Browsing by Author "Ankitha, M O"

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Development and evaluation of high yielding, mosaic tolerant backcross progenies in bitter gourd (Momordica charantia L.) variety Preethi using morphological, biochemical and molecular markers
(Department of Genetics and Plant Breeding, College of Agriculture ,Vellayani, 2024-05-23) Ankitha, M O; KAU; Bindu, M R
The present research work entitled ‘Development and evaluation of high yielding, mosaic tolerant backcross progenies in bitter gourd (Momordica charantia L.) variety Preethi using morphological, biochemical and molecular markers’ was conducted in the Department of Plant Breeding and Genetics, College of Agriculture, Vellayani and Farming Systems Research Station (FSRS), Sadanandapuram during the year 2020-2023, with an objective to develop high yielding mosaic tolerant backcross progenies in bitter gourd using morphological, biochemical and molecular markers. Thirty three bitter gourd genotypes, including KAU released varieties (2 No’s), NBPGR accessions (13 No’s), and local collections from all over India were used for screening mosaic tolerance. Out of the 33 genotypes, 26 genotypes were Momordica charantia var. charantia and seven were Momordica charantia var. muricata. All these genotypes were artificially inoculated with the three viruses Cucumber Mosaic Virus (CMV), Tomato Leaf Curl New Delhi Virus (ToLCNDV) and Papaya Ringspot virus (PRSV) through wedge grafting. Wedge grafting was done using the infected plant shoots as scion and the collected genotypes as root stock and regrowth from the cotyledonary axis was examined for symptom expression. Out of the 33 genotypes screened, three were highly resistant, four were resistant, five were moderately resistant, six were moderately susceptible, ten were susceptible and five were highly susceptible. The genotypes Lodhi local, Udayagiri local and Therthali local recorded a lowest Vulnerability Index of zero. Molecular markers reported in Cucurbitaceae family were validated for bitter gourd mosaic resistance gene. SSR-11-1 marker for CMV resistance and CAPS marker for Potyvirus resistance gene were used, but no amplification was obtained. Double Antibody Sandwich ELISA (DAS-ELISA) was performed to confirm the resistance reaction of three highly resistant genotypes identified in seedling screening. Optical density (OD) value of the genotypes for the three viruses, CMV, ToLCNDV and PRSV were less than twice the OD value of the un-inoculated healthy plant which confirmed highly resistant disease reaction of genotypes. Molecular confirmation was done by using coat protein primer (Deng primer) specific to the Begomovirus group. Deng primer amplifies coat protein gene of ToLCNDV (520 bp), so that band will be present in only susceptible genotypes and will be absent in resistant ones. Plant defense related enzymes such as peroxidase, polyphenol oxidase and phenyl alanine ammonialyase was estimated and there was increased rate of synthesis of these enzymes in the identified resistant genotypes. So the identified resistant genotypes, Lodhi local, Udayagiri local and Therthali local were used as the donor parent for imparting mosaic resistance into the bitter gourd variety Preethi. Lodhi local is M. charantia var. charantia genotype where as both Udayagiri local and Therthali local are M. charantia var. muricata genotypes. High yielding variety released from KAU viz., ‘Preethi’ was selected as the recurrent parent in the study. Preethi was crossed with the three donor parents and F1s were produced. The F1s were morphologically evaluated with the parents for seventeen characters and it was observed that all the characters of F1 were approximately the average of two parents. All the F1s were backcrossed with Preethi to produce BC1F1 segregants. In the backcross progeny of the cross involving Preethi and Lodhi local, a total of 176 BC1F1 lines were developed. BC1F1 lines were artificially inoculated for their disease reaction. Among the 176 BC1F1 lines, 22 were found to be highly resistant to mosaic disease, 30 were resistant, 30 were moderately resistant, 26 were moderately susceptible, 35 were susceptible and 33 were highly susceptible. Confirmation of resistance was done using DAS- ELISA, Deng primers and estimation of defense enzymes. All the 17 biometrical characters were recorded and the Euclidean distance of the highly resistant BC1F1 lines from the recurrent parent Preethi was calculated using proximity dissimilarity matrix analysis. The 14 BC1F1 lines with high phenotypic similarity to Preethi was backcrossed to develop BC2F1 lines. In the backcross progeny of the cross involving Preethi and Udayagiri local, a total of 170 BC1F1 lines were produced. Among them 15 BC1F1 lines were highly resistant. Resistant reaction of identified 15 BC1F1 was confirmed by DAS-ELISA, molecular screening and biochemical analysis. Euclidean distance of the highly resistant 15 BC1F1 lines from the recurrent parent revealed that eight lines showed similarity with Preethi and they were backcrossed to get BC2F1 lines. A total 147 BC1F1 lines of the cross involving Preethi and Therthali local were screened at seedling stage. Out of the 147 lines, 16 BC1F1 lines were highly resistant. DAS-ELISA, molecular screening using aforementioned Deng primer confirmed the resistant reaction of these lines. Euclidean distance using biometric characters found that, out of 16 highly resistant BC1F1 lines eight lines had close proximity with Preethi. These lines were used to produce BC2F1 lines. The 190 BC2F1 lines of the cross involving Preethi and Lodhi local were screened at seedling stage and in 24 BC2F1 lines, there was absence of virus coat protein band which confirmed the highly resistant disease reaction of the aforementioned lines. The 12 BC2F1 lines with the shortest Euclidean distance and high phenotypic similarity with Preethi were selfed to generate BC2F2 seeds. In the 134 BC2F1 lines of the cross involving Preethi and Udayairi local, seedling screening recorded 17 highly resistant lines. After molecular confirmation of mosaic resistance four BC2F1 lines with close proximity to Preethi were selfed to get BC2F2 seeds. Out of the 143 BC2F1 lines of the cross involving Preethi and Therthali local, 20 BC2F1 lines were highly resistant. The molecular analysis of the 20 BC2F1 lines also confirmed the highly resistant reaction. Four BC2F1 lines with the shortest Euclidean distance was selected and selfed to produce BC2F2 seeds. Although there were BC2F2 seeds of three different crosses, only the BC2F2 seeds of the cross involving Preethi and Lodhi local was carried forward for further backcrossing. This is due to the low yield potential of the backcross progenies of the crosses involving M. charantia var. muricata genotypes. So 206 BC2F2 lines of the cross involving Preethi and Lodhi local were artificially screened at seedling stage for mosaic incidence. Out of the 206 BC2F2 lines, 42 plants were highly resistant to bitter gourd mosaic viruses. The 42 mosaic tolerant backcross inbred lines developed in the study can be carried forward for the development of a mosaic tolerant essentially derived variety (EDV) in the background of high yielding variety Preethi. The backcross progenies obtained in the crosses involving muricata genotypes can be further evaluated for its nutraceutical values.
Development and evaluation of high yielding, mosaic tolerant backcross progenies in bitter gourd (Momordica charantia L.) variety Preethi using morphological, biochemical and molecular markers
(Department of Genetics and Plant Breeding, College of Agriculture, Vellayani, 2024-05-23) Ankitha, M O; KAU; Bindu, M R
The present research work entitled ‘Development and evaluation of high yielding, mosaic tolerant backcross progenies in bitter gourd (Momordica charantia L.) variety Preethi using morphological, biochemical and molecular markers’ was conducted in the Department of Plant Breeding and Genetics, College of Agriculture, Vellayani and Farming Systems Research Station (FSRS), Sadanandapuram during the year 2020-2023, with an objective to develop high yielding mosaic tolerant backcross progenies in bitter gourd using morphological, biochemical and molecular markers. Thirty three bitter gourd genotypes, including KAU released varieties (2 No’s), NBPGR accessions (13 No’s), and local collections from all over India were used for screening mosaic tolerance. Out of the 33 genotypes, 26 genotypes were Momordica charantia var. charantia and seven were Momordica charantia var. muricata. All these genotypes were artificially inoculated with the three viruses Cucumber Mosaic Virus (CMV), Tomato Leaf Curl New Delhi Virus (ToLCNDV) and Papaya Ringspot virus (PRSV) through wedge grafting. Wedge grafting was done using the infected plant shoots as scion and the collected genotypes as root stock and regrowth from the cotyledonary axis was examined for symptom expression. Out of the 33 genotypes screened, three were highly resistant, four were resistant, five were moderately resistant, six were moderately susceptible, ten were susceptible and five were highly susceptible. The genotypes Lodhi local, Udayagiri local and Therthali local recorded a lowest Vulnerability Index of zero. Molecular markers reported in Cucurbitaceae family were validated for bitter gourd mosaic resistance gene. SSR-11-1 marker for CMV resistance and CAPS marker for Potyvirus resistance gene were used, but no amplification was obtained. Double Antibody Sandwich ELISA (DAS-ELISA) was performed to confirm the resistance reaction of three highly resistant genotypes identified in seedling screening. Optical density (OD) value of the genotypes for the three viruses, CMV, ToLCNDV and PRSV were less than twice the OD value of the un-inoculated healthy plant which confirmed highly resistant disease reaction of genotypes. Molecular confirmation was done by using coat protein primer (Deng primer) specific to the Begomovirus group. Deng primer amplifies coat protein gene of ToLCNDV (520 bp), so that band will be present in only susceptible genotypes and will be absent in resistant ones. Plant defense related enzymes such as peroxidase, polyphenol oxidase and phenyl alanine ammonialyase was estimated and there was increased rate of synthesis of these enzymes in the identified resistant genotypes. So the identified resistant genotypes, Lodhi local, Udayagiri local and Therthali local were used as the donor parent for imparting mosaic resistance into the bitter gourd variety Preethi. Lodhi local is M. charantia var. charantia genotype where as both Udayagiri local and Therthali local are M. charantia var. muricata genotypes. High yielding variety released from KAU viz., ‘Preethi’ was selected as the recurrent parent in the study. Preethi was crossed with the three donor parents and F1s were produced. The F1s were morphologically evaluated with the parents for seventeen characters and it was observed that all the characters of F1 were approximately the average of two parents. All the F1s were backcrossed with Preethi to produce BC1F1 segregants. In the backcross progeny of the cross involving Preethi and Lodhi local, a total of 176 BC1F1 lines were developed. BC1F1 lines were artificially inoculated for their disease reaction. Among the 176 BC1F1 lines, 22 were found to be highly resistant to mosaic disease, 30 were resistant, 30 were moderately resistant, 26 were moderately susceptible, 35 were susceptible and 33 were highly susceptible. Confirmation of resistance was done using DAS- ELISA, Deng primers and estimation of defense enzymes. All the 17 biometrical characters were recorded and the Euclidean distance of the highly resistant BC1F1 lines from the recurrent parent Preethi was calculated using proximity dissimilarity matrix analysis. The 14 BC1F1 lines with high phenotypic similarity to Preethi was backcrossed to develop BC2F1 lines. In the backcross progeny of the cross involving Preethi and Udayagiri local, a total of 170 BC1F1 lines were produced. Among them 15 BC1F1 lines were highly resistant. Resistant reaction of identified 15 BC1F1 was confirmed by DAS-ELISA, molecular screening and biochemical analysis. Euclidean distance of the highly resistant 15 BC1F1 lines from the recurrent parent revealed that eight lines showed similarity with Preethi and they were backcrossed to get BC2F1 lines. A total 147 BC1F1 lines of the cross involving Preethi and Therthali local were screened at seedling stage. Out of the 147 lines, 16 BC1F1 lines were highly resistant. DAS-ELISA, molecular screening using aforementioned Deng primer confirmed the resistant reaction of these lines. Euclidean distance using biometric characters found that, out of 16 highly resistant BC1F1 lines eight lines had close proximity with Preethi. These lines were used to produce BC2F1 lines. The 190 BC2F1 lines of the cross involving Preethi and Lodhi local were screened at seedling stage and in 24 BC2F1 lines, there was absence of virus coat protein band which confirmed the highly resistant disease reaction of the aforementioned lines. The 12 BC2F1 lines with the shortest Euclidean distance and high phenotypic similarity with Preethi were selfed to generate BC2F2 seeds. In the 134 BC2F1 lines of the cross involving Preethi and Udayairi local, seedling screening recorded 17 highly resistant lines. After molecular confirmation of mosaic resistance four BC2F1 lines with close proximity to Preethi were selfed to get BC2F2 seeds. Out of the 143 BC2F1 lines of the cross involving Preethi and Therthali local, 20 BC2F1 lines were highly resistant. The molecular analysis of the 20 BC2F1 lines also confirmed the highly resistant reaction. Four BC2F1 lines with the shortest Euclidean distance was selected and selfed to produce BC2F2 seeds. Although there were BC2F2 seeds of three different crosses, only the BC2F2 seeds of the cross involving Preethi and Lodhi local was carried forward for further backcrossing. This is due to the low yield potential of the backcross progenies of the crosses involving M. charantia var. muricata genotypes. So 206 BC2F2 lines of the cross involving Preethi and Lodhi local were artificially screened at seedling stage for mosaic incidence. Out of the 206 BC2F2 lines, 42 plants were highly resistant to bitter gourd mosaic viruses. The 42 mosaic tolerant backcross inbred lines developed in the study can be carried forward for the development of a mosaic tolerant essentially derived variety (EDV) in the background of high yielding variety Preethi. The backcross progenies obtained in the crosses involving muricata genotypes can be further evaluated for its nutraceutical values.
Genetic variability in Chinese potato (solenostemom rotundifolius (poir) J K Morton) for yield and nematode tolerance
(Department of Plant Breeding and Genetics, College of Agriculture, Vellayani, 2019) Ankitha, M O; Lekha Rani, C
The present study entitled “Genetic variability in Chinese potato (Solenostemon rotundifolius (Poir) J.K. Morton) for yield and nematode tolerance” was carried out in the Department of Plant Breeding and Genetics, College of Agriculture, Vellayani during 2017-2019, with the objective to identify high yielding Chinese potato genotypes having nematode tolerance. Chinese potato is a minor tuber crop of the tropics in which heavy yield loss occurs due to root knot nematode infestation. The study comprised of two experiments. In the first experiment thirty accessions of Solenostemon rotundifolius (Poir) J.K. Morton, collected from ICAR - CTCRI Sreekariyam, local markets and farmers’ fields of major coleus growing tracts were evaluated for yield and nematode tolerance under field condition. These accessions were evaluated in Randomized Block Design (RBD) with thirty treatments and three replications during August 2018- January, 2019. Analysis of variance was conducted for all the thirteen characters studied. For all characters except for point of tuberization and susceptibility to nematode infestation, ANOVA revealed significant differences among all the genotypes evaluated. The genotype Kenichira local (T17) recorded the highest tuber yield plant-1 (295.37g) followed by CP9 (261.67g), Suphala (258.10g) and CP 8 (254.05g) which were on par whereas the lowest yield of 123.32g was recorded by Thottamkulam local (T10). Minimum days to flowering, maximum number of tubers plant-1 and maximum harvest index were observed for the genotype Kenichira local (T17). High genotypic coefficient of variation (GCV) and phenotypic coefficient of variation (PCV) were observed for tuber yield plant-1 and harvest index. Thus, selection for these characters would result in improvement of the genotype. High heritability coupled with high genetic advance was observed for number of tubers plant-1, tuber girth, tuber volume, average tuber weight, tuber yield plant-1, biological yield and harvest index. These characters, if selected for, would improve over generations. Tuber yield plant-1 was significantly and positively correlated with number of tubers plant-1, tuber girth, average weight of tubers and harvest index both at genotypic and phenotypic levels. So an improvement in these characters would enhance the tuber yield plant-1. Path coefficients were found out using tuber yield plant-1 as the dependent character and other correlated characters as independent variables. Path analysis revealed that number of tubers plant-1, average weight of tubers and days to flowering had positive direct effect on tuber yield plant-1. Mahalanobis’ D2 statistics was employed to study genetic divergence among the 30 genotypes which were grouped into ten clusters on the basis of relative magnitude of D2 values using Tocher’s method. Cluster I accommodated maximum number of genotypes and in sequence Clusters were having 7, 4, 4, 3,4, 3, 2, 1, 1 and 1genotypes respectively. The maximum inter-Cluster distance was observed between Clusters IV and VII. No close correspondence between geographical distribution and genetic divergence was observed. The second experiment was pot culture study for varietal reaction to root knot nematode. The same thirty genotypes evaluated in experiment I were raised in Completely Randomized Design with three replications during July, 2018 to September 2018. All the pots were artificially inoculated with second stage juveniles of Meloidogyne incognita obtained from pure culture, at the rate of 1000 juveniles plant-1. Nematode characteristics in both soil and root samples were studied. Maximum nematode population in soil was found in the genotype T8 (Parassala local 2). Root-knot index was calculated for each genotype based on scoring method suggested by Heald et al. (1989). According to this scoring method, the genotypes having 0-25 root knots per five gram of root was categorized as resistant. Fifteen genotypes were found to be in the category resistant. The genotype T11 (Pattambi local) showed highest mean values for number of larvae, root knot count, number of females and number of egg masses per five g root. The results of the current study showed the presence of wide range of variability in the thirty Chinese potato genotypes. Characters such as number of tubers plant-1 and average weight of tubers had positive significant correlation and direct association with tuber yield plant-1. Considering superior yield with nematode resistance, Kenichira local ranked first. It was followed by Suphala, CP8 and Edayur local. Kenichira local, CP 28 and Edayur local can be forwarded for further yield trials for variety development.