1. KAUTIR (Kerala Agricultural University Theses Information and Retrieval)
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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 Evaluation of F2 segregating population of chilli (Capsicum annuum L.) for yield and resistance to leaf curl virus(Department of Vegetable Science, College of Agriculture, Vellayani, 2022-06-20) Archa, P S; Lekshmi, S LThe project entitled “Evaluation of F2 segregating population of chilli (Capsicum annuum L.) for yield and resistance to leaf curl virus” was carried out at the Department of Vegetable Science, College of Agriculture, Vellayani, during summer 2021 to evaluate the F2 segregants of chilli crosses for yield and leaf curl virus resistance. In the present study two crosses viz., CHIVAR-6 x Sel-4 and CHIVAR-10 x Sel-3 were selected from the previous PhD research study conducted at the Department of Vegetable Science, College of Agriculture, Vellayani. The F2 population comprising of 200 segregants from the two crosses along with their parents were raised and evaluated for various characters and incidence of leaf curl virus. The results revealed variability among the segregants for various characters studied. Among the segregants maximum plant height was exhibited by C-2-182 (146.00 cm). The segregants of first cross, C-1-19, C-1-37, C-1-49, C-1-111, C-1-125, C-1-127, C-1-130, C-1-140 and C-1-163 were the earliest to flower (32.00 days).The days to harvest ranged from 51 days to 58 days among the segregants of the first cross and 52 days to 58 days in the second cross. The fruits per plant was highest in the segregant C-2- 161 (160) and C-1-149 (103) from both populations. Among the segregant population, maximum fruit length was noticed in the segregant C-2-42 (10.16 cm) of cross 2 whereas maximum fruit girth was noticed in C-1-145 (5.03 cm) of cross 1. Fruit pedicel length was highest in the segregant C-2-68 (4.49 cm). C-1-70 recorded the highest fruit weight (6.21 g) among the segregant population of the two crosses. C-2-70 had the maximum number of seeds per fruit of 119.00. Among the F2 population, the highest fruit yield per plant was exhibited by the segregant C-2-161 (518.79 g) followed by C-2-168 (420.40 g), C-1-117 (374.18 g) and C-1-151 (363.00 g). The ascorbic acid content ranged from 36 mg 100 g-1 to 144.00 mg 100 g-1 among the segregants. The highest carotenoid content was observed in C-1-196 and C- 2-112 (275.67 mg 100 g-1). In the present study, the scoring for chilli leaf curl virus was done and based on the scoring the segregants were categorized into highly resistant, resistant, moderately resistant, moderately susceptible, susceptible and highly susceptible. The coefficient of infection revealed that both the F2 segregants and their parents displayed highly resistant reaction to leaf curl virus. Enzyme analysis assay for peroxidase activity ranged from (12-37) unit activity1min-1 g -1 among the population of the cross 1 and in cross 2, it ranged from (11-47) unit activity-1min-1 g-1. Phenylalanine ammonia activity ranged from (15.3 µg-1 g-1min-1) to (28.2 µg-1 g-1min-1) and from (12.6 µg-1 g-1min-1) to (15.4 µg-1 g-1 min-1) in cross 1 and cross 2 respectively. Polyphenol oxidase activity of the segregant population of cross 1 ranged from 19-32 unit activity-1 min-1 g-1 and in the segregant population of cross 2 it ranged from 14-23 unit activity-1min-1 g -1 . The highest percentage of positive segregants in the F2 population of the cross CHIVAR-6 x Sel-4 was observed for days to first flowering (78 %), yield per plant (52 %), fruits per plant (40.5 %) and seeds per fruit (34.5 %). In the cross CHIVAR-10 x Sel3, highest positive segregation percentage was observed for plant height (81.5 %), yield per plant (69.5 %) and fruits per plant (56.5 %). Principal component analysis was carried out for the quantitative characters. Out of the thirteen principal component axes (PCA)s extracted, six PCAs with eigen values greater than one were retained for both the cross which accounted for total variation of 64.07 per cent and 67.31 per cent in the cross 1 and cross 2 respectively. The first two principal components contributed major part of the variation with a proportion of 16.78 per cent and 11.79 per cent in cross 1. In the second cross first two components contributed 18.95 per cent and 12.66 per cent respectively. Based on simple correlation study for various characters with yield per plant it was observed that for the F2 population of CHIVAR-6 x Sel-4 significant positive correlation was observed for fruits per plant (0.718), plant height (0.292), fruit weight (0.286) and fruit girth (0.16). F2 population of CHIVAR-10 x Sel-3 exhibited significant positive correlation for fruits per plant (0.818), plant height (0.286) and fruit length (0.184) with yield per plant. In case of the parents of cross 1 significant positive correlation was shown for fruits per plant (0.406). The chi-square analysis for goodness to fit to various gene interaction ratios revealed that the segregating population of cross 1 fitted to the ratio 12:3:1 for fruit surface. The segregants of the cross 2, fitted for the ratio 3:1 for fruit shape at pedicel attachment, 9:6:1 for fruit shape at blossom end and 9:3:4 for fruit surface character. The chi-square analysis for leaf curl virus resistance revealed that the observed ratio in the segregants holds a good fit to the ratio 3:1. The test results shows that the genetics of resistance is governed by a single dominant gene in both the crosses. Based on the yield and leaf curl virus incidence, the segregants C-2-161, C-2-168, C-1- 117, C-2-10, C-2-154 and C-1-151 were found to be superior and are suitable for further segregation studies.Item Integrated nutrient management in chilli (Capsicum annuum L.)(Department of Agronomy, College of Agriculture, Vellayani, 2000) Sharu, S R; Meera Bai, MA field experiment was conducted at the Instructional Farm attached to the College of Agriculture, Vellayani during 1999-2000 to study the combined effect of chemical fertilizers and organic manures on the productivity and quality of chilli, to assess the possibility of substitution of fertilizers by organic manures and also to work out the economics of production. The treatments consisted of combined application of chemical fertilizers and organic manures viz. poultry manure, vermicompost and neemcake in various ratios of 3: 1, 1: 1, 1:3 and 0:2. The control treatment was POP recommendation of KAU (20 t ha! of FYM + 75:40:25 kg N, P205 and K20). The experiment was laid out in randomised block design. An abstract of the result is given below. Plant height, number of branches, shoot-root ratio and dry matter content differed significantly with various treatments. All these parameters were found to be increasing with increased level of chemical nitrogen. Shoot-root ratio was highest for vermicompost applied plots whereas the maximum value for all other growth parameters was produced by poultry manure treatments. All the yield parameters were significantly influenced by various treatments. Higher fruiting phase and fruit set was observed with 2 increasing chemical nitrogen level and maximum value was obtained for poultry manure treatment (3: 1). Poultry manure treatment (1: 1) gave good performance with respect to number of fruits per plant, harvesting interval and total yield. Higher levels of poultry manure along with chemical fertilizers also performed well. Length of fruit was highest for vermicompost treated plots along with chemical fertilizers (1: 1). Highest level of chemical fertilizer along with poultry manure gave good results with respect to LAI and dry matter production. RGR, CGR and NAR was highest for vermicompost applied plots. Keeping quality and ascorbic acid content was higher for poultry manure treatments. Regarding residual nutrients high soil K was registered by higher level of neemcake along with chemical fertilizer. Highest soil N was noted by highest dose of poultry manure (0:2). Poultry manure and chemical fertilizer in equal proportion obtained highest value for soil P. Highest dose of poultry manure together with chemical nitrogen gave good result for NPK content of plants. NPK uptake was also higher for poultry manure treatments. Incidence of bacterial wilt was least in dual application of chemical fertilizer and neemcake in the ratio 3: 1. The economics of cultivation revealed that poultry manure and chemical fertilizer application in equal proportion (1: 1) gave maximum net returns and benefit-cost ratio.Item Eco-friendly management of important sucking pests of chilli(Department of Agricultural Entomology, College of Agriculture, Vellayani, 1999) Santhosh Kumar, T; Reghunath, PItem Genetic improvement of bird pepper (Capsicum Frutescens L.) by selection(Department Of Olericulture, College Of Horticulture, Vellanikkara, 1998) Sheela, K B; George, T EItem Screening of chilli genotypes for resistance to bacterial wilt and mosaic(Department Of Olericulture, College Of Horticulture, Vellanikkara, 1999) Fatima, A G; Salikutty JosephThe investigation on "Screening of chilli (Capsicum annuum L.) genotypes for resistance to bacterial wilt and mosaic" was conducted at the vegetable research farm of Department ofOlericulture, College of Horticulture, Vellanikkara during 1997-'98. Fifty three chilli accessions collected from various parts of the country and abroad were evaluated in the wilt sick soil. The level of resistance to bacterial wilt varied with the accessions, Out of the 53 accessions tested, 15 were resistant, 16 were moderately resistant, 13 were moderately susceptible, and the remaining nine were highly susceptible. Among the 15 resistant accessions nine were short fruited, five were long fruited and remaining one was medium long fruited. The chilli lines were catalogued as per the IBPGR descriptor. The extent of genetic variability for 13 characters viz. plant height, plant spread, days to first flower, days to first harvest, fruit length, fruit girth, pedicel length, number of fruits per plant, average fruit weight, fruit yield per plant, driage, number of harvests and total . duration were studied. The genotypic and phenotypic coefficients of variation, heritability, genetic advance and genetic gain were estimated. Significant differences were observed among the 53 genotypes for almost all the characters studied. Among the 53 genotypes the earliest flowering (59 days) genotype was CA 715 and the highest yielding (352.75 g) genotype was CA 728. CA 731 recorded the maximum number of fruits (108.50) per plant. High heritability coupled with high genetic gain was observed for the characters - fruit length, fruit girth, number of fruits per plant, average fruit weight and fruit yield per plant. The highest positive correlation with yield was expressed by the total duration. Average fruit weight exhibited the highest positive direct effect on yield. Based on the genetic divergence the 53 genotypes were grouped into seven clusters. Out of 53 accessions evaluated for mosaic resistance, nine were resistant, twelve moderately resistant and the remaining 32 were susceptible. The resistance showed by the nine accessions was confirmed by standard methods. The accessions CA 337, CA 731, CA 738, CA 739 and CA 744 were found to possess the resistance to both bacterial wilt and mosaic and can be recommended for disease prone areas. The F IS developed using the resistant parents were found susceptible to both bacterial wilt and mosaic.