1. KAUTIR (Kerala Agricultural University Theses Information and Retrieval)
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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 Evaluation of hybrids for yield and quality in chilli (Capsicum annuum L.)(Department of Olericulture, College of Agriculture,Vellayani, 2016) Aiswarya, C S; Sreelathakumary, IThe research projec t entitled “Evaluation of hybrids for yield and quality in chilli ( Capsicum annuumL.)” was conducted at Department of Olericulture, College of Agriculture, Vellayani during 2015-16. The objective of the study was to evaluate the yield and quality characters of F1 hybrids of chilli. The experimental material consisted of five parents viz., CA 3 (P1), CA 5 (P2), CA 6 (P3), CA 8 (P4) and CA 32 (P5) and 10 F1s produced in diallel mating design excluding reciprocals. The hybrid Arka Harita and variety Vellayani Athulya were used as checks for the estimation of standard heterosis. The experiment was laid out in Randomized Block Design (RBD) with 17 treatments and three replications for two seasons viz., May 2015 to September 2015 and October 2015 to February 2016. Analysis of variance showed significant differences among the treatments for almost all characters studied. Among the hybrids P4 x P5 recorded the highest fruit weight (9.66 g), flesh thickness (2.81 mm), green fruit yield plant-1 (962.93 g), dry fruit yield plant-1 (144.05 g) and yield plot-1 (27.72 kg). Maximum fruits plant-1 was recorded in the hybrid P3 x P4(148.76), fruit length in P1 x P5(12.61 cm) and fruit girth in P3 x P5 (4.43 cm). Among the parents P5 recorded highest fruit weight (6.73 g), flesh thickness (2.61 111m), green fruit yield plant-1 (448.70 g), dry fruit yield plant-1 (79.98 g) and yield plot-1 (12.91 kg). The hybrid P2 x P5 had high quality parameters like oleoresin (18.90 %), ascorbic acid (122.66 mg/lOOg) and colour value (195.39 ASTA units). The check variety Vellayani Athulya was superior for characters such as days to first flower (23. 83 days), days to first harvest (42.96 days), fruit length (12.66 cm), fruit girth (6.27 cm), fruit weight (17.36 g) and flesh thickness (3.31 mm). No incidence of white fly, bacterial wilt, leaf curl, fruit rot and mosaic were observed in the field. The incidence of thrips and mites were less in the parents and hybrid combinations. The highest standard heterosis for green fruit yield plant'1 among the hybrids was recorded in P4 x P5 (177.23 %) followed by P3 x P5 (147.35 %), and P2 x P5 (127.24 %). For fruit weight highest standard heterosis was observed in P4 x P5 (191.09 %) followed by P3 x P5 (188.12 %) and P2 x P5 (170.30 %). Maximum standard heterosis for yield plot'1 was recorded in P4 x P5 (177.34 %), P3 x P5 (147.35 %) and P2 x P5 (127.31 %). Among the hybrids the highest standard heterosis for the quality characters such as oleoresin (36.59 %), ascorbic acid (6.05 %), and colour value (8.17 %) were recorded in P2 x P5. Correlation for different characters showed that green fruit yield plant"1 had positive correlation with the primary branches plant'1, fruits plant"1, fruit length, fruit weight, flesh thickness and seeds fruit'1. On the basis of the present study the hybrids CA 8 x CA 32 (P4 x P5), CA 6 x CA 32 (P3 x P5) and CA 5 x CA 32 (P2 x P5) were found promising for yield characters such as fruit weight, green fruit yield plant'1, yield plot'1 and quality. Among the parents CA 32 (P5) was found superior. The superior hybrids identified viz., CA 8 x CA 32 (P4 x P5), CA 6 x CA 32 (P3 x Ps) and CA 5 x CA 32 (P2 x Ps) can be subjected to multilocational trials and if found superior can be recommended for variety release.Item Seed biopriming and spraying at fruit set for the management of chilli anthracnose caused by Colletotrichum capsicii (Sydow) Butler and Bisby(Department of Plant Pathology, College of Agriculture, Vellayani, 2019) Athira, P V; Radhkrishnan, N VThe study entitled ‘Seed biopriming and spraying at fruit set for the management of chilli anthracnose caused by Colletotrichum capsici (Sydow.) Butler and Bisby’ was conducted at College of Agriculture, Vellayani and Coconut Research Station (CRS), Balaramapuram during 2017- 2019 with the objective to study the seed borne nature of chilli anthracnose/fruit rot caused by Colletotrichum capsici and the effect of seed biopriming and spraying during fruit set for its management. Samples of chilli seeds were collected from five agro-ecological zones of Kerala viz. Northern, High range, Central, Special problem and Southern zones. The lowest percentage of infection was found in seed samples collected from Vellayani (6.62) and the highest in Parassala (43.33). Both externally and internally seed borne fungi and bacteria were isolated from the infected seeds. Fruit rot samples were collected from five locations of Kerala viz. Vellayani, Kumarakom, Thrissur, Wayanad and Kasargod. Five isolates (C1 to C5) of C. capsici were obtained. Vellyani isolate (C1) was the most virulent isolate which recorded a lesion size of 3.81 cm in detached fruit assay at seven days after inoculation (DAI). The isolate C1 was used for further studies. Six biocontrol agents viz. Trichoderma viride (KAU isolate), Pseudomonas fluorescens PN 026 (KAU isolate), Bacillus subtilis VLY 62 Bacillus pumilus VLY 17, Bacillus amyloliquefaciens VLY 24 and Piriformospora indica were screened in vitro against C. capsici using dual culture method. B. amyloliquefaciens recorded the highest percentage suppression of mycelial growth of C. capsici (62.96) followed by B. subtilis (56.30) and T. viride (51.85). P. fluorescens did not show the mycelial growth suppression of C. capsici. In vitro assays on chilli fruits revealed that B. amyloliquefaciens was most effective in controlling fruit rot with a lesion size of 2.71 cm 10 DAI followed by B. subtilis (lesion size - 2.97 cm) and T. viride (lesion size – 3.81 cm). Peroxidase and polyphenol oxidase activities were also higher in B. amyloliquefaceins treated chilli fruits before and after treatment. Standardization of priming techniques revealed that soaking of seeds for 1 h was found effective for T. viride and 4 h for other biocontrol agents. The effective soaking durations were followed for the respective treatments in further in vivo studies. Based on the in vitro assays, the best three treatments viz., B. amyloliquefaciens, B. subtilis and T. viride were taken for in vivo studies. In vivo evaluation of seed biopriming on the control of fruit rot revealed that the lowest disease severity was recorded in B. subtilis (PDI – 37.19) followed by B. amyloliquefaciens and T. viride (PDI in both - 40.00). The severity of anthracnose in leaves was lowest in B. subtilis (PDI – 10.60) which was on par with T. viride (PDI – 11.30) and B. amyloliquefaciens (PDI – 11.90). The number of fruits per plant, 100 seed weight and seed yield per plant were higher in T. viride. In vivo studies on the effect of seed biopriming and spraying during fruit set recorded the lowest disease severity for B. amyloliquefaciens (PDI – 28.13 at 15 DAI) which was on par with carbendazim 0.1 per cent (PDI - 29.38) and was followed by B. subtilis (PDI - 31.25) and T. viride (PDI - 32.5). The severity of anthracnose in leaves was lowest in B. subtilis (PDI - 8.00) which was on par with B. amyloliquefaciens (PDI - 8.10) and T. viride (PDI - 8.50). The number of fruits per plant, 100 seed weight and seed yield per plant were highest in T. viride treated plants. Thus, the present study indicated that seed biopriming and spraying with B. amyloliquefaciens VLY 24 at fruit set was found to be the most effective for the management of fruit rot / anthracnose of chilli which could be used as an ecofriendly measure to produce safe-to-eat crop.