PhD Thesis
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Item Breeding for multiple resistant hybrids in chilli (Capsicum annuum L.) against leaf curl viral disease and bacterial wilt(DEPARTMENT OF VEGETABLE SCIENCE COLLEGE OF AGRICULTURE VELLANIKKARA, THRISSUR, 2024-12-30) Divya, K Lekshmanan.; T, PradeepkumarChilli (Capsicum annuum L.) is one of the most economically important vegetable crops cultivated in warm humid tropics of India, but its production is hindered by various biotic stresses, particularly the diseases such as chilli leaf curl viral disease and bacterial wilt. These diseases are potential enough to drastically reduce both the yield as well as the quality of produce. The management measures are often ineffective in controlling the disease as the pathogen survives in the alternative host, plant debris or in the soil. Therefore, utilizing host plant resistance is the most viable and sustainable approach to manage these diseases. In this context, the present investigation entitled Breeding for multiple resistant hybrids in chilli (Capsicum annum L.) against leaf curl viral disease and bacterial wilt" was carried out at the Department of Vegetable Science, College of Agriculture, Vellanikkara, with the objective of identifying high yielding disease resistant parental lines and developing hybrids with resistance to both chilli leaf curl viral disease and bacterial wilt. The study was conducted in three experiments viz., evaluation of parental genotypes, development of F hybrids and evaluation of Fi hybrids for yield and resistant characters. Ninety-two chilli genotypes were evaluated along with the check varieties Anugraha and Ujwala for their resistance to leafcurl viral disease and bacterial wilt as well as for their yield potential. The genotypes studied exhibited significant variation for all the traits observed and some ofthe promising genotypes identified were LC 84 (plant height), AVPP 0512 (fruit set percentage), IC 363993 (days to first flowering and fruiting), EC 628901 (days to maturity of fruit), IC 561626 (fruit length), LC 111 (I) (fruit width), AVPP 905 (fruit weight), LC 10/2 (fruits per plant and fruit yield per plant) and LC 23 (dry matter content). High genotypic coefficient ofvariation and phenotypic coefficient of variation was observed for several traits, including fruit width, fruit wall thickness, fruit length, fruit yield per plant, fruit weight, fruits per plant, fruit set percentage, dry matter content, fruit bearing period, ascorbic acid content, capsaicin and oleoresin. Traits such as days to first flowering, days to fruiting, fruit width, fruit wall thickness, fruit bearing period, days to fruit maturity, fruit length, fruit width, fruit number, fruit yield, fruit set percentage, ascorbic acid, capsaicin and oleoresin exhibited both high heritability and high genetic advance. Hence, these chara cters can be im pro ved by selection as it show ed additive inherita nce. T he chara cters nam ely fru its pe r plant, fru it beari ng pe riod , fru it w eight, plan t heigh t and fru it set percentage show ed a signi fi cant positive dir ect infl uence on fru it yield per plant and sign ifi cant po sitive corr elation at the genotyp ic level. T herefo re, selectin g the genotyp es based on these tr aits w ould be effective in cro p im pro vem ent pro gr amm es targeting the yield. T he genetic diversity ana lysis identifi ed nin e distinct cl usters am ong the 94 genotyp es. C luster VIll , w ith 20 genoty pes, w as the largest and the sm allest w as cl uster IX w ith tw o genotyp es. T he sm allest inter cluster distance w as fo und betw een the clusters V II and vm, indicating close genetic relationships. The largest inter-cluster distance was observed between clusters V and IX, suggesting that genotypes from these clusters might provide valuable genetic diversity for breeding programs aimed at heterotic progeny. The genotypes were also ranked based on the economic characters to identify the best performers. In the field evaluation, twelve genotypes were found resistant to leaf curl virus and thirty-four genotypes showed moderate resistance to leaf curl virus. Whereas, for bacterial wilt, most of the genotypes were found resistant, it may be due to the lack of bacterial inoculum in the soil. Further, the genotypes identified from the parental screening were tested under artificial inoculation conditions to assess their reaction to both diseases. In the artificial screening, five genotypes were found resistant and five were found moderately resistant to bacterial wilt. With respect to leaf curl virus, ten genotypes were found moderately resistant, eight were moderately susceptible, and sixteen were classified as susceptible. Accordingly, the high yielding genotypes namely LC 10/1, LC 10/5, AVPP 0105, Ujwala, Chivar I and EC 566920 that got favourable ranking and demonstrated resistant reactions were selected as parents for subsequent hybridization programme. Eighteen F, hybrids were developed by crossing the bacterial wilt resistant lines vi:::., Ujwala, Chivar 1 and EC 566920 and moderately resistant leaf curl genotypes, LC 10/5, LC 10/1 and AVPP 0105 in partial diallel design and the hybrids were evaluated in open field and rain shelter for vegetative traits, yield, and disease resistance. Based on the per se performance in open field, several hybrids showed superior agronomic traits, such as Ujwala x AVPP 0105 for plant height, Chivar I x LC 10/1 for days to first flowering, AVPP 0105 x Ujwala for fruit length, EC 566920 x AVPP 0105 for fru it w idth, C hivar 1 x LC 10 /5 fo r fru its per plant and A VP P O 10 5 x EC 566920 fo r fruit weight and yield per plant. On estimation of heterosis in field evaluation, high estimates of Standard Heterosis (SH) and Heterobeltiosis (HB) was exhibited by the hybrids AVPP 0105 x Ujwala for fruit length, EC 566920 LC 10/5 for fruit wall thickness and Chivar 1 x LC 10/5 for fruit number. A high estimate of all the three heterosis was found in the hybrids, AVPP O 105 x EC 566920, LC 10/5 x Ujwala and LC IO /I x Chivar I for fruit weight and the AVPP 0105 EC 566920 exhibited highest heterosis for yield per plant. In rain shelter, the best hybrid found was Chivar l x LC IO/I for plant height, EC 566920 AVPP 0105 for fiuit set percentage, LC 10/5 EC 566920 for fruit length, EC 566920 x AVPP O I 05 for fruit width, LC I 0/5 x Chivar I for fruit weight, LC 10/5 EC 566920 for fruits per plant and fruit yield per plant. A high estimates of SH for fruit length, fruit number and fruit yield were exhibited by the hybrid LC 10/5 x EC 566920. While the hybrids LC 10/5 Chivar I exhibited high estimates for three types of heterosis for fruit weight. Combining ability analysis revealed that in open field, Ujwala and LC 10/5 were good combiners for fruit yield and fruit number per plant. Other good combiners included EC 566920 for fruit length and LC I 0/5 for fruit weight. In rain shelter, the parent LC 10/5 was identified as good combiner for fruit yield and fruit weight, LC 10/5 and Ujwala for fruits per plant, EC 566920 and AVPP 0105 were found to be good combiners for fruit length. The specific combining ability of the hybrids showed that significant positive SCA effects for fruit yield per plant was exhibited by the hybrid AVPP 0105 x EC 566920 (135.93) being the highest followed by Chivar 1 x LC 10/5 (72.42), AVPP 0105 Ujwala (57.49), LC 10/5 Chivar 1 (16.25) and LC 10/1 Chivar 1(15.54) in open field. While, the cross LC 10/1 x Ujwala showed the highest significant SCA for fruit yield per plant (70.49) followed by the crosses Chivar 1 x LC 10/5 (60.90), LC 10/5 x EC 566920 (57.67), Ujwala x AVPP 0105 (47.19), AVPP 0105 x EC 566920 (15.99) and Chivar I x LC 10/1 (14.91) in rain shelter. Four crosses namely AVPP 0105 x EC 566920 (21.46), Chivar 1 x LC 10/5 (17.25), AVPP 0105 x Ujwala (4.95) and LC 10/5 x EC 566920 (2.86) showed significant positive SCA for the trait fruit number per plant in open field condition and the crosses LC 10/5 EC 566920 (17.58), Chivar 1 x LC 10/5 (15.38), Ujwala x AVPP 0105 (10.54), AVPP 0105 x EC 566920(6.56), LC 10/1 x Ujwala (5.81) and Ujwala x 10/5 (5.55) showed significant positive SCA for fruit number in rain shelter condition The performance ofhybrids towards bacterial wilt resistance showed that three hybrids (LC 10/5 x Ujwala, AVPP 0105 x Ujwala and AVPP 0105 x EC 566920) were found resistant and five hybrids viz., Ujwala LC 10/5, Chivar I LC 10/5, Chivar I x AVPP 0I05, EC 566920 x AVPP 0105, LC IO /1 x EC 566920 were moderately resistant. No hybrids showed resistance to leaf curl virus but seven hybrids namely Ujwala LC 10/5, Ujwala LC 10 /1, Ujwala AVPP 0105, Chivar 1 LC 10 /I, Chivar I x AVPP 0105, LC IO /I x Ujwala, LC IO /I x Chivar I exhibited moderate susceptibility in both field and rain shelter evaluations to leaf curl resistance. Molecular characterization of the hybrids for disease resistance was done with the reported SSR marker CAMS 451 for bacterial wilt resistance and SSR markers viz., CA 516044 and PAU-LC-343-1 for leaf curl virus resistance after its validation in parental lines. The bacterial wilt marker was found positive in the hybrids Ujwala x LC 10/5, Ujwala x AVPP O I 05, Chivar I x LC 10/5, Chivar I x AVPP 0105, LC 10/5 x Ujwala, LC 10/5 Chivar I, LC 10/5 x EC 566920, AVPP 0105 Ujwala, AVPP 0105 Chivar I and AVPP 0105 EC 566920. The leaf curl virus marker PAU-LC-343-1 only showed polymorphism between resistant and susceptible parental lines and it was found positive for the hybrids AVPP 0105 Ujwala, Ujwala LC 10/5, LC 10/5 Ujwala, Chivar 1 Ujwala, LC 10 /1 Ujwala, Chivar 1 LC 10/5, LC 10/5 EC 566920, Ujwala x Chivar I, Ujwala AVPPO I 05, LC 10/5 Chivar t, LC I 0/5 x EC 566920 which indicated the presence of the leaf curl virus resistant gene though they were found moderately susceptible in phenotypic evaluation. Out of the eighteen hybrids evaluated, seven hybrids viz., Ujwala x LC 10/5, Ujwala x AVPP 0105, Chivar l x LC 10/5, LC 10/5 x Ujwala, LC 10/5 Chivar 1, LC 10/5 x EC 566920 and AVPP 0105 x Ujwala showed positive results for both bacterial wilt and leaf curl virus markers, indicating the presence of the respective resistant genes. In addition to their disease resistance, these hybrids also demonstrated superior field performance, making them promising candidates for further development. Therefore, the present study could identify high-yielding hybrids with improved resistance to bacterial wilt and leaf curl virus resistance. Several hybrids demonstrated high levels of heterosis for fruit yield which explains the dominant gene action prim ari ly infl uences th is tr ait. T he G C A an d SC A variances w ere signi fi can t fo r all the char acters exam in ed in the stu dy. T his highl ights the signi fi cance of both additive and non-additive vari ance in expressing these tra its, suggestin g tha t integr ated breedin g stra tegies such as hybrid developm ent and pur e lin e breeding should be em ployed to effectively harn ess bo th typ es of genetic variability . Th e pro mi sing parents identifi ed in the stu dy w ill se rve as valuable genetic resour ces fo r tra it-specifi c cro p im pro vem ent pro gra m m es in chili. T he identifi ed hybri ds can be fu rt her advanced to success ive genera tions to validate resistance and the supe rior hybri ds can be selected fo r advanced yield trials.Item Development of gynoecious genotypes with superior fruit quality in bitter gourd (Momordica Charantia L.) through marker assisted breeding(Department of Vegetable Science, College of Agriculture ,Vellanikkara, 2024-02-06) Anju M Sunny.; Pradeepkumar, TThe doctoral study entitled ‘Development of gynoecious genotypes with superior fruit quality in bitter gourd (Momordica charantia L.) through marker assisted breeding’ was undertaken with the objective of developing gynoecious bitter gourd lines with superior fruit quality through marker assisted breeding and to analyze the genetics of sex expression and fruit quality by generating F2 and back cross population. The work was carried out in the experimental field of the Department of Vegetable Science, College of Agriculture, Vellanikkara. Gynoecious line KAUMCGy- 101, identified from the Department of Vegetable Science, and three monoecious lines viz., Preethi, Priyanka, and MC 133 were used for the hybridization. Six hybrids were produced by crossing gynoecious inbred as both male and female parents. The hybrids were, Preethi × KAU-MCGy-101, Priyanka × KAUMCGy- 101, MC133 × KAU-MCGy-101, KAU-MCGy-101 × Preethi, KAU-MCGy- 101 × Priyanka and KAU-MCGy-101 × MC133. All the hybrids with gynoecious line as male or female parent exhibited high heterosis for earliness attributing traits like days to first female flower opening, node bearing first female flower, and days to first harvest. The traits such as a lower sex ratio and a greater number of fruits per plant contributed to higher yields in these hybrids. The superiority of hybrids having a gynoecious line as a maternal parent is prominent in the present study. The correlation studies revealed a positive correlation between fruit length (0.569), fruit weight (0.612), number of seeds (0.507), and number of harvests (0.619) with yield. While days to first female flower opening (-0.386), node bearing first female flower (-0.244), fruit girth (-0.018), and days to first harvest (-0.285) showed a non-significant negative correlation. Path analysis showed a positive direct effect of fruit weight (0.568), fruit girth (0.155), number of seeds (0.579), days to first harvest (0.009), number of harvests (0.755), and number of fruits per plant (0.036) on yield per plant. The sensory attributes, nutritional potentials, and shelf life of six bitter gourd hybrids and their parents were evaluated. Bitter gourd fruits with white or light green fruits were found to have a more appealing flavor and appearance than dark green fruits, resulting in a higher overall acceptability rating. The hybrid, KAU-MCGy-101 × MC 133 was found superior with 17.05 mg/100g calcium. Preethi and KAUMCGy- 101 × Priyanka exhibited maximum shelf life among the parents and hybrids, respectively. Among the hybrids, the cross KAU-MCGy-101 × Priyanka was superior with respect to yield and quality traits (fruit weight- 172.47 g, number of fruits per plant- 69.67 and yield per plant- 9.15 kg). The genetics of economically significant horticultural traits in the cross KAU-MCGy-101 x Priyanka was studied resorting generation mean analysis. The results of the A, B, C, and D scaling tests indicate that all the traits, except for days to the first female flower opening, do not adhere to an additive dominance model. The significant and positive additive effect (d) was observed for the number of tubercles and number of fruits per plant, indicating that the additive effect of the genes is predominant and that the selection of these traits should be delayed to later generations. Regarding the yield, the interaction effect of dominance x dominance (l) was highly significant, while the other interaction effects were insignificant. Therefore, recurrent selection is necessary for improving this trait. A complementary type of epistasis was observed for the number of fruits per plant, while all other traits were observed to be of the duplicate type. The χ2 analysis for goodness of fit indicated that gynoecy in the line KAUMCGy- 101 is controlled by a single recessive gene (gy-1). The inheritance pattern of fruit color indicates that green fruit color is dominant over white. The present study identified two gynoecious lines from the F2 population namely, KAU-MCGy-101-1 and KAU-MCGy-101-2 (green and light green fruited respectively). These gynoecious lines had better fruit quality and hold immense potential for future breeding programs in bitter gourd improvement. Marker-assisted selection is considered one of the important strategies for identifying different sex forms in crop plants. The present investigation resulted in identifying one SNP primer that could produce polymorphism between the monoecious and gynoecious parents. The six exonic regions with flanking introns of the gene floral homeotic protein AGAMOUS-like (McAG2) and two exonic regions with flanking introns of the gene ACO1 were sequenced by designing exons-specific primer pairs. The primer NETBG2 developed based on the exon 2 region of the gene ACO1 accounts for eight valid SNPs within the sequenced region of the gynoecious parent used in this study. The study confirmed the monogenic recessive nature of gynoecy. The improved gynoecious lines identified will help in developing cultivars with a higher proportion of female flowers. The results of the molecular work revealed the role of the 1-aminocyclopropane-1-carboxylate oxidase (ACO1) gene in the sex expression of the bitter gourd. The SNPs identified can be used for further studies on the SNP-based marker development for identifying gynoecious plants and have the potential in marker assisted breeding based on gynoecy in bitter gourd.Item Influence of rootstocks on yield, quality and bacterial wilt resistance in F1 hybrids of Tomato(Department of Vegetable Science, College of Agriculture,Vellanikkara, 2024-05-21) Remzeena, A.; Anitha, PTomato production in the tropics and subtropics is often hampered by the incidence of various pests and diseases. Among these, bacterial wilt caused by the soil-borne bacteria Ralstonia solanacearum poses a significant problem for tomato growers in Kerala. The warm, humid, tropical climate and acidic soil conditions prevailing in the state provide a favorable environment for wide spread occurrence of bacterial wilt in the state. Growing resistant varieties have been identified as one of the most effective management strategy. However, the development of bacterial wilt-resistant varieties or hybrids is challenging due to the quantitative nature of the trait, its linkage to small fruit size, and the diversity of pathogen strains. Therefore, an effective alternative is grafting tomato cultivars having high production potential onto bacterial wilt resistant rootstocks. In addition to providing complete resistance to bacterial wilt, grafting also helps in harnessing improved yield. In this context, the present study was undertaken with the objectives of identifying bacterial wilt-resistant rootstocks for tomatoes, evaluating the performance of the grafts for yield, quality, and bacterial wilt resistance, and determining their suitability for growing in the rainshelter. In experiment 1, ten F1 hybrids of tomato were collected and evaluated in sterilized medium for their yield and quality. Hybrids exhibited significant variation for yield and quality traits. Among the hybrids significantly high plant height was exhibited by Arka Apeksha. Days to flowering and harvest was minimum in Lakshmi. Arka Rakshak exhibited highest root length and spread followed by Arka Apeksha. Average fruit weight was significantly high in Arka Abhed (97.56g) followed by Arka Samrat (89.68g). Lakshmi recorded significantly highest fruit yield per plant (3.28 kg) which was on par with Arka Samrat (2.86 kg) and Arka Abhed (2.78 kg) followed by Arka Rakshak (2.65 kg), Sampurna (2.62 kg) and Arka Apeksha (2.59 kg). Fruit quality traits such as lycopene, vitamin C, TSS was the highest in Arka Apeksha. Sampurna recorded the highest acidity and total phenol was the highest in COTH3. NSC 620B recorded the highest Orthodihydroxy (OD) phenol and the lowest solasodine content was recorded in Arka Apeksha. Among the hybrids the highest bacterial incidence was recorded in Shivam (72.50 %) and the hybrid Arka Abhed recorded zero per cent incidence. Tomato Leaf Curl Virus (ToLCV) incidence was highest in COTH3 whereas, six hybrids Lakshmi, Sampurna, Arka Rakshak, Arka Abhed, Arka Samrat and Arka Apeksha was completely free from ToLCV incidence. In the experiment 2, six high yielding tomato hybrids from the experiment 1 (Lakshmi, Arka Samrat, Arka Abhed, Arka Rakshak, Sampurna and Arka Apeksha) were grafted on four brinjal rootstocks viz., Surya, Haritha, SM 3, SM 116 and two Solanum torvum rootstocks (KAU-1and TNAU-1). These grafts were evaluated for their yield, quality and bacterial wilt resistance in bacterial wilt sick field. Plant height, girth of graft (60 DAP), root length and spread, average fruit weight were significantly improved in the grafted plants compared to their non-grafted controls. The highest plant height was recorded in the grafts on SM 116 and Haritha and the lowest plant height was recorded on SM 3 irrespective of the scion. Girth of graft was significantly high when grafted on Haritha in all the hybrids which was followed by the grafts on Surya. Root length and spread were also significantly high in grafts on Haritha followed by the grafts on Solanum torvum rootstocks. Grafts on Haritha recorded the highest overall average fruit weight which was on par with the grafts on Surya. Days to flowering and days to harvest were delayed in the grafted plants compared to the non-grafted controls. However, significant improvement was recorded in the crop duration of grafted plants compared to non-grafts. Fruit yield was significantly improved compared to non-graft control on Haritha, Surya and SM 116 in all the hybrids. Arka Rakshak (4.17 kg) , Lakshmi (3.98 kg), Arka Samrat (3.85 kg), Arka Abhed (3.83 kg) and Arka Apeksha (3.76 kg) exhibited highest fruit yield per plant on Haritha, whereas, Sampurna showed the highest fruit yield per plant on Surya (3.75 kg). Among the 36 graft combinations, Arka Rakshak, Lakshmi, Arka Samrat, Arka Abhed, Arka Apeksha grafted on Haritha and Arka Rakshak, Sampurna, Lakshmi on Surya recorded the highest yield per plant and performed on par with each other. Total Soluble Solids (TSS) of the fruits of grafted plants were on par with that of non-grafted control in all hybrids. Acidity increased in the fruits of grafts compared to the non-grafts. Lycopene content of the grafts were on par with non-grafted control except in the grafts of Sampurna on Haritha and Solanum torvum rootstocks. Fruits of grafted plants also recorded a decrease in vitamin C compared to non-grafted control. However, vitamin C content of fruits of grafts on Haritha and Surya were on par with that of the non-grafted control in all the hybrids except Lakshmi. Total Phenol, OD Phenol and Solasodine content increased significantly in grafted plants compared to non-grafted control. Sensory evaluation of fruits of grafted and non-grafted plants indicated only non-significant difference between grafts and non-grafted control. Overall acceptability was similar or higher in grafts compared to non-grafts except in the grafts of Lakshmi and Sampurna on Solanum torvum rootstocks. Grafts on the brinjal rootstocks Surya, Haritha, SM3 and SM 116 recorded zero percent incidence of bacterial wilt. Whereas grafts on Solanum torvum rootstocks (TNAU- 1 and KAU- 1) recorded 6.67-13.33 per cent incidence. Rootstocks did not influenced the ToLCV incidence of the scion as ToLCV incidence was recorded in both grafts and nongrafted controls. Anatomical studies of graft union revealed the formation of thick callus and establishment of vascular connection between stock and scion in the form of vascular bridges at 20 DAP planting. At 40 DAP, differentiation of vascular tissues were initiated in all the grafts and 60 DAP well established vascular connections were observed. Callus thickness and cell wall thickness generally reduced whereas dimensions of xylem vessel and phloem tissue increased from 20 DAP to 60 DAP in all the grafts. In the experiment 3, eight high yielding hybrids identified from experiment 2 were evaluated in rainshelter during rainy season for yield and quality. Compared to open field, plant height, average fruit weight, crop duration and yield of the grafts generally increased inside the rainshelter. However, the days to flowering, days to first harvest, TSS and acidity of grafts reduced compared to open field. There was significant variation among the grafts for yield and quality when grown inside rainshelter. Arka Apeksha on Haritha recorded the highest plant height among the grafts. Arka Abhed on Haritha recorded the highest average fruit weight, fruit yield and crop duration (120.47g, 4.49kg, 167.20 days) which was on par with Arka Samrat on Haritha (117.78g, 4.33kg, 167.80 days). The highest TSS was recorded in the graft of Arka Apeksha on Haritha and acidity was highest in Sampurna on Surya. None of the grafts recorded bacterial wilt incidence when grown inside rainshelter. ToLCV incidence was highest in Arka Samrat on Haritha and Arka Rakshak on Surya whereas, Sampurna on Surya and Arka Abhed and Lakshmi on Haritha recorded zero per cent incidence. Economic analysis was performed for growing the grafts inside rainshelter and the graft of Arka Abhed on Haritha recorded the highest B:C ratio of 2.03. All the grafts realized a B:C ratio greater than 1.50 indicating the economic viability of growing grafts inside rainshelter. From the study, it can be concluded that grafting is an economic, effective and quick method for the management of bacterial wilt and the brinjal rootstocks used in the study can be successfully utilized for grafting tomatoes when grown in bacterial wilt affected areas. Apart from imparting resistance they also enhanced the yield of the tomato hybrids without impairing the fruit quality.Item Generation mean analysis in yard long bean (Vigna unguiculata subsp.sesquipedalis (L.) Verdcourt) for yield and mosaic resistance(Vegetable Science, College of Agriculture, Vellayani, 2024-02-13) Airina, C K.; KAU; Sarada, SThe present study ‘Generation mean analysis in yard long bean (Vigna unguiculata subsp. sesquipedalis (L.) Verdcourt) for yield and mosaic resistance ' was undertaken at the department of Vegetable Science, College of Agriculture, Vellayani, Thiruvananthapuram during 2017-2019 and at Pepper Research Station, Panniyur, Kannur during 2022-23 to develop high yielding and mosaic resistant yard long bean hybrids and to study the inheritance and gene action of yield and mosaic resistance using generation mean analysis. Seventy six cowpea genotypes were screened against the blackeye cowpea mosaic virus (BlCMV) to ascertain the disease reaction of the genotypes by artificial inoculation under pot culture method. Based on the extent of symptoms and vulnerability index (VI), three genotypes were found highly resistant, 11 genotypes showed resistant response, 13 genotypes were moderately resistant, 10 genotypes moderately susceptible, 20 genotypes susceptible and remaining 18 genotypes showed a highly susceptible reaction. The genotypes Manjari, VU-7 and EC-18734 were highly resistant to BlCMV. Five high yielding yard long bean genotypes viz; Vellayani Jyothika, Vyjayanthi, Geethika, KAU Deepika, and KAU Mithra which gave a susceptible response were selected as lines and three genotypes, viz. Manjari, VU-7 and EC-18734, which gave an immune response as testers for the development of 15 hybrids in a line x tester fashion. The hybrids and their eight parents were raised with a standard variety Lola and resistant check Manjari in a randomized block design with three replications in open field in Rabi 2022 and were tested for 19 yield characters and mosaic resistance. The mean squares due to parents were highly significant for all the characters, while for hybrids significant difference was observed for all the characters except pod girth and yield per plot. The PCV values for all the characters were found to be higher than the GCV values but in smaller magnitude, which implied a lesser influence of environmental factors for these characters. The PCV and GCV values ranged from 3.31 to 52.80 and 2.06 to 51.68, respectively. Heritability estimates expressed in percentage ranged from 26.00 % to 97.80 % and estimates of genetic advance ranged from 2.63 to 104. The genotypic correlation coefficients were higher in magnitude than that of phenotypic correlation coefficients for most of the traits under study, which clearly indicated the presence of inherent association among various characters. For yield per plant, significant positive correlation was estimated with vine length, pod length and pod weight, whereas significant negative correlation with branches per plant, days to first flowering and days to harvest. Significant GCA effects were recorded for all the characters except pod girth. Among the lines, KAU Deepika showed good general combining ability for days to first flowering, pod length, pod weight, 100 seed weight, yield per plant, yield per plot, days to harvest and keeping quality and among the testers, Manjari exhibited good GCA effect for vine length, pod length, pod weight, seeds per pod, pods per plant, yield per plant, yield per plot and keeping quality. Significant SCA effects were observed for 13 quantitative characters viz; vine length, primary branches per plant, terminal leaf length, terminal leaf width, lateral leaf length, lateral leaf width, days to first flowering, pod length, pod weight, 100 seed weight, and days to harvest, pod protein and keeping quality. Vyjayanthi x EC 18734, KAU Deepika x Manjari and KAU Mithra x Manjari were good specific combiners for pod weight and Vellayani Jyothika x EC 18734, Vyjayanthi x EC 18734, Githika x VU7 and KAU Deepika x Manjari for 100 seed weight. Desirable significant standard heterosis has been identified for 12 characters studied viz; no. of branches per plant, terminal leaf width, lateral leaf width, days to first flowering, days to harvest, pod weight, pods per plant, yield per plant, yield per plot, 100 seed weight, pod protein content and keeping quality. The crosses KAU Deepika x Manjari and KAU Mithra x Manjari registered significant positive heterosis over mid, better, and standard parents for pod yield and high mid-parent heterosis and standard heterosis for pods per plant. The highest magnitude of standard heterosis was identified for pods per plant (101.14 %), followed by yield per plant (75.30 %). Besides the heterotic potential, the hybrid KAU Mithra x Manjari, KAU Deepika x Manjari and Githika x Manjari were resistant to mosaic disease. In field evaluation during Rabi 2022, among the three testers, Manjari alone exhibited an immune response (VI-0.00) for mosaic disease. Other major pests and diseases observed in the field were pod borer, pod bug, fusarium wilt and anthracnose. The three crosses Githika x Manjari, KAU Deepika x Manjari and KAU Mithra x Manjari were selected and six generations i.e. P1, P2, F1, F2, BC1 and BC2 of each cross were evaluated under open field conditions to study the inheritance and gene action of mosaic resistance and yield parameters. For mosaic resistance, the scaling tests were non-significant which implied that additive-dominance model was adequate in Cross I and II, while dominance x dominance epistasis was prominent in cross III. Predominance of dominant gene action was noticed in cross II and III for yield per plant, while dominance x dominance (l) action in cross I. Duplicate type of epistasis was also observed in cross I and III for the trait. Epistatic interactions were observed for all the characters, except vine length and number of branches per plant in cross I (Githika x Manjari), additive x dominance being prominent in most of the traits. Predominance of dominant gene or dominance x dominance (l) interaction was noticed in majority of the traits in cross II ( KAU Deepika x Manjari). Significance of both additive x additive (i) component and dominance x dominance component or either one of the component was identified for the inheritance of yield traits in cross III (KAU Mithra x Manjari). Duplicate type of epistasis was revealed for eleven characters viz; vine length, terminal leaf length, lateral leaf length, days to flowering, pod girth, pod weight, hundred seed weight, yield per plant, crop duration, protein content and keeping quality, of which eight were present in cross II. The yard long bean hybrid KAU Deepika x Manjari, with good general combining ability for yield characters, high heterotic potential, high yield and mosaic resistance was identified as the best cross from the study.Item Breeding yard long bean(Vigna unguiculata subsp.sesquipedalis (L.) Verdcourt) for anthracnose resistance through conventional and molecular marker analysis(Department of Vegetable Science, College of Agriculture ,Vellayani, 2022-12-30) Merin Elza George; Sarada, SThe study entitled ―Breeding yard long bean (Vigna unguiculata subsp. sesquipedalis (L.) Verdcourt) for anthracnose resistance through conventional and molecular marker analysis‖ was carried out at the Department of Vegetable Science, College of Agriculture, Vellayani, Thiruvananthapuram, Kerala, during 2019-2022. The objective of the study was to identify molecular marker(s) linked with anthracnose disease resistance in the F2 segregating population of yard long bean, using bulk segregant analysis to enable marker assisted selection along with conventional breeding. The study was undertaken in six experiments. In experiment I, 50 genotypes of vegetable cowpea collected from different parts of India, including the released varieties of SAUs and ICAR institutes were screened against the most virulent isolate of Colletotricum gloeosporioides through artificial inoculation. Among the 50 genotypes tested, VU 53, with semi-trailing growth habit was found to be highly resistant with disease severity of 3.67 ± 0.13 %. Three susceptible, high yielding long podded varieties viz., KAU Deepika, Vellayani Jyothika and Githika, selected as female parents were crossed with VU 53, the most resistant genotype as male parent for the development of three hybrids. In experiment II, two crossing blocks were laid to produce the seeds of three hybrids and their F2 progenies. The three hybrids were evaluated along with the parents under replicated trial in the main field for trailing nature, yield and quality in experiment III. Significant variation was noticed on mean performance of yard long bean parents and hybrids for most of the characters studied. Earliest flowering was observed in KAU Deepika x VU 53 (57.33 ± 0.57 days) and delayed flowering in Githika x VU 53 (71.66 ± 1.15 days). Among the hybrids, the highest pod length was recorded in KAU Deepika x VU 53 (24.50 ± 1.00 cm), while the Vellayani Jyothika x VU 53 had the maximum pod girth (2.90 ± 0.10 cm). Maximum pod weight and pods per plant was recorded in KAU Deepika x VU 53 (19.22 ± 0.58 g and 79.33 ± 0.59 respectively) among hybrids. The cross Vellayani Jyothika x VU 53 (16.55 ± 0.20 g) exhibited maximum seed weight. Among the three hybrids, KAU Deepika x VU 53 (1416.00 ± 126.09 g) recorded the highest yield per plant and was on par with Githika x VU 53 (1343.33 ± 75.06 g). Among the hybrids, KAU Deepika x VU 53 (67.85 ± 0.96 days) was significantly superior for days to harvest. The longest duration among hybrids was observed in KAU Deepika x VU 53 (126.56 ± 0.37 days) and the shortest duration was recorded in Vellayani Jyothika x VU 53 (121.31 ± 0.58 days). High heritability and genetic advance was recorded for vine length, days to first flowering, pod length, pod weight, pods per plant, yield per plant, yield per plot, hundred seed weight and keeping quality. Yield per plant had significant positive phenotypic and genotypic correlation with pod weight, followed by pods per plant, length of terminal leaf, seeds per pod, pod length, crop duration, keeping quality and days to harvest. Pods per plant could be considered as the most important yield trait for enhancing the yield in yard long bean because of its high, positive correlation and direct effect with yield per plant along with high heritability and genetic advance. In experiment IV, parents, three hybrids and F2 progenies were evaluated for resistance to natural incidence of C. gloeosporioides in the main field, as unreplicated trial and without any plant protection measures. All the three F1 were found to be field tolerant. Out of 175 F2 plants of the cross KAU Deepika x VU 53, 164 plants were susceptible and 11 were resistant. In the case of Vellayani Jyothika x VU 53, 175 plants were susceptible among the 187 individual F2 progenies observed. Similarly, in the cross Githika x VU 53, 188 plants were susceptible while 12 plants were found to be symptomless. The F2 progenies of the high yielding hybrid KAU Deepika x VU 53 were evaluated for resistance to C. gloeosporioides through artificial inoculation in experiment V. Out of 196 plants, 185 plants were found to be susceptible whereas 11 plants were resistant which could be utilized in marker assisted breeding programme. The segregation for anthracnose resistance in F2 plants was in the ratio 15:1 (185 susceptible plants out of 196), which suggests that the inheritance of anthracnose resistance may be controlled by two recessive genes. Bulked segregant analysis was done using the DNA from the resistant parent, susceptible parent, resistant F2 bulk and susceptible F2 bulk in experiment VI. Bulked segregant analysis with the SSR primer CLM0008 revealed a polymorphic band at ≈ 300 bp which was appeared in the resistant parent and bulk. Bulked segregant analysis with ISSR primer UBC 811 produced polymorphic bands at ≈ 1100 bp, which were present in resistant parent and resistant bulks. The identified markers linked with resistance were validated over the resistant F2 lines obtained.Item Breeding hotset indeterminate tomato (Solanumlycopersicum L.) resistant to bacterial wilt suitable for protected cultivation(Department of Vegetable Science, College of Agriculture, Vellanikkara, 2021) Archana, K A; Pradeep Kumar, TThe present investigation was undertaken to develop an indeterminate hotset tomato with bacterial wilt resistance through line × tester analysis. The experiment was conducted at the Department of Vegetable Science, College of Agriculture, Vellanikkara, Kerala Agricultural University, during the year 2018- 2020. The first experiment was the performance evaluation of 35 tomato genotypes for two seasons in the year 2018, summer evaluation from January 2018 and rainy season evaluation from July 2018, in two protected structures viz., polyhouse and rainshelter. Genotypes exhibited significant variation for vegetative, flowering, fruit, yield and biochemical traits under both growing structures across season. Under polyhouse during summer the genotypes EC- 164263, EC-620387, EC-620401, EC-620406, EC-620410, and EC-620417 performed better for hotset traits (flowers with exerted stigma, pollen viability and fruit set per cent) and yield traits (average fruit weight, number of fruits per plant and yield). In rainshelter, the genotypes EC-165395, EC-165690, EC- 538153, EC-620401, EC-620406, EC-620410 were superior. During rainy season, EC-164263, EC-538153, EC-620401, EC-620406, EC-620410, EC-631369 were superior under polyhouse, and EC-620395, EC-620401, EC-620406, EC-620410, EC-631369 and EC-631379 inside rainshelter, for hotset traits and yield traits. The pooled data of flowers with exerted stigma, pollen viability, fruit set per cent, number of fruits per cluster, days to first fruit set, average fruit weight, pericarp thickness, number of fruits per plant and yield per plant were subjected to multivariate analysis for discrimination of genotypes into clusters. Under polyhouse seven clusters and inside rainshelter five clusters were observed. The selection index was also applied for ranking of genotypes based on the hotset distinctions and yield attributes. The hotset genotypes with high yield potential, identified suitable for protected cultivation were EC-164263, EC-538153, EC- 620387, EC-620389, EC-620401, EC-620406, EC-620410, EC-620417 and EC-631369. The genotypes EC-620401 (1), EC-620406 (2) and EC-620410 (3) were selected as hotset line for the line × tester analysis. In the second experiment the genotypes were tested for bacterial wilt resistance. The 35 tomato genotypes were sown in 98 well pro-trays holding sterilised soil medium. Another set of pro-trays holding the same medium were drenched with bacterial suspension with OD adjusted 0.8 to 1.3 at 600 nm and kept as the sick pro-trays. The twenty-one days old seedlings were used for inoculation through root dip method. With the help of sterilized scissors the tertiary roots of the seedlings were sectioned. The root clipped seedlings were dipped in bacterial suspension for thirty minutes. The inoculated seedlings were transplanted in the sick pro-trays. The entire experiment was conducted inside rainshelter with three replications. Each replication had five plants per genotype. Periodical observation on bacterial wilt symptom expression was taken from third day onwards. The disease index has revealed EC-620382 (0.20) and Arka Abha (0.20) as highly resistant. Nine genotypes viz: EC-165395 (0.24), EC-165700 (0.25), EC-521067 B (0.25), EC-620376 (0.30), EC-620378 (0.28), EC-620427 (0.21), EC-620429 (0.23), Akshay (0.21), Anagha (0.28) were resistant. From these EC-620382 (4), EC-620427 (5), EC-620429 (6) and Arka Abha (7) were selected as testers. In the third experiment, the identified lines and testers were crossed and seeds were collected for twelve cross combinations. The fourth experiment was the evaluation of F 1 hybrids from third experiment during summer in two protected structures viz., polyhouse and rainshelter. The cross combinations were laid along with the parents and two checks viz., one check hybrid (Abhilash) and one check variety (Akshaya). The mean performance, relative heterosis (RH), heterobeltosis (HB), standard heterosis (SH) and combining ability studies were conducted. For vegetative traits, the cross combination 3 × 7 exhibited superiority in the mean performance with significant positive sca effects in both the structures. For flowering traits, the cross 2 × 5 exhibited significant positive sca effects for pollen viability and significant negative sca effects for flowers withexerted stigma with significant RH, HB and SH in both the structures. In the case of fruit and yield traits, the cross combination 2 × 5 exhibited negative significant sca effects for days to first fruit set and positive significant sca effects for pericarp thickness, average fruit weight and yield per plant with significant RH, HB and SH. Inside rainshelter, 3 × 5 and 3 × 7 noted significant sca effects and positive significant heterosis for fruit and yield traits. For biochemical traits, the cross combination 2 × 5 exhibited positive significant sca effects and positive significant RH, HB and SH for TSS, ascorbic acid and acidity under polyhouse. In the seedling stage, all cross combinations exhibited resistance reaction to bacterial wilt in the challenge inoculation. Depending on the mean performance, heterosis and sca effects, the cross combination 2 × 5 was recommended for polyhouse and the crosses 3 × 5 and 3 × 7 were recommended for rainshelter. None of the parents revealed significant and desirable gca effect for all traits studied. The comprehensive assessment of the parents by considering gca estimates revealed that among lines EC-620406 is a good general combiner for vegetative, fruit and yield characters under polyhouse, and EC-620406 and EC- 620410 could be regarded as good general combiners for vegetative, reproductive, fruit and yield, quality characters and shelf life inside rainshelter. In the case of testers EC-620427 and Arka Abha were good combiners for vegetative, reproductive, fruit characters and shelf life in both the growing structures. Dominant gene action was observed predominantly for characters studied under both the structures. Plant height at harvest, days to 50% flowering, days to first fruit set, days to first fruit harvest, number of fruits per plant, average fruit weight, yield per plant, yield per plot, lycopene, ascorbic acid, shelf life, flowers with exerted stigma, pollen viability, number of flowers per cluster, number of fruits per cluster and fruit set per cent exhibited dominant gene action under both the structures. Pericarp thickness exhibited complete dominance inside rainshelter.In the fifth experiment, available SSR markers were validated for bacterial wilt resistance. Two SSR markers, SLM6124 and SLM6-110, produced polymorphism between resistant and susceptible genotypes, two distinct bands for resistant genotypes and four bands (two distinct and two fainted) for susceptible genotypes. In conclusion, the work indicates the change in the behaviour of genotypes under different protected structures in different seasons. Hence the selection of genotype and structure depending on the season is important. The heterosis breeding is effective in improving hotset traits in tomato. The hybridisation involving one resistant parent can generate bacterial wilt resistant off-springs. The application of molecular markers can effectively reduce the time and labour intensive field evaluation.Item Breeding for yellow vein mosaic virus (YVMV) resistance in OKRA (Abelmoschus esculentus (L.) Moench)(Department of Vegetable Science, College of Horticulture, Vellanikkara, 2020) Alphy Mathew; Pradeepkumar, T