Browsing by Author "Namboodiri Raji Vasudevan"

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Assessment and induction of variability in plumbago species for high plumbagin content
(Department of Plant Breeding and Genetics, College of Horticulture, Vellanikkara, 2010) Namboodiri Raji Vasudevan; Radhakrishnan, V V
The study entitled "Assessment and induction of variability in Plumbago species for high plumbagin content" was carried out in the Department of Plant Breeding and Genetics, College of Horticulture, Vellanikkara during 2005-2009. The main objective of the study was to induce variability in Plumbago species for high plumbagin content through -in vitro mutagenesis. A detailed survey was conducted throughout Kerala and accessions of Plumbago were collected from different ecogeographical regions ranging from Western Ghats to coastal regions of Kerala. The species Plumbago rosea seemed to be mainly distributed in highlands and medium altitude especially in the midlands of Kerala. The passport data of the collected accessions were prepared and indigenous collection(IC) numbers were obtained from NBPGR, New Delhi. Twenty five accessions of Plumbago rosea and one accession of Plumbago zeylanica were catalogued. Twenty six accessions thus collected were evaluated in replicated trial for genetic variability with respect to their biometrical traits and quality. To know the causes of failure of seed set in Plumbago rosea floral biology of the two species of Plumbago was studied . .The data were subjected to statistical analysis and results interpreted. The twenty six accessions were grouped into seven clusters which showed that there is no parallelism between the geographical distribution and clustering pattern. The path coefficient analysis indicated that large sized leaves and increased dry root weight contributed maximum to plumbagin content. Based on the ranking for dry root weight and plumbagin content three accessions were subjected to in vitro mutagenesis. In vitro regeneration through direct organogenesis and indirect organogenesis was standardised in Plumbago rosea in MS medium. Nodal segments were identified as best explants showing direct regeneration. The in vitro regenerated plants from nodal cultures on cultivation produced significantly large tuberous roots with moderate plumbagin content compared to conventional rooted cuttirigs. The callus derived from leaves, regenerat~d shoots, and roots. Thus, mass multiplication of Plumbago rosea through tissue culture was standardised. In vitro mutagenesis of selected accessions of P. rosea was successfully carried out. Based on percentage of regeneration, LDso values of 20 Gy and 40 Gy were fixed for nodal cultures and callus cultures respectively. The hardened plants obtained from selected accessions through in vitro mutagenesis showed significant variation for leaf number and size. Based on these characters variants were selected and carried over for field establishment in pot culture. The tissue culture variants on field establishment showed wide variability with respect to its stature, plant type and other morphological traits. Three in vitro mutants having plant type with large leaves and short stature for high plumbagin content were identified. The plumbagin content of these in vitro mutants have to be evaluated for its commercial exploitation.
Characterisation of brinjal (solanum melongena L.) and its wild relatives
(Department of plant breeding and genetics, College of Agriculture, Padannakkad, 2021) Lintu, P; Namboodiri Raji Vasudevan
The study entitled “Characterization of brinjal (Solanum melongena L.) and its wild relatives” was carried out at the Department of Plant Breeding and Genetics, College of Agriculture, Padannakkad during 2018-2020. The main objectives of the study was to characterize the brinjal genotypes and its wild relatives based on morphological characters; analyze the genetic variability in collected accessions and to develop selection index for cultivated types. The experimental meterial consisted of 25 S. melongena accessions and five wild relatives (S. mammosum, S. macrocarpon, S. insanum, S. incanum and S. gilo) collected from North Kerala (Malappuram-11, Kozhikode-5, Kannur-4, Kasaragod- 3, Wayanad-1) and Regional station, NBPGR, Thrissur (6). The passport data of thirty accessions were prepared and these were evaluated for 17 qualitative and 22 quantitative characters based on IPGRI descriptor in field experiment laid out in Randomized Block Design with three replications. The morphological characterization based on qualitative characters showed wide variation for stem colour, leaf lobing, fruit shape and fruit colour. The results of analysis of variance indicated significant differences for all the quantitative characters indicating presence of high genetic variability. The mean performance of genotypes revealed distinct variation between cultivated and wild accessions for most of the characters. The wild accessions recorded lower values for fruit yield and fruit weight but longer duration for flowering and fruit set. Eight S. melongena accessions (SM 27, SM 25, SM 23, SM 20, SM 10, SM 23, SM 24 and SM 8) had high fruit yield per plant (more than 1000 g). The accession SM 27 had shown superiority for important yield component traits like fruit yield, fruit diameter and fruit weight. Among all accessions, the green fruited S. melongena accession SM- 25 showed lesser incidence of shoot and fruit borer. Three wild accessions S. mammosum (SM 22), S. gilo (SM 29) and S. insanum (SM 30) showed no incidence of fruit and shoot borer. The variance component analysis revealed high heritability coupled with high genetic advance as per cent of mean for all flowering and fruit characters indicatingthat most likely the heritability is due to additive effects making selection effective based on these characters. Association analysis revealed that plant height, days to first flowering, number of long styled flowers, fruit diameter, fruit weight and number of fruits per plant shown significant genotypic correlation and direct effect showing true association of these characters with fruit yield. Selection based on all these characters will help to achieve efficient improvement in fruit yield. The UPGMA clustering of 30 eggplant accessions for qualitative traits revealed three groups based on anthocyanin pigmentation of plant parts and leaf prickliness, traits important for stress tolerance. The genetic diversity analysis based on Mahalanobis D 2 statistics for 22 quantitative characters grouped 30 accessions into eight clusters. The clustering patern showed the S. melongena accessions collected from North Kerala grouped under cluster I (22) and cluster III (2). All the five wild accessions were grouped in five different clusters (III, IV, VI, VII and VIII). The green fruited accessions SM 25 and SM 27 collected from NBPGR were placed in cluster III and cluster V indicating their distinctness. The character fruit yield per plant, leaf blade width, number of fruits per plant and leaf blade length hade made major contribution towards genetic divergence with maximum by fruit yield per plant. The maximum intra-cluster distance was reported in cluster I, followed by cluster III. The remaining are solitary clusters. The highest inter- cluster distance was recorded between solitary clusters V and VIII, V and IV and V and III providing scope for hybridization between genotypes of these highly divergent cluster especially involving wild accession SM 30 for fruit and shoot borer resistance. Selection index involving discriminant functions based on relative economic importance of various characters showed a combination of four characters (Fruit yield per plant + Number of long styled flowers + Fruit diameter + Fruit weight) with maximum relative efficiency. Based on high selection index score involving four character combination and overall cluster ranking for three yield attributes two green fruited accessions SM 25 and SM 27 and six purple fruited accessions SM-8, SM- 10, SM-18, SM-20, SM-23 and SM 24 are identified as promising. Among these,the green fruited accession SM 25 had shown very low incidence of fruit and shoot borer. Based on selection index score and cluster divergence (high inter-cluster distance) the SM-27 is identified as promising parent in intra-specific hybrid involving of SM-27 x SM-25 and inter-specific hybrids involving SM-27 x S. insanum and SM-27 x S. macrocrpon. These crosses may be attempted in future breeding program for obtaining progenies superior for yield as well as shoot and fruit borer and bacterial wilt resistance.
Characterization and hybridization of nymphaea spp.
(Department of Plant Breeding and Genetics, College of Agriiculture, Padannakkad, 2018) Manju, A; Namboodiri Raji Vasudevan
Characterization of okra [Abelmoschus esculentus L. Moench] genotypes in North Kerala
(Department of Plant Breeding and Genetics, College of Agriculture, Padannakkad, 2017) Aswathi G Prasad; Namboodiri Raji Vasudevan
Development of F1 hybrids in okra [Abelmoschus esculentus L. Moench]
(Department of Plant Breeding & Genetics, College of Agriculture,Padannakkad, 2019) Jaseera, U A; Namboodiri Raji Vasudevan
The project entitled “Development of F1 hybrids in okra [Abelmoschus esculentus L .Moench]” was carried out at the Instructional farm, College of Agriculture, Padannakkad during April-July 2019 to study heterosis and combining ability. The experiment was carried out in two parts. In part I, six diverse parents viz. AE5, AE16, AE18, AE20, AE30 and Salkeerthi were raised in a crossing block. They were crossed in half diallel fashion and 15 F1 hybrids were produced. In part II, the hybrids were evaluated along with their parents and checks in a randomized block design with 26 genotypes and three replications. Arka Anamika and Salkeerthi were used as OPV checks and Manjima and Arka Nikita as F1 hybrid checks. Parents of Manjima viz. Gowreesapattam local and IC282257 were also included as checks. Half diallel analysis was adopted for combining ability analysis. Relative heterosis, heterobeltiosis and standard heterosis using F1 hybrid Arka Nikita as standard check were worked out for all the characters. The estimation of heterosis revealed significant standard heterosis in the hybrids in desirable direction for growth, earliness and fruit traits. Three hybrids AE30 x AE18, AE30 x Salkeerthi and AE20 x AE30 showed highly significant positive standard heterosis for plant height. Three hybrids AE30 x Salkeerthi, AE30 x AE5 and AE18 x Salkeerthi showed highly significant positive standard heterosis for primary branches per plant. Two hybrids AE16 x AE5 and AE18 x AE5 showed highly significant negative standard heterosis for internode length. Two hybridsAE16 x Salkeerthi and AE20 x Salkeerthi showed highly significant negative standard heterosis for days to flowering. One hybrid AE18 x AE5 showed highly significant negative standard heterosis for days to 50% flowering. Five hybrids AE16 x AE30, AE16 x AE18, AE16 x AE5, AE20 x AE18, and AE30 x AE18 showed highly significant negative standard heterosis for node of fruit set. None of the hybrids showed significant positive standard heterosis for number of fruiting nodes. For fruit length AE20 x AE18 and AE20 x Salkeerthi showed significant positive standard heterosis. Three hybrids AE16 x AE30 AE5 x Salkeerthi and AE30 x AE5 showed significant positive standard heterosis for fruit girth. For fruit weight the hybrids AE30 xAE5, AE18 x AE5, AE20 x Salkeerthi, and AE20 x AE18 showed significant positive standard heterosis. None of the crosses showed significant positive standard heterosis for number of fruits per plant, marketable fruits per plant, marketable fruits per plant and yield per plant. The hybrid AE30 x Salkeerthi showed significant positive standard heterosis for mucilage content. Analysis of variance for combining ability revealed significant difference among the genotypes for all traits except fiber content, indicating sufficient variability for selection. The gca variance/ sca variance ratio indicated preponderance of non-additive gene action for all traits. None of the cross combinations exhibited high significant combining ability effects in desirable direction for all characters studied. The association of sca effects of outstanding crosses with gca effects of parents for each of the characters revealed that the high specific combiners involved high x high, high x low and low x low general combiners as parents. A combination of mean performance and gca effect was used to identify best parents and it revealed AE16, AE30 and AE20 as better performing parents for maximum number of characters. Even though the mean performance of AE16 was higher for fruit weight, number of fruiting nodes, yield per plant and marketable yield per plant, it was a poor general combiner for characters viz. number of fruiting nodes, fruit weight, and yield per plant compared to AE20 and marketable yield per plant compared to AE30. High gca effects for fruit yield in AE20 and AE30 were associated with good gca effects for number of fruits per plant and fruit weight. The parental lines AE20 and AE30 performed well even they were affected by yellow vein mosaic disease and fruit and shoot borer. Hence they can be used in further breeding program for higher yield. The parental line AE20 was the high general combiner for all of the three earliness attributes such as days to first ﬂowering, days to 50% ﬂowering, and node of fruit set, indicating its potential for exploiting earliness in okra. Promising crosses were identified based on mean performance, sca effect and standard heterosis for important growth and yield characters. None of the hybrids exhibited significant standard heterosis in the desirable direction for yield. Hence the hybrids showing lower value of negative standard heterosis were selected. The four better performing crosses identified were AE30 x AE5, AE20 x AE5, AE20 x Salkeerthi and AE30 x Salkeerthi. All these four crosses were good performers for marketable yield even when they were affected by yellow vein mosaic disease and shoot and fruit borer. In addition, these crosses showed good performance for few other yield contributing characters also. The cross AE30 x AE5 performed well for fruit weight, number of fruiting nodes and yield per plant. The cross AE20 x AE5 showed good performance for number of fruits per plant, marketable fruits per plant and yield per plant. AE20 x Salkeerthi was a good performer for fruit weight and fruit length. AE30 x Salkeerthi was good performer for plant height, primary branches per plant, internode length and mucilage content.
Evaluation of brinjal (Solanum melongena L.) genotypes for resistance to bacterial wilt (Ralstonia solanacearum)
(Department of Plant Breeding and Genetics , College of Agriculture, Padannakkad, 2023-12-11) Muslepally Niharika; Namboodiri Raji Vasudevan
The current study entitled “Evaluation of brinjal genotypes for resistance to bacterial wilt (Ralstonia solanacearum)” was carried out in the Department of Plant Breeding and Genetics, College of Agriculture, Padannakkad during 2020-2023. The main objectives of the study were to evaluate brinjal genotypes for resistance to Bacterial wilt (BW) and examination of the mechanism of resistance through anatomical and biochemical parameters as well as estimation of yield characters in resistant lines. The experimental material consisted of thirty-one accessions which included eleven accessions (SM-1, SM-2, SM-3, SM-4, SM-5, SM- 8, SM-9, SM10, SM-31, SM-32, SM-33) collected from North Kerala, seventeen accessions (SM-11 to SM-27) from NBPGR. It also included three released varieties and hybrid of KAU (Haritha, Surya, Ponny and Neelima) as resistant checks and two susceptible checks (SM-26[S.incanum] and SM-27[S.insanum]). In experiment I, three weeks old seedlings of all brinjal genotypes were screened for resistance to BW in a completely randomized design with three replications. Based on percentage disease incidence (PDI), two accessions SM-15 and SM-25 were rated as highly resistant (HR: 0 PDI) and accessions SM-1 was rated as resistant (R: 1-10 PDI). Accessions SM-1, SM-2, SM-5, SM-11, SM-17, SM-24 and KAU hybrid Neelima were rated as moderately resistant (MR: 11-20 PDI). Accessions SM-4, SM-8, SM-14 and SM-19 were rated as susceptible (S: 21-30 PDI). Moderately susceptible (MS: 31-40 PDI) accessions were SM-3, SM-32, SM-33, SM-13 and SM-16. Accessions SM-9, SM-10, SM-12, SM 18, SM-20, SM-21, SM-22, SM-23, SM-26 and SM-27 were rated as highly susceptible (HS: >40 PDI). Biochemical parameters viz., Polyphenol oxidase (PPO) enzyme activity, total phenols, and total sugars (both reducing and non-reducing) were assessed at 12 and 24 hours post inoculation (hpi).In this analysis using twenty two accessions consisting of eight genotypes from resistant categories (HR, MR, R) and eight from HS group along with four RC ( Ponny, Haritha, Surya and Neelima) as well as two SC (SM-26, SM-27) were used. A control group with mock inoculation was also part of the analysis. Two factor ANOVA demonstrated significant differences in these biochemical parameters among all tested brinjal genotypes. At 12 and 24 hpi, the most significant rise in PPO activity was observed in the RC followed by the R group, HR germplasm and MR group compared to their respective control samples. Moreover at 24 hpi the resistant (R) genotypes exhibited a significant 3.5-fold increase in PPO activity compared to the control group. Resistant checks exhibited the highest phenolic content followed by the HR, R and MR germplasm at 12 and 24 hpi. The highest amount of total sugars, which includes both reducing and non-reducing sugars, was observed in RC followed by HR germplasm, R germplasm, and MR germplasm after 24 hpi. Correlation analysis revealed a significant negative correlation between biochemical parameters viz., PPO enzyme activity, total phenol content, total sugars including non-reducing sugars (12 and 24 hpi) and disease incidence. A positive correlation was observed between disease incidence and reducing sugars at 12 hpi whereas, negative correlation was observed between the same at 24hpi. The biochemical analysis indicated that PPO and phenols played a positive role in the resistance against R. solanacearum in brinjal. However, the role of sugar content in plant defense is still unclear and requires further studies for a better understanding of sugar metabolism. In the current study different aspects of the stem vascular anatomy viz., number of small and large vessels, total number of vessels, ratio of large to small vessels and average vascular area in the eggplant germplasm and correlation of these characters with disease incidence were analysed. A significant variation for anatomical characters was observed among all the genotypes. Among the germplasm HR accessions SM-15, SM-25 and R accession SM 1 showed highest number of large vessels, higher ratio of large vessels to small vessels and higher average vascular area compared to all other accessions. These anatomical parameters are found to play a significant role in the temporal and spatial distribution of the pathogen within the vascular vessels. After analyzing the response of various brinjal genotypes to disease incidence, as well as considering biochemical and anatomical parameters, it was observed that eight genotypes (SM-1, SM-2, SM-5, SM-11, SM-15, SM-17, SM-24, and SM-25) exhibited resistance against BW. These genotypes along with four KAU released resistant checks were further evaluated in the field in experiment II. Field evaluation was carried out in a randomized block design with three replications for sixteen quantitative and two qualitative characters. Per se performance of all genotypes revealed significant variation for all the quantitative characters indicating presence of high genetic variability. Association analysis revealed that leaf area, root dry weight and average fruit weight showed significant positive genotypic correlation and direct effect depicting true association of these characters with fruit yield. Selection based on these characters will help achieve efficient improvement in fruit yield. Among the local accessions, resistant accession SM-1 exhibited the maximum early fruit yield of 972.68 g followed by the Moderately resistant accession SM-11 (965.77 g). Accession SM-1 was also superior for plant height, earliness, average fruit weight and SM-11 for number of fruits per plant. Therefore, resistant accession SM-1 could be regarded as a promising genotype for potential release as a new variety. Highly resistant accessions SM-15 (oval green fruits with intermediate calyx prickles) and SM-25 (oval purple fruits and no prickles on the calyx), displayed excellent plant and flower characteristics like stem girth, branching, days to first and 50 per cent flowering but reported lower early yields. These can be used in hybridization programs either as parents to develop F1 hybrid or as recombinants in recombination breeding for resistance to bacterial wilt.
Evaluation of pre-sowing interventions on seed quality, storage and field performance of Okra (Abelmoschus esculentus L. Moench)
(Department of Seed Science and Technology, College of Agriculture, Vellanikkara, 2024-04-09) Adheena, P; Namboodiri Raji Vasudevan
The research work entitled ‘Evaluation of pre sowing interventions on seed quality, storage, and field performance of okra (Abelmoschus esculentus L. Moench)’, was conducted as two experiments in the Department of Seed Science and Technology, College of Agriculture, Vellanikkara, during 2022-2023. Five months old seeds (variety – Arka Anamika) were subjected to fourteen pre sowing treatments namely, T1-Control, T2-Hydration-Dehydration (12 hours), T3-PEG 6000-13.5% (-0.25Mpa) 6 hours, T4-KNO32%(6hours), T5-sandmatric (60% WHC-3hours), T6-Trichoderma viride 4g/kg of seed, T7-Pseudomonas fluorescens 10g/kg of seed, T8-Hydration-Dehydration (24 hours), T9-PEG 6000-13.5% (-0.25Mpa) 12 hours T10-KNO3 2% (12 hours) T11-sand matrix (60% WHC -6 hours), T12-T.viride 4g/kg+P indica 5x105 spores Ml-1) 10 ml/kg were carried out. The initial seed quality parameters such as germination per cent -94%, vigour index I-1474, vigour index II-2.73, and moisture percent – 7.2 respectively, were assessed before storage and field experiments. In experiment I, the seeds were subjected to eleven of the fourteen presowing treatments mentioned earlier with three replications. These were then dried to less than eight percent moisture, packed in 700g polythene bags and stored under ambient conditions. The observations for all quality parameters were recorded immediately after the treatments and at monthly intervals for six months of storage period. The treatments displayed significant variations across all the investigated seed quality parameters. Among the treatments, treatment T9(PEG 6000-13.5% (-0.25Mpa) 12 hours) recorded the best seed qualities in all months of storage, followed by treatment T4 (KNO3 2% - 6 hours). The storage study clearly demonstrated that the quality of seeds consistently diminished with an extended storage period, regardless of the treatments applied. In the case of germination, all treatments, including control maintained the Indian Minimum Seed Certification Standard (IMSCS) of 65 percent up to the sixth month of storage. Seed quality parameters such as germination percent, vigour index I, vigour index II, seedling length, seedling dry weight and seedling fresh weight decreased with the advancement of the storage period. The electrical conductivity of seed leachate, mean germination time, time taken for 50% germination, seed moisture percent and seed microflora percent were found to be increasing over the period of storage. In experiment II, the seeds were subjected to thirteen treatments and control mentioned earlier. Among these, seven best treatments along with control were selected based on germination percentage and vigor index for the field experiment. The experiment was laid out in RBD (Randomized Block Design), with three replications. Maximum germination percentage was obtained in T4 (PEG 6000-13.5% (-0.25MPa) 6 hours -99.66) and it was on par with T10(Trichoderma viride at 4g/kg of seed), T5(PEG 6000-13.5% (-MPa) 12 hours), T6 (KNO3 2% (6 hours), T3 (hydration-dehydration (24 hours), T9 (sandmatric (60% WHC – 6 hours) and T11 (P. fluorescens at 10g/kg of seed). The results indicated that the pre sowing treatments showed significant differences for all the characters studied. In terms of growth characters, T3 (PEG 6000-13.5% (-0.25MPa) 6 hours) had the maximum number of branches per plant. T8 also had the least number of days to first and 50% flowering. All the fruit characters such as fruits per plant, fruit length (cm), fruit weight (g) at maturity and fruit yield (t/ha) were recorded maximum in treatment T8(P. fluorescens at 10g/kg of seed) which was followed by T7 (Trichoderma viride at 4g/kg of seed). Similarly, all the seed yield characters such as, sees per fruit, seed yield per plant (g) and 100 seed weight(g) were also highest in T8 followed by T7. This underscores the significant impact of biocontrol agents such as P. fluorescens and T. viride on both fruit yield and seed yield characters. The ranking of traits in Experiment II aimed to identify the most effective treatments for enhancing the field performance of okra. Based on the total scores, T8(P. fluorescens at 10 g/kg of seed) emerged as the best treatment followed by T7(T. viride at 4g/kg of seed). In conclusion, treatments T9(PEG 6000-13.5% (-0.25Mpa) 12 hours) and T4 (KNO3 2% (6 hours) were found to be maintaining the seed quality. Additionally, treatments involving P. fluorescens and T. viride proved to be valuable for enhancing fruit yield and seed yield in okra variety Arka Anamika.
Molecular characterization of brinjal (Solanum melongena L.) genotypes and their performance assessment in summer
(Department of Genetics and Plant Breeding, College of Agriculture, Padanakkad, 2023-05-31) Chakravaram, Alekhya; Namboodiri Raji Vasudevan
Morphological and biochemical characterization of Brinjal (Solanum melongena L.) genotypes
(Department of Plant Breeding and Genetics, College of Agriculture, Padanakkad, 2022) Alan Thomas; Namboodiri Raji Vasudevan
The study entitled “Morphological and biochemical characterization of brinjal (Solanum melongena L.) genotypes” was carried out in the Department of Plant Breeding and Genetics, College of Agriculture, Padannakkad during 2019-2021. The study was conducted in two experiments and the objectives were to characterize the brinjal genotypes based on morphological, biochemical and quality characters; analyze the genetic variability in collected accessions and to identify best genotypes having high yield, superior quality as well as resistance/ tolerance to fruit and shoot borer. The experimental material consisted of two wild species (S. insanum and S. incanum) and twenty eight S. melongena accessions including collections from North Kerala (Kannur-5, Kasaragod-4, Malappuram-1), accessions from NBPGR regional station, Thrissur as well as KAU released varieties (Ponny, Haritha and Surya). The first experiment was laid out in a randomized block design with 30 genotypes in three replications and observations were recorded for 12 qualitative, 18 quantitative and 8 fruit quality and biochemical characters. The analysis of qualitative characters showed wide variation for corolla colour and fruit characters such as curvature, shape, apex shape, pedicel and calyx prickles, flesh density, fruiting pattern and colour. The results of analysis of variance revealed significant differences for all the quantitative characters indicating presence of high genetic variability. The brinjal genotypes SM-1, SM-5 and SM-11 showed superiority for percent medium and long styled flowers (67.59%, 42.78%, 61.75%), fruit setting percentage (63.89%, 37.59%, 55.45%), days to first harvest (61.33, 63.67, 61.67), fruit weight (111.18g, 115.28g, 106.87g) and marketable fruit yield (1874.67g, 1619.67g 1673.33g). The variance component analysis revealed high heritability coupled with high genetic advance as per cent of mean for all the fruit and yield characters as well as pericarp thickness, anthocyanin in fruit peel and vitamin C indicating that most likely the heritability is due to additive effects making selection effective based on these characters. Correlation and path analysis revealed that fruit setting percentage, days to first harvest, fruit weight and number of fruits per plant showed significant genotypic correlation and direct effect depicting true association of these characters with fruit yield. Selection based on these characters will help to achieve efficient improvement in fruit yield. The UPGMA clustering of 30 eggplant accessions for qualitative traits revealed six groups based on fruit curvature, corolla colour, fruit shape, fruit apex shape, fruit flesh density, fruit colour. The genetic diversity analysis based on Mahalanobis D2 statistics for 18 quantitative characters grouped 30 accessions into thirteen clusters. The character fruit weight contributed maximum towards diversity. The maximum intra-cluster distance was reported in cluster V followed by cluster IV. The highest inter-cluster distance was recorded between cluster VII and XII followed by clusters VII and VIII indicating a wide range of diversity between these clusters providing scope for hybridization between superior genotypes of these highly divergent clusters. The accessions SM-1, SM-2, SM-5, SM-9, SM-10 and SM-11 showed superior ranking in their respective clusters based on three yield attributes viz., fruit weight, fruit setting percentage and marketable fruit yield identified in association and divergence analysis. In the second experiment brinjal accessions were screened for resistance to fruit and shoot borer in a completely randomized design in three replications. The observations were recorded for percentage of shoots infested and percentage of fruits infested at ten days intervals and the accessions were grouped into six categories based on severity of damage on fruits. Wild accessions SM-26 (S. incanum) and SM-27 (S. insanum) were found to be immune, as none of these plants showed symptoms of infestation. SM-6 and SM-7 were rated as highly resistant accessions. SM-1, SM-2, SM-3, SM-4, SM-5, SM-8, SM-9, SM-11, SM-14 and Haritha were found to be moderately resistant. SM-10, SM-13, SM-20, SM-22, Ponny and Surya were grouped as tolerant. All the remaining accessions were susceptible. Correlation studies between fruit infestation by fruit and shoot borer with biochemical characters revealed a positive significant correlation of fruit infestation with total sugars and protein content while a negative correlation of fruit infestation was obtained with solasodine content as well as phenol content. The present study resulted in identification of a fair number of high yielding resistant lines amongst the wide collection of indigenous brinjal germplasm used. The wild relatives from highly divergent clusters like cluster I (SM-26), cluster VIII (SM-27) and S. melongena accessions SM-6 and SM-7 can be exploited for their shoot and fruit borer resistance. Accessions SM-1, SM-2, SM-5, SM-9, SM-10 and SM-11 with higher nutrients (protein >1.22 g/100g and vitamin C >5.03 mg/100g), a balance of biochemical content (solasodine and phenol) in addition to high fruit yield (~1300g to ~2100g) and comparatively lesser infestation of fruit and shoot borer can be considered as the promising parents in future crop improvement programs.
Seed invigoration studies in okra [Abelmoschus esculentus (L.) Moench]
(Department of Seed Science and Technology, College of Agriculture, Vellanikkara, 2025) Kota Harshitha Padmaja.; Namboodiri Raji Vasudevan
The study entitled “Seed invigoration studies in okra [Abelmoschus esculentus (L.) Moench]”was conducted at the Department of Seed Science and Technology, College of Agriculture, Vellanikkara, during 2022-2024. This research investigated the effects of osmopriming with PEG 6000 (13.5% at -0.25 MPa for six hours) and biopriming with Pseudomonas fluorescens @10g/kg on growth, yield, seed quality and seed longevity of five okra varieties—Aruna (V1), Anjitha (V2), Pusa-5 (V3), Salkeerthi (V4), and Varsha Uphar (V5). The study comprised two experiments. Experiment 1 focused on the effects of priming treatments on the varietal performance of okra in terms of growth, yield, and seed quality, while experiment 2 examined seed longevity under storage conditions. Experiment 1 followed a Randomized Complete Block Design (RCBD) with three replications, resulting in 15 treatment-variety combinations. Seeds of the five okra varieties were subjected to three priming treatments: T1 (osmopriming with PEG 6000 solution at -0.25 MPa for six hours), T2 (Pseudomonas fluorescens at 10 g/kg of seed), and a control (non-primed seeds). Experiment 2 followed a Completely Randomized Design (CRD) with the same priming treatments and varieties replicated three times. Seed initial quality parameters were assessed immediately after priming treatment. Among the varieties Salkeerthi (V4) achieved the highest germination rate followed by Varsha Uphar and showed superior performance over other varieties due to high seed vigour indices and lowest EC. The combination Salkeerthi-PF (V4×T2: 93.66 %) followed by Varsha Uphar-PF (V5xT2: 90.66%) showed superiority in seedling vigour and growth attributes of okra In the Experiment 1, the results indicated that both priming treatments significantly enhanced field performance across all varieties compared to the control. Varieties displayed significant variation in growth, yield, and seed quality traits. Varsha Uphar (V5) emerged as the top performer for field emergence, early flowering plant height and seed yield per plant under priming conditions. Pusa-5 (V3) showed superior fruit weight and yield per plant, with the combination Pusa-5 x Pseudomonas fluorescens recording the highest number of fruits per plant and Pusa-5 x PEG producing the highest fruit weight and yield. Salkeerthi (V4) exhibited the highest seed count per pod. Among the treatments, T2 (Pseudomonas fluorescens) consistently demonstrated a greater positive impact on growth, fruit yield, and seed quality compared to T1 (PEG 6000 (13.5% at -0.25 MPa for six hours). In the Experiment 2, storage study was conducted with the same five okra varieties, using the same priming treatments along with control. Seed quality parameters were monitored for six months. All varieties and treatments maintained germination rates well above the Indian Minimum Seed Certification Standard (IMSCS) threshold of 65 percent. However a progressive decline in seed quality was observed over time. This decline was evident in reductions in key traits such as shoot length, root length, seedling dry weight, vigour indices, and enzymatic activities including dehydrogenase, α-amylase, and catalase. Concurrently, negative trends were noted, with increases in parameters such as electrical conductivity (indicating membrane deterioration), mean germination time, time to 50 percent germination, seed moisture content, and the percentage of microflora contamination, all of which are indicators of seed aging and reduced vigour. Among the varieties evaluated, Salkeerthi (V4) consistently emerged as the top performer in maintaining superior seed quality during the storage period followed by Varsha Uphar. This was particularly notable when the seeds were treated with T2 (Pseudomonas fluorescens). Seeds treated with T2 retained higher enzymatic activity, including significantly enhanced levels of dehydrogenase, α-amylase and catalase, which are critical for metabolic processes during germination. These enzymes are known to play essential roles in energy production, starch breakdown, and oxidative stress management, contributing to better seed vigour and viability. This superior performance highlighted the potential of biological priming with Pseudomonas fluorescens not only improved seedling vigour during cultivation but also mitigate the negative effects of storage, ensuring sustained seed quality over time. The findings of this study highlighted the significant role of priming treatments in improving the growth, yield, and seed quality of okra varieties. Among the varieties studied, Varsha Uphar (V5) and Pusa-5 (V3) demonstrated superior field performance, with Pseudomonas fluorescens (T2) emerging as the most effective priming treatment. Although Salkeerthi (V4) demonstrated superior initial seed quality, its field performance was comparatively lower, highlighting the role of environmental factors and genotypic traits in bridging the gap between seed quality and productivity. Biopriming has demonstrated significant efficacy in maintaining seed viability and quality during storage. Notably, the okra varieties Salkeerthi and Varsha Uphar have shown exceptional resilience, consistently preserving seed quality parameters. These results underscored the potential of incorporating Pseudomonas fluorescens as a seed priming agent to enhance both okra productivity and seed longevity. Furthermore, research exploring the molecular mechanisms behind the observed enhancements in seed vigor and resilience, particularly focusing on enzyme activities such as dehydrogenase, α-amylase, and catalase, could offer a deeper understanding of the biological processes involved.