Loading...
Kerala Agricultural University, Thrissur
The history of agricultural education in Kerala can be traced back to the year 1896 when a scheme was evolved in the erstwhile Travancore State to train a few young men in scientific agriculture at the Demonstration Farm, Karamana, Thiruvananthapuram, presently, the Cropping Systems Research Centre under Kerala Agricultural University. Agriculture was introduced as an optional subject in the middle school classes in the State in 1922 when an Agricultural Middle School was started at Aluva, Ernakulam District. The popularity and usefulness of this school led to the starting of similar institutions at Kottarakkara and Konni in 1928 and 1931 respectively.
Agriculture was later introduced as an optional subject for Intermediate Course in 1953. In 1955, the erstwhile Government of Travancore-Cochin started the Agricultural College and Research Institute at Vellayani, Thiruvananthapuram and the College of Veterinary and Animal Sciences at Mannuthy, Thrissur for imparting higher education in agricultural and veterinary sciences, respectively. These institutions were brought under the direct administrative control of the Department of Agriculture and the Department of Animal Husbandry, respectively. With the formation of Kerala State in 1956, these two colleges were affiliated to the University of Kerala. The post-graduate programmes leading to M.Sc. (Ag), M.V.Sc. and Ph.D. degrees were started in 1961, 1962 and 1965 respectively.
On the recommendation of the Second National Education Commission (1964-66) headed by Dr. D.S. Kothari, the then Chairman of the University Grants Commission, one Agricultural University in each State was established. The State Agricultural Universities (SAUs) were established in India as an integral part of the National Agricultural Research System to give the much needed impetus to Agriculture Education and Research in the Country. As a result the Kerala Agricultural University (KAU) was established on 24th February 1971 by virtue of the Act 33 of 1971 and started functioning on 1st February 1972. The Kerala Agricultural University is the 15th in the series of the SAUs.
In accordance with the provisions of KAU Act of 1971, the Agricultural College and Research Institute at Vellayani, and the College of Veterinary and Animal Sciences, Mannuthy, were brought under the Kerala Agricultural University. In addition, twenty one agricultural and animal husbandry research stations were also transferred to the KAU for taking up research and extension programmes on various crops, animals, birds, etc.
During 2011, Kerala Agricultural University was trifurcated into Kerala Veterinary and Animal Sciences University (KVASU), Kerala University of Fisheries and Ocean Studies (KUFOS) and Kerala Agricultural University (KAU).
Now the University has seven colleges (four Agriculture, one Agricultural Engineering, one Forestry, one Co-operation Banking & Management), six RARSs, seven KVKs, 15 Research Stations and 16 Research and Extension Units under the faculties of Agriculture, Agricultural Engineering and Forestry. In addition, one Academy on Climate Change Adaptation and one Institute of Agricultural Technology offering M.Sc. (Integrated) Climate Change Adaptation and Diploma in Agricultural Sciences respectively are also functioning in Kerala Agricultural University.
Browse
Search Results
ThesisItem Open Access Genetic variability, path analysis and stability parameters in sesame(Department of Plant Breeding, College of Agriculture, Vellayani, 1985) Sverup, John; KAU; Gopinathan Nair, VBiometric analysis in a varietal collection of sesame was undertaken to study the genetic variability, correlations, path analysis and stability parameters. One hundred sesame types were evaluated in replicated trials at Vellayani in uplands during rabi and at Kayamkulam in rice fallows during summer. Genetic variability and correlations were estimated and path analysis worked out independently as both the locations. Location trials for estimating stability parameters were conducted at three places viz. in uplands during rabi at Pattambi and Vellayani and in rice fallows during summer at Kayamkulam. Large values for genotypic coefficients of variation were obtained for characters such as number of capsules on branches, number of capsules perplant, number of capsules on main stem and number of branches during rabi as well as summer. The lowest genotypic coefficient of variation was obtained for number of days to maturity during both rabi and summer. High values of heritability were recorded by seed protein content , seed oil content, height upto first capsule and weight of 1000 seeds under both conditions.ThesisItem Open Access Diallel analysis in rice bean(Vigna umbellata( Thunb.) ohwi & ohashi)(Department of Plant Breeding and Genetics, College of Agriculture, Vellayani, 1999) Preeti, S V; KAU; Radha Devi, D SA diallel analysis in ricebean (Vigna umbellata (Thunb.) Ohwi and Ohashi) was carried out in the Department of Plant Breeding and Genetics, during 1997 - '98. The experimental material consisted of six parental lines and 30 F I hybrids, laid out in Randomised Block Design with three replications. The six parents were 3 LG, 5 LG, 6 LG, 8 LG, 9 LG, and 100 LG obtained from the germ plasm collection maintained at NBPGR, Thrissur. The observations were recorded on yield and yield attributing characters. Significant differences were detected among the mean performance of the genotypes, for all the characters studied. The combining ability analysis carried out by Method I, Model I of Griffing's approach (1956), revealed that the parent, 8LG was the best general combiner for most of the yield attributing traits. Among the crosses, 8LG x 3 LG exhibited outstanding sea for seed yield per plant. The crosses involving 8 LG were found to be good specific combiners. The combinations involving 3 LG and 6 LG also gave good specific combining ability effects. The numerical analysis by Hayman's approach indicated overdominance for almost all characters, which was confirmed by graphical analysis. The dominance of decreasing alleles in the parents was indicated by the negative value of F for all characters except, plant height, length of pods and number of seeds per pod. An almost equal distribution of genes with positive and negative effects was indicated by the ratio of H2 to 4H} for all the characters. The regression coefficient of covarince between parents and their offsprings in each array (Wr) on variance of all progenies in each parental array (Vr) did not- differ from unity, for plant height, length of pods, seed yield, 100 seed weight, days to maturity and protein content, indicating that assumption of non-allelic interaction was satisfactory for these characters. The Vr - Wr graph indicated that the parents were genetically divergent for days to first flowering, number of pods per plant, number of seeds per pod, 100 seed weight, days to maturity, root weight and nodule weight. Manifestation of heterosis was seen for all the characters studied. Among the hybrids, 8 LG x 3 LG was the most outstanding for yield and yield related characters. The crosses, 8 LG x 9 LG, 8 LG x 100 LG, 6 LG x 9 LG, 100 LG x 8 LG and 6 LG x 3 LG also performed better in yield and yield attributing characters. In general, hybrids involving 8 LG and 6 LG were found to be heterotic.ThesisItem Open Access Combining ability in vegetable cowpea(Department of Plant Breeding, College of Agriculture, Vellayani, 1992) Rejatha, V; KAU; Ramachandra Nair, NA 6 x 6 diallel analysis was conducted at the Department of Plant Breeding, College of Agriculture, Vellayani, during 1990, aimed at analysing the combining ability, gene action and heterosis of six vegetable cowpea (Vigna unguiculata var-sesquipedalis) lines collected from the germplasm maintained in this department. The experiment I consisted of crossing the six parental lines in all possible combinations, without reciprocals. The material for experiment II consisted of the six parental lines and fifteen hybrids. They were grown in a Randomised Block Design with three replications.The combining ability analysis was carried out based on method 2 under model I as suggested by Griffing (1956). The treatments showed significant differences in most of characters except number of pods/plant and fruit yield/plant. The variance due to general combining ability was significant and higher in magnitude than specific combining ability for the characters days to flowering, mean weight of pod, mean length of pod, number of seeds/pod, length of internode and seed/pod ratio. It was found that the parent selection 104 and selection 145 were the best general combiners for most of the characters studied. The parent selection 129 was the best general combiner for earliness. The hybrids selection 145 x selection 129 was the best specific combiner for mean weight of pod and number of seeds/pod. The hybrid selection 145 x kurutholapayar was the best specific combiner for earliness. The significance of g.c.a. and s.c.a. variances for most of characters indicate the importance of additive and non-additive gene action in controlling the inheritance of these characters. But additive gene action played a major role suggesting that improvement could be made through selection. Heterosis was calculated over mid and better parental values. Maximum positive heterosis was found for the character fruit yield/plant. Since considerable heterosis was evident in most of the characters, heterosis breeding can be attempted in cowpeaThesisItem Open Access Induction of polyploidy in kacholam(Department of Plant Breeding and Genetics, College of Horticulture, Vellanikkara, 1996) Ajithmohan, N K; KAU; Pushkaran, KA trial on induction of polyploidy in Kaempferia galanga L. was undertaken at the Department of Plant Breeding and Genetics, College of Horticulture, Vellanikkara, during the period 1994-'95. A local selection Vellanikkara collected from the genetic stock maintained at AICRP on M & AP was used for the study. The objective was to create variability in kacholam by developing polyploids. The rhizomes of the crop were treated with colchicine for inducing polyploidy. Five concentration of colchicine viz., 0.05, 0.15, 0.25, 0.35 and 0.45 per cent (C2 to C6, C1 being control i.e., 0%) was tried for two time durations viz., four hours and six hours (T1 and T2), the same treatment being repeated on two consecutive days. Two methods of treatment were tried the first (M1) being chemical application in a hole drilled close to the sprouting bud and the second (M2) being the ordinary cotton swab method. Rhizomes with two different stages of bud sprouting were used: (1) with just emerging buds (S1) and (2) buds at an advanced stage of sprouting (S2). The treated rhizomes were planted in the field and their growth was examined. In the end of the crop season, 18 variant plants were identified and they were put to detailed morphological and cytological study in the next growing season. Mitotic study of the parent material confirmed that the chromosome number of kacholam is 55. Of the 18 variants identified one was found to contain 110 chromosomes in the somatic cells. As kacholam is proposed to be a pentaploid the induced polyploid must be a decaploid. The polyploid was obtained from the treatment combination S1M1T1C6. It was characterised by small plant size and reduced vigour. The leaves were thick with reduced size. Stomatal size increased conspicuously with their numbers reduced. The rhizome development was found retarded and the per plant yield was also less. The rhizome morphology was on par with the normal plants. The plant flowered neither in the first season nor in the second. In addition to the polyploid, there other stable variants were obtained from the experiment. They were also characterised by reduced vigour and yield.ThesisItem Open Access Heterosis breeding in sesame (Sesamum indicum L.).(Department of Plant Breeding and Genetics, College of Horticulture, Vellanikkara, 2011) Gayathri, G; KAU; Dijee, BastianThe study entitled ‘Heterosis breeding in sesame (Sesamum indicum L.)’ was undertaken at the Department of Plant Breeding and Genetics, College of Horticulture, Vellanikkara. The objectives of the study were to collect and evaluate different genotypes of sesame for morphological traits and yield attributes, to identify useful parents producing heterotic crosses and developing hybrids in sesame. The study also intended to develop male sterile lines in sesame through interspecific hybridization with Sesamum malabaricum. Sesamum indicum and Sesamum malabaricum accessions were collected from Kerala and Tamil Nadu and evaluated for their morphological traits. Wide range of variation was noticed for characters like plant height, number of days to flowering and seed yield per plant which contributed maximum to genetic divergence. The genotypes studied were grouped into six clusters. High genotypic coefficient of variation (GCV) was recorded for number of capsules per plant, plant height, seed yield per plant and number of branches per plant. High heritability with high genetic advance as per cent of mean was recorded for number of days to flowering, plant height, number of branches per plant, number of capsules per plant and seed yield per plant. This indicates that the characters are governed by additive gene effects and selection for these traits will be effective. Association analysis revealed that seed yield per plant was correlated to plant height, number of capsules per plant and number of days to flowering. Path coefficient analysis indicated maximum positive direct effect by number of capsules per plant, capsule length, plant height and 1000 seed weight on seed yield per plant. In order to develop hybrids, fourteen parents were selected based on the per se performance of the genotypes. They were crossed in line X tester mating design. Forty eight hybrid combinations obtained were raised in the field along with the parents and evaluated for their heterosis and combining ability effects. Parental genotypes AVTS-06-5, AVTS-06-10, IVTS-06-12, KYM-1, Tilak and TMV-6 were identified as high combiners based on general combining ability (gca) effects. Two combinations viz. AVTS-06-5 X KYM-1 and IVTS-06-12 X TMV-3 had significant values of per se performance, specific combining ability (sca) effects and standard heterosis for seed yield per plant. They can be evaluated for their hybrid vigour over locations and seasons. The crosses AVTS-06-5 X TMV-3, AVTS-06-5 X TMV-6 and TCR 3279A X KYM-1 have been identified as potential cross combinations for isolation of promising segregants as the parents involved in these crosses had high significant gca effects for seed yield per plant but the hybrids recorded non significant sca effects. Interspecific hybridization between S.malabaricum and S.indicum was attempted to develop male sterile lines. Seed set was noticed in three interspecific hybrids which failed to germinate due to embryo abortion. Hence these embryos were rescued and raised in vitro to obtain the hybrids.ThesisItem Open Access Gene pyramiding for bacterial blight resistance in rice variety Uma (Mo 16)(Department of Plant Breeding and Genetics, College of Horticulture, Vellanikkara, 2016) Tintumol, Joseph; KAU; Rose Mary, FranciesExploiting host-plant resistance through pyramiding of resistance genes have been recommended as the best approach to impart durable resistance to rice varieties in order to combat the bacterial blight (BB) disease caused by Xanthomonas oryzae pv.oryzae (Xoo). In lieu of this, F1s were produced by hybridizing the susceptible elite rice variety Uma with resistant donor parent Improved Samba Mahsuri (ISM) harbouring three R-genes xa5, xa13 and Xa21. BC1F1 individuals were generated by backcrossing the F1s using variety Uma as the recurrent parent. The present study aimed to identify the R-genes introgressed individuals in the BC1F1 population as well as to produce BC2F1s and BC1F2s of the identified R-genes introgressed BC1F1s. Foreground selection of the BC1F1 individuals was done using the R gene linked molecular markers. Restriction digestion of the PCR product of STS marker RG 556, linked to R gene xa5, with Dra1 restriction enzyme, resulted in production of alleles of size 128 bp, 514 bp, 587 bp, 624 bp, 650 bp and 836 bp in all the BC1F1 individuals as well as the parents indicating the presence of R gene xa5 in all the individuals studied. Amplification of DNA of the individuals with the functional marker xa5 SR further confirmed the presence of R gene xa5 in both the parents as well as in all the BC1F1s. Restriction digestion of the PCR product of STS marker RG 136, linked to R gene xa13, with Hinf1, produced alleles similar to that of the donor parent ISM in three BC1F1s namely, plant no. 8.3.2, plant no. 8.3.3 and plant no. 8.3.9, indicating the presence of R gene xa13 in these plants. The presence of gene xa13 in the identified BC1F1s was further affirmed by using the functional marker xa13 promoter. The analysis had resulted in the production of 560bp allele associated with the resistant allele of gene xa13 in homozygous state from donor parent ISM in the three BC1F1s mentioned above. Out of the 95 BC1F1 individuals scored with the STS marker pTA 248 linked to R gene Xa21, only BC1F1s plant no. 8.3.2, plant no. 8.3.3 and plant no. 8.3.9 were found to possess Xa 21. Results thus obtained revealed thatBC1F1plant no. 8.3.2, plant no. 8.3.3 and plant no. 8.3.9 were R gene pyramids (xa 5+xa 13+ Xa 21). Background profiling of the three R-genes introgressed BC1F1s using 22 rice microsatellite markers, revealed presence of the donor parent allele in the homozygous state. PCR analysis with the marker RM 307, however, revealed the presence of alleles from both the parents, ISM and Uma in the BC1F1 plant no. 8.3.2. This indicated that the plant was heterozygous at the marker locus and can be expected to segregate for the alleles at this locus in subsequent generations. Considering the segregation of the 22 markers the per cent recurrent parent genome recovery in the R-genes introgressed BC1F1s was estimated to be higher in BC1F1 plant no.8.3.2 but lower than the expected estimate of 75 per cent. This was also confirmed by graphical genotyping. The dendrogram thus generated out of the marker data, grouped the R-genes introgressed BC1F1s with ISM indicating that the three R-genes introgressed BC1F1s exhibited greater similarity with donor parent parent ISM at the genome level. Evaluation of BC1F1 individuals for morphological traits revealed presence of wide variability. The three R-genes introgressed BC1F1s were late in flowering compared to the recurrent parent Uma. Two of these genotypes i.e.,plant no. 8.3.2 (234 days) and plant no. 8.3.3 (228 days) flowered later than the donor parent. However, the three R-genes introgressed BC1F1s resembled the recurrent parent Uma with respect to grain and kernel characteristics. Backcrossing the three R-genes introgressed BC1F1s i.e., plant no. 8.3.2, plant no. 8.3.3 and plant no. 8.3.9 to the recurrent parent Uma resulted in 28 BC2F1s. Simultaneously, selfing of these individuals produced 850 BC1F2 seeds. Foreground and background profiling of these generations can ensure precise identification of genotypes that resembles the recurrent parent Uma possessing the resistance genes of interest with maximum recovery of recurrent parent genome.ThesisItem Open Access Evaluation of superior cultures for yield and yellow vein Mosaic resistance in okra(Department of Plant Breeding and Genetics College of Agriculture, Vellayani, 2016) Nikitha, J; KAU; Arya, KThe present study entitled “Evaluation of superior cultures for yield and yellow vein mosaic resistance in okra (Abelmoschus esculentus (L.) Moench)” was carried out in the Department of Plant Breeding and Genetics, College of Agriculture, Vellayani during 2014-2016, with the objective to identify high yielding and yellow vein mosaic resistant cultures of okra from those evolved through inter-varietal hybridization programme. Fifteen superior cultures of okra obtained from the previous project in the Department viz., VLYA 1, VLYA 2, VLYA 3, VLYA 4, VLYA 5, VLYA 6, VLYA 7, VLYA 8, VLYA 9, VLYA 10, VLYA 11, VLYA 12, VLYA 13, VLYA 14 and VLYA 15 along with two check varieties Varsha Uphar and Kiran were evaluated in a Randomized Block Design (RBD) with three replications during summer season of 2015. The analysis of variance was calculated for the traits under study viz., days to 50 per cent flowering, number of fruits plant-1, fruit weight (g), fruit length (cm), fruit girth (g), yield plant-1 (g), plant height (cm) and duration (days) and these were found to be highly significant for all the genotypes evaluated. The maximum yield was recorded by the genotype VLYA 2 which was on par with genotypes VLYA 5, VLYA 10, VLYA 11, VLYA 13 and VLYA 15 and the minimum yield was observed by the check variety Kiran. The yield plant-1 exhibited moderate GCV (18.42%) and PCV (19.05%), high heritability (94.00%) coupled with high genetic advance (36.69%). The yield plant-1 was found to be significantly and positively correlated with number of fruits plant-1, fruit length, fruit girth, fruit weight and plant height both at genotypic and phenotypic levels. Days to 50 per cent flowering and yellow vein mosaic disease incidence was found to be negatively correlated with yield plant-1. Very high positive and significant inter-correlation was noticed between height of plant and number of fruits plant-1. The path analysis showed that number of fruits plant-1 and fruit weight showed the maximum positive direct effect towards yield. The number of fruits plant-1 had high indirect effect through fruit length. The scoring for yellow vein mosaic disease and the vulnerability index revealed that the genotypes VLYA 5, VLYA 11 and VLYA 13 were resistant to the disease during all stages of crop growth. Number of white flies was found to be highest in VLYA 10 and lowest in VLYA 2. The incidence of fruit and shoot borer was also scored and five genotypes viz., VLYA 2, VLYA 4, VLYA 11, VLYA 13 and VLYA 14 were found to be immune and VLYA 3, VLYA 5, VLYA 15 and Varsha Uphar were found to be resistant. The glass house experiment of vector transmission and graft transmission was conducted for the confirmation of disease resistance and the vulnerability index was calculated to check the severity of the disease. The genotypes VLYA 5, VLYA 11 and VLYA 13 received a score ‘0’ which indicated that these genotypes were highly resistant. Hence the genotypes which obtained a vulnerability index of ‘0’ during both field evaluation and glass house experiment were confirmed to be resistant to yellow vein mosaic disease. Hence the present study revealed that the cultures VLYA 5, VLYA 11 and VLYA 13 were having high yield and yellow vein mosaic disease resistance. So these genotypes can be used for further trials before releasing for field cultivation.ThesisItem Open Access Combination breeding for high protein cowpea (Vigna unguiculata L. Walp)(Department of Plant Breeding and Genetics, College of Horticulture, Vellanikkara, 2015) Sarath, P S; KAU; Jiji, JosephCowpea (Vigna unguiculata L. Walp) is one of the most important legume crops grown in India. It is a versatile pulse crop owing to its nutritional value, weed smothering nature, drought tolerant characters, soil restoring properties and multi-purpose uses. Protein deficiency has been reported to be one of the main nutritional problems in the developing world. About one billion people are reported to be suffering from protein deficiency and malnutrition worldwide. Studies have revealed that protein content in cowpea grain ranges between 18 to 40 per cent depending on the genotypes. Identifying high yielding varieties of cowpea with high protein content will not only contribute to food security and alleviate poverty but could also contribute to the alleviation of protein deficiencies. Review on the earlier research pointed to poor emphasis on the genetic improvement of cowpea for improved protein content. Hence, the present study was envisaged to combine the high protein trait with high yielding genotypes. The study was grouped under three experiments, i) Evaluation of cowpea genotypes, ii) Hybridisation of the selected genotypes in line x tester design, iii) Evaluation of F1 hybrids. The experiments were conducted at College of Horticulture, Kerala Agricultural University, Vellanikkara during 2014-2015. All the crop management practices were followed as per KAU (2011). Evaluation of cowpea genotypes revealed that there was wide variability for all the traits studied except branches per plant among bushy and semi trailing types of cowpea. In trailing type, variability was observed for plant height, number of pods per plant, pod weight grain yield per plant and seed protein content. Among the twenty two genotypes evaluated, ten genotypes that exhibited a protein content of above 25 per cent were selected for hybridization programme. The selected genotypes (Vellayani Jyothika, Bhagyalakshmi, Anaswara, Kanakamony, Lola, Vyjayanthi, AV-5, PKB-3, PKB-4 and Sharika) were hybridized in line x tester (6 x 4) design. High magnitude of phenotypic coefficient of variation (PCV), genotypic coefficient of variation (GCV), heritability and genetic advance was observed for plant height, grain yield per plant and length of pods were observed in parents and hybrids suggesting scope for genetic improvement of these traits through selection. Seeds per pod and protein content exhibited low PCV and GCV but high heritability and low genetic gain, indicating that these traits were governed by non-additive gene action and therefore breeding method other than simple selection is required. Combining ability analysis revealed that higher magnitude of specific combining ability (SCA) variances than the general combining ability (GCA) variances for the traits like pods per plant, length of pod, test weight, grain yield per plant and seed protein content indicating preponderance of non-additive gene action in the inheritance of these traits. Higher estimates of GCA variances over SCA variances for plant height, days to flowering, days to first harvest, days to last harvest, pod-weight and seeds per pod implies the preponderance of additive gene action in controlling these traits. The hybrids were ranked based on mean value, sca effects and estimates of heterosis for the traits like days to flowering, pods per plant, seeds per pod, test weight, grain yield per plant and protein content. Four hybrids with the lowest scores were selected. Hybrids H2 (Vellayani Jyothika x PKB-3), H10 (Anaswara x PKB-3), H11(Anaswara x PKB-4) and H12 (Anaswara xSharika) were found to be the most promising. The transgressive segregants with high yield and protein content can be identified on further evaluation of the segregating population from the above hybridsThesisItem Open Access In vitro mutagenesis and evaluation of somatic embryo derived plantlets in cassava (Manihot esculenta Crantz.)(Department of Plant Breeding and Genetics, College of Horticulture, Vellanikkara, 2016) Riya, Antony; KAU; Jiji, JosephThe present study ‘In vitro mutagenesis and evaluation of somatic embryo derived plantlets in cassava (Manihot esculenta Crantz.)’ was conducted in the Department of Plant Breeding and Genetics, College of Horticulture during 2014-15. They study attempted to assess the variability existing among the in vitro derived plantlets of cassava genotypes Sree Jaya and CC1 as well as to generate further variability through in vitro mutagenesis. With the aim to induce variability, in vitro mutagenesis of callus derived from cassava genotypes Sree Jaya and CC1 was attempted earlier in the department. This had resulted in 10 somatic embryo derived plantlets in primary hardening stage and 58 plantlets yet to be transferred for hardening. The above plantlets formed the basic material for field evaluation undertaken in the present study. Sree Jaya and CC1 genotypes were planted as control. Out of the 58 plantlets transferred from the in vitro cultures to hardening, only 34 plantlets survived i.e., the survival was found to be 58.62 per cent. All the ten plants that were already in the primary hardening stage survived. Observations were recorded during field evaluation of the in vitro mutagen treated plants at three, six and nine months after planting as per the descriptor of cassava (Fukuda et al., 2015). The plants varied with respect to qualitative characters like colour of apical leaves, leaf retention, shape of leaf lobe, petiole colour, leaf orientation, colour of stem exterior, extend of root peduncle, shape of tuber, root colour, colour of root pulp and colour of root cortex. Variability was also observed for quantitative characters like length and width of leaf lobe, length to width ratio of leaf lobe, petiole length, distance between leaf scars, height of plant, tuber weight per plant, tuber girth, stem girth, extend of root peduncle, starch content and dry matter content. Among the mutagen treated plants of Sree Jaya none of in vitro mutagen treated plants were found to be superior with respect to tuber yield while in CC1 genotype, six plants yielded better than the control. Sensory evaluation of the tubers produced by in vitro mutagen treated plants as well as control plants was done by twelve panelists to assess consumer perception. The tubers from plant 32 (Sree Jaya; 1.2 % EMS), followed by plant 31 (Sree Jaya; 1.2 % EMS) and plant 42 (CC1; 0.9 % EMS) were most preferred for various sensory attributes evaluated. In vitro mutation being a potential method to induce variability, mutation of callus derived from genotypes was as attempted to create more variants. The callus cultures of Sree Jaya and CC1 genotypes were established as per the protocol standardised by Magaia, (2015). Friable embryogenic calli production was higher in the media MS + 8 mg L-1 2,4-D + 1 mg L-1 NAA + 0.5 mg L-1 BAP using leaf explants. Calli were subjected to physical (γ irradiation at 30- 60 Gy at an interval of 10Gy) and chemical (EMS 0.1 - 0.9 % at an interval of 0.1%) mutagens as advocated by Magaia, (2015). However, regeneration of mutagen treated friable calli was not obtained in both genotypes. Quantum of variability expressed in the in vitro mutated plants of cassava with respect quantitative traits shows the efficiency of in vitro mutagenesis in creating variability in cassava. In vitro mutagenesis is a potential tool in the hands of plant breeder to create variability especially in vegetative propagated crops. The evaluation of in vitro mutagen treated plants in the field showed wide variation with respect to most morphological as well as biometrical traits. All the plants evaluated can hence, be advanced to next generation of evaluation (M1V1) with replication to identify the mutants. From the results obtained on induction of in vitro mutation to create more variants in cassava, it is concluded that the friable callus in both the genotypes need to be cultured in alternate regeneration medium for successful regeneration of somatic embryos.
