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Open Access
Inheritance of resistance to leaf hopper [Amrasca biguttula biguttula (Ishida)] in okra, Abelmoschus esculentus (L.) Moench.
(Department of Plant Breeding and Genetics, College of Agriculture, Vellayani, 2003) Deepthi, Sivanandan; KAU; Sunny, K Ommen
Okra is an important vegetable crop grown in India and abroad for its fresh green pods. The leafhopper Amrasca biguttula biguttula is a major sucking pest of okra causing high damage to plants. High frequency of fruit picking and repeated application of chemical pesticides to tackle the hopper menace, often leaves toxic residues in the fruits. So it is inevitable that pest resistant varieties should be developed. Hence a study was undertaken to study the genetic variability, for yield and its component characters as well leafhopper resistance indices in a collection of okra genotypes, to estimate the combining ability and heterosis as well as gene effects involved in the inheritance of these characters using line x tester analysis. Forty okra germplasms collected from vanous sources were evaluated simultaneously for yield and leaf hopper resistance. ANOV A revealed that the treatments varied significantly for leafhopper resistance and also there was significant variation among treatments for yield and yield attributes viz., days to first flowering, leaf axil bearing first flower, number of primary branches, number of fruits per plant, length of fruit, girth of fruit, weight of fruit, yield per plant duration. Six genotypes exhibited resistance to the leafhopper throughout the crop duration. High values for phenotypic and genotypic coefficients of variation was recorded for number of primary branches followed by leafhopper population count. High heritability was exhibited by yield per plant followed by duration. Maximum genetic advance was observed for number of primary branches followed by yield per plant. Correlation analysis indicated that most character combinations had higher genotypic correlation coefficient than phenotypic correlation coefficient. Yield exhibited significant and positive correlation with number of fruits and average fruit weight and negative significant association with leaf axil bearing first flower, leafhopper population count and leafhopper injury score. Path analysis was carried out for nine biometric as well as two leafhopper injury indices which had high correlation with yield. Highest positive direct effect was exhibited by number of fruits while the highest negative direct effect on yield was recorded for leafhopper population count per plant. Resistant as well as susceptible genotypes were selected based on leafhopper population counts and leafhopper injury score. Five resistant lines (female parent) viz., Nemom (T21), re 45792, Venjaramood (T23), AE 279 and Palappur (T20) and three susceptible testers (male parent) viz., Venganoor (T1S), Aruna (T37) and Kalliyur (T24) were selected as parents for L x T analysis. These were crossed in a line x tester fashion to produce 15 hybrids. During L x T programme highly significant sea as well as gea effects were obtained for yield. Lt was the best line while T 2 was the best tester. Among hybrids L3 x T 2 was the best considering leafhopper resistance as well as yield and yield attributes. Negative and significant sea effects were observed for days to first flowering and leafhopper population count. It possessed all the desirable characters like high yield, greater weight and girth of fruits and number of fruits. It is also an early flowering type. The ratio of additive to dominance variance was less than one for most of the traits studied including leafhopper population counts and leafhopper injury , scores, indicates the predominance of non-additive gene action. Since there is preponderance of non additive gene effects for characters such as yield and its components as well as leafhopper resistance parameters, exploitation of hybrid vigour is an appropriate breeding approach where yield and leafhopper resistance are considered.
Open Access
Compatibility studies in monopodial orchids
(Department of Plant Breeding and Genetics, College of Agriculture, Vellayani, 2003) Ninitha Nath, C; KAU; Lekha Rani C
A research programme "Compatibility studies In monopodia! orchids" was carried out in the Department of Plant Breeding and Genetics, College of Agriculture, Vellayani during 2001-2003 with the objective of undertaking intra and intergeneric hybridization and in vitro embryo culture in monopodial orchids. Twelve monopodial orchid genotypes comprising of six mono generic and six bigeneric hybrids were selected as parents after initial evaluation. They were evaluated adopting completely randomized design with six replications. Analysis of variance revealed significant differences for almost all the characters studied. Genotypic and phenotypic coefficients of variation were high for number of aerial roots, leaf area and width of leaf. Characters like number of aerial roots, width of leaf, leaf area and number of flowers per inflorescence had high heritability coupled with high genetic advance. Significant positive inter-correlation at genotypic and phenotypic levels was observed for length of flow'er and width of flower with number of leaves per cane, number of aerial roots, number of spikes per cane, length of inflorescence and length of scape. The 12 parental genotypes were crossed in all possible combinations (144) after preliminary studies on floral biology. A total of 116 crosses were done including 50 crosses, 54 reciprocals and 12 selfs. Incompatibility reaction was noticed at different stages ranging from flower abscission before the onset of any visible post pollination change to instances where seeds geminated but aborted in culture. A total of 58 combinations attempted succumbed to incompatibility at these different stages from pollination to deflasking. Harvestable green capsules were obtained from 58 combinations and they were inoculated in MS half strength basal medium. Percentage capsule yield ranged from 8 to 38 in the various hybrid combinations. Percentage filled seeds ranged from 18 to 76 in the various combinations. Capsules from twelve combinations did not contain seeds and seeds from ten combinations did not germinate on inoculation. Protocorms of developing seedlings from twelve combinations aborted at various stages of in vitro development. The remaining 24 cross combinations were taken through three to four subculture passages. Seedlings having 2-3 leaves and 2-4 roots were deflasked. Significant differences among the combinations were observed with respect to number of days taken for germination initiation, number of days taken for development of protocorms, chlorophyll, first leaf and first root primordia and for deflasking. Significant differences in seedling morphology were observed among the 24 hybrid combinations at deflasking with respect to all the seven vegetative characters studied.
Open Access
Genetic variability and character associations in Anthurium andreanum Linden
(Department of Plant Breeding and Genetics, College of Agriculture, Vellayani, 2002) Asish, K Binodh; KAU; Mayadevi, P
Genetic variability studies was conducted on fifty different genotypes of Anthurium andreanum Linden, generated from a previous hybridisation programme in the Department of Plant Breeding and Genetics, College of Agriculture, Vellayani. The analysis of variance revealed significant variation among the fifty genotypes for all the seventeen quantitative characters studied. This reveals the high genetic potential for the improvement of this crop. Variability studies indicated that high phenotypic and genotypic coefficients of variation for the characters of total anthocyanin content, pollen fertility, inclination of candle to spathe and duration of interphase. Except for leaf area and number of flowers per candle, all the other characters were highly influenced by genotypic variation. High heritability with a good genetic advance was found for all characters except for suckering ability and number of spadices/plant/year which exhibited medium heritability and high genetic advance. These results indicated that selection of plants which were phenotypically superior with respect to fifteen of the characters studied will certainly result in a significant improvement in the next generations. Plant height was found to have significant positive phenotypic correlation with internode length, leaf area and days from emergence to maturity of inflorescence. Candle length showed significant positive correlation with leaf area, number of flowers per candle, life of spadix and duration of female phase. Genotypic correlations were higher and for most of the characters it showed high positive correlations. Most of the estimates of the environmental correlation coefficients for the characters are low and insignificant indicating the least effect of environment in the expression of the characters studied. Pollen fertility ranged from 7.03 per cent in PR X FR(2) to 50.80 per cent in U X MW. The protogynous nature of the flower and low pollen fertility suggests the hybrid nature of the crop. During the months from March to July, the pollen emergence pattern was less where the maximum and minimum temperatures were relatively high. Path coefficient analysis revealed that the characters leaf area and duration of female phase are more associated with number of flowers per candle and 40 per cent variation in flower production was attributed by the environment. High selection index values were recorded by the genotype LR X DT followed by FR X MW(l), PR X LR (3), MW X FRO). If parents are selected based on selection index values, 45 per cent genetic gain can be expected in the next generation.
Open Access
Impact of seed deterioration on seedling vigour in mango (Mangifera indica L.)
(Department of Plant Breeding and Genetics, College of Horticulture, Vellanikkara, 2002) Anila, P; KAU; Girija, T
The present study on 'Impact of seed deterioration on seedling vigour in mango' was undertaken at the Department of Plant Breeding and Genetics, College of Horticulture, Vellanikkara during 1999-2001 with the objectives of assessing the variability of seedling characters obtained fr0111 a single plant, the effect of seed deterioration on seedling characters and to ascertain the critical moisture content of the varieties. Three varieties of mango were selected for the study. Assessment of variability of seedling characters of these varieties revealed that seedling girth is the most variable character, variability within varieties and between varieties was high for this character. Moreover, the response of girth to variation in seed weight due to loss in moisture content of the seed was also high indicating that this character may be influenced by both genetic factor as well as the physiological condition of the seed. The critical, moisture content was estimated to be 24% for Chandrakkaran, 30% for Moovandan and 28% for Puliyan. Seedling characters like height, girth, internodal length, number of leaves etc. were studied. These characters were found to be highly depended upon the moisture content of seed. There was considerable reduction in these characters with loss of moisture from seed. Polyembryonic nature of these varieties were not affected by seed desiccation. Biochemical characters like chlorophyll content, phenol content and sugar content were found to decrease with seed desiccation. Electrolyte leakage was found to be high with seed desiccation leading to reduction in viability. Seedling vigour was found to be positively correlated with biochemical characters.
Open Access
Legume pod borer resistance and genetic divergence in domestic germplasm of yard-long bean (Vigna unguiculata ssp. sesquipedalis(L.) Verdc.)
(Department of Plant Breeding and Genetics, College of Agriculture, Vellayani, 2000) Vidya, C; KAU; Sunny Oommen, K
The present study aimed at the evaluation of variability in domestic germplasm of yard-long bean for yield, and legume pod borer resistance was carried out at the Department of Plant Breeding and Genetics, College of Agriculture, Vellayani. Data for the investigation was collected from two field experiments conducted during the period 1998-2000. Fifty diverse genotypes of yard-long bean were evaluated for yield and related characters in a field experiment in randomised block design with three replications. Analysis of variance revealed significant differences among the varieties for all the twelve characters studied. High PCV and GCV were observed for yield of vegetable pods per plant, number of pods per plant, number of pods per inflorescence, length of main stem and pod weight. High heritability coupled with high genetic advance were also observed for these characters. Pod yield per plant showed high positive correlation with number of pods per plant, number of pods per inflorescence, pod weight and length of harvesting period. at genotypic level. Path analysis revealed that number of pods per plant and pod weight were the primary yield contributing characters owing to their high direct effect on pod yield. 2 So selection based on these characters will result in improvement of yield in yard-long bean. Based on Mahalanobis D2 statistic, the 50 cultivars were grouped into four clusters. Cluster I formed the largest cluster with 28 varieties while cluster IV had only a single cultivar. The genetic distance was maximum . ' between clusters I and IV and minimum between clusters III and IV. Cluster I had the highest intracluster distance. The single variety Vs 47 of cluster IV was identified as the highest yielder of green pods. Hybridisation of this variety with varieties having high pod number per plant or pod weight would be beneficial. The cultivars Vs 45 and Vs 49 belonging to cluster III possessed the highest pod weight and pod number per plant respectively. So hybridisation programmes utilising these varieties as parents is worthy of consideration for developing high yielding varieties in yard-long bean. In the field screening programme for legume pod borer resistance all the 50 yard-long bean cultivars were evaluated on the basis of overall plant resistance index (Ipr} computed using a combination of flower, pod and seed damage measurements viz., number of larvae in 25 flowers, percentage pod infestation and seed damage index (computed based on the number of damaged seeds in a sample of 25 pods) respectively. Cultivars showed significant differences among them for these damage . parameters as well as for resistance index computed based on them. The cultivars suffering least flower damage were Vs 5 and Vs 33. Lowest pod damage were recorded for the cultivars Vs 34, Vs 39 and Vs 42. Seed damage index value was the lowest for cultivar Vs 2. 3 Vs 34 with the lowest Ipr value was identified as the most resistant among the 50 yard-long bean varieties. The cultivars Vs 2, Vs 29, Vs 39 and Vs 42 were on par with Vs 34. Correlation analysis of the different damage parameters did not suggest any relationship between flower damage and pod damage or seed damage. However pod damage showed high positive correlation with seed damage. Cluster analysis based on the different damage parameters enabled to group varieties into seven clusters. Based on cluster means of the various damage parameters, cluster IV and I were those suffering least flower and pod damage respectively. So hybridisation programmes utilising varieties from these two clusters could lead to the production of varieties with higher level of legume pod borer resistance. Studies on relationship between pod damage and two pod characters viz., pod wall thickness and fibre content of pods indicated that these pod characters did not influence infestation and damage by legume pod borer. Based on superior yield performance and high level of resistance to legume pod borer, the cultivar Vs 42 is identified as a variety suitable for cultivation in legume pad borer endemic areas. Further, breeding programmes utilising the varieties with high yield and legume pod borer resistance identified in this study could help in evolving better yielding varieties with resistance to pod borer in yard-long bean.
Open Access
Genetics of bruchid (Callosobruchus sp.) resistance and yield in cowpea
(Department of Plant Breeding and Genetics, College of Horticulture, Vellanikkara, 2001) Jyothi, C; KAU; Kanakamany, M T
The present study 'Genetics of bruchid (Callosobruchus sp.) resistance and yield in cowpea' was undertaken in the Department of Plant Breeding and Genetics, College of Horticulture, Kerala Agricultural University, Vellanikkara. The study was carried out to estimate the various genetic parameters of characters, to identify the yield components, to study association of characters related to pulse beetle resistance and to identify superior genotypes and hybrids having high yield and tolerance to pulse beetle. High variability among parents and hybrids was observed for most of the yield and bruchid resistance traits. The characters namely number of eggs laid, number of adult beetles emerged, number of bore holes produced, loss of weight per seed and tannin content exhibited higher values of heritability, genetic advance and genotypic coefficient of variation, indicating the preponderance of additive gene effects. A positive association was found to exist among yield attributes and also with yield in parents and hybrids. Genotypes having a thicker seed coat showed better resistance to pulse beetle attack and this character was found to be independent in gene action. Kanakamoni among the lines and EC 390231 among the testers were found to be the most promising genotypes for hybridization and selection since they recorded high positive gca. For heterosis breeding the crosses Kanakamoni x IC 201092 followed by C 152 x EC 390231 were found to be superior for pod yield. Kanakamoni and C 152 among the lines and EC 390231 and IC 201092 among the testers showed high tolerance to pulse beetle attack and are recommended for evolving resistant varieties using these genotypes through hybridization and selection. For evolving hybrids showing resistance to pulse beetle the crosses, C 152 x EC 367711 and V 240 x IC 201092 were rated supreme.
Open Access
RAPD analysis to assess the genetic stability in tissue culture derived black pepper plants
(Department of Plantation Crops and Spices, College of Horticulture, Vellanikkara, 2000) Haneesh Babu, T P; KAU; Nazeem, P A
As part of the Post Graduate programme in the Department of Plantation Crops and Spices, College of Horticulture, Vellanikkara experiments were conducted at the Centre for Plant Biotechnology and Molecular Biology, College of Horticulture, Vellanikkara during the period from 1997 to 1999; to standardise the method of DNA isolation and the protocol for RAPD analysis in- black pepper so as to assess the genetic stability and clonal fidelity of tissue culture derived black pepper plants. Three methods described by Dellaporta et at. (1983); Doyle- and Doyle (1987) and Rogers and Bendich (1994) were tried. Modification of these methods were tried to find out the effect of grinding the tissue in liquid N2 and use of jJ- mercapto ethanol. The method suggested by Rogers and Bendich (1994) was found better in terms of yield and quality of DNA. Grinding with liquid N2 and use of jJ~ mercapto ethanol was found effective. Tender leaves were found to be the best source for recovery of quality DNA. Different levels and possible combinations of dNTPs, primer and enzyme were tried to standardise optimum levels of reaction components for RAPD analysis of black pepper. Best thermal cycle was identified for the amplification of black pepper genomic DNA. Different concentration of template DNA tried was found not influencing the amplification pattern. Sixty decarner primers were screened for amplification of black pepper genomic DNA. Ten primers selected for good amplification were used to screen five varieties of black pepper. Three primers, which showed polymorphism and stability of amplification, were used for analysis of TC plants. Tissue culture regenerants derived by bud culture were subjected to RAPD analysis using three primers (OPP-l, OPP-8, OPP-14). All the regenerants studied gave a uniform RAPD profile except in two regenerants where there was difference in expression of two non-distinct bands. The present study was effective in optimizing the protocol for RAPD analysis in black pepper and is the first of its kind reported in this valuable spice crop. The primers identified for varietal screening and the RAPD profile developed for the five important varieties can be utilised for fingerprinting of these varieties. The results also ensure the genetic stability and clonal fidelity of the TC plants and the suitability of tissue culture protocol for commercialisation.
Open Access
Variability in morphological, physiological and biochemical characters in kalmegh (Andrographis paniculata Nees.)
(Department of Plant Breeding and Genetics, College of Horticulture, Vellanikkara, 2000) Laju Paul, K; KAU; Ibrahim, K K
An experiment ID kalmegh (Andrographis panicu/ata Nees.) was conducted in the Department of Plant Breeding and Genetics, College of Horticulture, Vellanikkara during 1998-2000, with the objectives of understanding the morphological variability, growth pattern, optimum stage of harvest and the variation in different biochemical compounds among the accessions. The accessions were collected from Kerala and neighbouring states. Ten accessions were compared based on 50 morphological, 16 physiological and 3 biochemical characters. In general, accessions showed uniform root, inflorescence, flower and fruit characters. However a limited variation for habit, stem and leaf characters existed among most of the accessions. In general, accessions showed variability for characters namely total plant dry weight, stem dry weight, leaf dry weight and root dry weight when observed at 1, 2, 3 and 4 months after transplanting. Ranking of the accessions was not consistent on the various dates of harvest. Optimum stage of harvest is recommended as 3 months after transplanting. At this stage maximum herbage yield was recorded by accession Ac-4. Physiological parameters namely Leaf area and LAI showed steady increase up to three months after transplanting and thereafter it declined. LAR, RGR, CGR and NAR recorded higher values at earlier dates. Heritability (broad sense) of characters showed inconsistency at various dates of harvest. However leaf dry weight showed higher heritability on all dates. At 3 months after transplanting i.e. the optimum stage of harvest, heritability was high for all the characters relating to herbage yield and most of the physiological parameters. Biochemical studies revealed that the total phenol content and andrographolide content varied considerably among the accessions. Phenol content in the plant increased with an increase in dry weight while Andrographolide content increased with a proportionate increase in moisture content.
Open Access
Combining ability and heterosis in bittergourd (Momordica charantia L.)
(Department of Plant Breeding and Genetics, College of Agriculture, Vellayani, 2000) Iswara Prasad, C M; KAU; Manju, P
The present investigation "Combining ability and heterosis in bittergourd (Momordica charantia L.)" was conducted in the Department of Plant Breeding and Genetics, College of Agriculture, Vellayani, involving seven parents, 21 hybrids without reciprocals and the check variety Preethi with a view to assess the general and specific combining abilities, the nature of gene action and to estimate the extent of heterosis for 13 characters in bittergourd. Significant differences were noticed among the 29 genotypes for all the characters studied with respect to the mean performance. Among the parents MC 17 (P,) and MC 40 (P6) and among the hybrids MC 18 x MC 40 (P2 ~ P6) had the high mean performance for yield and most of the yield attributes. The estimates of PCV and GCV for most of the traits were comparatively high with very high estimates of heritability and genetic advance indicating the scope of improvement through selection. The combining ability analys.is revealed that both GCA and SCA variances were significant for all the characters indicating the involvement of both additive and non-additive gene action. However, the ratio of additive to dominance variance was less than unity for most of the characters indicating the predominance of non-additive gene action and thereby suggesting the importance of heterosis breeding programme in crop improvement. The parent MC 40 (P6) and the hybrid MC 18 x MC 40 (P2 x P6) were the best general and specific combiners respectively for yield and most of the yield related components. Several )1ybrids possessed significant relative heterosis, heterobeltiosis and standard heterosis for all the characters except significant standard heterosis for 100 seed weight. The hybrid MC 18 x MC 40 (P2 x P6) recorded the maximum positive standard heterosis for yield and most of the yield attributes. However, the hybrids MC 17 x MC 40 (PI x P6), MC 17 x MC 53 (PI x P7) and MC 18 x MC 53 (P2 x P7) also exhibited good performance with regard to yield and related characters.

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