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 Androgenesis in rice (Oryza sativa L.) breeding(Department of Plant Breeding and Genetics, College of Horticulture, Vellanikkara, 2004) Chandrahasan, V T; KAU; Dijee BastianAn investigation was carried out in rice, at the College of Horticulture, Vellanikkara to produce doubled haploid lines through anther culture technique. The study included production of a hybrid between IR 36 (ovule parent) and PTB 45 (pollen parent), evaluation of parents and hybrid, culturing the anthers of F1 to produce doubled haploids and analyse the effect of growth regulators (2,4-D, Kn, IAA and IBA) and carbon source (sucrose and maltose) on callus induction. There was significant difference among the parents and hybrid. The hybrid recorded significantly different values for plant height, panicle length, grains / panicle, grain weight and grain yield / plant. Among the 24 treatments used for anther culture, callus induction was observed in 11 treatments. Callus induction percentage ranged from 0 to 4.18. Maximum callus induction percentage was recorded in N6 medium supplemented with maltose 60 mg/l, 2, 4-D 2mg/l and Kn 0.5 mg/l (4.18%) followed by N6 medium supplemented with maltose 60 mg/l, 2, 4-D 2 mg/l and Kn 1mg/l (3.32%). A significant increase in anther culture efficiency was observed when sucrose was replaced by maltose in the presence of growth regulators 2,4-D/Kn but not in the presence of IAA/Kn. Callus induction frequency was high in 2,4-D/Kn combination followed by IAA/Kn combination irrespective of carbon source. IBA/Kn combination was totally non-responsive. Main effects of 2, 4-D and Kn were significant, but there was no interaction between 2, 4-D and Kn when sucrose was used as carbon source. Among the two levels of 2, 4-D, 3 mg/l (0.6%) was superior to 2 mg/l (0.24%) and among the two levels of kinetin 0.5 mg/l (0.71%) was superior to 1 mg/l (0.12%). Main effects of 2, 4-D only was significant when maltose was used as carbon source. Main effect of 2, 4-D indicated that there was significant reduction in callus induction response when level of 2, 4-D increased from 2mg/l (3.75%) to 3mg/l (2.31%). Sixty six calli were obtained through anther culture of which 57 were embryogenic calli and the rest non-embryogenic calli. The percentage of embryogenic calli (86.45%) was higher than non-embryogenic calli (13.6%). 2, 4-D/Kn combination produced more number of embryogenic calli (88.3%) than IAA/Kn combination (66.7%). Thirty green plants and five albinos were obtained from regeneration medium. The frequency of green plant and the albinos were 85.71 per cent and 14.29 per cent respectively. Regeneration frequency of embryogenic and non-embyogenic calli were 27.19 per cent and 22.22 per cent respectively. Among 30 green plants obtained , 21 were homozygous diploids and the rest haploids. Frequency of spontaneous doubling was 70 per cent. Of the 30 regenerated plants taken for hardening 24 survived and all were observed for grains per panicle and seed setting percentage. The values of grains per panicle and seed setting percentage ranged from 87 to 106 and 89.79 to 95.33 respectively.ThesisItem Open Access Standardisation of selection criteria for cocoa hybrids(Department of Plant Breeding and Genetics, College of Horticulture, Vellanikkara, 1998) Raji Varghese; KAU; Pushkaran, KInvestigation on standardisation of selection criteria for cocoa hybrids was conducted at Cadbury-KAU Co-operative cocoa Research Project (CC RP) Farm of Kerala Agricultural University, Vellanikkara during 1994-96. Twenty nine hybrids grown under Progeny Trial I and their 18 parents maintained in CYT-I were used for the study. The influence of seedling height and girth on yield was more pronounced in the case of seedlings one year after sowing than with those of 4 mas, 5 mas and 6 mas. The vegetative vigour measured by the height and diameter of trunk was found to be better correlated with precocity. The correlation coefficients of pod characters viz., length, width and weight of pods, number of beans, wet bean weight and pericarp thickness and seed characters viz., length, width, thickness and dryweight worked out between hybrids and female parents showed significant relationship in the case of pod length (r = 0.649) and number of beans (r = 0.606). But with mid parental value, the hybrids showed high correlation for the characters pod length, pod weight, number of beans, seed length, seed width and seed thickness (0.65, 0.45, 0.86, 0.70, 0.76 and 0.70 respectively). Heritability estimated by regressing offspring on female parent was high for the characters pod width, seed length and seed width (0,7, 0.64 and 0.78 respectively). Among the 29 hybrids studied, the hybrid H-4 of the cross GI 10.3 x GVI 54 was found to be promising in terms of both pod and wet bean yield. With the seedling characters of hybrids taken one year after sowing, a multiple regression equation for wet bean yield was fitted as: Y = 43 + 0.195 x1 + 3.70 X2 Where, x1 and X2 are height and girth of one year old seedlings respectively. This can be taken as a seedling selection criteria for cocoa hybrids.ThesisItem Open Access Genetic analysis of segregating generations of irradiated interspecific hybrids in okra (Abelmoschus spp.)(Department of Plant Breeding and Genetics, College of Agriculture, Vellayani, 1997) Sophia John; KAU; Manju, PA study* was. conducted in the Department of Plant Breeding and Genetics, College of Agriculture, Vellayani during l996-'97 to estimate the extent of variability generated in the f 2M? and F3M3 generations as a result of hybridisation and hybrid irradiation of the interspecific hybrids between A. s esculenins and A. manihot and also to isolate high yielding yellow vein mosaic disease resistant lines from among the segregating generations In the l-^M-, generation, the irradiated treatments were found to be late flowering and had more number of leaves per plant, flowers per plant and fruits per plant Irradiation was found to increase pollen sterility and was maximum in 10 kR However seed set was lower for the irradiated treatments. Average fruit weight and weight of fruits per plant was maximum in plants belonging to the treatment 20 kR. Fruit length and girth were found to increase with increasing radiation doses. Number of ridges per fruit, fruiting phase and plant duration were higher in the irradiated treatments when compared to 0 kR and was maximum in 40 kR Plant height was highest in the treatment 30 kR Irradiation was found to increase YVM disease incidence and fruit and shoot borer incidence and it was maximum in 30 kR among the irradiated treatments. However a few high yielding YVM disease resistant plants resembling the cultivated parent were also observed in 30 kR ■Genotypic coefficient of variation, heritability and genetic advance were high for number of branches per plant and number of seeds per fruit in all the irradiated treatments in F2M2. High heritability with high genetic advance were observed for leaf number, number of flowers per plant, Iruits • ' per plant and pollen sterility in 20 kR and 30 kR. Significant positive * . correlation of number of leaves per plant, flowers per plant and fruits per plant with weight of fruits per plant and also among themselves was observed in all the irradiated treatments in F2M0. Average fruit weight and fruit yield A* • 0 per plant were positively correlated in treatments 0 kR, 10 kR, 40 kR, P, and P2. % In F3M3 the irradiated treatments were found to be late flowering and had more number of leaves, branches, flowers and fruits per plant. Pollen sterility was lower for the irradiated treatments, when compared to the unirradiated treatment and was lowest in 30 kR. However the number of seeds per fruit was more in 30 kR compared to the other treatments excluding parental treatments. Irradiation was found to decrease average fruit weight but fruit yield per plant was more for the irradiated treatments due to the larger number of fruits and was maximum in 40 kR. Length of fruit increased with increasing radiation doses. Significant differences among the irradiated treatments were not observed with respect to number of ridges per fruit. Irradiation was found to increase the fruiting phase as well as plant duration. Plant height was maximum in 10 kR when compared to all the other treatments. Yellow vein mosaic disease incidence was high in the cultivated parent and the higher dose radiation treatments viz , 30 kR and 40 kR. From the present study *a few recombinants which resembled the cultivated parent, with high yield and YVM disease resistance could be isolated from 30 kR, which suggested that 30 kR could be ideal radiation dose for evolving high yielding YVM disease resistant lines in okra. Fruit and shoot borer incidence was highest in the cultivated parent and was also high in 30 kR. High to moderately high genotypic coefficient of variation was observed.lor number of branches per plant, leaves per plant, flowers per plant, fruits per plant, weight of fruits per plant and number of seeds per fruit in all irradiated treatments in F3M3. High heritability and genetic advance were observed lor number of fruits per plant, weight of fruits per plant, flowers per plant and pollen sterility in all the irradiated treatments. Number of leaves per plant, flowers per plant and fruits per plant were positively correlated with fruit yield per plant in all the treatments while average fruit weight had significant positive correlation with fruit yield per plant in 0 kR, P, and P2 in the F3M3 generation. As a future line of work, high yielding, YVM disease resistant plants assembling the cultivated parent which have been isolated from the treatment 30 kR will be further evaluated for a few more generations and if found superior and YVM disease resistant it will finally be developed into a YVM disease resistant variety.ThesisItem Open Access Combining ability in bhindi (Abelmoschus esculentus (L) Moench)(Department of Plant Breeding and Genetics, College of Agriculture, Vellayani, 1995) Rajani, B; KAU; Manju, PThe study was carried out in the Department of Plant Breeding and Genetics, College of Agriculture , Vellayani during 1994-95 to estimate the combining ability of six genetically divergent parental strains of bhindi and their 30 F1 hybrids obtained by crossing the six parents in a diallel pattern. The magnitude of heterosis and nature of gene action governing the yield of fruits and other important yield attributes was also elicited through Hayman's numerical and graphical approach. The combinig ability analysis by the Method 1 of Griffing's (1956) approach revealed that the parent P4 (NBPGR/TCR 864) was the best general combiner for yield and a few yield related characters. Among the hybrids P1 X P4 (NBPGR/TCR 893 x NBPGR/TCR 864) exhibited outstanding s.c.a effects for yield. Non addictive gene action was found to govern days to first flowering number of flowers per plant, length of fruit, girth of fruit, weight of single fruit, weight of fruits per plant and number of seeds per fruit while the remaining characters were governed by addictive gene action.ThesisItem Open Access Studies on seed dormancy in rice (Oryza sativa. L.) with special reference to short duration varieties(Faculty of Plant Breeding and Genetics, Agriculture College & Research Institute, Coimbatore, 1961) Gopinathan Nair, V; KAU; Ponnaiya, B W XWork done in cereals and other crop plants on the factors related to seed dormancy (causes, tissues involved, stage of maturity at harvest, variation in period and genetics), which are important from a practical breeding point of view, has been critically reviewed with special reference to rice. Studies were undertaken on six short duration varieties of rice and their hybrids to estimate the period of dormancy, to understand the relative roles of the hull and the embryo and also to understand the mode of inheritance of the character. A new method was adopted in the estimation of dormancy. The period required for germination from flowering, determined by germination tests at periodic intervals, rendered a reliable estimate of inter and intravarietal variability for germination and formed the criterion for comparison of varieties and hybrids.ThesisItem Open Access Marker assisted backcross breeding for pyramiding genes conferring resistance to bacterial blight in rice variety uma(Department of Plant Breeding and Genetics, College of Horticulture, Vellanikkara, 2018) Megha, L M; KAU; Rose Mary FranciesAs in other rice growing locales around the world, bacterial blight (BB) caused by Xanthomonas oryzae pv. oryzae (Xoo) assumes a huge role in deciding rice profitability in Kerala. The elite rice varieties of Kerala, both PTB 39 (Jyothi) and Mo 16 (Uma), are found to be extremely susceptible to bacterial blight. Since both the major rice cropping seasons (virippu and mundakan) in the state coincide with monsoons, the control of the disease through chemicals or biological agents proves inadequate owing to the washing-off of the applied materials. Host-plant resistance is advocated as the most effective breeding strategy to combat the bacterial blight (BB) pathogen. Considering the impact of the disease on food security and sustainability, efforts were taken to introgress three R-genes (xa5, xa13 and Xa21) into the variety Uma from donor parent Improved Samba Mahsuri (ISM) through Marker Assisted Selection (MAS). Further, backcrossing to Uma (recurrent parent) and advancing the resultant BC1F1s have resulted in production of BC2F1 generation (21 Nos.). The present study aimed to identify BC2F1 plants pyramided with genes (xa5, xa13 and Xa21) conferring resistance to bacterial blight using functional markers. In addition, advancing the R-gene introgressed BC2F1s to BC3F1 and BC2F2 generation was envisaged. Pathotyping of BC1F2s (850 Nos.) and generating BC1F3s from the plants exhibiting resistance to BB pathogen was also aimed at. Foreground selection of the BC2F1 individuals using the xa5 gene linked STS marker RG 556 and functional marker xa5 SR confirmed the presence of the R-gene in the parents as well as the 21 BC2F1 individuals. Screening of BC2F1 individuals with STS marker RG 136 linked to R-gene xa13 and functional marker xa13 promoter revealed that the BC2F1 Plant No. 8.3.9.10 was heterozygous at xa13 locus while, all other BC2F1 individuals possessed alleles similar to that of the recurrent parent (RP) Uma. The result also pointed out that BC2F1 Plant No. 8.3.9.10 was a 2-R-gene pyramid (xa5xa5 + Xa13xa13). Foreground selection with STS marker pTA 248 to detect the presence of Xa21 gene revealed that none of the BC2F1 plants analysed except BC2F1 Plant No. 8.3.9.10, possessed the resistant allele of R-gene Xa21. However, presence of alleles of both the parents in Plant No. 8.3.9.10 indicated that it was heterozygous at Xa21 locus. Results obtained thus revealed that, of the 21 BC2F1s subjected to foreground selection, BC2F1 Plant No. 8.3.9.10 was the only 3-R-gene introgressed pyramid (xa5xa5 + Xa13xa13 + Xa21xa21). In addition, the 3-R-gene introgressed BC2F1 Plant No. 8.3.9.10 was subjected to background screening using 22 rice microsatellite (RM) markers. Background profiling revealed that the banding pattern in Plant No. 8.3.9.10 was similar to recurrent parent in case of thirteen RM markers. The plant was found to be heterozygous at five other marker loci. Considering the segregation of the 22 markers, the magnitude of recovery of recurrent parent genome in 3-R-gene introgressed BC2F1 Plant No. 8.3.9.10 was found to be 81.82 per cent. The dendrogram based on molecular data grouped the individuals into two major clusters. Cluster 1 was monogenic with only the donor parent ISM and cluster 2 comprised of the recurrent parent Uma and Plant No.8.3.9.10, further suggesting that the 3-R-gene introgressed BC2F1 Plant No. 8.3.9.10 was more similar to the recurrent parent Uma. Wide variability was observed among the BC2F1 individuals for various morphological traits. The 3-R-gene introgressed BC2F1 Plant No. 8.3.9.10 was shorter in duration than both the parents and also possessed red kernels similar to the recurrent parent Uma. The dendrogram generated based on the morphological characters also indicated greater similarity between the 3-R-gene pyramid and recurrent parent Uma. The identified 3-R-gene pyramid (BC2F1 Plant No. 8.3.9.10) was backcrossed to both recurrent parent Uma as well as selfed resulting in production of BC3F1s (15 Nos.) and BC2F2s (28 Nos.) respectively. Bioassay of BC1F2 population (106 Nos.) through leaf clipping method of pathotyping suggested by IRRI (1991) revealed that more than half the BC1F2 individuals screened exhibited resistance to BB pathogen. The plants that exhibited moderate reaction to BB infection ranged between 16.87 per cent and 34.78 per cent in progeny of BC1F2 Plant No. 8.3.2 and BC1F2 Plant No. 8.3.9 respectively. Selfing of the BC1F2 individuals exhibiting resistance and moderate resistance to BB pathogen resulted in production of 725 BC1F3 seeds. Modern molecular techniques make it possible to use markers and probes to track the simultaneous introgression of several R-genes into a single cultivar during a crossing programme. Foreground and background profiling of backcross generations can ensure precise identification of R-gene introgressed genotypes that resemble the recurrent parent Uma.ThesisItem Open Access Molecular documentation of njavara types of rice (Oryza sativa L.) for cultivar identification(Department of Plant Breeding and Genetics, College of Horticulture, Vellanikkara, 2007) Shareesh, N; KAU; Elsy, C RCharacterisation and evaluation of Njavara types of rice (Oryza sativa L.) was under taken in the Department of Plant Breeding and Genetics and Centre for Plant Biotechnology and Molecular Biology, College of Horticulture, Vellanikkara during 2005 - 2007 with the objective of molecular characterization and gene sequencing in Njavara for developing suitable molecular markers for cultivar identification. Njavara genotypes exhibited high variability with respect to lemma and palea colour with two major classes viz., yellow (straw colour) and black types. Detailed characterization revealed that yellow type could be further grouped into gold furrows on straw (N3 & N5) and brown furrows on straw (N4 & N7). Three genotypes viz., N1, N2 and N6 exhibited a lemma and palea colour dominated by black. N1 and N2 exhibited variations in black colour for lemma and palea as pure black, black furrows/black patches on straw background whereas N6 exhibited light shade of black. Variations in seed coat colour as red, light brown and brown were also observed among the genotypes. The method suggested by Dellaporta et al. (1983) with slight modifications was found to be effective in isolating good quality genomic DNA from Njavara. Good amplifications were observed when RAPD analysis was performed with sequences OPA 1, OPA 4, OPA 6, OPA7 , OPA 9, OPN 6, OPN 18, OPP 6, OPP 11 and OPE 6. OPA 1 and OPP 11 were found to be promising in the amplification of rice genomic DNA with maximum amplification. Amplification of Njavara DNA with primer OPE 6 exhibited unique bands (1.375 kb , 1.29 kb and 0.44 kb ) for Njavara genotypes and hence are valuable as DNA markers for the identification of this unique cultivar. The dendrogram with RAPD markers showed distinct clusters for Njavara. Cloning and sequencing of the unique molecular band with M 13 primer gave the sequence data of a gene segment of size 762 bp.The homology search of this sequence with BLASTN showed that it has maximum identity with genes from Oryza sativa (japonica cultivar-group) mitochondrial gene for tRNA-Asn, complete sequence, O. sativa mRNA for chilling-inducible protein, O.sativa rbbi2-5 gene for putative Bowman Birk tryspin inhibitor, O.sativa rbbi2-3 gene for putative Bowman Birk trypsin inhibitor, O.sativa rbbi2-4 gene for putative Bowman Birk trypsin inhibitor and O. sativa (japonica cultivar-group) mRNA for chilling tolerance related protein.The homology of cloned DNA fragments of Njavara (N5) with BBI genes (rbbi 2-3, rbbi 2-4 and rbbi 2-5 ) is a preliminary indication of the medicinal property (anticarcinogenic) of this unique medicinal cultivar of Kerala and also its thermostable nature. Sequence analysis revealed the presence of five ORF’s . The longest open reading frame had 180 bases encoding 59 amino acids in the predicted coding region. Among the amino acids, serine was occurring more frequently than other amino acids. ORF in +3 reading frame was found to be of a residue length of 102 bases, encoding 33 amino acids. Genscan tool determined two internal exons from the clone with a length of 91 and 129 residues. Sequence analysis of the data with VecScreen showed strong match to vector sequences in the database eventhough the sequences were not matching with pSCA (vector used in the present study) vector. Alignment of sequences through CLUSTAL W programme revealed poor homology with query sequence and vector sequence used for cloning. Homology was shown between the sequences when BLAST 2 SEQUENCES programme was used. These results are to be confirmed through further studies.ThesisItem Open Access Inheritance of resistance to leaf hopper [Amrasca biguttula biguttula (Ishida)] in okra, Abelmoschus esculentus (L.) Moench.(Department of Plant Breeding and Genetics, College of Agriculture, Vellayani, 2003) Deepthi, Sivanandan; KAU; Sunny, K OmmenOkra is an important vegetable crop grown in India and abroad for its fresh green pods. The leafhopper Amrasca biguttula biguttula is a major sucking pest of okra causing high damage to plants. High frequency of fruit picking and repeated application of chemical pesticides to tackle the hopper menace, often leaves toxic residues in the fruits. So it is inevitable that pest resistant varieties should be developed. Hence a study was undertaken to study the genetic variability, for yield and its component characters as well leafhopper resistance indices in a collection of okra genotypes, to estimate the combining ability and heterosis as well as gene effects involved in the inheritance of these characters using line x tester analysis. Forty okra germplasms collected from vanous sources were evaluated simultaneously for yield and leaf hopper resistance. ANOV A revealed that the treatments varied significantly for leafhopper resistance and also there was significant variation among treatments for yield and yield attributes viz., days to first flowering, leaf axil bearing first flower, number of primary branches, number of fruits per plant, length of fruit, girth of fruit, weight of fruit, yield per plant duration. Six genotypes exhibited resistance to the leafhopper throughout the crop duration. High values for phenotypic and genotypic coefficients of variation was recorded for number of primary branches followed by leafhopper population count. High heritability was exhibited by yield per plant followed by duration. Maximum genetic advance was observed for number of primary branches followed by yield per plant. Correlation analysis indicated that most character combinations had higher genotypic correlation coefficient than phenotypic correlation coefficient. Yield exhibited significant and positive correlation with number of fruits and average fruit weight and negative significant association with leaf axil bearing first flower, leafhopper population count and leafhopper injury score. Path analysis was carried out for nine biometric as well as two leafhopper injury indices which had high correlation with yield. Highest positive direct effect was exhibited by number of fruits while the highest negative direct effect on yield was recorded for leafhopper population count per plant. Resistant as well as susceptible genotypes were selected based on leafhopper population counts and leafhopper injury score. Five resistant lines (female parent) viz., Nemom (T21), re 45792, Venjaramood (T23), AE 279 and Palappur (T20) and three susceptible testers (male parent) viz., Venganoor (T1S), Aruna (T37) and Kalliyur (T24) were selected as parents for L x T analysis. These were crossed in a line x tester fashion to produce 15 hybrids. During L x T programme highly significant sea as well as gea effects were obtained for yield. Lt was the best line while T 2 was the best tester. Among hybrids L3 x T 2 was the best considering leafhopper resistance as well as yield and yield attributes. Negative and significant sea effects were observed for days to first flowering and leafhopper population count. It possessed all the desirable characters like high yield, greater weight and girth of fruits and number of fruits. It is also an early flowering type. The ratio of additive to dominance variance was less than one for most of the traits studied including leafhopper population counts and leafhopper injury , scores, indicates the predominance of non-additive gene action. Since there is preponderance of non additive gene effects for characters such as yield and its components as well as leafhopper resistance parameters, exploitation of hybrid vigour is an appropriate breeding approach where yield and leafhopper resistance are considered.ThesisItem Open Access Compatibility studies in monopodial orchids(Department of Plant Breeding and Genetics, College of Agriculture, Vellayani, 2003) Ninitha Nath, C; KAU; Lekha Rani CA research programme "Compatibility studies In monopodia! orchids" was carried out in the Department of Plant Breeding and Genetics, College of Agriculture, Vellayani during 2001-2003 with the objective of undertaking intra and intergeneric hybridization and in vitro embryo culture in monopodial orchids. Twelve monopodial orchid genotypes comprising of six mono generic and six bigeneric hybrids were selected as parents after initial evaluation. They were evaluated adopting completely randomized design with six replications. Analysis of variance revealed significant differences for almost all the characters studied. Genotypic and phenotypic coefficients of variation were high for number of aerial roots, leaf area and width of leaf. Characters like number of aerial roots, width of leaf, leaf area and number of flowers per inflorescence had high heritability coupled with high genetic advance. Significant positive inter-correlation at genotypic and phenotypic levels was observed for length of flow'er and width of flower with number of leaves per cane, number of aerial roots, number of spikes per cane, length of inflorescence and length of scape. The 12 parental genotypes were crossed in all possible combinations (144) after preliminary studies on floral biology. A total of 116 crosses were done including 50 crosses, 54 reciprocals and 12 selfs. Incompatibility reaction was noticed at different stages ranging from flower abscission before the onset of any visible post pollination change to instances where seeds geminated but aborted in culture. A total of 58 combinations attempted succumbed to incompatibility at these different stages from pollination to deflasking. Harvestable green capsules were obtained from 58 combinations and they were inoculated in MS half strength basal medium. Percentage capsule yield ranged from 8 to 38 in the various hybrid combinations. Percentage filled seeds ranged from 18 to 76 in the various combinations. Capsules from twelve combinations did not contain seeds and seeds from ten combinations did not germinate on inoculation. Protocorms of developing seedlings from twelve combinations aborted at various stages of in vitro development. The remaining 24 cross combinations were taken through three to four subculture passages. Seedlings having 2-3 leaves and 2-4 roots were deflasked. 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 and first root primordia and for deflasking. Significant differences in seedling morphology were observed among the 24 hybrid combinations at deflasking with respect to all the seven vegetative characters studied.