Browsing by Author "Krishnan Nair, N"

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Comparative study of the contribution of biometric characters on yield in dessert varieties of banana
(Kerala Agricultural University, 1984) Vijayaraghavakumar; George, K C; Krishnan Nair, N
Investigations of twelve morphological characters were carried out on the crop raised at the KAU Banana Research Farm, Kannara. Fifty six dessert varieties of banana plants were grown in randomised blocks of three replications. The analysis revealed that all the twelve characters showed high significant difference among the varieties. All the phenotypic and genotypic correlations of the characters) with yield were positive. From the path coefficient analysis the character having maximum contribution to yield is 'weight of hands'. The 'weight of fingers' and 'number of fingers' also influence the yield indirectly. The genetic advance through discriminant function was found to be less than that through straight selection. Chenkadali and Red banana were the best two varieties selected through the method of selection indices.
Cytogenetic studies on intervarietal hybrids of sesamum (Sesamum indicum L.)
(Department of Agricultural Botany, College of Agriculture Vellayani, Trivandrum., 1984) Chandramony, D; Krishnan Nair, N
Effect of mutagens on the growth response and mutation rate in chillies
(Department of Agricultural Botany, College of Agriculture, Vellayani, 1984) Asha, M S; Krishnan Nair, N
Efficacy of certain growth regulators in inducing flowering in pineapple (Ananas Comosus)
(Kerala Agricultural University, 1978) Balakrishnan, S; Aravindakshan, M; Krishnan Nair, N
A study was undertaken at Pineapple Research Centre, University Main Campus, Vellanikkara in 1976—77 to find a cheaper growth regulator for uniform flower induction in pineapple. The findings showed that a combination treatment of 25 ppm ethrel, 2% urea and 0.04% calcium carbonate was much effective than ethrel application alone ensuring higher percentage of flowering and poduction of better sized, shaped and uniform fruits. The cost of treatment was found to be low, 1.2 paise per plant.
Estimation of induced variability in chillies
(Department of agricultural botany , College of agriculture Vellayani, Trivandrum., 1985) Lekha Rani, C; Krishnan Nair, N
Gamma ray induced polygenic variability in Bhindi
(Department of Agricultural Botany, College of Agriculture, Vellayani, 1986) Ahmed Regina; Krishnan Nair, N
Genic manipulations in sweet potato adopting induced mutations
(Department of Agricultural Botany, College of Agriculture,Vellayani, 1989) Suma Bai, D I; Krishnan Nair, N
An experiment was conducted at the Department of Agricultural Botany, College of Agriculture, Vellayani during 1987-1989 for genetic manipulations in sweet potato through gamma ray induced mutagenesis for increased variability and to isolate out genotypes having wider adaptability and better performance. Stem cuttings of 8 to 10 cm length bearing two nodes each, taken from fifteen sweet potato varieties were used for radiosensitivity analysis. Gamma irradiation was done by a 60 Co gamma cell unit installed in the Radio Tracer Laboratory of Kerala Agricultural University, Trichur. The material was subjected to exposure of 2-10 kR at intervals of 2 kR. The chosen dose rate was 0.162 MR/h. The direct effect of doses on the material was assessed on the basis of days to start sprouting, days to complete sprouting, sprouting percentage, vine length, branch and tuber number and weight of tubers per vine. The exposures above 4 kR caused lethality in the majority of the varieties and hence comparative analysis for ratiosensitivity was assessed at the 2 kR level. The gamma ray exposed population started sprouting late. The days taken for completion of sprouting were also more in all the varieties. Gamma rays, in addition, reduced the sprouting percentage. The percentage lethality varied depending on variety. The vine length and number of branches per vine also varied from variety to variety. They were found to be comparatively less in treated population. The tuber number and weight of tubers per vine were found to be significantly increased by gamma irradiation at 2 kR. Based on the above observations the fifteen varieties were classified into three, viz. low, medium and high radiation sensitive categories. Induced mutagenesis was done in continuation with the radiosensitivity analysis using three varieties, each selected from the low, medium and high radiation tolerant groups. The planting materials selected for gamma irradiation included fresh cuttings, rooted cuttings and rooted tubers which were exposed to radiation at a range of 500 – 2500 r, at 500 r intervals. The dose rate was 0.162 MR/h. The irradiated materials along with the control were planted on the subsequent day. In vM1 generation the direct effect of gamma rays was assessed based on days taken to start sprouting, days taken to complete sprouting, sprouting percentage, lethality on the 30th day of planting and at harvest, vine length, branch number per vine, fresh weight of vine, tuber number per vine, weight, length, girth and volume of tuber and tuber yield per vine. From vM1 plants 3-4 noded cuttings were taken from the basal, middle and top portions for raising vM2 generation. VM3 and vM4 generations were also raised in the same manner. In vM2, vM3 and vM4 generations the yield parameters were analysed in detail. Classification of the phenotypes and frequency analysis were also done. The salient findings of the experiment are the following: There was a delay in sprount initiation and for completion of sprouting caused by gamma ray exposure. A decrease in sprouting percentage and an increase in lethality were noticed under higher levels of exposures. Similarly a reduction in vine length and branch number per vine were found at higher exposures. The fresh weight of vine was reduced and the tuber number increased at higher exposures. There was an increase in mean tuber weight, length, girth, volume and tuber yield per vine at higher exposures. All the exposures and the different modes of treatment induced phenotypic variants both in negative and positive directions. Positive variants were in higher frequency in later generations. Irradiation of rooted cuttings was found to be more economical or beneficial compared to fresh cuttings and rooted tubers. The study enabled to isolate out two promising types, one each from S5 and Bhadrakalichuvala. These mutants outyielded the control and are being multiplied by vine cuttings for farm trials in different agroecological milieus of the State.
Genic status in relation to radlosensltlvity, mutation frequency and spectrum in Bhindi
(Department of Agricultural Botany, College of Agriculture, Vellayani, 1985) Mareen Abraham; Krishnan Nair, N
In vitro techniques In relation to induced nutations in groundnut
(Department of Agricultural Botany, College of Agriculture, Vellayani, 1987) Arya, K; Krishnan Nair, N
The present investigation entitled In vitro techniques In relation to induced mutations in Groundnut was carried out in the Department of Agricultural Botany College of Agriculture, Vellayani, during 1984-86.All the works related to tissue culture analysis was done at the Plant Tissue Culture Laboratory, attached to Tropical Botanic Gardens and Research Institute, Kumarapuram, Trivandrum. The main objective of the experiment was to standardise the best embryo culture technique in groundnut to standardise a successful mutation breeding programme by using the most potent chemical mutagen, etbylmethane sulphonate. The project has also envisaged to standardise the techniques to assess the correct stage of embryo treatment with the mutagen and to standardise the best mode of treatment of the mutagen solution to the embryoids and embryos.
Induced chemical mutagenesis in Rose under in vitro culture
(Department of Agricultural Botany, College of Agriculture,Vellayani, 1991) Uma, B; Krishnan Nair, N
The present investigation entitled “Induced chemical mutagenesis in rose (Rosa chinensis) under in vitro culture” was carried out in the Tissue Culture Laboratory attached to the Horticultural Department, College of Agriculture, Vellayani during 1989-90. The main objectives of the experiment were to standardize a suitable culture medium for the growth and development of axillary buds and to standardize a successful method of chemical mutagenesis in rose under in vitro culture using the most potent chemical mutagen, ethyl methane sulphonate. The standardization of hormone levels in the culture medium (ms) was done at three stages of explant development viz. culture establishment, axillary bud proliferation and in vitro rooting. Surface sterilization of axillary buds were standardized by using mercuric chloride selecting out three concentrations 0.06, 0.08 and 0.1 per cent and 3 periods of treatment 5, 10 and 15 minutes. The axillary buds used were of 4 maturity stages ie. Axillary buds at the time of flower harvest and 2, 4 and 6 days after flower harvest. The various concentrations of ethyl methane sulphonate tested include 0.125, 0.25, 0.375 and 0.5 per cent. Two methods of mutagen treatments were tried ie. direct treatment and cotton swab method. In the direct treatment the axillary buds were subjected to EMS treatment at different periods treating the buds at the time of culturing, 2 days after culturing, 4 days after culturing and 6 days after culturing. In the cotton swab method buds were treated with EMS in the plant itself at various stages ie. at the time of flower harvest and 2,4 and 6 days after flower harvest. Surface sterilization of axillary buds was found to be most successful with mercuric chloride at 0.08 per cent for 15 minutes of the various levels of hormonal combinations tested BAP 2 mg/1 +2.4-D 1 mg/1 was found to be the best for culture establishment and BAP 2 mg /1 +GA 1mg/1 for shoot proliferation. Maximum rooting was obtained in full strength MS medium supplemented with IAA 2 mg/1 of the two methods of mutagen treatments tried direct treatment of axillary buds with EMS was not found to be effective as the buds turned brown and no further development occurred. In the cotton swab method, lower concentrations of EMS (0.125 and 0.25 per cent) gave a better performance based on days taken for bud take multiple shoot production and rooting percentage. A decrease in survival percentage was noted with increase in mutagen concentration. Higher concentration of EMS (0.375 and 0.5 per cent) curbed multiple shoot production in buds excised at the time of flower harvest and delayed multiple shoot production in other stages. The percentage cultures showing rooting and the number of roots/shoot also decreased with increase in concentration of EMS. Increase in maturity of buds also delayed multiple shoot production and decreased rooting percentage of the 4 stages of buds used for in vitro culture, buds excised at the time of flower harvest was found to be the best. But mutagen treatment retarded their performance. For mutagen treatment buds excised 4 days after flower harvest was found to be best followed by buds excised 2 days after flower harvest. Buds excised 6 days after flower harvest showed a poor performance in the normal and treated populations. The experiment clearly demonstrated that induced mutagenesis in rose can be successfully done adopting in vitro culture techniques.
Induced mutagenesis in rose under in vivo and in vitro culture
(Department of Agricultural Botany, College of Agriculture, Vellayani, 1993) Wilson, D; Krishnan Nair, N
Investigations were carried out at the Department of Agricultural Botany and Tissue Culture Laboratory attached to the Department of Horticulture, College of Agriculture, Vellayani during the period from 1989-1993 on “Induced mutagenesis in rose under in vivo and in vitro culture. Induced mutagenesis adopting in vivo method was carried out with three rose cvs. Alliance, Suraga and Folklore belonging to Hybrid Tea group. The cv. Folklore alone was utilized for induced mutagenesis adopting in vitro culture. The budwoods of three selected cultivars were collected at three different stages of growth and exposed to Gamma rays at 20, 30, 40, 50 and 60 Gy, and budded on rooted stock plants and effect of gamma rays on morphological attributes were recorded. In vitro culture conditions were standardized for cv. Folklore. Budwoods were collected at five different growth stages and exposed to gamma rays at 20, 30, 40 and 50 Gy, before culturing. The in vitro variations in terms of culture establishment, shoot proliferation and rooting efficiency were studied. Multiple shoots were also subjected to gamma irradiation to study their in vitro variations. Gamma irradiation of bud woods induced inhibition and reduction in sprouting and survival. Growth retardation exhibited in the form of reduction in plant height and number of branches. The cultivars showwed no significant interaction with different doses of gamma rays for sprouting and survival. The ED50 was estimated as 38Gy. One reddish yellow mutant was isolated from cv. Folklore from 30 Gy treated population and one mutant for increased number of petals from 40 Gy treated population of the same cultivar. In addition, gamma exposure induced variation in size and shape of leaves at 30 and 40 Gy. The treatment of mercuric chloride 0.08 per cent for 12 minutes had the minimum contamination rate for shoot tip and axillary bud explants, and 0.06 per cent for 12 minutes was most effective in the case of internodal segments and leaf disc explants. Axillary buds of 1.0 cm length for enhanced release of axillary bud, internodal segments of 0.5 cm and leaf discs of 1.0 cm with a petiole portion for callus induction were identified as the most suitable explants. Axillary buds excised 4 days after flower opening had the best response in culture establishment. MS basal medium supplemented with BAP 2.5 mg/1+2,4-D 0.5 mg/1 recorded bud break percentage of 80 per cent within 4 days. Early multiple shoot induction and highest number of shoots/culture observed in medium supplemented with kinetin 2.0 mg/1 + GA3 1.0 mg/1. Addition of BAP 2.0 mg/1+ GA3 0.75 mg/1 was the best for getting highest percentage of cultures with multiple shoots. Flower bud initiation was observed in combination of BAP 2.0 MG/1 + GA3 0.5 MG/1. The best medium for in vitro rooting was found to be IAA and NAA 1.0 mg/1 each, along with activated charcoal 500 mg/1. Successful hardening and ex vitro establishment of plantlets were achieved by surface inoculation of germinated spores of mycorrhizae (VAM) in liquid suspension. Highest survival rate of 66.67 per cent was observed by inoculation with Glomus etunicatum against no plants in the untreated lot. Minimum number of days to flowering (105) was taken in plantlets inoculated with G. etunicatum BAP 0.5 mg/1 + NAA 2.0 mg/1 +2, 4-D 0.5 mg/1 was the best combination for callus induction and BAP 0.5 mg/1 + NAA 0.1 mg/1 + ascorbic acid 5 mg/1 had the highest callus proliferation. In vitro rhizogenesis obtained from internodal and leaf calli in MS medium supplemented with BAP 0.5 mg/1 + NAA 2.5 MG/1 + 2, 4-D 0.5 mg/1. Gamma irradiation of axillary buds delayed bud break, reduced percentage of bud break, multiple shoot production and rooting efficiency and also induced morphological variations in leaf and growth pattern. The estimated value for ED50 was 33 Gy under in vitro culture. Exposure of multiple shoots to gamma rays induced several morphological abnormalities and reduced the shoot production and rooting efficiency.
Induced mutations in banana var. Nendran
(Department of Agricultural Botany, College of Agriculture, Vellayani, 1990) Radha Devi, D S; Krishnan Nair, N
The present investigations was carried out in the Department of Agricultural Botany, College of Agriculture, Vellayani during 1985-88 and in the plant tissue culture Laboratory attached to the Department of Plantation Crops, College of Horticulture, Vellanikkara, Thrissur during 1986-88. The project was taken up to standardise the techniques for induced mutagenesis in-vitro and in-vitro in banana (Musa paradiciaca L.) var. nendran and aslo to analyse the direct effect of 60 Co gamma rays on growth and bunch characters in the vM1 and vM3 generations. One, two and three months old suckers of various sizes (after removal of 25 to 75 per cent of the pseudostem) were exposed to 1.0, 1.5, 2.0, 2.5 and 3.0 kR gamma rays. For in-vitro mutagenesis, isolated shoot tips were exposed to 0.50, 0.75, 1.00, 1.25 and 1.50 kR gamma rays. Ex-vitro analysis of five plants per treatment per exposure was done in the vM1 generation for various growth, bunch and fruit characters.
Induced mutations in Bhindi (Abelmoschus esculentus L. Moench)
(Division of Agricultural Botany, College of Agriculture, Vellayani, 1985) Pillay Mahalekshmy Krishna; Krishnan Nair, N
Mutations induced in bhindi (Abelmoshus esculentus L. Moench) Var. Anakomban by the most potent physical mutagen, 60 Co-gamma rays were studied using six doses. The investigation was carried out at the Department of Agricultural Botany, College of Agriculture, Vellayani during the year 1982-84. The direct effect of the mutagen was assessed in the M1 generation and the extent of variability in he M2 with special reference to polygenic and economically important characters. The doses employed were 10 to 60 kR at an interval of 10 kR exposures.
Pre-mature conversion of axillary vegetative buds into inflorescences in banana
(Kerala Agricultural University, 1979) Nair, M N C; Krishnan Nair, N
Statistical analysis of the influence of biometric characters on yield in some culinary varieties of banana
(Kerala Agricultural University, 1984) Vijayaraghavakumar; George, K C; Krishnan Nair, N
The plants were grown on a three replicated RBD with thirty culinary varieties of banana at the Banana Research Station (KAU) Kannara. Measurements ort thirteen morphological characters were taken for the study. These biometric characters had shown high significant difference among the varieties. All the significant phenotypic and genotypic correlations of the characters with yield were positive. From the path coefficient analysis, it was seen that the yield is influenced by the number of fingers and as the number of hands increases, the number of fingers per hand decreases. No significant gain in genetic advance was observed when the genetic advance through discriminant function was compared with that through straight selection. The analysis with restricted selection (to girth) indicated that the character, number of fingers, had the maximum genetic advance. The varieties Poykunnam and Walha were noted for their highest values of selection indices.