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Open Access
Induced chemical mutagenesis in Rose under in vitro culture
(Department of Agricultural Botany, College of Agriculture,Vellayani, 1991) Uma, B; KAU; 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.
Open Access
Variety Sensitivity Analysis in Cucumis melo L. using Gamma Rays and Ethyl Methane Sulphonate
(Department of Agricultural Botany, College of Agriculture,Vellayani, 1990) Nelson Lopez; KAU; Mercy, S T
The effect of gamma rays and 'EMS on ten Cucumis melo L. varieties was studied in the M1 generation. Germinability of seeds was not significantly affected by the different mutagen doses. However in general germination percentage decreased in varieties Panavalli, Attenganam local, Lucknow Sweet, Verma Surprise and Punthala local with gamma ray treatment while in Mudikode local, Pulliporan, Vellanad local and Co-1 germinability was better. EMS treatments in Mudikode local, Hara Madhu, Pulliporan, Puthala local and Co-1 resulted in decreased germination percentage. Significant delay in completion of germination compared to control was observed in different levels of gamma ray treatments in some of the varieties while early germination was noted in some others. Survival percentage, in general, was reduced with mutagen treatment in most of the varieties. Chlorophyll chimeras were noticed in both mutagen treatments. Morphological variations observed included leaf and fruit abnormalities. In general the lower doses of gamma rays resulted in early flowering of male flowers while 30 kR treatment resulted in delayed male flowering. Among EMS treatments, 1.0% and 2.0% treatments in general resulted in a delayed production of first male flower. In the case of appearance of first female flower a significant delay was observed in the higher doses of gamma ray treatments in Co-1 and Attenganam local while a significantly early appearance of first female flower was noted with lower doses of gamma ray treatments in Mudikode local, Lucknow Sweet and Pulliporan. The 1.5 % and 2.0% EMS treatments in general produced first female flower earlier than control and 1.0% treatment. In most of the varieties the EMS treatments in general resulted in the apperance of the first male flower at lower nodes compared to control. EMS treatment induced appearance of first female flower at lower nodes than gamma ray treatment. Increase in sex ratio (male to female) due to some of the EMS treatments was observed in some varieties while a decrease was observed in others. Irradiation with higher doses of gamma rays caused decreased sex ratio in Panavalli, Lucknow Sweet, Hara Madhu, Pulliporan and Punthala local. In general in all varieties there was reduction in pollen and seed fertility with increase in dose of gamma rays and EMS except 10 kR gamma ray treatment and 1.5% EMS treatment where a slight increase in seed fertility was noticed. Different varieties showed differential response to different levels of gamma rays and EMS for number of fruits produced per plant and also for lenght and girth of fruit. Higher doses of gamma rays in Mudikode local, Co-1 and Pulliporan recorded greater fruit weight compared to control while 30 kR treatment in Panavalli and Punthala local recorded lower fruit weight compared to control. In Mudikode local, Panavalli, Vellanad local and Co-1 irradiation of gamma ray in general resulted in significantly lower yields than their control while in Attenganam local gamma ray irradiation resulted in significantly increased yield compared to control. Significantly lower fruit set compared to control occured in 20 kR treatment in Panavalli, Punthala local, Pulliporan and Co-1 whereas 10 kR treatment in Lucknow Sweet and Vellanad local resulted in a significant increase in fruit set. Lower levels of EMS treatments in Hara Madhu, Co-1, Pulliporan and Panavalli induced significantly lower fruit set compared to control. Irradiation with gamma rays resulted in significantly lower number of seeds compared to control in Mudikode local and Punthala local while in Pulliporan greater number of seeds than control was produced due to gamma ray treatment. In Co-1 and Attenganam local, 2.0% EMS treatment resulted in a significant reduction in 100 seed weight while lower levels of EMS treatments in Lucknow Sweet resulted in a significant increase in 100 seed weight compared to their control. The 10 kR treatment of all varieties in general resulted in slight decrease in mean length of main vine compared to control whereas the higher levels of gamma rays resulted in slight increase in mean length of main vine. In general the 2.0% EMS treatment of most of the varieties induced slight reduction in mean length of main vine while the lower levels of EMS resulted in slight increase in mean length of main vine compared to control.
Open Access
Cytotoxic and clastogenic effects of some insecticides in allium cepa, L
(Department of Agricultural Botany, College of Horticulture, Vellanikkara, 1983) Jayaprakash Naik, B; KAU; Vijayakumar, N K
In the present investigation, the cytotoxic and clastogenic effects of three very commonly used insecticides, namely, aldrin, carbofuran and phorate were tested in Allium cepa, L., a test system. Four concentrations of each insecticides were used for the study. These concentrations were fixed taking into consideration of their field dose of application in insect control. The treatment periods fixed were 12, 24 and 48 hours. The mitotic index was computed from 4000 cells and indices of each division phases were also computed. The chromosome abnormalities were scored from about 100 to 150 cells of each phases in each treatments. Aldrin was found to be drastically mitodepressive compared to carbofuran and phorate. While phorate increased mitotic index in the lowest dose, carbofuran showed only marginal reduction. However, both the compounds reduced mitotic index in higher doses and the field doses. Aldrin exhibited a dose and period responsiveness, while carbofuran and phorate could not with regard to mitotic index. The study also revealed that aldrin is an effective toxicant on both genetic material and proteins. The various chromosome abnormalities noticed were stickiness, bridges, laggards, blurred chromosome borders, chromatin bridge, micronuclei, non-orientation of metaphase, precocious movement in anaphase, chromatin bodies, irregular anaphase, star metaphase, strays, beaked nuclei, break, C-metaphase and unequal nuclei in their decreasing order of occurrence. Unlike aldrin, carbofuran and phorate could not induce anomalies to a significant level in the lowest doses tried, 0.0075 and 0.02 per cent respectively. Chromosome bridge being the most frequent abnormality found in carbofuran, which was followed by stickiness and laggards. The frequency of abnormalities found in field and higher doses were more or less same. Phorate, on the other hand showed linear relationship in inducing chromotoxicities with respect to concentrations and period of treatment. The major types of abnormalities recorded were bridges, breaks and stickiness. The results showed that all the insecticides tried were capable of affecting the genetic material as well as protein, but to different degrees depending on concentrations. It can be tentatively concluded that they cannot be considered completely safe at the field dose of application on the cellular constituents of the organism. The results call for extensive testing of these chemicals in other test systems also.
Open Access
Genetic variability and correlation studies in cocoa
(Department of Agricultural Botany, College of Horticulture, Vellanikkara, 1983) Gregory, Zachariah; KAU; Kumaran, K
Investigation on the generic variability and correlation studies in cocoa were undertaken in the Department of Agricultural Botany, College of Horticulture, Vellanikkara during the period from July 1980 to August 1981 in a well established cocoa garden at Alpara in Trichur district, to elucidate information on the extent of variability and the degree of association existing among the 26 important plant, pod and bean characters, in a group of 135 cocoa tress, variety Forastero. Considerable variability was noted among all the characters of the sexually reproduced population of cocoa trees. Number of flowers per unit length on the trunk, number of pods per tree per year, weight of pod, volume of pod and wet weight of beans per pod showed maximum variability. Shell percentage and seed index manifested considerable variability among the bean characters. Phenotypic coefficient of variation (P.C.V.), genotypic coefficient of variation (G.C.V.) and heritability were estimated for 7 pod and bean characters. Both (P.C.V.) and (G.C.V.) were highest for attributes such as thickness of pod husk, number of beans per pod and weight of pod. Moderately high heritability was observed for weight of pod, thickness of pod husk and number of germinated beans. Volume of beans showed the lowest heritability. Yield from trees was found to be positively correlated with 6 of the characters studied, while number of germinated beans per pod and pod value were negatively correlated with yield. Out of the eight characters, pod value had the maximum contribution to yield. Number of pods per tree per year was found strongly associated with yield. Seed index and trunk girth also were positively and significantly correlated with yield. Phenotypic (rp) correlations among seven characters indicated that number of beans per pod was positively correlated with weight of pod. Positive correlations were also established between volume of beans and wet weight of beans per pod. Among the seven characters observed for genetypic (rg) correlations, wet weight of beans showed positive correlation with diameter of the pod and pod weight. Positive phenotypic as well as genotypic correlations were established in the case of wet weight of beans per pod with number of beans per pod and volume of beans. Number of beans per pod in turn, showed positive correlation with weight of pod at both levels. From the present studies it was evident that characters like diameter of pod, wet weight of beans per pod, number of beans per pod, number of germinated beans per pod, volume of pod, volume of bean, pod value, number of cushions on trunk, trunk girth, number of pods per tree per year and seed index have direct influence on the yield of cocoa. These traits can be considered while selecting cocoa trees for using in breeding programmes.
Open Access
Chromosome behaviour and pollen analysis in anthurium sp
(Department of Agricultural Botany, College of Agriculture, Vellayani, 1992) Bindu, M R; KAU; Mercy, S T
Chromose behaviour and pollen characters had been studied in five commercially important varieties of Anthurium andreanum viz. Honeymoon Red, White (album), Lady Jane (Pink), Chillired and Pink. Some morphological characters were also recorded. The varieties show distinct differences in morphological characters. They can be identified from one another even in the absence of their typical spadices. All the varieties have a somatic chromosome number of 30+2B. The basic chromosome number is x=15. Two B chromosomes are present irrespective of the varietal type. The B chromosomes are either acentric or telocentric and round or rod shaped. Their size is always smaller than the smallest A chromosome. The karyotype of all the five varieties was analysed. On the basis of total chromosome length (TCL), average chromosome length (ACL) and arm ratio (r), the variety Pink appears to be most advanced. When the relative chromosome length (RCL) was taken in to consideration, the variety Chillired is found to be most advanced. With regard to the character, chromosome asymmetry, Lady Jane appears to be most advanced. When the karyotype asymmetry as a whole is considered, all the varieties are falling in the '3B' category which represents a high position in evolution. During meiosis, all the varieties exhibited a wide range of abnormalities like univalent formation, unequal seperation, presence of laggards, micronuclei etc. This point out the hybrid nature of the species. All the varieties are found to be protogynous with distinct interphase. This is an adaptation for natural cross pollination. However, natural crossing is occuring only to a limited extent. The pollen production capacity of the varieties varies significantly. The varieties Honeymoon Red and Pink produce the highest amount of pollen. All the varieties have round pollen with a single germ pore. The pollen size among the varieties does not vary significantly. However, the variety Lady Jane has the largest pollen. Pollen fertility is very low, when it was tested by acetocarmine staining and in vitro pollen germination methods. The latter is found to be more reliable in estimating the pollen fertility. All the varieties have paracytic type of stomata. But the varieties vary widely in their size and distribution. Morphological variations, karyotypic differences, meiotic abnormalities, high pollen sterility and the wide variability in stomatal characters point out the basic hybrid nature of the species.
Open Access
Induced mutations in cowpea
(Department of Agricultural Botany, College of Agriculture, Vellayani, 1989) Mini, V; KAU; Vijayagopal, P D
Seeds of cowpea ( vigna unguiculata) cultivar kuruthola-payar were subjected to induced mutagenesis using four doses of gamma rays (10 to 40 krad) and four doses of EMS (0.5 to 2.0 per cent) and their effects in the M1 and M2 generations were studied. The germination percentage was observed to decrease prgogressively with the increase in dose of both mutagens although the reduction was more drastic with EMS. Reduction in survival percentage was observed with increase in the dose of gamma rays and EMS. The growth of shoot and root and plant height were reduced by both the mutagens, although gamma rays showed greater shoot inhibition and EMS showed greater root inhibition. The pollen fertility as well as seed fertility decreased linearly with increase in doses of both the mutagens. Chlorophyll chimeras were observed only in the 30 krad and 40 krad gamma ray treatments. Morphological variations noticed included plants with alterations in the number, size and shape of leaflets. The chlorophyll mutation frequency estimated on M2 progeny row basis showed an increase with increasing doses of gamma rays, except in the 40 krad treatment, which showed a slight decrease. In the case of EMS, maximum mutants were observed at the lowest dose. The chlorophyll mutation frequency estimated on M2 seedling basis showed dose-dependence. The frequencies of the different types of chrolophyll mutants did not show any dose-relationship. The segregation ratio of chlrophyll mutants was higher for EMS than gamma irradiation. The viable mutation frequencies did not show any definite relationship with the doses in both the mutagen treatments. The mutagenic effectiveness in inducing chlrophyll mutations was high at the lowest dose of both mutagens. On the basis of lethality, 20 krad of gamma rays was the most efficient, while on the basis of injury and sterility, 10 krad was the most efficient. With EMS, the 0.50 per cent treatment was the most effective as well as the most efficient treatment on the basis of lethality, injury and sterility. The mutagenic efficiency in inducing chlorophyll mutations was higher for gamma rays with respact to lethality and injury, while on the basis of sterility, EMS proved to be more effcient than gamma rays.
Open Access
Anther culture in cocoa
(Department of Agricultural Botany, College of Horticulture, Vellanikkara, 1992) Sunil, K P; KAU; Achamma Oommen
Investigations on anther culture of cocoa (Theobroma cacao L.) were carried out at the College of Horticulture, Kerala Agricultural University, Vellanikkara, during 1990-'92 with the objective of studying the amenability of cocoa anther under in vitro conditions for the production of haploids. The fertility and viability of pollen grains of cocoa were found to be 35 and 61 per cent respectively. Anthers at tetrad stage (bud length 1.75 mm) were subjected to a two-stage culture procedure involving incubation and subculture (after 4 weeks) on modified H3 basal medium supplemented with 1 mg 1-1 NAA and 0.1 mg 1-1 2-iP for 50 days (stage 1) and subsequent weekly transfer to ½ Ms basal media supplemented with 0 to 1 mg 1-1 2-iP and 0 to 3 mg 1-1 GA3 (stage II). Proembryoids were obtained in stage 1 medium via callus within 45 days of culture, only when anthers derived from Criollo, Trinitario and H2 were cultured. Serial subculturing of embryoids in stage II media led to formation of shootlets and rootlets. With four sub- cultures in stage II in a span of one month, the embryoids could be germinated into plantlets of size 2.5 cm with two leaflets and one rootlet. This is the first report of plantlet recovery from cocoa anthers via indirect embryogenesis. The plantlets were dried up after an elapse of 3 months. The most favourable combination for root development was Ms medium supplemented with 2 mg 1-1 2-iP, 0.1 mg 1-1 NAA and 126 mg 1-1 PG. The factors influencing anther callus induction were: stage of anther development, minimum temperature in the field of donor plants, type and strength of basal medium, type and concentration of auxins and cytokinins, carbohydrate source, sucrose level, presence of CW and PG, physical environment and gamma and UV rays. Anther callus multiplication was influenced by type of basal medium; type and concentration of growth regulators; carbohydrate source; sucrose level; presence of amino acids; organic supplements; ethylene releasing and inhibiting chemicals; adenine and its derivatives; unusual regulants.; gibberellins and growth inhibitors; light and gamma rays. The factors influencing indirect embryo- genesis were found to be stage of anther development and light. Hybrid genotype (H2 and H1) responded more favourably to callus induction, callus multiplication, callus rhizogenesis and were stable with respect to seasonal changes. However, they took more number of days for callus initiation. Criollo took minimum period for callusing. Chlorine water treated for 3-4 min was the best chemical identified for surface sterilization of flower buds of cocoa. A single auxin or cytokinin alone in the basal medium could not initiate anther callusing. Thermic shock pre-treatments were ineffective for callus induction. Light had no role in callus induction. UV rays had no role in altering anther callus growth. Time of subculturing in cell suspension culture was found to be 15 days. Calloids developed in cell suspensions were not amenable to organogenesis or embryogenesis. Isolated microspore culture was unsuccessful.
Open Access
Ergonomic influence of plant morphology on yield in sesamum
(Department of Agricultural Botany, College of Agriculture, Vellayani., 1990) Ganga Rani, B R; KAU; Gopakumar, K
The study is basic and appears new to its type. A prototype model to assess meritwise ergonomics in morphologically diverse seed propagated field crop communities in which seeds make the produce proper is presented. The approach seems to promise greater scope for varietal/genetic improvement of crops of the category as against the conventional multivariate methods that are being widely practiced. Trust is on the elaboration of the source and the flow of a part of it to make the sink. Hypothetical views on the influence of plant morphology on yield factor are expressed and their validity tested. Relevant aspects are discussed in detail. Cultivated sesamum represents the material studied.

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