Loading...
![Thumbnail Image](assets/images/Collection.png)
Theses
Browse
Search Results
ThesisItem Open Access Induction of heteroploidy in Dendrobium sp.(Department of Plant Breeding and Genetics, College of Agriculture ,Vellayani, 2021-12-27) Revathi, B S; Beena Thomas; KAUThe present study entitled “Induction of heteroploidy in Dendrobium sp.” was carried out at the Department of Plant Breeding and Genetics, College of Agriculture, Vellayani during 2019-21. The study was undertaken to induce heteroploidy in Dendrobium crumenatum using antimitotic agent colchicine via in vitro and in vivo technique. In in vitro induction of heteroploidy in Dendrobium crumenatum, the explant used in the micropropagation was stem nodal segments containing one axillary bud and the basal medium chosen was VW medium. The best combination of surface sterilization agents identified were, 20 per cent sodium hypochlorite for 20 minutes followed by 0.1 per cent mercuric chloride for 5 minutes and 70 % alcohol for 2 minutes. The medium VW+1 mgL-1 BA + 0.5 mgL-1 2,4-D was chosen for callus induction, callus proliferation and PLB formation. The explants were maintained in dark for callus induction and proliferation and for subsequent stages a photoperiod of 16 hours light and eight hours dark was provided. For the induction of heteroploidy, PLBs were subjected to eight different colchicine treatments in basal VW suspension medium. Colchicine treatments were based on the concentration of colchicine (0.05%, 0.10%, 0.15%, 0.20%) and duration of exposure of PLBs to colchicine (24 and 48 hrs). For shoot induction, VW basal medium supplemented with the hormones BA (1mgL-1) and NAA (0.1 mgL-1) was used. The maximum survival percentage of cultures at shoot multiplication stage after different colchicine treatments was observed to be 83.33 per cent, and the minimum survival percentage noted was 25 per cent. In in vivo induction of heteroploidy in Dendrobium crumenatum, D. crumenatum plantlets were subjected to eight different colchicine treatments, based on colchicine concentration (0.05%, 0.1%) and the duration of exposure of plantlets to these doses of colchicine (24 hrs, 48 hrs, 72 hrs, 96 hrs). The highest percentage of plants showing response after colchicine treatment was found to be 83.33 per cent (observation recorded after 2 weeks of colchicine treatment) and the lowest percentage recorded was 16.67 per cent. The observations shoot length, diameter of pseudobulb, number of leaves and width of leaves showed mean values greater than their corresponding control means, whereas the observations, diameter of shoot and length of leaf noted lower mean values than corresponding control. The mean value for the character height of pseudobulb were found to be same for treated and control plantlets. The character, number of leaves recorded high PCV and GCV. Moderate PCV and GCV were recorded for the characters viz., diameter of pseudobulb, length of shoot, length of leaf and width of leaf. The characters, diameter of shoot and length of pseudobulb obtained low PCV and GCV. Significant positive genotypic correlation was observed between length of shoot and height of pseudobulb, diameter of shoot and width of leaf, length of pseudobulb and number of leaves, number of leaves and length of leaf and width of leaf and number of leaves. Flow cytometry analysis of the colchicine treated in vivo and in vitro D. crumenatum samples were performed at Rajiv Gandhi Institute for Biotechnology, Poojapura. The histogram peaks obtained after the analysis of control (diploid) and treated samples were compared for interpretation of the results. In the in vitro treated samples, the maximum tetraploids (66.67 %) were obtained from treatments 0.15% colchicine, 24 hrs and 0.10 % colchicine, 48 hrs. On analyzing the histogram peaks of in vivo treated samples, the highest tetraploid induction (50%) was noticed in treatment 0.05% colchicine, 96 hrs. It was concluded from the present investigation that, for Dendrobium crumenatum which was subjected to both in vitro and in vivo colchicine treatments, in vitro colchicine treatment was found effective than in vivo colchicine treatment, when the concentration and duration of exposure to colchicine used for the study were same.ThesisItem Open Access Evaluation of tomato genotypes for tomato leaf curl virus (tolcv) resistance(Department of Plant Breeding and Genetics, College of Agriculture, Vellanikkara, 2021) Anjitha, A R; KAU; Deepthy Antony, PTomato (Solanum lycopersicum, 2n=24) is a widely grown vegetable in India, exhibiting wide variability for plant traits. Worldwide, tomatoes are susceptible to many diseases like damping off, bacterial wilt, early blight, leaf curl virus disease, leaf spot etc. Among them, tomato leaf curl virus disease (ToLCD), caused by whitefly-transmitted begomoviruses is more severe and it can cause up to 100 per cent yield loss. Although, the cultivated tomatoes are susceptible to Tomato leaf curl virus (ToLCV), different levels of resistance were identified in wild relatives of tomato. Utilization of these natural resources will aid ToLCV management through crop improvement. The present study entitled ‘Evaluation of tomato genotypes for Tomato Leaf Curl Virus (ToLCV) resistance’ was carried out at Department of Plant Breeding and Genetics, College of Agriculture, Vellanikkara during 2019-21. The experimental material consisted of 27 tomato genotypes including eight NBPGR (National Bureau of Plant Genetic Resources) accessions, five breeding lines from the World Vegetable Centre, Taiwan, nine commercial hybrids, four KAU varieties and one local collection from Idukki. All 27 genotypes were screened for ToLCV resistance under natural conditions in randomized block design with two replications during January- May 2021. The disease response was assessed after 30 days of transplanting by adopting the score chart suggested by Banerjee and Kalloo (1987). Among the genotypes tested, Ansal was found to be highly resistant, Kaustubh, EC 519806 (S. pimpinellifolium), Arka Rakshak and local collection (Idukki) were identified as resistant genotypes. The genotypes found to be highly resistant and resistant were subjected to whitefly mediated artificial inoculation. The resistant and highly resistant genotypes remained asymptomatic, whereas the susceptible genotypes (Anagha and Manuprabha) exhibited ToLCV symptoms after artificial inoculation. The morphological growth characters such as plant height, number of primary branches per plant, days to flowering and trichome density differed significantly among the genotypes evaluated in the present study. Density of both glandular and non-glandular trichomes on both abaxial as well as adaxial leaf surfaces were recorded. Correlation analysis between trichome density, and disease severity index and per cent disease incidence showed that glandular trichome density on abaxial and adaxial surfaces of leaf was significantly and negatively correlated with per cent disease incidence and disease severity index. However, the negative correlation was stronger between the abaxial glandular trichome density and ToLCV incidence. The glandular trichome density of the resistant genotypes identified in the field screening was found to be high. Non-glandular trichome density on abaxial and adaxial side of the leaf was significantly and positively correlated with per cent disease incidence and disease severity index. Screening for the reported Ty genes using the primers TG178 (SCAR), SCAR-2, P6-25, TY-1/3_K (SCAR), 18IY13 (Indel), SLM 4-34 (SSR) and SLM 10-46(SSR)linked to the ToLCV resistance genes Ty-1, Ty-2, Ty-3, Ty-1/3, Ty-4, Ty-5 and Ty-6 respectively was done in the present study. Seventeen genotypes produced amplicon using TG178 and ten genotypes produced amplicons using SLM4-34. However, there was no pattern in the amplification of the markers TG178 and SLM 4-34. Seven genotypes recorded the presence of Ty-1/3 in homozygous condition (AVTO 1727, AVTO 1726, AVTO 1706, AVTO 1707, EC 538153, EC 620428 and EC 620486) and seven genotypes in heterozygous condition (Ansal, Virang, Aryaman, Durg, Raymond, Abhiraj, Pranay). Four genotypes each carried the resistant allele for Ty-2 in the homozygous state (AVTO 1726, AVTO 1706, AVTO 1707 and AVTO 0922) and in the heterozygous state (AVTO 1727, Ansal, Arka Rakshak and Aryaman). Resistant allele for Ty-3 was present in the genotype AVTO 1726 and AVTO 1707 in homozygous state. Whereas, it was in heterozygous condition in AVTO 1727. None of the genotypes evaluated in the present study revealed the presence of amplicons corresponding to resistant allele of Ty-4 and Ty-6. The resistant genotypes identified in the present study viz., Ansal, Kaustubh, Arka Rakshak, EC 519806 and local collection (Idukki) can be used for resistance breeding. The present study revealed that trichome density can be used as a reliable morphological marker for ToLCV resistance. The donors for Ty-2, Ty-3 and Ty-1/3 identified in this study can be used for gene pyramiding in future breeding programmes.ThesisItem Open Access Genotype x environment interaction in advanced breeding lines of Cowpea (Vigna unguiculata (L.) Walp)(Department of Plant Breeding and Genetics, College of Agriculture, Vellanikkara, 2021) Swathi, S; KAU; Jiji JosephCowpea (Vigna unguiculata (L.) Walp) is an important tropical and subtropical annual legume crop grown for its green pods, grains and is also being used as a forage crop. It is one among the widely cultivated and consumed grain legumes, globally. As the grains contain high amount of protein (23.4 %) possessing better biological value on dry weight basis, cowpea is often considered as “vegetable meat”. Its ability to fix atmospheric nitrogen and drought tolerance makes it a suitable component in all major cropping systems. The present study entitled ‘Genotype x environment interaction in advanced breeding lines of Cowpea (Vigna unguiculata (L.) Walp)’ was an attempt to identify suitable and stable lines for general cultivation as a dual purpose type (both as grain purpose and vegetable purpose). Materials used for the study comprised of five cowpea cultures in stabilized F 7 generation developed as a result of pedigree selection from two crosses at the Department of Plant Breeding and Genetics, College of Agriculture, Vellanikkara, along with two check varieties, Anaswara and Kanakamony. The crop was raised during February 2021 to May 2021 over three environments viz., RARS Pattambi, CoA Vellanikkara and RRS Vyttila. Field experiments were laid out in plots of size 65 m 2 adopting randomized block design (RBD) with three replications. Observations were recorded on twelve characters: plant height (cm), number of branches, days to first flowering, days to first harvest, days to last harvest, number of pods per plant, pod length (cm), pod weight (g), number of seeds per pod, test weight (g), grain yield per plant (g) and protein content (%). All the observations were recorded at the time of harvest except for days to first flowering. The recorded observations were subjected to individual, location wise analysis of variance (ANOVA) followed by pooled analysis of variance (pooled ANOVA) over three locations. From the pooled ANOVA, the characters that exhibited significant genotype x environment (G x E) interaction were further assessed for stability using three models of stability. The Eberhart and Russell model, the Additive Main effects and Multiplicative Interaction effects (AMMI) model and the Genotype main effects plus Genotype-by- Environment interaction effect (GGE) biplot were the three models of stability used for the study.ANOVA revealed significant difference between lines for all the twelve characters considered. However, the Bartlett’s test for examining the homogeneity of error variance was found to be significant only for six characters. These six characters viz., days to first flowering, days to last harvest, number of pods per plant, number of seeds per pod, grain yield per plant and protein content were subjected to pooled ANOVA across three environments. Significant G x E interaction was observed in the six characters considered and were hence forwarded for analysing the stability. The Eberhart and Russell model recognizes a stable genotype as the one with high mean performance, non-significant regression (bi) as well as deviation from regression (S 2 di) values. The genotypes were ranked according to their mean values and stability parameters and it was observed that genotype L 2 with the lowest score was the most stable one followed by L 1 and L 3 respectively. The AMMI model with its additive as well as multiplicative formulations could interpret the complex G x E patterns effectively through the AMMI biplots. Genotypes were scored and then ranked , according to their stability index (SI) value computed on the basis of rank of AMMI stability value (rASV) and the rank of performance for each character (rY). It was observed that L 2 with its lowest score ranked as the best and stable genotype followed by L 1 and L 5 . The GGE biplot model enabled effective interpretation of genotype x environment interaction by providing visual understanding of genotype and test- environment evaluation through mean versus stability graph, ranking of genotypes, ranking of environments and which won where analysis. On an overall basis it was - - identified from GGE biplot method that L 1 , L 2 and L 3 were the most stable and superior performing genotypes. Comparison of results from the three models of stability confirmed L 1 and L 2 as the most stable and promising genotypes. Hence these genotypes can be evaluated in large fields so as to confirm with the results and for checking the suitability of these genotypes to be released as a variety.ThesisItem Open Access Genetics of shattering resistance in rice (Oryza sativa L.)(Department of Plant Breeding and Genetics, College of Horticulture, Vellanikkara, 2020) Akhil, K P; KAU; Biju, SRice is the staple food crop of Kerala. Among the plethora of rice varieties available Jyothi is by far the most popular in the state owing to its consumer preference. Easy seed shattering leads to significant loss in Jyothi which can be overcome by transferring shattering resistance to it. Screening of genotypes for shattering resistance identified donors like Athira and Triveni with good combining ability. The present experiment was thus envisaged to transfer shattering resistance to Jyothi from the donors and to study the nature of inheritance of seed shattering trait using six parameter model of generation mean analysis. Observations were recorded in the two crosses viz., Jyothi x Aathira and Jyothi x Triveni for eleven quantitative characters viz. days to 50 per cent flowering, plant height, tillers per plant, panicles per plant, panicle length, spikelets per panicle, seeds per panicle, days to maturity, test weight, grain yield per plant and shattering per cent in six generation (P1, P2, F1, F2, B1 and B2) obtained from the two crosses. Panicle per plant, test weight, grain yield per plant and shattering per cent recorded significant heterosis in the desirable direction in both the crosses. Mean effect (m) was significant and positive for all the characters studied in both the crosses. The additive component (d) was significant and positive for days to 50 per cent flowering, tillers per plant, panicles per plant, days to maturity, grain yield per plant and shattering per cent in the cross Jyothi x Triveni while the other characters recorded significant and negative additive gene effect. The characters tillers per plant, test weight and shattering per cent showed significant positive additive gene effect in the cross Jyothi x Aathira and rest of the characters showed significant and negative additive component. Dominance gene effect was observed to be significant and negative for most of the characters studied in both the crosses. Non-allelic interactions were observed to be significant in most of the characters except days to 50 per cent flowering, tillers per plant, days to maturity and shattering per cent in the cross Jyothi x Aathira. The epistatic interaction model of generation mean analysis was found adequate for obtaining gene actions for all the characters. Among the three type of interactions dominance x dominance interaction was found to be more important for all the characters. Additive x additive and additive x dominance gene interactions were found to be equally important for most of the characters studied in both the crosses. Dominance gene effect was observed controlling the genetic variance in most of the traits studied. Presence of additive and non-additive along with epistatic interaction revealed the complex nature of inheritance of the characters. Predominant dominant gene effect along with duplicate epistasis limits the scope of direct selection. In the F2 populations characters showed high heritability in both the populations studied. Plant height, panicle length and days to maturity were found to have low genetic advance. Plant height recorded moderate genetic advance, whereas, other characters exhibited high genetic advance in F2 population derived from the cross Jyothi x Triveni. Days to maturity showed low genetic advance, days to 50 per cent flowering and panicle length recorded moderate genetic advance and other characters recorded high genetic advance in F2 population derived from the cross Jyothi x Aathira. As shattering resistance is governed predominantly by additive gene effects selection in the early segregating generations will be highly rewarding. The selected lines may be advanced to further generations to identify lines with high yield coupled with shattering resistance and can be forwarded to develop high yielding varieties with low shattering or bi-parental mating among the selected lines may be undertaken to recover superior recombinants with high yield and shattering resistance.ThesisItem Open Access Development of doubled haploids for iron toxicity tolerance in rice (Oryza sativa L.)(Department of Plant Breeding and Genetics, College of Horticulture, Vellanikkara, 2020) Chakravarthi, Marri; KAU; Dijee, BastianRice is the staple food crop of the people of Kerala. The production of rice in Kerala is impeded by many biotic and abiotic stresses. Iron toxicity is one of the major abiotic stresses of acidic soils in Kerala. The present study “Development of doubled haploids for iron toxicity tolerance in rice (Oryza sativa L.)” was taken up with the objective of developing doubled haploids with tolerance to iron toxicity through in vitro anther culture. Doubled haploids being homozygous stable lines, can be used both as immortal populations for QTL mapping as well as varieties, if suitable agronomic traits are present in them. Therefore, this study was taken up which comprised of three experiments. In experiment I, two tolerant genotypes (Swetha and Mangala Mahsuri) and two susceptible genotypes (Cul-90-03 and Cul 8709) were crossed with Tulasi. In the second experiment the parents along with their hybrids were evaluated for biometric characters and yield. The hybrids obtained from the crosses were significantly different for all the characters observed. Panicles per plant and grain yield per plant recorded highly significant and positive relative heterosis and heterobeltiosis. The anthers from the F1s produced in the previous experiment were used for anther culture studies in the third experiment. Sterilisation with various sterilants like 70 % ethanol, 0.1 % mercuric chloride, 5.25% sodium hypochlorite and their combinations were done. Explant sterilisation with 5.25% sodium hypochlorite for 5 to 20 minutes was effective in controlling contamination in the in vitro cultures. Study to know the best number of days of cold pre-treatment at 10oC was done (0, 3, 6, 9, 12, 15 days). Cold pre-treatment of anthers at 10oC for 9 days was found to be optimum for most of the genotypes studied. Two different media viz., N6 and B5 were tried with different combinations of 2,4 - D and Kn. N6 media responded better than B5 media for callus induction in all the growth hormone combinations. The effect of carbon source on callusing was studied using maltose and sucrose at various levels (30,40,50 mg/L) and it was found that maltose at 30g/L gave the best callus induction (7.95%). Among the auxins used in the present study,2,4-D was found to be better than NAA for callus induction while among cytokinins, Kinetin responded better than BAP for callus induction. The growth hormone combination 2,4- D (2mg/L) + Kn (0.5mg/L) was adjudged the best for callus induction. Additives like silver nitrate (AgNO3), casein hydrolysate (CH), yeast extract (YE), proline and activated charcoal were added to the basal media to improve callusing. when AgNO3 is applied from 0 to 1ml with 0.1 ml gradation, 0.5-0.6ml of 0.1N AgNO3 was found to be better in callus induction as well as the days to callus induction was reduced at these concentrations. 250 – 500 mg/L of CH and 250mg/L proline were found to induce significant response for callusing while activated charcoal and yeast extract did not have any considerable effect on callus induction. Hybrid H1 recorded good callus response when maltose at three levels was tried in the media (30, 40, 50g/L) whereas hybrid H2 gave uniform response at all the levels of maltose. There was significant variation among the genotypes in their response to all the factors studied. The best responses were as follows: - H1(Swetha x Tulasi) - N6+2,4-D (2mg/L) + Kn (0.5mg/L) + 30g/L maltose +0.5ml (0.1 N AgNO3) + 250mg/L proline + 250mg/L CH +2.5g/L gelrite gellan gum. H2(Mangala Mahsuri x Tulasi) - N6+2,4-D (2mg/L) +Kn (0.5mg/L) + 30g/L maltose +0.5ml (0.1N AgNO3) +250mg/L proline+250mg/L CH +2.5g/L gelrite gellan gum. H3(Cul-90-03 x Tulasi) - N6+2,4-D (2mg/L) +Kn (0.5mg/L) + 30g/L maltose + 0.5ml (AgNO3) + 250mg/L proline + 250mg/L CH + 2.5g/L gelrite gellan gum. H4(Cul 8709 x Tulasi)- B5 + 2,4-D (2mg/L) + Kn (0.5mg/L) + 30g/L maltose + 0.5ml (0.1N AgNO3) + 250mg/L proline + 250mg/L CH + 2.5g/L gelrite gellan gum. The calli obtained from the different genotypes were plated on two different callus regeneration media R1 (MS+ NAA(1mg/L) + Kn (2mg/L) + IAA (0.5mg/L) + CW (5%)) and R2 (MS+NAA (0.25mg/L) + BAP (0.75mg/L) + Kn(0.25mg/L)). There was no response in R1 media. Callus regenerated into plantlets in R2 but all the plantlets obtained were albinos leading to mortality and hence plantlet hardening and field planting could not be undertaken.ThesisItem Open Access Characterisation of brinjal (solanum melongena L.) and its wild relatives(Department of plant breeding and genetics, College of Agriculture, Padannakkad, 2021) Lintu, P; KAU; Namboodiri, Raji VasudevanThe study entitled “Characterization of brinjal (Solanum melongena L.) and its wild relatives” was carried out at the Department of Plant Breeding and Genetics, College of Agriculture, Padannakkad during 2018-2020. The main objectives of the study was to characterize the brinjal genotypes and its wild relatives based on morphological characters; analyze the genetic variability in collected accessions and to develop selection index for cultivated types. The experimental meterial consisted of 25 S. melongena accessions and five wild relatives (S. mammosum, S. macrocarpon, S. insanum, S. incanum and S. gilo) collected from North Kerala (Malappuram-11, Kozhikode-5, Kannur-4, Kasaragod- 3, Wayanad-1) and Regional station, NBPGR, Thrissur (6). The passport data of thirty accessions were prepared and these were evaluated for 17 qualitative and 22 quantitative characters based on IPGRI descriptor in field experiment laid out in Randomized Block Design with three replications. The morphological characterization based on qualitative characters showed wide variation for stem colour, leaf lobing, fruit shape and fruit colour. The results of analysis of variance indicated significant differences for all the quantitative characters indicating presence of high genetic variability. The mean performance of genotypes revealed distinct variation between cultivated and wild accessions for most of the characters. The wild accessions recorded lower values for fruit yield and fruit weight but longer duration for flowering and fruit set. Eight S. melongena accessions (SM 27, SM 25, SM 23, SM 20, SM 10, SM 23, SM 24 and SM 8) had high fruit yield per plant (more than 1000 g). The accession SM 27 had shown superiority for important yield component traits like fruit yield, fruit diameter and fruit weight. Among all accessions, the green fruited S. melongena accession SM- 25 showed lesser incidence of shoot and fruit borer. Three wild accessions S. mammosum (SM 22), S. gilo (SM 29) and S. insanum (SM 30) showed no incidence of fruit and shoot borer. The variance component analysis revealed high heritability coupled with high genetic advance as per cent of mean for all flowering and fruit characters indicatingthat most likely the heritability is due to additive effects making selection effective based on these characters. Association analysis revealed that plant height, days to first flowering, number of long styled flowers, fruit diameter, fruit weight and number of fruits per plant shown significant genotypic correlation and direct effect showing true association of these characters with fruit yield. Selection based on all these characters will help to achieve efficient improvement in fruit yield. The UPGMA clustering of 30 eggplant accessions for qualitative traits revealed three groups based on anthocyanin pigmentation of plant parts and leaf prickliness, traits important for stress tolerance. The genetic diversity analysis based on Mahalanobis D 2 statistics for 22 quantitative characters grouped 30 accessions into eight clusters. The clustering patern showed the S. melongena accessions collected from North Kerala grouped under cluster I (22) and cluster III (2). All the five wild accessions were grouped in five different clusters (III, IV, VI, VII and VIII). The green fruited accessions SM 25 and SM 27 collected from NBPGR were placed in cluster III and cluster V indicating their distinctness. The character fruit yield per plant, leaf blade width, number of fruits per plant and leaf blade length hade made major contribution towards genetic divergence with maximum by fruit yield per plant. The maximum intra-cluster distance was reported in cluster I, followed by cluster III. The remaining are solitary clusters. The highest inter- cluster distance was recorded between solitary clusters V and VIII, V and IV and V and III providing scope for hybridization between genotypes of these highly divergent cluster especially involving wild accession SM 30 for fruit and shoot borer resistance. Selection index involving discriminant functions based on relative economic importance of various characters showed a combination of four characters (Fruit yield per plant + Number of long styled flowers + Fruit diameter + Fruit weight) with maximum relative efficiency. Based on high selection index score involving four character combination and overall cluster ranking for three yield attributes two green fruited accessions SM 25 and SM 27 and six purple fruited accessions SM-8, SM- 10, SM-18, SM-20, SM-23 and SM 24 are identified as promising. Among these,the green fruited accession SM 25 had shown very low incidence of fruit and shoot borer. Based on selection index score and cluster divergence (high inter-cluster distance) the SM-27 is identified as promising parent in intra-specific hybrid involving of SM-27 x SM-25 and inter-specific hybrids involving SM-27 x S. insanum and SM-27 x S. macrocrpon. These crosses may be attempted in future breeding program for obtaining progenies superior for yield as well as shoot and fruit borer and bacterial wilt resistance.ThesisItem Open Access Morpho-molecular characterisation of D x D hybrids developed using 'annur', the dwarf ecotype of WCT coconut ( Cocos nucifera L.)(Department of plant breeding and genetics, College of Agriculture, Padannakkad, 2021) Anuprasad, T E; KAU; Sujatha, RCoconut is one of the most extensively grown crop in the world, playing a significant role in the economic, cultural, and social life of over 80 tropical countries. Coconut cultivars are classified into tall (variety typica) and dwarf (variety nana) types. Short statured palms are currently receiving more attention due to various socio-economic factors. However, the poor quality of nuts for various processing aspects and high susceptibility of dwarf palms to pest and diseases makes them unsuitable for large scale cultivation. The solution for this problem is development of suitable hybrids by combining the desirable features of tall and dwarf palms. West Coast Tall (WCT) is the most widely cultivated variety in Kerala and several ecotypes of WCT were reported. In a study initiated in 2005 at RARS Pilicode, an ecotype of WCT was detected in Annur, a place in Kannur district which showed dwarfing nature with nut qualities similar to WCT. The Annur ecotype was crossed in 2007-08 with the dwarf cultivars Malayan Yellow Dwarf (MYD) and Gangabondam (GB). The hybrid seed nuts along with interse seed nuts of Annur were planted at RARS Pilicode in 2009. The first flowering was recorded in 2014. The present study aims at evaluation of plant stature, yield, nut quality and other important morphological traits of Annur and the hybrids developed from it. The interse of Annur, Annur x GB and Annur x MYD were compared with corresponding characters of the respective parents as well as WCT, Keraganga (WCT x GB) and Kerasree (WCT x MYD). Significant reduction in height was observed for hybrids viz. Annur x MYD (2.251 m) and Annur x GB (2.065 m) which was on par with Annur (2.725 m) and considerably lower than the corresponding values of dwarf cultivars viz., MYD (5.2 m) and GB (8.885 m). Number of nuts per palm per year was on par in Annur (58.2) and Annur x MYD (55.4) while that was lower in hybrid Annur x GB (34.3). However, since the palms started flowering only in 2014, stabilization of yield is not attained. Nut weight and kernel thickness were significantly higher in Annur x MYD whereas these were on par in Annurand Annur x GB. Copra content in Annur and both hybrids were on par. In general, Annur x MYD showed superior performance for nut characters compared to Annur x GB. Annur palms were significantly similar to WCT for most of the characters except height, rate of leaf production, nuts per bunch, nut water content. When the yield of hybrids of Annur were compared with the standard check varieties viz., Keraganga (WCT x GB) and Kerasree (WCT x MYD), (101.5 and 104.25 nuts per palm per year) yield of Annur x GB and Annur x MYD were low. However, both hybrids showed nut characters similar to the respective released varieties ie, Annur x GB was similar to Keraganga and Annur x MYD showed similar nut characters with Kerasree except copra content (161.432 g and 193 g respectively). Better palms from each cross were analysed and palm numbers 1, 2, 15, 19, 20 and 28 were identified as better palms from interse of Annur. The better performing palms of hybrid, Annur x MYD were palm numbers 43, 44, 47 and 49. Three palms from Annur x GB (palm numbers 53, 55 and 56) were identified as better palms. Correlation analysis revealed significant positive genotypic correlation of nut yield per palm with all reproductive and yield characters and with most of vegetative and nut characters. Path coefficient analysis showed high positive direct effect on number of female flowers per inflorescence, number of bunches per palm per year, number of nuts per bunch, pole to pole circumference of nut, nut weight (with husk), shell and meat weight, quantity of liquid endosperm and copra content. High heritability coupled with high genetic advance was exhibited by the characters height of palm, leaf length, number of green leaves, number of inflorescences at the time of observation and number of female flowers per inflorescence. This indicates that these characters are governed by additive gene action and selection based on these characters will be effective. For both hybrids, height of the palm showed negative heterosis which indicates the dwarf nature of the hybrids. In hybrid Annur x MYD, most of nut charactersshowed heterosis over mid parent (relative heterosis) and better parent (heterobeltiosis). The standard heterosis was significant when compared with Keraganga but was not significant with Kerasree. Molecular characterization of the Annur (interse) and the hybrids from it was also attempted using Simple Sequence Repeat markers (SSR). Good quality genomic DNA is the prerequisite for any molecular work. DNA was isolated from all the parental palms as well as check cultivar Kerasree. The quality and quantity of genomic DNA obtained was verified using agarose gel electrophoresis and spectrophotometer. The quantity of DNA samples ranged from 350 to 1300 ng/μl with good quality. Screening of SSR markers for parents and check palms revealed polymorphism for the primers CAC02, CAC11, CNZ40, CnCirA9, CnCirB12, CnCirC3, CnCirC5, CnCirC7, CnCirE2, CnCirE12, CnCirF2, CnCirG11, CnCirH4 and CnCirH7. Out of 34 SSR markers, 27 were monomorphic between WCT and interse of Annur. Genetic Similarity analysis using the SSR markers revealed the high similarity between of interse palms of Annur and WCT. Dwarf palms viz. MYD and GB also showed high genetic similarity with each other. The present study revealed that the genotype Annur is a dwarf ecotype of WCT with similar nut quality and hence is a very promising genotype for breeding for dwarfness. The hybridization of ecotype Annur with MYD is found to be superior in yield characters compared to the hybridization with Gangabondam. However, both hybrids inherited the short stature from Annur and are promising. Since the yield characters needs to be stabilized, evaluation based on important vegetative and reproductive characters as well as molecular fingerprinting needs to be continued inorder to identify the full potential of these dwarf hybrids.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.