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Open Access
Evaluation of hepatoprotective effect of ethanolic extract of eugenia jambolana (njaval) leaves on paracetamol induced toxicity in rats
(Department of Pharmacology and Toxicology, College of Veterinary and Animal Sciences Mannuthy, 2008) Midhun, M V; Aravindakshan, C M
Open Access
Enhancement of propagation efficiency in exotic varities of heliconia
(Department of Pomology and Floriculture, College of Agriculture, Vellayani, 2008) Reshmi, C R; KAU; Sheela, V L
Heliconias are among the most popular garden plants, both for the ease with which they can be grown and the sheer magnificence of the blooms. Studies were conducted to standardize rapid propagation techniques under in vitro and in vivo conditions. Three heliconia varieties belonging to three distinct groups viz., St. Vincent Red (small erect type), Golden Torch Adrian (hybrid) and Sexy Pink (large pendent type) were selected for the study. For in vitro culture establishment, shoot tip explants were effective. The treatment of shoot tips with 0.10 per cent mercuric chloride for ten minutes followed by dipping in 0.05 per cent mercuric chloride for five minutes (after trimming) resulted in better surface sterilization. Longitudinal cutting of the in vitro established shoot tip with apical dome into two halves and culturing them separately produced the highest number of axillary buds. Addition of 0.05 per cent activated charcoal to the establishment media reduced the media browning and hastened shoot initiation. For culture establishment of all the three varieties, MS medium supplemented with BA 5.00 mg l-1 was found to be the best. Murashige and Skoog medium supplemented with BA 2.00 mg l-1 resulted in the highest shoot proliferation in the variety St. Vincent Red. In Golden Torch Adrian, BA 2.00 mg l-1 + NAA 0.20 mg l-1 gave better results. In the variety Sexy Pink, Kinetin 5.00 mg l-1 + NAA 0.20 mg l-1 was the best. For further multiplication in Sexy Pink, BA 1.00 mg l-1 was sufficient. Solid culture medium was better for shoot proliferation in the variety Sexy Pink. Higher sucrose concentration (40.00 g l-1) increased the multiplication rate, but reduced the length of shoots as well as the number of leaves. Addition of activated charcoal to the media as well as exposure of cultures to light had negative effect on shoot proliferation. Full MS medium was found to be the best for in vitro rooting of the variety Sexy Pink. Addition of NAA 0.50 mg l-1 to the MS medium gave better results for in vitro rooting in Golden Torch Adrian and Sexy Pink. Sucrose @ 30.00 g l-1 was sufficient for in vitro rooting in the variety Sexy Pink. Activated charcoal delayed root initiation and reduced the number of roots in the variety Sexy Pink. Sand recorded 90.00 per cent survival in all the three varieties after two months of planting out. At varietal level, significant difference was evident in the total number of suckers. In the first experiment, the variety St. Vincent Red (3.82) was significantly superior in terms of total number of suckers. However, in the second experiment, St. Vincent Red (4.06) was on par with Golden Torch Adrian (4.10). The variety Sexy Pink produced comparatively taller suckers in both the trials. Varietal variation in the number of leaves was observed only in the earlier stages. During the preliminary field experiment, the variety Sexy Pink excelled in leaf area at almost all stages of observation. Among the three varieties, highest collar girth was recorded by suckers of Sexy Pink variety during the first two stages of observation. However, towards the later stages, it was statistically on par with St. Vincent Red. Foliar spray was superior to rhizome dip in terms of total number of suckers, height of suckers and the number of leaves. In the case of leaf area, both the treatments were more or less on par. Application of growth regulators had pronounced effect on sucker production at all the stages during the first experiment when BA 750 mg l-1 produced the highest number (4.19) of total suckers. In the second experiment, variation was evident only in the total number of suckers. Here, BA 850 mg l-1 produced the highest number (4.33) of suckers and it was on par with BA 700 mg l-1 (4.00) and GA3 650 mg l-1 (3.79). Irrespective of the stage of plant growth, gibberellic acid produced taller suckers and BA 500 mg l-1 resulted in the shortest suckers. BA treatments recorded comparatively higher number of leaves. Growth regulator application had remarkably influenced the leaf area of suckers also. Application of BA 1000 mg l-1 (3.53 cm) and GA3 800 mg l-1 (3.33 cm) recorded higher collar girth in suckers. VG interaction exerted significant variation in the number of suckers. At varietal level, BA 750 mg l-1 produced the highest number of suckers in St. Vincent Red (4.75), GA3 500 mg l-1 in Golden Torch Adrian (4.63) and GA3 750 mg l-1 in Sexy Pink (4.00). Among VG treatment combinations in the second experiment, the highest number of suckers (4.75) in the variety St. Vincent Red was produced by BA 700 mg l-1. The varieties Golden Torch Adrian (4.88) and Sexy Pink (3.75) recorded the highest with BA 850 mg l-1. Gibberellic acid produced taller suckers. In the second experiment, VG interaction had no significant effect on the height of suckers. Regarding the number of leaves, BA resulted in comparatively higher number of leaves in both the experiments. In all the three varieties, BA 850 mg l-1 produced the highest number of leaves. Collar girth was found to increase with increase in the concentrations of BA and GA3 in all the three varieties. The economics of foliar application of growth regulators revealed that BA 850 mg l-1 significantly enhanced the profit in the varieties Golden Torch Adrian and Sexy Pink. Although negligible, BA 700 mg l-1 recorded slight positive response in the variety St. Vincent Red with respect to profit.
Open Access
Comparative evaluation of membrane protein and biofilm vaccines against duck pasteurellosis
(Department Of Poultry Sciences,College of Veterinary and Animal Sciences, Mannuthy, 2008) Indu, K; KAU; Krishnan Nair, C
A research work was undertaken to prepare effective vaccines against P. multocida grown under different conditions and assess their immunopotency in one month old ducklings. The purity of the Pasteurella multocida A: 1 strain (DP1) and A: 4 strain (PA4) was confirmed as per standard procedures. Pathogenicity of DP1 and PA4 was assessed in six to eight week old mice. The isolates killed the intraperitoneally inoculated mice within eight hours and within 24 h when injected by subcutaneous route. Pasteurella multocida A: 1 was used for the preparation of different vaccines. The organism was grown in BHIB for preparation of ordinary bacterin. The in vitro biofilm formation of the organism was assessed by growing it under nutrient restricted conditions. For this, the organism was grown in TSB (0.32 per cent) supplemented with 0.3 per cent bentonite clay. For preparation of OMP suspension, the organism was grown in iron restricted condition viz., BHIB supplemented with 100 µM 2, 2’ Dipyridyl and the OMPs were extracted using sodium lauryl sarcosinate. The protein concentration of OMP suspension was estimated to be 3 mg/ml. Median lethal dose (LD50) of DP1 was 10-7.5, which contained 32 viable cells/ ml and that of PA4 was 10-7.38, which contained 24 viable cells/ ml when determined in one month old ducklings. Oil adjuvant vaccines were prepared using ordinary bacterin, bacterin made from biofilm and OMP suspension and performed the sterility, safety and potency tests of the vaccine employing standard procedures. A total of 260 four week old ducklings were divided into four groups with 65 birds in each group and the first three groups were vaccinated with ordinary bacterin, OMP vaccine and biofilm vaccine respectively. The fourth group served as control. The birds were vaccinated with 0.5 millilitre of vaccine intramuscularly in the thigh region. Blood was collected from all the ducks pre-vaccination, at weekly intervals upto 3 weeks post vaccination (PV) and then at 15 days interval upto 60 days, by cardiac puncture or by jugular venipuncture. Passive haemagglutination using GA-SRBC sensitized with sonicated antigen of DP1 was used to measure the humoral immune response. The IHA titres obtained for biofilm vaccine group on day 14 was very much higher than the other two groups. The antibody titre was observed from day seven onwards for all the groups. All the vaccine groups have shown significant difference from the control group at all the stages of the study. On homologous challenging, biofilm vaccine gave higher protection rates of 80 per cent than the 70 and 50 per cent protection rates of ordinary bacterin and OMP vaccine respectively, when challenged with 100 LD50 dose on day 20 PV. On day 60 PV, biofilm vaccine gave higher protection rate of 70 per cent than the 60 and 50 per cent protection rates respectively of ordinary bacterin and OMP vaccine, when challenged with 100 LD50 dose. On heterologous challenging, biofilm vaccine gave higher protection rates of 70 per cent, while only 50 per cent protection was afforded by both bacterin and OMP vaccine, when challenged with 100 LD50 dose on 20 day PV. On day 60 PV, biofilm vaccine gave higher protection rate of 60 per cent while both the other vaccines gave only 50 per cent protection, when challenged with 100 LD50 dose. All the birds challenged on day 40 PV, either with homologous and heterologous organisms died. In most cases, the death occurred due to coliform infection along with stressful factor such as increased atmospheric humidity due to heavy rainfall at that time. In few cases, birds died due to pasteurellosis which might be due to lack of protective level of antibody titre. Biofilm vaccine proved to be the best among the three vaccines tried. Further field trials are to be done before advocating this vaccine for commercial use.
Open Access
Growth and survival of penaeus monodon in monosex and mixed sex culture under laboratory condition
(Department of Aquaculture, College of Fisheries, Panangad, 2008) Bajaniya Viralkumar, Chhaganlal; KAU; Mohanakumaran Nair, c
Sexual dimorphism is apparent in the black tiger shrimp, Penaeus monodon with females achieve larger size than the males. This character may be attributed to behavioral and/or physiological differences between the sexes. An experiment was developed to determine if there were advantages in rearing all female or all male P. monodon as opposed to mixed-sex populations. Juvenile shrimps (4.46±0.54 g) were collected from earthen pond and individually hand sexed and stocked in the circular cement tanks. Treatments all male, all female and mixed-sex were stocked @ 8 nos./tank. Each treatment had five replicates. The shrimps were offered commercial shrimp feed. The experiment was conducted for a period of 50 days. At harvest, all female shrimps had shown significantly higher growth than all male and mixed-sex treatment. Survival was not significantly different among treatments. FCR of all female was significantly lower than the all male and mixed-sex treatment. Result of the present study demonstrates a benefit to all female culture of P.monodon against the all male or mixed-sex culture. Thus culture of all female may be commercially more attractive to entrepreneurs. Although additional research is required to find a reliable and quick procedure for separation of the sexes or techniques for the production of all female populations.
Open Access
Effect of blood urea nitrogen,mineral status and uterine PH on fertility in dairy cows
(Department of Animal Reproduction, Gynaecology and Obstetrics, College of Veterinary and Animal Sciences, Mannuthy, 2008) Seena, N S; KAU; Athman, K V
An investigation was carried out with the objective of studying the effect of BUN and uterine pH on fertility in dairy cows under farm and field conditions and also for correlating the mineral status with fertility using 40 crossbred dairy cows selected at random during oestrus, 20 each from those belonging to University Livestock Farm, Mannuthy (Group I) and those brought for insemination at Artificial Insemination Centres at Mannuthy and Kokkalai (Group II). All the cows in Group I were found to be maintained in a relatively high nutritious diet computed as per the scientific feeding standards compared to Group II animals. Detailed clinico-gynaecological examination was carried out and blood samples and uterine mucus were collected from all the selected cows during oestrus for estimation of biochemical parameters and uterine pH respectively. They were inseminated during the most appropriate period of oestrus and were subjected to pregnancy diagnosis at 60 days post insemination. Conception rates in both the groups were compared in relation to each parameter. The mean duration of oestrus was slightly higher in Group II (30.00 ± 2.11 hours) compared to Group I (26.10 ± 1.74 hours). Intensity of oestrus was high, medium and low in 40, 45 and 15 per cent of animals respectively in Group I and 50, 40 and 10 per cent in Group II. Physical changes of reproductive tract viz. degree of vulval oedema and hyperemia of vestibular mucous membrane were more pronounced in animals of Group II compared to Group I, where as degree of tonicity was high in Group I compared to Group II. Characteristics of cervical mucus were also found to be affecting fertility. Better conception rate was obtained in animals with clear and stringy cervical mucus exhibiting typical type of fern pattern. Spinnbarkeit value did not vary much between conceived and non-conceived animals. Uterine pH did not show a marked variation between groups, even though a slightly higher value was recorded in Group I. But, an inverse relationship could be obtained between BUN level in serum and uterine pH during oestrus. Correlation between uterine pH and BUN level was highly significant (P<0.01) with a correlation co-efficient of r = -0.896 and r = - 0.753 in groups I and II respectively. The mean blood urea nitrogen level in animals of Group I was significantly higher (P<0.05) than that in Group II. The BUN level also varied significantly (P<0.05) between conceived and non-conceived animals of both groups. A marginal increase in plasma glucose level could be noticed in conceived animals compared to non-conceived animals of Group I. The mean serum total protein was significantly higher (P<0.01) in Group I compared to Group II. The serum level of minerals viz. calcium, phosphorus, manganese, zinc and copper were also correlated with fertility. The mean level of serum calcium and manganese varied significantly between groups I and II, but there was no significant difference in serum phosphorus, zinc and copper between two groups. Also, a slightly higher mean value was observed for serum calcium, phosphorus, manganese and zinc in conceived animals compared to non-conceived. But serum copper level did not vary between conceived and non-conceived animals. In light of these findings, it can be concluded that the elevation in systemic concentration of urea is likely to impair fertility in dairy cows as a consequence of alterations in uterine environment. The benefits of feeding excess dietary protein and urea to maintain peak milk production should be compared with potential negative effects on fertility. Hence, a good nutritional management is essential for improved fertility in dairy cows.
Open Access
Effect of gonadotropin releasing hormone and prostaglandin for improving reproductive efficiency in goats
(Department of Animal Reproduction, Gynaecology and Obstetrics, College of Veterinary and Animal Sciences, Mannuthy, 2008) Julliet; KAU; Joseph, Mathew
With the objective of studying the effect of GnRH and prostaglandin for improving reproductive efficiency in goats the study was carried out at University Sheep and Goat Farm, Mannuthy using 42 cycling goats. Based on the behavioural and physiological changes associated with oestrum the goats were divided into two groups viz., Group I and Group II. Group I animals were those that exhibited pronounced oestrus signs and were divided into two subgroups namely Group IA and Group IB. Group II animals were those that exhibited weak oestrus signs and were divided into three subgroups namely Group IIA, IIB and IIC. Group IA animals were administered 0.0042 mg Buserelin (1 ml Receptal) a potent GnRH analogue on day 0, and Group IB served as the Control. Blood was collected prior to GnRH administration and breeding from all does. The mean duration of oestrum in Group IA and IB was 19.33 ± 0.45 and 33 ± 0.58 h respectively. The conception rate in Group IA and IB was 50 per cent and 66.66 per cent respectively. The serum P4 level on day 0 in does in Group IA and IB was 0.43 ± 0.05 ng/ml and 0.40 ± 0.05 ng/ml respectively. Group IIA and Group IIB does were treated as per the CO-Synch protocol (i/m inj. of 0.0042 mg of Buserelin (1 ml Receptal) on day 0, 125 µg cloprostenol (0.5 ml clostenol) on day 7; 0.0042 mg of Buserelin and mating on day 9) and prostaglandin protocol respectively (two intramuscular injections of 125 µg cloprostenol (0.5 ml clostenol) 11 days apart followed by mating at 72 and 96 h), while Group IIC served as the control. The oestrus response, oestrus onset interval, duration of oestrum and conception rate in Group IIA was 90.9 per cent, 47.6 ± 0.45 h, 24.5 ± 0.63 h and 40 per cent respectively. The oestrus intensity score of induced oestrus ranged from 0 to 13. The serum P4 level in pregnant and non pregnant does was not significantly different on days 0, 7 and 9 (P>0.05). The oestrus response, oestrus onset interval, duration of oestrum and conception rate in Group IIB was 81.8 per cent, 54 ± 1.006 h, 39.77 ± 1.54 h and 66.66 per cent respectively. The oestrus intensity scores in induced oestrus ranged from 0 to 13. The serum progesterone level in does that became pregnant and those that were non pregnant were not significantly different on day 0, 11, and at 72 and 96 h. In Group II C the duration of oestrum and pregnancy rates was 40 ± 0.91 h and 33.33 per cent respectively. Pregnancy diagnosis was done at three months of gestation by abdominal palpation and the accuracy of the method was 90.9 per cent. Mean gestation length was 146.03 ± 0.76 days. Litter size at birth in Group IA, IB, IIA, IIB and IIC was 2, 2, 2, 1.83 and 2 respectively. Average birth weight of kids was 2.35 ± 0.164 kg and the mean birthweight of male and female kid was 2.42 ± 0.98 kg and 2.28 ± 0.36 kg respectively. Thus from the present study, it can be concluded that :- 1. Administration of GnRH on the day of oestrum in animals exhibiting pronounced oestrus signs failed to improve conception rate when compared to the control. 2. In animals exhibiting weak oestrus signs both CO-Synch and double prostaglandin protocols resulted in higher conception rate when compared to control group. 3. The double prostaglandin protocol was found to be more efficient in improving conception rate in animals exhibiting weak oestrus signs.
Open Access
Effective agricultural information delivery system-an action research among farmers
(Department Of Agricultural Extension, College Of Agriculture, Vellayani, 2008) Nazreen Hassan, S; KAU; Kishore Kumar, N
Extension providers and client expectations include superior information accessing and dissemination, ongoing farmer-extension-research communications and marketing. AgIDS offer tremendous potential for accelerating development. They are transforming our lives, creating wealth and impacting every facet of human endeavor. Agricultural marketing requires connectivity between the market and exporters, growers, traders, industry consumers, through wide area network of national and international linkages in order to provide day-to-day information with regard to commodity arrivals and prevailing rates etc. this study was carried out with the objective of bringing out the underlying facts in the Information Communication technology available to the benefit of the farmers. Thiruvananthapuram district has been purposively selected for the study because this is the only district in Kerala having information kiosks being operated in the Krishibhavans. From the ten Krishibhavans three Krishibhavans were selected based on the maximum numbers of users of this ICT facility based on the records available in the Krishibhavans. The respondents were selected by random sampling method. 60 user farmers and 30 non-user farmers from each panchayat were selected and they formed the respondents of this study. A total of 270 farmers were contacted for the study. From a review of related literature and discussion with experts a comprehensive list of variables were selected. The dependent variables included attributes of ICT, Communication behaviour, information need and skill requirement. Majority of the farmers came under middle age group. Majority of the farmer in both the categories were found to be marginal farmers. Mostly the users were in a better socio economic group. The Extension Service must be able to provide information that makes a difference. ICTs are tools that help build human network, increase public awareness and provide access to information and knowledge for the use of people. They include Telephone, Fax, GIS, Radio, Television, Print, Internet, Video, Audio, Computer and technologies on the drawing boards. Possession of ICT tools by users was found to be higher than the nonusers except for farm magazines where the nonusers out-numbered the users. The mean of the socio technical variables was found to be the maximum for physical compatibility and desirability in the case of users. This was followed by social acceptability and simplicity. This was followed by physical compatibility and social acceptability. In both the cases user education had the minimum score. So this area needs more attention. Majority of farmers in both the categories perceived efficiency of ICT as ‘saving time and money in interacting’ and has ‘all information the farmer wants’ in the nonuser category. This was followed by one stop shop information by the users and supports marketing in the case of non users. There existed significant relation ship between the dependent variables. Also significant relationship was observed in the relationship that existed between some independent variables and dependent variables. A majority of the users claim that they slightly agree to the fact that their productivity has increased compared to the previous year. Analysis of variance showed a comparison between the user group and the non user group. It was found that the user group was higher in the case of all dependent variables. But in the case of information need it was found to be almost similar. A need assessment can help Extension educators to decide whether an extension program should be improved and how the services should be better delivered. The farmers needed information on agriculture such as market rates, bio pesticides, bio fertilizers. These areas ranked top in their information needs. This was followed by organic farming, plant protection and cropping practices. The skill requirement of the non-users farmers was more than the user farmers. The action research was conducted in the form of training on the skills of using computers. The participants for the research were selected by random sampling from the list of non user farmers’ interviewed. The farmers were exposed to the skills for five hours for two days i.e., for ten hours each to a group of thirty members. The influence of Training on the non-users observance on their knowledge gain, and skill acquisition at different intervals of time on the existing ICT facility was studied by documenting the knowledge gain, and skill acquisition at one week, one month and three months interval by the trainees. The results of paired‘t’ test on knowledge gain and skill acquisition showed high significance between different intervals of time. As perceived by the farmers it was found that lack in skill was the major problem that prevented most farmers in accessing through the ICT facility. The farmers also gave out some suggestions to bring this facility in a more effective manner. The study indicated anew strategy for solving the problems in technology dissemination by finding out the actual needs of the farmers in harnessing the benefits of ICT.
Open Access
Intra and inter generic hybridization and molecular charatrization in monopodial orchids
(Department of Plant Breeding and Genetics, College of Agriculture, Vellayani, 2008) Beena, Thomas; KAU; Lekha Rani, C
A research programme entitled “Intra and inter generic hybridization and molecular characterization in monopodial orchids” was carried out in the Department of Plant Breeding and Genetics, College of Agriculture, Vellayani during 2005-2008 with the objective of undertaking intra and intergeneric hybridization, in vitro embryo culture and molecular characterization in monopodial orchids, as a preliminary step to develop novel hybrids. Fifteen monopodial orchid genotypes comprising of six genera viz., Aranda, Aranthera, Kagawara, Mokara, Renanthera and Vanda, with good cut flower qualities and high demand in the market were selected as parents after initial evaluation. They were evaluated adopting completely randomized design with five replications. Analysis of variance revealed significant differences for almost all the characters studied. Genotypic and phenotypic coefficients of variation were high for thickness of leaf, leaf area and number of aerial roots. High heritability (>70 %) combined with high genetic advance (>70 %) was observed for number of aerial roots, width of leaf, thickness of leaf, leaf area, number of spikes per shoot and number of flowers per inflorescence. Significant positive inter-correlation at genotypic and phenotypic levels was observed for length of flower and width of flower with number of spikes per shoot. The character number of spikes per shoot recorded significant positive correlation with leaf area. Number of flowers per inflorescence was positively correlated with number of leaves per shoot and length of inflorescence. Out of the six genera studied, four viz., Aranda, Aranthera, Kagawara and Mokara, exhibited free-flowering nature. Seasonal flowering was observed mainly from June to December in Vanda, whereas it was confined to two seasons, from February to March and August to October in Renanthera. Inflorescence axis was found to be arching in Aranthera and Renanthera while the rest of the genotypes produced erect inflorescence axis. The 15 parental genotypes were crossed in all possible combinations after preliminary studies on floral biology. A total of 225 cross combinations were attempted including 105 crosses, 105 reciprocals and 15 selfs. Incompatibility reactions were noticed at different stages ranging from flower abscission before the onset of any visible post pollination change to instances where seeds germinated but aborted in culture. Mature green capsules were harvested from 70 combinations at 70 to 90 per cent maturity. Among them 15 combinations did not yield any seeds in the capsule while the remaining 55 combinations were cultured axenically. Among the 55 combinations inoculated in vitro, no germination was obtained from seeds of 12 combinations. Out of the 43 combinations that germinated successfully, seven combinations showed arrested development. Thus out of the total 55 combinations inoculated in vitro 36 combinations developed successfully. These were subcultured three to four times. Seedlings having 2-3 leaves and 2-3 roots were deflasked and planted out. MS half strength was selected as the best basal medium. For improving the in vitro growth of hybrid monopodial orchid seedlings refinement of this medium by supplementing with IAA (8 mg l-1) and NAA (2 mg l-1) was beneficial. 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, first shoot and first root primordia and for deflasking. Significant differences in seedling morphology were observed among the 36 hybrid combinations at deflasking. These were kept in humidity chamber for acclimatization for one month, transferred to net house for hardening and maintained there for further growth. In the present study, RAPD was employed for studying the genetic diversity and for the fingerprinting of 20 monopodial orchid hybrids, making use of arbitrary primers to amplify random DNA sequences in the genome. To identify the promising primers for RAPD analysis, 70 decamer primers of kit A, B, C and D were screened using the DNA of hybrid H-2. Based on the performance in DNA amplification, eight decamer primers were identified for RAPD analysis. Primers that produced highest number of polymorphic bands which were intense and reproducible were selected. They were OPB-07, OPB-15, OPB-l7, OPC-04, OPC-05, OPC-08, OPC-15 and OPD-02. a total of 57 scorable bands (average of 7.125 bands per primer) were generated by the selected eight primers of which six were monomorphic and the remaining 51 were polymorphic (89.47%). The estimation of Jaccard’s coefficients and construction of dendrogram by using UPGMA revealed the presence and extent of genetic similarities among the 20 monopodial orchid hybrids. The overall similarity coefficients ranged from 0.40 to 0.84. Cluster analysis revealed that at 0.69 similarity coefficient, the 20 monopodial orchid hybrids got divided into six groups. Among the 20 hybrids, H-18, H-7, H-13, H-17, H-19 and H-20 stood separately in clusters II, III A, III B, IV, V and cluster VI respectively. This substantiates the moderately broad distribution of genetic variability, which can be attributed to the broad genetic base in their ancestry. Cluster I A contained four hybrids viz., H-1, H-10, H-3 and H-9. This grouping is justified by the presence of a common parent i.e., Arachnis Maggie Oei Red Ribbon in their parentage. Moreover, two common species viz., Arachnis hookeriana and Arachnis flos-aeris are involved in their ancestry. All these support their belonging to the same cluster. The three hybrids such as H-5, H-6 and H-8 fell in cluster I B. RAPD technique is relatively simpler, quicker, less expensive and non-radioactive than other molecular characterization techniques. The results of present investigation proved that it can detect sufficient polymorphisms in genetic distance studies in monopodial orchids. A research programme entitled “Intra and inter generic hybridization and molecular characterization in monopodial orchids” was carried out in the Department of Plant Breeding and Genetics, College of Agriculture, Vellayani during 2005-2008 with the objective of undertaking intra and intergeneric hybridization, in vitro embryo culture and molecular characterization in monopodial orchids, as a preliminary step to develop novel hybrids. Fifteen monopodial orchid genotypes comprising of six genera viz., Aranda, Aranthera, Kagawara, Mokara, Renanthera and Vanda, with good cut flower qualities and high demand in the market were selected as parents after initial evaluation. They were evaluated adopting completely randomized design with five replications. Analysis of variance revealed significant differences for almost all the characters studied. Genotypic and phenotypic coefficients of variation were high for thickness of leaf, leaf area and number of aerial roots. High heritability (>70 %) combined with high genetic advance (>70 %) was observed for number of aerial roots, width of leaf, thickness of leaf, leaf area, number of spikes per shoot and number of flowers per inflorescence. Significant positive inter-correlation at genotypic and phenotypic levels was observed for length of flower and width of flower with number of spikes per shoot. The character number of spikes per shoot recorded significant positive correlation with leaf area. Number of flowers per inflorescence was positively correlated with number of leaves per shoot and length of inflorescence. Out of the six genera studied, four viz., Aranda, Aranthera, Kagawara and Mokara, exhibited free-flowering nature. Seasonal flowering was observed mainly from June to December in Vanda, whereas it was confined to two seasons, from February to March and August to October in Renanthera. Inflorescence axis was found to be arching in Aranthera and Renanthera while the rest of the genotypes produced erect inflorescence axis. The 15 parental genotypes were crossed in all possible combinations after preliminary studies on floral biology. A total of 225 cross combinations were attempted including 105 crosses, 105 reciprocals and 15 selfs. Incompatibility reactions were noticed at different stages ranging from flower abscission before the onset of any visible post pollination change to instances where seeds germinated but aborted in culture. Mature green capsules were harvested from 70 combinations at 70 to 90 per cent maturity. Among them 15 combinations did not yield any seeds in the capsule while the remaining 55 combinations were cultured axenically. Among the 55 combinations inoculated in vitro, no germination was obtained from seeds of 12 combinations. Out of the 43 combinations that germinated successfully, seven combinations showed arrested development. Thus out of the total 55 combinations inoculated in vitro 36 combinations developed successfully. These were subcultured three to four times. Seedlings having 2-3 leaves and 2-3 roots were deflasked and planted out. MS half strength was selected as the best basal medium. For improving the in vitro growth of hybrid monopodial orchid seedlings refinement of this medium by supplementing with IAA (8 mg l-1) and NAA (2 mg l-1) was beneficial. 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, first shoot and first root primordia and for deflasking. Significant differences in seedling morphology were observed among the 36 hybrid combinations at deflasking. These were kept in humidity chamber for acclimatization for one month, transferred to net house for hardening and maintained there for further growth. In the present study, RAPD was employed for studying the genetic diversity and for the fingerprinting of 20 monopodial orchid hybrids, making use of arbitrary primers to amplify random DNA sequences in the genome. To identify the promising primers for RAPD analysis, 70 decamer primers of kit A, B, C and D were screened using the DNA of hybrid H-2. Based on the performance in DNA amplification, eight decamer primers were identified for RAPD analysis. Primers that produced highest number of polymorphic bands which were intense and reproducible were selected. They were OPB-07, OPB-15, OPB-l7, OPC-04, OPC-05, OPC-08, OPC-15 and OPD-02. a total of 57 scorable bands (average of 7.125 bands per primer) were generated by the selected eight primers of which six were monomorphic and the remaining 51 were polymorphic (89.47%). The estimation of Jaccard’s coefficients and construction of dendrogram by using UPGMA revealed the presence and extent of genetic similarities among the 20 monopodial orchid hybrids. The overall similarity coefficients ranged from 0.40 to 0.84. Cluster analysis revealed that at 0.69 similarity coefficient, the 20 monopodial orchid hybrids got divided into six groups. Among the 20 hybrids, H-18, H-7, H-13, H-17, H-19 and H-20 stood separately in clusters II, III A, III B, IV, V and cluster VI respectively. This substantiates the moderately broad distribution of genetic variability, which can be attributed to the broad genetic base in their ancestry. Cluster I A contained four hybrids viz., H-1, H-10, H-3 and H-9. This grouping is justified by the presence of a common parent i.e., Arachnis Maggie Oei Red Ribbon in their parentage. Moreover, two common species viz., Arachnis hookeriana and Arachnis flos-aeris are involved in their ancestry. All these support their belonging to the same cluster. The three hybrids such as H-5, H-6 and H-8 fell in cluster I B. RAPD technique is relatively simpler, quicker, less expensive and non-radioactive than other molecular characterization techniques. The results of present investigation proved that it can detect sufficient polymorphisms in genetic distance studies in monopodial orchids.
Open Access
Concurrent growing of green manure crops in dry and wet seeded rice
(Department of Agronomy, College of Horticulture, Vellanikkara, 2008) Anitha, S; KAU; Jose, Mathew
An investigation entitled ‘Concurrent growing of green manure crops in dry and wet seeded rice’ was conducted at Agricultural Research Station, Mannuthy to develop a comprehensive technology package for the system of concurrent growing of green manure crops in direct seeded rice. The investigation consisted of four experiments viz., Experiment Ia - Concurrent growing of green manure crops in dry seeded rice, Experiment Ib - Residual effect of concurrent growing of green manure crops in dry seeded rice, Experiment IIa - Concurrent growing of daincha in wet seeded rice and Experiment IIb - Residual effect of concurrent growing of daincha in wet seeded rice. The experiment on concurrent growing of green manure crops in dry seeded rice consisted of two green manure crops (horse gram and cowpea), three methods of incorporation (Incorporation by cono weeder, desiccation by 2,4 - D spray @1.0 kg ha-1 and allowing for self decomposition) and two levels of nitrogen (100 and 75% of recommended N) and a control without green manure crops . Among the two green manure crops, cowpea was the best in supplying the required quantity of green matter with 25 per cent savings of N fertilizer and a substantial reduction in weed incidence. All the three methods of incorporation were found to be equally effective. Hence in places where there is a difficulty in self decomposition, cowpea can be effectively incorporated by conoweeder or by spraying 2, 4-D. The cowpea variety used in this study was a short duration bush type variety facilitating additional pod yield from cowpea before it was incorporated. Concurrent growing of cowpea along with dry seeded rice is a viable system as it resulted in increased productivity, profitability and sustainability dry seeded rice. In the experiment to study the residual effect of concurrent growing of green manure crops in dry seeded rice, the main plots of dry seeded rice crop during the 1st crop season were divided into two sub plots and applied 100 and 75 per cent N to the subplots. The results revealed that concurrent growing of green manure crops were effective in increasing the yield and sustaining soil fertility status compared to pure crop of rice receiving 5 t ha-1 of FYM and 100 per cent of the recommended nitrogen. But there was no savings of N fertilizer to the succeeding transplanted rice crop as the highest yield of succeeding rice was achieved only when it received 100 per cent of the recommended N. The profitability of the rice- rice cropping system was the highest with concurrent growing of cowpea in dry seeded rice. The experiment on concurrent growing of daincha in wet seeded rice consisted of two stages of incorporation of daincha (20 DAS and 30DAS), three methods of incorporation (Incorporation by cono weeder, desiccation by 2, 4 - D spray @1.0kg ha-1 and Desiccation by Chlorimuron ethyl+ met sulfuron methyl spray @ 4.0 g ha-1 met sulfuron methyl spray @ 5 g ha-1) and two levels of nitrogen (100 and 75% of recommended N) and a control without daincha. Results indicated that concurrent growing of daincha can be successfully practiced in wet seeded rice with improved productivity. Incorporation of 30 days old daincha employing any of the three methods of incorporation was equally effective in increasing the productivity and profitability of wet seeded rice. Incorporation of daincha at 30 DAS could add about 14 t ha-1 of green matter with minimum investment and resulted in 70 per cent weed suppression. Concurrent growing of daincha receiving both 100 and 75 per cent of recommended N produced significantly higher yield than pure crop of rice receiving 5 t ha-1 of FYM and 100 per cent of the recommended nitrogen. Hence there was a saving of 25 per cent N without affecting the yield. The highest yield was obtained when 100 per cent of recommended N was applied to the system. The treatments for the experiment to study the residual effect of concurrent growing of daincha in wet seeded rice were similar to that of dry seeded rice. The results showed that concurrent growing of daincha and its incorporation at 30 DAS was effective in increasing the yield of succeeding rice and sustaining soil fertility status compared to pure crop of rice receiving 5 t ha-1 of FYM and 100 per cent of the recommended nitrogen. The highest yield of succeeding rice was achieved only when it received 100 per cent of the recommended N hence there was no savings of N fertilizer to the succeeding transplanted rice crop. Concurrent growing of daincha in wet seeded rice increased the profitability of the rice- rice cropping system. Concurrent growing of green manure crops in dry and wet seeded rice is a management alternative to reduce the production cost and to increase the yield of rice and is a practical model for sustainable rice production.

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