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Open Access
Standardisation of selection criteria for cocoa hybrids
(Department of Plant Breeding and Genetics, College of Horticulture, Vellanikkara, 1998) Raji Varghese; KAU; Pushkaran, K
Investigation on standardisation of selection criteria for cocoa hybrids was conducted at Cadbury-KAU Co-operative cocoa Research Project (CC RP) Farm of Kerala Agricultural University, Vellanikkara during 1994-96. Twenty nine hybrids grown under Progeny Trial I and their 18 parents maintained in CYT-I were used for the study. The influence of seedling height and girth on yield was more pronounced in the case of seedlings one year after sowing than with those of 4 mas, 5 mas and 6 mas. The vegetative vigour measured by the height and diameter of trunk was found to be better correlated with precocity. The correlation coefficients of pod characters viz., length, width and weight of pods, number of beans, wet bean weight and pericarp thickness and seed characters viz., length, width, thickness and dryweight worked out between hybrids and female parents showed significant relationship in the case of pod length (r = 0.649) and number of beans (r = 0.606). But with mid parental value, the hybrids showed high correlation for the characters pod length, pod weight, number of beans, seed length, seed width and seed thickness (0.65, 0.45, 0.86, 0.70, 0.76 and 0.70 respectively). Heritability estimated by regressing offspring on female parent was high for the characters pod width, seed length and seed width (0,7, 0.64 and 0.78 respectively). Among the 29 hybrids studied, the hybrid H-4 of the cross GI 10.3 x GVI 54 was found to be promising in terms of both pod and wet bean yield. With the seedling characters of hybrids taken one year after sowing, a multiple regression equation for wet bean yield was fitted as: Y = 43 + 0.195 x1 + 3.70 X2 Where, x1 and X2 are height and girth of one year old seedlings respectively. This can be taken as a seedling selection criteria for cocoa hybrids.
Open Access
Genetic analysis of segregating generations of irradiated interspecific hybrids in okra (Abelmoschus spp.)
(Department of Plant Breeding and Genetics, College of Agriculture, Vellayani, 1997) Sophia John; KAU; Manju, P
A study* was. conducted in the Department of Plant Breeding and Genetics, College of Agriculture, Vellayani during l996-'97 to estimate the extent of variability generated in the f 2M? and F3M3 generations as a result of hybridisation and hybrid irradiation of the interspecific hybrids between A. s esculenins and A. manihot and also to isolate high yielding yellow vein mosaic disease resistant lines from among the segregating generations In the l-^M-, generation, the irradiated treatments were found to be late flowering and had more number of leaves per plant, flowers per plant and fruits per plant Irradiation was found to increase pollen sterility and was maximum in 10 kR However seed set was lower for the irradiated treatments. Average fruit weight and weight of fruits per plant was maximum in plants belonging to the treatment 20 kR. Fruit length and girth were found to increase with increasing radiation doses. Number of ridges per fruit, fruiting phase and plant duration were higher in the irradiated treatments when compared to 0 kR and was maximum in 40 kR Plant height was highest in the treatment 30 kR Irradiation was found to increase YVM disease incidence and fruit and shoot borer incidence and it was maximum in 30 kR among the irradiated treatments. However a few high yielding YVM disease resistant plants resembling the cultivated parent were also observed in 30 kR ■Genotypic coefficient of variation, heritability and genetic advance were high for number of branches per plant and number of seeds per fruit in all the irradiated treatments in F2M2. High heritability with high genetic advance were observed for leaf number, number of flowers per plant, Iruits • ' per plant and pollen sterility in 20 kR and 30 kR. Significant positive * . correlation of number of leaves per plant, flowers per plant and fruits per plant with weight of fruits per plant and also among themselves was observed in all the irradiated treatments in F2M0. Average fruit weight and fruit yield A* • 0 per plant were positively correlated in treatments 0 kR, 10 kR, 40 kR, P, and P2. % In F3M3 the irradiated treatments were found to be late flowering and had more number of leaves, branches, flowers and fruits per plant. Pollen sterility was lower for the irradiated treatments, when compared to the unirradiated treatment and was lowest in 30 kR. However the number of seeds per fruit was more in 30 kR compared to the other treatments excluding parental treatments. Irradiation was found to decrease average fruit weight but fruit yield per plant was more for the irradiated treatments due to the larger number of fruits and was maximum in 40 kR. Length of fruit increased with increasing radiation doses. Significant differences among the irradiated treatments were not observed with respect to number of ridges per fruit. Irradiation was found to increase the fruiting phase as well as plant duration. Plant height was maximum in 10 kR when compared to all the other treatments. Yellow vein mosaic disease incidence was high in the cultivated parent and the higher dose radiation treatments viz , 30 kR and 40 kR. From the present study *a few recombinants which resembled the cultivated parent, with high yield and YVM disease resistance could be isolated from 30 kR, which suggested that 30 kR could be ideal radiation dose for evolving high yielding YVM disease resistant lines in okra. Fruit and shoot borer incidence was highest in the cultivated parent and was also high in 30 kR. High to moderately high genotypic coefficient of variation was observed.lor number of branches per plant, leaves per plant, flowers per plant, fruits per plant, weight of fruits per plant and number of seeds per fruit in all irradiated treatments in F3M3. High heritability and genetic advance were observed lor number of fruits per plant, weight of fruits per plant, flowers per plant and pollen sterility in all the irradiated treatments. Number of leaves per plant, flowers per plant and fruits per plant were positively correlated with fruit yield per plant in all the treatments while average fruit weight had significant positive correlation with fruit yield per plant in 0 kR, P, and P2 in the F3M3 generation. As a future line of work, high yielding, YVM disease resistant plants assembling the cultivated parent which have been isolated from the treatment 30 kR will be further evaluated for a few more generations and if found superior and YVM disease resistant it will finally be developed into a YVM disease resistant variety.
Open Access
Combining ability in bhindi (Abelmoschus esculentus (L) Moench)
(Department of Plant Breeding and Genetics, College of Agriculture, Vellayani, 1995) Rajani, B; KAU; Manju, P
The study was carried out in the Department of Plant Breeding and Genetics, College of Agriculture , Vellayani during 1994-95 to estimate the combining ability of six genetically divergent parental strains of bhindi and their 30 F1 hybrids obtained by crossing the six parents in a diallel pattern. The magnitude of heterosis and nature of gene action governing the yield of fruits and other important yield attributes was also elicited through Hayman's numerical and graphical approach. The combinig ability analysis by the Method 1 of Griffing's (1956) approach revealed that the parent P4 (NBPGR/TCR 864) was the best general combiner for yield and a few yield related characters. Among the hybrids P1 X P4 (NBPGR/TCR 893 x NBPGR/TCR 864) exhibited outstanding s.c.a effects for yield. Non addictive gene action was found to govern days to first flowering number of flowers per plant, length of fruit, girth of fruit, weight of single fruit, weight of fruits per plant and number of seeds per fruit while the remaining characters were governed by addictive gene action.
Open Access
Studies on seed dormancy in rice (Oryza sativa. L.) with special reference to short duration varieties
(Faculty of Plant Breeding and Genetics, Agriculture College & Research Institute, Coimbatore, 1961) Gopinathan Nair, V; KAU; Ponnaiya, B W X
Work done in cereals and other crop plants on the factors related to seed dormancy (causes, tissues involved, stage of maturity at harvest, variation in period and genetics), which are important from a practical breeding point of view, has been critically reviewed with special reference to rice. Studies were undertaken on six short duration varieties of rice and their hybrids to estimate the period of dormancy, to understand the relative roles of the hull and the embryo and also to understand the mode of inheritance of the character. A new method was adopted in the estimation of dormancy. The period required for germination from flowering, determined by germination tests at periodic intervals, rendered a reliable estimate of inter and intravarietal variability for germination and formed the criterion for comparison of varieties and hybrids.
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
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.
Open Access
Variability analysis of allogamous traits in rice
(Department of Plant Breeding and Genetics, College of Horticulture, Vellanikkara, 2000) Deepa, K P; KAU; Radhakrishnan, V V
The research project entitled "Variability analysis of allogamous traits In rice (Oryza saliva L.)" was carried out in the College of Horticulture, Vellanikkara, Thrissur and the Agricultural Research Station, Mannuthy, Thrissur during the period 1998-99. The major objective of the study was to estimate the amount of variability for floral traits influencing out-crossing in high yielding, local and wild genotypes and CMS lines. It also evaluated the association of these floral traits to out-crossing and identified the genotypes with good morphological traits favouring out-crossing, which can be utilized for restructuring rice flower to suit hybrid seed production. Statistical analysis revealed significant variation in all the 18 characters studied viz, plant height, flag leaf angle, panicle exsertion at flowering and maturity, per cent out-crossing, anther length, filament length, pollen fertility, pollen viability, residual pollen, stigma length, stigma diameter, stigma hair length, angle between stigmatic lobes, stigma exsertion per cent, glume angle, duration of spikelet opening and flowering period in thirty three genotypes of rice. Highest genotypic coefficient and phcnotypic coefficients of variations were observed for STigma exsertion followed by per cent out-crossing and residual pollen. Correlation studies revealed significant positive correlation between out- crossing and the floral traits flag leaf angle and spikelet opening-closing duration. All the traits except residual pollen showed high heritability coupled with genetic gain. Statistical studies showed V20A and V20B, Jaya, Kanchana, Bharathi, Neeraja, Kairali, Nandyar, Chennellu, Oryza longistamina, Oryza oJjicinalis and Oryza spontanea with good floral traits favouring out-crossing.

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