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Open Access
Genetic divergence, prepotency and inbreeding depression in para rubber (Hevea brasiliensis Muell. Arg.)
(Department of Plant Breeding, College of Agriculture, Vellayani, 1992) Kavitha Mydin, K; KAU; Gopinathan Nair, V
A study on genetic divergence, prepotency and inbreeding depression in rubber was undertaken in an effort to identify clones for use as components of polyclonal seed gardens. Forty clones of Indian, Indonesian, Malaysian and Sri Lankan origin were evaluated in a replicated trial at the Rubber Research Institute of India. Genetic variability, correlations and the cause and effect relationships of dry rubber yield and its components were worked out. Genetic divergence was estimated employing the Mahalanobis' D2 techinique. The factors of divergence were identified through principal factor analysis. Twenty promising clones from genetically divergent clusters were subjected to seedling progeny analyses for the estimation of propotency based on performance of their open pollinated seedling progenies and inbreeding depression in the first generation of selfing. Significant clonal variation was revealed in respect of all the physiological, morphological and structural attributes studied as mean values for the fourth year of tapping for the stress period and for the peak yield period. High genetic variability for volume of latex under stress, plugging index under stress, annual mean dry rubber yield and dry rubber yield during the stress and peak periods was indicated by the high estimates of genotypic coefficient of variation. Additive gene effects offering scope for improvement through selection was indicated for dry rubber yield, latex flow rate and volume of latex during the three periods, girth increment rate, annual mean plugging index and plugging index under stress, by the moderate to high heritability estimates along with high genetic advance for these traits. Non- additive gene action was indicated by the high heritability and low genetic advance for dry rubber content during the three periods, girth and bark thickness. At both genotypic and phenotypic levels, annual mean dry rubber yield showed moderate to high positive correlations with dry rubber content and latex flow rate during the three periods, girth, girth increment rate, length of the tapping panel and bark thickness and negative correlations with yield depression under stress and plugging index during the three periods. Dry rubber yield under stress emerged as a more important component than peak dry rubber yield by its higher magnitude of positive direct effect on annual mean dry rubber yield. Latex flow rate during the stress and peak periods and annual mean volume of latex exhibited high positive direct effects on annual mean dry rubber yield while plugging index during the peak yield period, volume of latex under stress and girth increment rate had negative direct effects on annual mean dry rubber yield. The magnitude and direction of the effects of the components on dry rubber yield during the three periods varied indicating these relationships to be under different genetic control. Selection for a high dry rubber yield under stress, annual mean volume of latex and latex flow rate during the stress and peak periods and against a high plugging index during the peak period, volume of latex under stress and girth increment rate would help achieve improvement in annual mean dry rubber yield. Considerable genetic diversity was revealed by the wide range of D2 values and intra and inter cluster distances. The forty clones were grouped into eight genetically divergent clusters irrespective of their country of origin indicating the absence of any relationship between geographical diversity and genetic divergence. Volume of latex, plugging index, latex flow rate, dry rubber content and dry rubber yield contributed more towards divergence than the morphological and structural attributes. Supporting evidence was obtained from principal factor analysis which revealed the yield factor to be the main factor of divergence with respect to the clusters studied. Junveile rubber yield on test tapping, number of latex vessel rows and number of leaf flushes in seedling progenies exhibited high heritability and genetic advance indicating scope for their use as early selection parameters, while girth exhibited high heritability and low genetic advance. These three traits showed significant positive correlations with juvenile rubber yield, of which girth exhibited the strongest association. Juvenile rubber yield, number of latex vessel rows, girth and number of leaf flushes were identified as important traits for being accorded simultaneous emphasis in the computation of performance index and index scores for the determination of recovery of superior seedlings as estimates of prepotency. Nine clones were identified as likely preopotents on the basis of seedling progeny analysis at the age of two years. Selfing resulted in a lower fruit set than open pollination in the clones in general. No significant inbreeding depression was recorded for juvenile vegetative traits and rubber yield in seedlings. Clones PB 28/83, PB 215, RRII 105, AVT 73, PB 217, PB 252, Ch 26, PB 242 and PB 5/51 were identified as likely prepotents from three genetically divergent clusters. They recorded superiority for yield and various yield components. These clones exhibited synchrony in flowering and are suggested as components of a nine parent polyclonal seed garden. For a seven parent seed garden the clones suggested to be excluded are PB 5/51 and PB 242. A polyclonal seed garden comprising these nine or seven clones as components could generate good quality polycross seed material. Appropriate seed garden layouts have been suggested.
Open Access
Superovulation, Sychronisation of oestrus and embryo transfer in crossbred cows
(Department of Animal Reproduction, College of Veterinary and Animal Sciences, Mannuthy, 1992) Suresan Nair, S P; KAU; Neelakanta Iyer, C P
The object of the present investigation was to ascertain the influence of varying doses of FSH and PGF2₻on various parameters of superovulation and embryo collections, with the ultimate aim of fixing the optimum dose of FSH and PGF2 ₻ required for successful superovulation in crossbred cows. Detailed investigation was made in a herd of 32 crossbred cows belonging to the University Livestock Farm, attached to the College of Veterinary and Animal Sciences, Mannuthy, during the period from April 1989 to December, 1991. The animals were randomly divided into 6 groups based on 3 doses of FSH and 2 doses of PGF2 ₻ administered. It was observed that 20 mg of FSH, with 25 mg of PGF2 induced satisfactory superovulation response and 20 mg of FSH with 15 mg of PGF2 ₻ resulted in better embryo quality. Further increase in the dose did not show any improvement in the responses. Right ovary showed more response than the left. Day 11 was found to be ideal for starting superovulation treatment, and day 6 for embryo collection, though statistically no significant influence was noticed by day of collection on superovulation response. Parity and age of donors had no influence on superovulation. Rainy and summer months were found to be better seasons for superovulation treatment than winter. Shorter duration (24 hr) of oestrum was noticed in more number of animals. 20 mg of FSH and 25 mg of PGF2 ₻ (group 3) yielded better cervical dilatation and flushing efficiency. Level of progesterone increased following superovulation treatment and declined 3 days before oestrum and reached the lowest level on day of oestrum. Pregnancy rate achieved was 33.3 per cent, but calving percentage was nil.
Open Access
Status, availability and transformation of magnesium in acid soils of Kerala
(Department of Soil Science and Agricultural Chemistry, College of Horticulture, Vellanikkara, 1992) Prema, D; KAU; Jose, A I
The investigation consisted of four parts, namely (1) magnesium status of soils in Kerala (2) evaluation of laboratory indices of Mg availability (3) transformation of applied Mg in soil and (4) pattern of Mg uptake by banana from different sources at different levels. In Part I, one hundred and fifty surface samples were collected from all over the State of Kerala, to study the status of Mg as well as properties in relation to the behaviour of Mg in these soils. In part 2, some selected chemical agents were tried in twenty selected soils in order to evolve a suitable extractant for available Mg. In Part 3, two acid rice soils of Kerala namely, Karappadam and laterite were incubated at field capacity for a period of 180 days with and without the addition of magnesium sulphate, magnesite and dolomite at the rate of 1250, 2500 and 3750 kg MgO ha-1, to monitor the pattern of release of Mg from applied sources . Soil samples were drawn regularly at 15 days interval for the determination of available Mq and at 60 days interval for the determination of other important chemical properties. In Part 4, a field experiment of banana was conducted to study the response to applied Mg.
Open Access
Ochratoxicosis in quails (Coturnix coturnix japonica) with special reference to Inununopathological response
(Centre of Excellence in Pathology, College of Veterinary and Animal Sciences, Mannuthy, 1992) Amir Abbas, Farshid; KAU; Rajan, A
In this investigation the pathological effects of OA in quail embryo and adult quail were studied with special reference to the immune system. Ochratoxin A (OA) was inoculated into the quail embryos, at the dose rate of 0.02 ^g per embryo. There was 68.66 per cent mortality which clearly indicated the direct action of OA. The embryos which were sacrificed on the 13th and 16th day of incubation showed significant reduction in the body weight, weight of bursa of Fabricius, spleen and thymus. Histological changes in these lymphoid organs were, atrophy, necrosis and depletion of lymphoid elements. Ultrastructurally the changes were time dependent. There were changes in the shape of the nucleus with condensation of granular and fibrillar components of the nucleoli. The adverse immunobiological effect of OA on the developing lymphoid organs was established by histological and ultra structural studies. OA at the dose rate of 50 /ag/bird/day for a period of 60 days was administered through oesophageal intubation. Pathological changes were sequentially documented with special reference to the immune system. In the OA fed quails, the clinical signs included emaciation and hyperexcitation at the later part of the experiment. There was highly significant reduction in the body weight, weight of bursa of Fabricius, spleen and thymus. The reduction in the weight of lymphoid organs gave evidence to the adverse effects of OA on the immune system. There was reduction in the total erythrocyte count (TEC), haemoglobin (Hb) concentration and packed cell volume in OA fed birds indicating the significant damaging effect on the haemopoietic sytem. Estimation of total serum protein (TSP), serum globulin (SGI) and serum immunoglobulin fractions clarified the biological adverse effect of OA on the humoral immune system. Highly significant reduction in total leukocyte count (TLC) and T cell dependent lymphopenia proved the immunosuppressive effect of OA. There was reduction in T cells, increase migration indices in response to Fowl pox antigen in leukocyte migration inhibition test (LMIT), the reduction in the cutaneous response to 2,4-dinitrochlorobenzene (DNCB) and phytohaemagglutinin-M (PHA-M) and spleen indices in the graft versus host reaction (GVHR), clarified the immunotoxicity of OA on the cell-mediated immune system.
Open Access
Requirements of protein and energy for broilers during summer season
(Department of Poultry Science, College of Veterinary and Animal Sciences, Mannuthy, 1992) Amritha Viswanath; KAU; Ramakrishnan, A
An experiment was designed and conducted to establish the requirements of protein and energy for broilers during the summer season in the hot and humid atmosphere of Kerala. Four trials were conducted in a span of two years. In each trial the following energy-protein combinations at starter, and subsequent finisher diets were tested in a completely randomised design. Treatment Starter Finisher Diet 1 22% CP:2900 Kcal ME/kg 19% CP:3000 Kcal ME/kg Diet 2 24% CP:2900 Kcal ME/kg 19% CP:2900 Kcal ME/kg Diet 3 26% CP:2900 Kcal ME/kg 19% CP:3000 Kcal ME/kg Diet 4 26% CP:2900 Kcal ME/kg 19% CP:2900 Kcal ME/kg Trials corresponding to the same period for the two years were pooled and the results were presented as Period A (started in early summer and ended in peak summer) and Period B (started in peak summer and ended in late summer). Except for the difference in nutrient intake, all the management practices followed were uniform for the differenttrials and treatment groups. Feed and water were given ad lib. The chicks were fed with starter diet upto six weeks of age and finisher diet upto eighth week of age. Results of the study revealed that body weight at eighth week of age was not influenced by different- energy protein levels in the diet during both Period A and Period B. But difference between periods was statistically (P < 0.01) significant. Broiler chicks reared during Period A showed significantly lower mean body weight at eight week than Period., B. Dietary combination of 22:2900 in the starter and 19:3000 in the finisher stage upto eight weeks of age was found to be optimum for growth of broilers in summer months in Kerala. Body weight gain was not influenced by the dietary. treatments and by periods upto sixth week of age. Thereafter body weight gain was influenced by season. Broiler chicks reared during Period B showed higher body weight gain than Period A. Maximum body weight gain was recorded at fifth week of age in both Period A and Period B. Feed consumption was not affected by dietary treatments in both Period A and Period B, but was significantly affected by periods at seventh and eighth week of age. Feed efficiency was also not affected by different dietary treatments upto eight weeks of age. Broiler chicks reared during Period A showed poorer feed efficiency from sixth week onwards.
Open Access
Seed dormancy in groundnut
(Department of Agricultural Botany, College of Horticulture, Vellanikkara, 1992) Presanna Kumari, K T; KAU; Narayanan Namboodiri, K M
The present investigation entitled "Seed dormancy in groundnut" was undertaken in the Department of Agricultural Botany, College of Horticulture, Vellanikkara during 1987-1990 using the 419 genotypes received from ICRISAT, Hyderabad. The 419 genotypes possessed varying levels of dormancy at the time of harvest. Genotypes with varying degrees of dormancy were present in all the three botanical groups, viz., hypogaea, fastigiata and vulgaris. The dormancy period of genotypes ranged from 20 to 110 days. The hypogaea genotypes required longer period of rest. The nature of breakage of dormancy and the period of dormancy were found to be two independent phenomena. The factors for dormancy in groundnut were found to be residing in two distinct sites, the cotyledons and the seed coat (testa). Leaching improved the germinability of decoated seeds where as it failed to elicite germination in intact seeds. This indicates that germination inhibitors may be present in the cotyledons and testa retarded the removal of the same. Different genotypes responded differently to various presowing treatments. HgCl2 1, 1000 for five minutes was found to be the best treatment for breaking dormancy. The study of germinability of F1,F2 and F3(embryonic generation) seeds on the day of harvest indicated that dormancy was controlled by polygenes.
Open Access
Feasibility and utilization of agricultural technologies among scheduled caste farmers
(Department of Agricultural Extension, College of Horticulture, Vellanikkara, 1992) Rajendran, P; KAU; Menon, A G
A Study was conducted in Kerala State with the over-riding objective of analyzing the feasibility perception and utilization pattern of agricultural technologies by the scheduled caste farmers of the state and the constraints in and the consequences of utilization of technologies by them. The study was conducted covering all the five agro-climatic regions of the state, using probability proportionate to size random sampling procedure. Three hundred and thirty seven scheduled caste farmers from five panchayaths coming under five Blocks with the highest scheduled caste population representing each agro-climatic region were selected as the respondents. Five enterprises viz, coconut cultivation, tuber crops cultivation, banana cultivation, cattle rearing and goat rearing were selected and five specific practices for each of these enterprises were selected for assessing the utilization pattern of farmers. Feasibility of technology was analysed in terms of different attributes. Fifteen attributes viz., initial cost, availability of raw materials, availability of supplies and services, physical compatibility, efficiency profitability, availability of technology, simplicity suitability time utilization pattern, social acceptability, rapidity of returns, income generation potential, regularity of returns and viability, were selected for the study. The characteristics of the farmers such as education, family size, experience in farming, farm size, annual income, indebtedness, social participation, extension guidance, extension participation, cosmopoliteness, achievement orientation, development orientation, risk orientation, economic motivation, market orientation, self confidence, level of aspiration, rational orientation and innovativeness were selected for the study. These variables were quantified using standardized procedures. Statistical methods such as mena, percentage analysis, zero-order correlation, Kruskallwalli’s one-way analysis of variance, Kendall’s coefficient of concordance, spearman rank order correlation and stepwise regression analysis were employed for analyzing the data. The major findings of the study were: 1. Goat rearing was perceived as the most feasible enterprise while cattle rearing was perceived the least feasible enterprise by the respondents in general, 2. Agro-climatic differentiations caused variations in the perception of feasibility of the enterprises. 3. Simplicity, initial cost, physical compatibility, suitability, availability of raw materials, efficiency and availability of technology were found to be the crucial determinants of feasibility of agricultural technologies in general. 4. More than 50 percent of the respondents were distributed in the medium category with respect to the level of utilization of the selected enterprises, 5. Feasibility perception of the enterprises and its utilization by the respondents were found significantly related with respect to only coconut and cattle enterprises. 6. There was marked inter regional differences in most cases with respect to feasibility perception and utilization of practices for the five enterprises studied, 7. Lack of technical knowledge, lack of necessary supporting services and unavailability of raw materials were reported as the major constraints in the utilization of agricultural technologies in general. 8. Untimely and ineffective utilization of inputs and inclusion in the defaulters list of credit agencies were reported as the major consequences of utilization of agricultural technologies in general. 9. The characteristics of the respondents viz., extension guidance, risk orientation, self confidence, education, economic motivation, market orientation and cosmopoliteness were found to be significant in influencing and explaining the variation in the utilization of the enterprises by the scheduled caste farmers. Based on the findings of the study, a model for the effective implementation of agricultural development programmes among scheduled caste farmers in the state has been suggested.
Open Access
Improvement of propogation efficiency of anthurium species in Vitro
(Department of Horticulture, College of Agriculture, Vellayani, 1992) Sreelatha, U; KAU; Ramachandran, Nair S
Attempts were made, to improve the propagation efficiency of Anthurium species through enhanced release of axillary buds and callus-mediated somatic organogenesis/embryogenesis, in the plant tissue culture laboratory of the Department of Horticulture, College of Agriculture, Vellayani during 1990-92. Four species of Anthurium namely, A. andreanum, A. crystallinum, A. veitchii and A. grande were selected for the study. Shoot tips from in vitro grown seedling were used as explants for the enhanced release of axillary buds. Cent percent survival was observed in all the cytokinin treatments. The maximum number of shoots (4.50) was observed with kinetin 2.0 mg/1 as well as BA 1.0 mg/1. Treatments with kinetin was free of callus growth. In treatments with BA and 2ip, callus growth was observed at the base of the explant. Treatments with Ms inorganic salts as well as sucrose did not influence multiple shoot formation. One fourth strength of MS major rutrients with full strength of micro nutrients was ideal for multiple shoot induction. Glucose produced less number of shoots than sucrose. One percent sucrose did not influence multiple shoot induction. The longest shoot (0.95cm) was observed at 0.4 percent agar. Light was necessary for the enhancement of axillary buds. In darkness, callus growth was observed, from which many adventitious shoots were produced. Segments of leaf, petiole, spathe, spike and inflorescence stalk were used a explants for callus initiation. Combinations of 2, 4-D and BA were efficient in initiating callus. In A.andreanum, 2, 4-D 0.08 mg/1 and BA 1.0 mg/1 was ideal for callus initiation. Combination of 2, 4-D, 0.2 mg/1 and BA 1.0 mg/1 was the best for callus initiation in A. veitchii. In A. grande, the best callus initiation was observed with 2, 4-D 0.5 mg/1 and BA 1.0 mg/1. Modified MS medium with reduced salt concentrations was ideal for callus initiation in all the species. Inositol when reduced to half concentration (of the normal) influenced callus initiation. The leaf explant (with the smallest vascular bundles) among the other explants, had the highest number of cultures free of microbial contamination. Basal portions of leaf responded, better than the apical portions, to in vitro culture. Continuous darkness was necessary for callus initiation and growth. MS medium with ¼ strength major nutrients was ideal for callus multiplication. Attempts,made on callus-mediated somatic embryogenesis, were not successful. Shoot regeneration and growth of the shoots were the best in MS medium with BA 0.5 mg/1 and IAA 2.0 mg/1. No rooting treatments were required as the shoots rooted spontaneously. Plantlets survived, better than micro shoots, exvitro. The plantlets required less hardening treatments. Sand was the best potting medium for planting out. Nutrient solutions when used for the irrigation the plantlets, had a negative influence on the survival of plantlets. Treatments with VAM (Glomus constrictum and G. etunicatum) was beneficial for the survival as well as growth of the plantlets. Cytological examinations of the root tip squashes made on random number of plantlets, at planting out, showed a normal diploid chromosome count. Attempts, to correlate the biochemical properties with in vitro response, of different explants as well as species, were not successful. Based on the existing facilities of the plant tissue culture laboratory of the department of Horticulture, College of Agriculture, Vellayani, the cost of single anthurium plantlet was worked out to be Rs.3.00/=.
Open Access
Fruit component and seedling progeny analysis of komadan coconut types
(Department of Plant Breeding, College of Agriculture, Vellayani, 1992) Manju, P; KAU; Gopimony, R
The present study was undertaken with a view to unravel the genetic status of a coconut type, Komadan, popular in the Central Travancore region of Kerala, in relation to its origin by comparing its three generations with WCT and NCD through fruit component and seedling progeny analysis. The study revealed that the Komadan types showed significant superiority for majority of the mother palm characters especially number of bunches and spadices and number of nuts per palm per year. Number of nuts per palm per year and number of female flowers per bunch had high heritability combined with moderate to high genetic advance indicating the predominance of additive genes. Among the Komadan palms, 33 per cent were of self pollinating nature thereby occupying a position in between WCT and NCD regarding pollination system. All the Komadan palms had nuts of different shades of brown while 70 per cent of WCT palm had nuts of green shade and NCD palms had varying shades of green, olive and brown nuts indicating the distinction of Komadan as a separate group. Komadan types were superior to WCT in all seednut characters except polar diameter of nut, oil content, thickness of husk and husk/nut ratio. It behaved as a distinct type regarding thickness of meat. One or the other of the Komadan generations was found to be on par with NCD for majority of the seednut characters. Komadan types occupied an area midway between NCD and WCT based on Niu kafa-Niu vai Introgression hypothesis with a clear progression through generations towards better weight of unhusked nut. Inbreeding depression was noticed in WCT and NCD as indicated by significant reduction in embryo and kernel weight in selfed nuts compared to open pollinated nuts. In Komadan there was no inbreeding depression indicating a high degree of homozygosity. The seednuts of Komadan types showed early germination compared to WCT and NCD. Regarding seedling characters, Komadan behaved as a distinct type for total leaf area over both WCT and NCD. Number of seedlings with split leaves was also more in Komadan. This type was superior to WCT for seedling vigour index also. Estimation of prepotency based on recovery of quality seedlings showed that 40 to 60 per cent of Komadan palms were prepotent where as the same in WCT and NCD were only about 20 per cent. Analysis of petiole colour of seedlings showed that 71 to 82 per cent of seedlings among the three Komadan generations showed moderates brown colour (bronze) ; 97 per cent of WCT seedlings had different shades of green and wider variations in petiole colour were noticed in NCD seedlings. It can be concluded that the Komadan type maintained its genetic identity over generations with respect to economically important characters viz. Kernel, copra, and oil content and also in the recovery of quality seedlings which inturn reflects its prepotent nature. The collection and maintenance of typical komadan germplasm through inter se crossing and development of isolated seed gardens for large scale production of komadan seedlings are suggested as future line of work.

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