Browsing by Author "Pradeepkumar, T"

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Adaptability of cauliflower genotypes in the high ranges of Kerala
(Kerala Agricultural University, Vellanikara, 2002) Pradeepkumar, T; Sajith Babu, D.; Aipe, K C
Breeding for gynoecy in bitter gourd (Momordica charantia L.)
(Department of Vegetable Science, College of Horticulture, Vellanikkara, 2019) Minnu Ann, Jose; Pradeepkumar, T
Breeding for high parthenocarpic expression and improved fruit quality in cucumber (cucumis sativus L.)
(Department of Vegetable Science, College of Agriculture, Vellanikkara, 2025-10-29) Athira, K S; Pradeepkumar, T
Cucumber (Cucumis sativus L.) is a widely cultivated cucurbitaceous vegetable and traits like parthenocarpy and gynoecy boost productivity under protected conditions where pollinators are forbidden. Although parthenocarpic cucumber was introduced early in India, public-sector hybrid development remains limited. Kerala Agricultural University launched a breeding program in 2011, leading to the release of KPCH-1, a high-yielding, early-maturing, parthenocarpic hybrid with moderate disease resistance and a cluster-bearing habit, mostly confined to upper nodes. However, poor cluster formation at lower nodes and late-stage fruit deformities limit its potential vis-a-vis popular private sector hybrids. With only few public-sector options available, farmers are forced to rely on costly private hybrids. This highlights the need for improved public sector parthenocarpic hybrids for protected cultivation, prompting the present study on “Breeding for high parthenocarpic expression and improved fruit quality in cucumber (Cucumis sativus L.)”. The study comprised of four experiments aimed at evaluating and identifying cucumber lines with high parthenocarpic expression and yield, developing F₁ hybrids through diallel crossing, assessing their mean performance, combining ability and heterosis and validating the reported SSR markers linked to parthenocarpy. In the first experiment, twelve gynoecious and parthenocarpic cucumber lines were evaluated, revealing significant variation for all traits except ovary length and crop duration. Among the genotypes evaluated, several stood out for specific agronomic and market-preferred traits. CS 134 was notable for its high fruit weight and lack of deformities, while CS 135 excelled in fruit number per plant, indicating strong yield potential. CS 136 demonstrated superiority across multiple parameters, including compact growth, high parthenocarpic fruit set, extended harvesting duration and top yield performance, making it a strong candidate for commercial cultivation and breeding. CS 138 showed early and compact fruiting traits. CS 140 was distinguished by its longer fruits, appealing for market preferences. CS 141 displayed excellence in fruit quality traits such as girth, flesh thickness, and TSS, along with ideal cluster fruiting and absence of deformities. CS 142 and CS 143 were among the earliest to reach harvest and showed favorable flesh quality and shelf-life traits. CS 144 was superior in early flowering and parthenocarpic expression. CS 145 also showed high sweetness levels, aligning with consumer preferences. Overall, CS 136 emerged as the most promising genotype for yield and adaptability under protected conditions, while others offered valuable traits for targeted improvement in breeding programs. High phenotypic coefficient of variation (PCV) and genotypic coefficient of variation (GCV) were observed for traits such as node at which the first female flower emerged, node at which parthenocarpic expression occurred, parthenocarpic fruit set (%), parthenocarpic fruit expansion (%), number of fruits per plant, percentage of deformed fruits and physiological loss in weight, indicating a strong genetic influence and suggesting good potential for selection. High heritability coupled with high genetic advance as percent of mean was recorded for several key traits including node at which the first female flower emerged, node of parthenocarpic expression, parthenocarpic fruit set and expansion percentages, node at which clustered fruit appeared, number of fruits per cluster at middle nodes, fruit length, number of fruits per plant, percentage of deformed fruits, yield per plant, total soluble solids (TSS) and physiological loss in weight. These findings suggest that these traits are primarily governed by additive gene action and, therefore, selection for their improvement would be highly effective. In the correlation study, yield per plant was found significantly and positively correlated with parthenocarpic fruit set percentage, parthenocarpic fruit expansion percentage, node of clustered fruit appearance, number of fruits per plant and number of harvests. Path coefficient analysis revealed that several traits have a positive direct influence on fruit yield per plant. Key contributors included parthenocarpic fruit set, early flowering, fruit number, and fruit size characteristics. Traits that showed both strong positive correlations and direct effects on yield, such as parthenocarpic fruit set, fruit expansion, number of fruits, and frequency of harvest, are particularly promising for selection in cucumber breeding programs targeting improved productivity under protected cultivation. From the twelve gynoecious parthenocarpic lines evaluated, six best performing lines (CS 135, CS 136, CS 137, CS 141, CS 142 and CS 143) were selected as parents for diallel crossing programme based on selection index and the thirty F1 hybrids so developed were evaluated under naturally ventilated polyhouse conditions for various traits along with the parents and two commercial checks – KPCH -1 and Multistar. During the crossing programme, the application of silver thiosulphate (STS) successfully induced male flowers across all parental lines without causing significant variation in the timing of flower emergence or pollen viability. While these traits remained consistent, crossing efficiency and seed set varied notably among genotypes. Based on the general combining ability (GCA) effects for various traits, the parent CS 142 emerged as the best general combiner, exhibiting superior GCA for the maximum number of traits, i.e., eight traits. These include early flowering (days to first female flower anthesis and node at which first female flower emerged), reproductive efficiency (node at which parthenocarpic expression occurred and length of ovary), and fruit quality traits (fruit length and TSS), along with favorable performance in days to first harvest and number of fruits per cluster at upper nodes. This makes CS 142 a valuable parent in cucumber breeding for improving earliness, parthenocarpy and fruit quality. Based on the specific combining ability (SCA) effects observed across traits, the top five hybrids identified were CS 143 × CS 137, CS 135 × CS 141, CS 143 × CS 136, CS 142 × CS 136, and CS 135 × CS 142. The hybrid CS 143 × CS 137 exhibited superior performance for average fruit weight, fruit length, fruit girth, flesh thickness, number of fruits per plant, and total soluble solids, indicating excellent potential for fruit quality and productivity. CS 135 × CS 141 excelled in parthenocarpic fruit set and expansion, fruit length and girth, number of fruits per plant, yield per plant and TSS, making it a strong candidate for yield enhancement through parthenocarpy. CS 143 × CS 136 demonstrated high SCA for parthenocarpic traits, number of harvests, yield per plant, and TSS. CS 142 × CS 136 was notable for earliness, favorable average fruit weight and girth, higher TSS, and lower physiological loss in weight while CS 135 × CS 142 was superior in internodal length, ovary length, fruit girth, TSS and physiological loss in weight. Based on the analysis of mean performance across key traits, the hybrid CS 141 × CS 142 emerged as the most outstanding performer, ranking first with superiority in six traits, including days to first female flower anthesis, node at which the first female flower emerged, node of parthenocarpic expression, flesh thickness, days to first harvest and lowest percentage of deformed fruits. Following this, CS 143 × CS 136 ranked second, excelling in four important traits including parthenocarpic fruit set percentage, fruit expansion percentage, number of fruits per plant and yield per plant, highlighting its strong potential for enhancing both parthenocarpic fruit setting efficiency and yield. Several hybrids exhibited high levels of heterosis for yield and associated traits, highlighting their potential for commercial cultivation under protected environments. Five SSR markers previously linked to parthenocarpy in cucumber (SSR01148, SSR01012, SSR10476, SSR19174, and SSR16226) were tested for validation, but four showed no amplification while SSR10476 lacked polymorphism between parthenocarpic and non-parthenocarpic lines, indicating their ineffectiveness in the current genetic background. The top four hybrids, based on their performance for various traits, high GCA estimates of their parents, high SCA estimates and pioneer heterotic performance were CS 143 × CS 136, CS 141 × CS 142, CS 141 × CS 135 and CS 135 × CS 141. This study also aimed to address key limitations of the commercial hybrid KPCH-1, including limited cluster-bearing at lower nodes and fruit deformities. Among the 30 hybrids developed, CS 137 × CS 141 and CS 142 × CS 141 showed earlier expression of clustered fruits compared to KPCH-1 and hybrids such as CS 137 × CS 136, CS 141 × CS 142, and CS 141 × CS 143 exhibited complete absence of fruit deformities, while several others showed marked reduction. Parthenocarpic fruit set and fruit expansion percentages, showing strong positive correlations, high heritability and direct effects on yield, emerged as key selection criteria in developing high-yielding parthenocarpic cucumber hybrids for protected cultivation.
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
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, T
The 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.
Development of inbreds in bitter gourd (momordica charantia L.) through conventional and biotechnological approaches
(Department of Vegetable Science, College of Horticulture, Vellanikkara, 2020) Reshmika, P K; Pradeepkumar, T
Development of parthenocarpic gynoecious hybrids in cucumber (Cucumis sativus L.) for protected cultivation
(Department of Olericulture, College of Horticulture, Vellanikkara, 2017) Ajay Bhardwaj; Pradeepkumar, T
Development of tropical gynoecious lines in cucumber (Cucumis sativus L.)
(Department of Olericulture, College of Horticulture, vellanikkara, 2016) Karthika, A K; Pradeepkumar, T
The present study ‘Development of tropical gynoecious lines in (Cucumber sativus L.) was carried out at Department of Olericulture, College of Horticulture, Kerala Agricultural university, Vellanikkara, Thrissur during August - November 2014 and February - May 2015 to evaluate the F1 hybrids and their F2 population for identifying stable tropical gynoecious lines of salad cucumber. Twelve hybrids produced by crossing gynoecious line EC 709119 with selected tropical monoecious parents were evaluated for gynoecy under rainshelter. Observations on important quantitative and qualitative characters were recorded. These hybrids were selfed to generate F2 population. F2 population was evaluated for expression of gynoecious character, viz., days taken for female flower anthesis, node at which first female flower emerged and total number of female flowers. The data was subjected to analysis of variance and variability among the genotypes was calculated. Most of the characters exhibited high heritability except for fruit parameters like fruit length, fruit girth and flesh thickness. For gynoecy F2 population from the cross EC 709119 x IC 538186 was observed as the most promising one. This population took only minimum days to form female flower and took minimum number of nodes to form female flower with highest number of female flowers and minimum male flowers. Sex ratio was estimated for parents, F1 hybrids and F2 population. Some of the parents having high sex ratio failed to transmit the same to its hybrid progenies. Among the parents, IC 538186 exhibited highest sex ratio. The highest sex ratio among the F2 population was for EC 709119 x IC 538186. Two populations viz., EC 709119 x IC 527427 and EC 709119 X IC 538186 exhibited a sex ratio of more than 2. The 4 F2 population evaluated for gynoecious trait were classified into monoecious and gynoecious character and tested for goodness of fit based on chi square test with monohybrid ratio of 3:1 being monoecy dominant over gynoecy. Out of the 4 populations, 2 populations were found to express significant value and fit in 3:1 ratio for dominant monoecious trait. The other 2 populations failed to fit in the 3:1 ratio. Bitterness was an important quality character which was absent in most of the parents except three of them during initial harvest. The crosses involving parents prone to bitterness were found to be bitter during later harvest, though all crosses were free of bitterness during initial stage. During later harvests, five parents were found to be bitter. Downy mildew incidence on parents and F1 hybrids were analyzed and Percentage of Disease Intensity (PDI) was estimated. Among parents, IC 538186 exhibited minimum infection and falls under the category of moderate resistance. Hybrid, EC 709119 x IC 538186 exhibited minimum infection and falls under the category of moderate resistance. Among 12 F2 populations, EC 709119 x IC 538186 produced maximum number of true gynoecious plants whereas eight F2 populations failed to produce even one true gynoecious plant. This population also exhibited moderate resistance against downy mildew disease and could be selected for developing true breeding stable gynoecious line for future breeding programme. Present investigation proved the scope of developing tropical gynoecious line from temperate lines by crossing with potential-monoecious lines and making selection in advance segregating generations for gynoecy.
Exploitation of cytoplasmic genetic male sterility (CGMS)system i chilli (Capsicum annuum L.)for the development of hybrids resistant to bacterial wilt
(Department of Vegetable Science ,College of Agriculture, Vellanikkara, 2025-12-18) Malavika, O; Pradeepkumar, T
Chilli botanically known as Capsicum annuum (2n=24, Solanaceae) is an important vegetable crop extensively cultivated in tropical and subtropical parts of the world. However, the crop faces major challenges due to its small flower size which complicates hybrid seed production and susceptibility to various biotic stresses, both of which restrict its yield potential. Developing host plant resistance to bacterial wilt through heterosis breeding using cytoplasmic gentic male sterility system and identified resistance sources is an effective method to mitigate the biotic stress and to realise the yield potential in chilli. With this context the current study entitled as “Exploitation of Cytoplasmic Genetic Male Sterility (CGMS) System in Chilli (Capsicum annuum L.) for the development of hybrids resistant to bacterial wilt” was carried out at the department of vegetable science during May 2022-Novemener 2024. Initially 17 chilli genotypes comprised of seven male sterile, maintainer and 10 restorer lines were evaluated at department of Vegetable Science, College of Agriculture, Vellanikkara, during May 2022-23. The statistical analysis of various characters exhibited significant differences among lines and restorer lines. The analysis on pollen sterility revealed that four lines were completely sterile, two were partially sterile and one line was found partially fertile throughout growing period. Among the lines, the highest plant height was recorded in VI046838 (116.66 cm), while VI060627 exhibited earliness in terms of days to flowering (24.56 days), fruiting (28.46 days), and maturity (44.30 days). Superior mean performance for fruit traits such as fruit weight, fruit length, fruit wall thickness, and fruit width was observed in VI046838. The mean performance of the genotypes for yield and quality parameters revealed notable differences. Fruit set percentage and fruit- bearing period were highest in AVPP9907, with values of 73.77% and 119.96 days, respectively. The highest fruit yield per plant and number of seeds were recorded in VI060629. The highest value of ascorbic acid observed in AVPP9907 (213.82 mg/100 g). Significant differences were also noted for oleoresin content, with AVPP9907 recording the highest value (18.10 %). Under field screening for bacterial wilt incidence, three genotypes were resistant, three were susceptible, and VI046838 was moderately susceptible. However, none of the seven genotypes showed resistance under artificial inoculation. Out of 10 restorer lines, AVPP9905 was found to be superior for multiple traits, including, days to first flowering, fruit weight, fruit length, fruit-bearing duration, number of fruits per plant, and overall yield. Chivar-1 showed the highest ascorbic acid content (197.83 mg/100 g), while LC 217 recorded the highest oleoresin content (18.37%). Highest capsaicin content was observed in AVPP9703 (1.06%). Bacterial wilt screening among the restorer lines revealed that seven were resistant, two were susceptible, and one was moderately resistant. High genotypic and phenotypic coefficient of variation was observed for fruit per plant, fruit length, fruit set percentage, fruit bearing period, fruit width, fruit wall thickness. Path analysis of the characters revealed that fruits per plant, fruit set percentage, and fruit bearing had a direct positive effect on yield, Twenty-four hybrids were produced from a cross involving 3 × 8 (L × T) mating design as a part of the second experiment. In third experiment Parents and hybrids, along with the standard check Sierra were evaluated for various characters. The ANOVA for combining ability revelated presence of significant general combining ability for parents and specific combining ability for hybrids. Predominance of non additive gene action was evident for almost all the characters under study. Significant heterosis was observed for most of the quantitative traits. Yield and contributing characters showed significant difference among parents, hybrids and check. The hybrid AVPP0516 × Anugraha exhibited the highest mean fruits per plant (179.65) and yield per plant (822.12 g). AVPP0517 was the best combiner for fruits per plant, Among the testers significantly highest positive GCA for yield per plant was noticed in Ujwala. In lines, AVPP9907 had highest GCA for yield per plant. Among the testers, Ujwala had maximum GCA for yield per plant. Regarding biochemical characters, VI059328 recorded highest GCA for ascorbic acid, Chivar-1 for oleoresin and AVPP9703 had highest GCA for capsaicin content. AVPP0516 × Anugraha, AVPP0517 × VI059328, and AVPP9907 × Ujwala were best combiner for yield per plant. For fruit setting percentage, highest SCA was observed in the cross AVPP0516 × LC 217. Highest SCA for ascorbic acid was observed in the hybrid AVPP0516 × VI059328. AVPP0517 × Ujwala exhibited maximum SCA for oleoresin. On estimation of heterosis for number of fruits per plant, the hybrid AVPP0516×Anugraha recorded superiority in terms of relative heterosis (137.88%), heterobeltiosis (102.26%) and standard heterosis (212.71%). Artificial screening of hybrids revealed that AVPP0517 × VI059328 was highly resistant, with a disease incidence of 10.05%, followed by AVPP0516 × Anugraha (10.35%) and AVPP0517 × EC566920 (11.50%). The reported DNA marker for bacterial wilt resistance was validated using the parental lines and their hybrids. The primer CAMS 451 exhibited polymorphism, producing the expected band size of 220 bp for susceptible genotypes and 210 bp for resistant genotypes. All 24 hybrids tested positive for the marker and were confirmed to be heterozygous in nature. The study stands out for the successful development of three promising F1 hybrids, namely, AVPP0516 × Anugraha, AVPP0517 × VI059328, and AVPP9907 × Ujwala. Based on their mean performance, combining ability, and heterosis, they were recognized as potential genotypes for further evaluation and utilization in breeding programs. Exceptional standard heterosis and resistance to bacterial wilt were also observed in four hybrid, AVPP0516 × Ujwala, AVPP0517 × Anugraha, AVPP0517 × Ujwala, and AVPP9907 × Anugraha which are potential candidates for replicated and multilocational testing under bacterial wilt prone zones in Kerala.
Functional analyses of phytomelatonins by omics approach
(Centre for Plant Biotechnology and Molecular Biology , College of Horticulture , Kerala Agricultural University, 2020) Nivethitha, B; Pradeepkumar, T
Genetic variation in tomato for yield and resistance to bacterial wilt
(Kerala Agricultural University, Vellanikara, 2001) Pradeepkumar, T; Dijee, Bastian; Joy, M; Radhakrishnan, N V; Aipe, K C
Heterosis breeding exploiting gynoecy in cucumber (Cucumis sativus L)
(Department of Olericulture, College of Horticulture, Vellanikkara, 2013) Airina, C K; Pradeepkumar, T
The present study ‘Heterosis breeding exploiting gynoecy in cucumber (Cucumis sativus L.)' was carried out at Department of Olericulture, College of Horticulture, Kerala Agricultural University, Vellanikkara, Thrissur during February-May 2012 and November 2012 to March 2013 to study the combining ability of gynoecious line with selected monoecious lines in cucumber and to investigate the scope of heterosis breeding exploiting gynoecious line. Twelve monoecious cucumber genotypes were collected from different parts of the country and was crossed in a topcross manner with a stable gynoecious inbred introduced from USA (EC 709119) as female parent. Observations on important 15 quantitative characters and 10 qualitative characters were recorded in five randomly selected plants. The F1 hybrids along with their parents were evaluated to obtain information on combining ability and heterosis. In this experiment, maleness was successfully induced in the gynoecious line (EC 709119) by spraying silver thiosulphate @ 200 ppm. The male flowers produced were uniform and normal as monoecious cultivars with high pollen fertility. Inspite of the temperate origin, the gynoecious character was stable throughout the life span. The data were subjected to combining ability analysis according to top cross method. Significant GCA effects were observed for all the characters except days to first male flower anthesis. Among 12 parents, CS-123 was observed as the good general combiner for fruit yield per vine, length of main vine, branches per plant, number of harvests, duration of the crop, fruits per plant and number of seeds per fruit. Heterosis values were estimated over mid, better and standard parents. Significant heterosis was observed for all the characters studied except average fruit weight. Almost all the hybrids produced significantly higher number of fruits per plant which contributed to increase in total yield. For vegetative characters and yield contributing characters like vine length, number of branches, number of fruits and number of harvests, EC 709119 x CS-123 was proved to be the best cross. The next best crosses with respect to quantitative characters were EC 709119 x IC 410638, EC 709119 x IC 410617 and EC 709119 x IC 538155). The performance of these hybrids with respect to qualitative characters viz, free from bitterness and crispness was also good. Hence, these hybrids can be advanced for testing under different agroclimatic conditions for commercial exploitation of hybrid vigour.
Influence of weather on the yield of pepper cv. panniyur 1 (Piper nicrum L.)
(Kerala Agricultural University, 1999) Pradeepkumar, T; Kumaran, K; Aipe, K C; Manomohandas, T P
Influence of weather on the yield of black pepper variety Panniyur 1 was studied by resorting correlation and regression analysis. Among the different weather variables, mean maximum temperature in March first fortnight and June second fortnight, total sunshine hours received during February first fortnight, March first fortnight and April second fortnight, total rainfall during March second fortnight and September second fortnight- mean maximum relative humidity during March first fortnight and mean minimum relative humidity during March second fortnight and July first fortnight were found to be significantly correlated with the pepper yield of succeeding year. By combining three weather variables viz., mean maximum temperature during March first fortnight, mean maximum temperature during June second fortnight and mean minimum relative humidity during July first fortnight, a regression equation was derived with an R2 can be used in predicting the pepper yield at the end of July first fortnight.
Inheritance of male sterility and development of new male sterile line in ridge gourd (Luffa acutangula (L.) Roxb.
(Department Of Olericulture, College Of Horticulture, Vellanikkara, 2011) Kannan, D; Pradeepkumar, T
The present study entitled “Inheritance of male sterility and development of new male sterile line in ridge gourd Luffa acutangula (L.) Roxb.” was undertaken in the Department of Olericulture, College of Horticulture, Vellanikkara during 2010-11. The objective of the study was to investigate the inheritance of male sterility in ridge gourd and to develop new male sterile line in ridge gourd using back cross generations of sterile hybrids. Study also aims in evaluating the performance of F1 hybrid, MS x Arka Sumeet for horticultural characters. Male sterile line is now maintained under in vitro condition. All the in vitro regenerated plants exhibited stability in the expression of male sterility. F2 seeds resulted from the selfing of F1 hybrid, MS x Arka Sumeet was raised to study the expression of male fertility. Out of 106 plants raised in the F2 generation, 56 plants were male fertile and 50 plants were male sterile. There were observable differences between the male sterile and male fertile plants with respect to male flower production whereas female flowers in both types were similar. Chi square test was employed to test the goodness of fit and the 9:7 (fertile: sterile) complementary gene action ratio was found to be significant. The Chi square test suggested that two dominant genes might have certain interactions with cytoplasmic male sterility (CMS). Two dominant fertility restorer gene viz., Rf1 and Rf2 is now proposed for this model. Assuming that MS line in ridge gourd is having a genotype, S (rf1rf1 rf2rf2) carrying both fertility restorer gene in homozygous recessive state and sterile cytoplasm, S, and Arka Sumeet possess a genotype N (Rf1Rf1 Rf2Rf2) carrying both fertility restorer gene in homozygous dominant state and normal fertile cytoplasm, N, F1 will be male fertile as the genotype of F1 is S (Rf1rf1 Rf2rf2). Here though F1 is inheriting a sterile cytoplasm from male sterile female parent, presence of both dominant fertility restorer gene, viz., Rf1 and Rf2 restores the fertility of F1. In F2, presence of both dominant fertility restorer gene in either homozygous or heterozygous condition ensures male fertility. All three way crosses viz, (MS x Deepthi) x Arka Sumeet, (MS x IC-92685) x Arka Sumeet, (MS x IC-92671) x Arka Sumeet and (MS x CO2) x Arka Sumeet regained fertility indicating the presence of dominant fertility restorer gene in Arka Sumeet. The sterile hybrids on back crossing with respective pollen parents also exhibited male fertility at various stages of crop growth. Restoration of male fertility in BC1 generation indicate the unstable nature of sterile cytoplasm. F2 segregants producing fertile racemes during last stage of crop growth have more potential for evolving stable male sterile lines. Selective mating of these plants with male sterile plants or selfing can be advocated for developing new male sterile lines. The F1 hybrid (MS x Arka Sumeet) exhibited significant heterobeltiosis for days to emergence of first female flower, node to first male flower, node to female flower, number of fruits per plant and yield per plant. High heterosis exhibited by the F1 hybrid (MS x Arka Sumeet) indicates the scope of exploiting the male sterile line in heterosis breeding. This is the first study which attempted to find out the inheritance of male sterility and fertility restoration in ridge gourd and is the first report of presence of cytoplasmic male sterility and dominant fertility restorer gene in cucurbits.
Interspecific hybridization in capsicum
(Department of Olericulture, College of horticulture, Vellanikkara, 1990) Pradeepkumar, T; Gopalakrishnan, T R
The present investigation "Interspecific hybridization in Capsicum" was carried out at the College of Horticulture, Vellanikkara, Thrissur during September 1988-April 1990 to study cross compatibility among five Capsicum species and to exploit heterosis in interspecific hybrids. Eighty four chilli accessions, when subjected to the modern taxonomic treatments were found to fall under C. annum L. (62), C. frutescens L. (7), C. chinense Jacq. (14) and C. baccatum L. (1) Protein electrophoretic focussing revealed species specific protein bands in C. chinense, C. baccatum and C. chacoense. Fruit set was obtained in all the 28 crosses made among C. annuum.C. frutescens, C. chinense, C. baccatum and C. chacoense. Viable F1 and F2 seeds were obtained in eight crosses viz., C. annuum x C. chinense (P), C. annuum x C. chinense (NP), C.frutescens x C. annuum, C.chacoense x C. annuum, C. frutescens x C. chinense (P), C. chinense (P) x C. frutescens, C. frutescens x C. chinense (NP) and C. chinense (NP) x C. frutescens.
Molecular characterization of gynoecy in bitter gourd (Momordica charantia L.)
(Department of Plant Biotechnology, College of Agriculture, Vellanikkara, 2021) Nivethitha, B; Pradeepkumar, T
Bitter gourd (Momordica charantia L.) is an important vegetable of tropics and sub-tropics of Asia belonging to Cucurbitaceae family. The immature fruits of bitter gourd are valued for its culinary and medicinal importance. Having highest amount of ascorbic acid and iron content, it is considered to be the most nutritive among all the cucurbitaceous vegetables. Heterosis is well exploited in bitter gourd for early maturity, increased yield and other agronomic traits through development of hybrids. However, the production of hybrids is labour-intensive involving manual bagging and hand pollination, thereby increasing the cost of seed production. The predominant sex form of bitter gourd is monoecious which bears separate male and female flowers on the same plant. However, gynoecious type bearing only female flowers were also reported in few locations of India, Japan and China. These gynoecious bitter gourd lines can be exploited as female parent to make hybrid seed production economical and easier, as it eliminates the need for emasculation and assisted pollination. It also aids in maintaining the genetic purity of hybrids and helps in harnessing the benefit of hybrid vigour including early maturity and high yield. Usually, the sex expression in cucurbits is highly influenced by environment and hormones, which makes the early phenotypic identification of gynoecy challenging. Identification of molecular markers tightly linked to gynoecy trait would ease the identification of gynoecious line in breeding programmes. In this study, 20 putative candidate genes governing sex expression were selected from different literatures and the gene sequences were retrieved from bitter gourd and cucumber genome assembly in NCBI GenBank database. Four ethylene biosynthesis genes (ACO1, ACS2, ACS3. ACS4 and ACS7), three MADS-box transcription factor encoding genes (AG6, MADS-boxTF23 and McAG2), one auxin related gene (CsARF5) and 12 WRKY transcription factor encoding genes comprise the list. A total of 20 gene-specific primer sets were designed from the selected region of each of the 20 genes. Genomic DNA was isolated from monoecious genotype, MC-136 and gynoecious, KAUMCGy-101. Efforts were made to amplify all the 20genes, however, only seven gene-specific primer sets designed from bitter gourd produced PCR amplification. The amplicons of expected product size from both the samples were sequenced. Sequence variation analysis was done by comparing the monoecious and gynoecious sequences generated to the reference sequence (monoecious) available in NCBI database for bitter gourd. Six valid variations including three SNPs and three In/Dels were found in AG6 and McAG2. All the variations except SNP1 of AG6 were present in non-coding regions. In/Del of 48 bp ([TC] 24 ) in AG6 gene caused a significant difference in the number of ‘TC’ repeats in the sequences which was used for the development of SSR marker. The marker showed clear polymorphism between monoecious and gynoecious genotypes used. It was further validated in three other monoecious lines namely, Priya, Priyanka and the wild type M. charantia var. muricata. Expected banding pattern showing polymorphism for gynoecious line was obtained for all the three monoecious lines screened. Thus, the study identified two potential candidate genes, AG6 and McAG2 for sex expression in bitter gourd. The SSR marker developed needs to be validated in large number of population and more number of varieties to confirm its use as a reliable polymorphic marker in marker-assisted selection of gynoecious lines of bitter gourd.
Performance of strawberry varieties in Wayanad District of Kerala
(Kerala Agricultural University, Vellanikara, 2002) Pradeepkumar, T; Sajith Babu, D; Aipe, K C
Tropical vegetables: New role as industrial raw material
(Department of Vegetable Science, College of Horticulture, Kerala Agricultural University, Vellanikkara, 2020) Alphy, Mathew; Pradeepkumar, T