of analysis of variance indicated significant differences for all the quantitative characters indicating presence of high genetic variability. The mean performance of genotypes revealed distinct variation between cultivated and wild accessions for most of the characters. The wild accessions recorded lower values for fruit yield and fruit weight but longer duration for flowering and fruit set. Eight S. melongena accessions (SM 27, SM 25, SM 23, SM 20, SM 10, SM 23, SM 24 and SM 8) had high fruit yield per plant (more than 1000 g). The accession SM 27 had shown superiority for important yield component traits like fruit yield, fruit diameter and fruit weight. Among all accessions, the green fruited S. melongena accession SM- 25 showed lesser incidence of shoot and fruit borer. Three wild accessions S. mammosum (SM 22), S. gilo (SM 29) and S. insanum (SM 30) showed no incidence of fruit and shoot borer. The variance component analysis revealed high heritability coupled with high genetic advance as per cent of mean for all flowering and fruit characters indicatingthat most likely the heritability is due to additive effects making selection effective based on these characters. Association analysis revealed that plant height, days to first flowering, number of long styled flowers, fruit diameter, fruit weight and number of fruits per plant shown significant genotypic correlation and direct effect showing true association of these characters with fruit yield. Selection based on all these characters will help to achieve efficient improvement in fruit yield. The UPGMA clustering of 30 eggplant accessions for qualitative traits revealed three groups based on anthocyanin pigmentation of plant parts and leaf prickliness, traits important for stress tolerance. The genetic diversity analysis based on Mahalanobis D 2 statistics for 22 quantitative characters grouped 30 accessions into eight clusters. The clustering patern showed the S. melongena accessions collected from North Kerala grouped under cluster I (22) and cluster III (2). All the five wild accessions were grouped in five different clusters (III, IV, VI, VII and VIII). The green fruited accessions SM 25 and SM 27 collected from NBPGR were placed in cluster III and cluster V indicating their distinctness. The character fruit yield per plant, leaf blade width, number of fruits per plant and leaf blade length hade made major contribution towards genetic divergence with maximum by fruit yield per plant. The maximum intra-cluster distance was reported in cluster I, followed by cluster III. The remaining are solitary clusters. The highest inter- cluster distance was recorded between solitary clusters V and VIII, V and IV and V and III providing scope for hybridization between genotypes of these highly divergent cluster especially involving wild accession SM 30 for fruit and shoot borer resistance. Selection index involving discriminant functions based on relative economic importance of various characters showed a combination of four characters (Fruit yield per plant + Number of long styled flowers + Fruit diameter + Fruit weight) with maximum relative efficiency. Based on high selection index score involving four character combination and overall cluster ranking for three yield attributes two green fruited accessions SM 25 and SM 27 and six purple fruited accessions SM-8, SM- 10, SM-18, SM-20, SM-23 and SM 24 are identified as promising. Among these,the green fruited accession SM 25 had shown very low incidence of fruit and shoot borer. Based on selection index score and cluster divergence (high inter-cluster distance) the SM-27 is identified as promising parent in intra-specific hybrid involving of SM-27 x SM-25 and inter-specific hybrids involving SM-27 x S. insanum and SM-27 x S. macrocrpon. These crosses may be attempted in future breeding program for obtaining progenies superior for yield as well as shoot and fruit borer and bacterial wilt resistance.