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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 Gene action and gene expression analysis in tomato (Solanum iycopersicum L.) under moisture stress(Department of Plant Breeding and Genetics, College of Agriculture, Vellayani, 2021) Chippy, A K; KAU; Beena, ThomasThe present investigation entitled ‘‘Gene action and gene expression analysis in tomato (Solanum lycopersicum L.) under moisture stress” was conducted during the period 2017-2021, in the Department of Plant Breeding and Genetics, College of Agriculture, Vellayani. Thirty-two genotypes including local genotypes of tomato were collected from different sources and studied under three different experiments. In the first experiment, twenty-one F1 hybrids derived from the line x tester mating and their ten parents were transplanted in the field and the treatment mean sum of square due to genotypes was found to be highly significant for all the characters studied which would ultimately indicate diverse nature of selected genotypes. The mean performance showed wide range of variation for most of the characters studied. Among lines, L7 (Pusa Ruby) showed higher mean performance for all-out of nine characters viz., plant height, fruit length, fruit girth, fruit volume, fruit weight, yield per plant, yield per plot, root length, root volume and relative water content. Among three testers, T2 (Kuttichal Local) showed favourable mean performance for seventeen traits viz., plant height, primary branches per plant, number of leaves per plant, number of flowering clusters per plant, number of fruits per cluster, fruit length, fruit girth, fruit volume, fruit weight, yield per plant, yield per plot, vitamin C, total acidity, stomatal frequency, root length, root volume and proline content. Under moisture stress (Second experiment), among the lines, L7 (Pusa Ruby) showed higher mean performance for eleven characters viz., plant height, fruit length, fruit girth, fruit volume, fruit weight, yield per plant, yield per plot, total soluble solids, root length, root volume and pollen viability. Among three testers, T2 (Kuttichal Local) showed favourable mean performance for sixteen traits viz., plant height, primary branches per plant, number of leaves per plant, number of flowering clusters per plant, number of fruits per cluster, number of fruits per plant, fruit length, fruit girth, fruit volume, total soluble solids, total acidity, stomatal frequency, root length, root volume and canopy temperature. Based on general combining ability analysis, the line L6 (Arka Alok) ranked as top by exhibiting significant gca effects for six traits viz., fruit length, fruit girth, fruit volume, fruit weight, specific leaf area and root length. Among the testers, T3 (Kottayam Local) had superior gca effects for Days to 50% flowering, number of flowering clusters per plant, number of fruits per cluster, fruit length, fruit volume, yield per plot, total soluble solids, lycopene, titrable acidity canopy temperature and proline content. Under moisture stress, the line L3 (Akshaya) ranked as top by exhibiting significant gca effects for ten traits viz., primary branches per plant, number of fruits per cluster, number of fruits per plant, fruit weight, yield per plant, yield per plot, stomatal frequency, specific leaf area, canopy temperature and pollen viability. Among the testers, T1 (Palakkad Local) had superior gca effects for plant height, number of fruits per cluster, number of fruits per plant, fruit girth, fruit volume, yield per plant, yield per plot, total soluble solids, relative water content, canopy temperature and proline content. In the case of hybrids, Based on mean performance, the crosses L1 x T1 (Vellayani Vijay x Palakkad Local), L2 x T3 (Anagha x Kottayam Local), L3 x T1 (Akshaya x Palakkad Local), L3 x T3 (Akshaya x Kottayam Local), L4 x T1 (PKM 1 x Palakkad Local), L4 x T2 (PKM 1 x Kuttichal Local), L5 x T1 (Arka Meghali x Palakkad Local), L5 x T2 (Arka Meghali x Kuttichal Local), L5 x T3 (Arka Meghali x Kottayam Local), L6 x T2 (Arka Alok x Kuttichal Local) and L6 x T3 (Arka Alok x Kottayam Local) were superior for different yield characters. Under moisture stress, Hybrids L3 x T1 (Akshaya x Palakkad Local), L3 x T3 (Akshaya x Kottayam Local), L4 x T1 (PKM 1 x Palakkad Local), L4 x T2 (PKM 1 x Kuttichal Local), L5 x T2 (Arka Meghali x Kuttichal Local), L7 x T2 (Pusa Ruby x Kuttichal Local) and L7 x T3 (Pusa Ruby x Kottayam Local) were superior for yield based on mean value. Based on combining ability studies under normal field condition, identified superior crosses such as L1 x T1 (Vellayani Vijay x Palakkad Local), L2 x T1 (Anagha x Palakkad Local), L2 x T3 (Anagha x Kottayam Local), L3 x T1 (Akshaya x Palakkad Local), L3 x T3 (Akshaya x Kottayam Local), L4 x T1 (PKM 1 x Palakkad Local), L4 x T2 (PKM 1 x Kuttichal Local), L6 x T2 (Arka Alok x Kuttichal Local), L6 x T3 (Arka Alok x Kottayam Local), L7 x T1 (Pusa Ruby x Palakkad Local) and L7 x T3 (Pusa Ruby x Kottayam Local) exhibited higher sca effects for yield per plant. Under moisture stress, identified superior crosses such as L1 x T2 (Vellayani Vijay x Kuttichal Local), L2 x T3 (Anagha x Kottayam Local), L3 x T1 (Akshaya x Palakkad Local), L4 x T2 (PKM 1 x Kuttichal Local), L5 x T2 (Arka Meghali x Kuttichal Local), L6 x T2 (Arka Alok x Kuttichal Local) and L7 x T3 (Pusa Ruby x Kottayam Local) exhibited higher sca effects for yield per plant. Based on heterosis, Overall, nineteen hybrids (L1 x T1, L1 x T2, L1 x T3, L2 x T1, L2 x T2, L2 x T3, L3 x T1, L3 x T3, L4 x T1, L4 x T2, L4 x T3, L5 x T1, L5 x T2, L5 x T3, L6 x T1, L6 x T2, L6 x T3, L7 x T1 and L7 x T3) from twenty one crosses revealed significant and positive heterobeltiosis for yield per plant under normal field condition. In the case of gene action, dominance genetic variance (σ2D) is higher than additive genetic variance (σ2A) was observed for all the traits under normal field condition and water stress condition, indicating that traits are controlled by non-additive gene action. Correlation study revealed yield per plant was positively and significantly correlated with the traits viz., primary branches per plant, number of flowering clusters per plant, number of fruits per cluster, number of fruits per plant, fruit girth, fruit volume, fruit weight and yield per plot. Based on qRT-PCR, the expression of both genes (moisture stress related genesSlDREB 1 and SlWRKY 4) was upregulated under water stress in all selected genotypes and the expression was more than moisture stress tolerant check variety. The result is in accordance with the analysis of moisture stress related physiological characters in these genotypes in the field under stress. From the study, identified tolerant sources for moisture stress viz., Akshaya, Pusa Ruby and Kuttichal Local, these lines and tester can be used in breeding programmes for moisture stress tolerance. Based on mean performance and gca, the genotypes Vellayani Vijay, Akshaya, Arka Meghali, Arka Alok and Kottayam local which showed superiority in yield and fruit quality traits can be used for breeding for improvement of yield and quality traits. The hybrids L3xT1 (Akshaya x Palakkad Local), L4 x T2 (PKM 1 x Kuttichal Local), L5 x T2 (Arka Meghali x Kuttichal Local) and L7 x T3 (Pusa Ruby x Kottayam Local) which showed superiority for yield and quality characters with tolerance to moisture stress can be recommended for release after yield trials.ThesisItem Open Access Studies on induced mutations in rice (Oryza sativa L.)(Division of genetics and plant breeding ,Agricultural college and research institute , Coimbatore., 1971) Gopinathan Nair, V; KAUThesisItem Open Access Breeding brinjal (Solanum melongena L.) for resistance to brinjal shoot and fruit borer(Department of Plant Breeding and Genetics, College of Agriculture, Vellanikkara, 2021) Neeraja, Puthiamadom; KAU; Jiji, JosephBrinjal shoot and fruit borer is one of the most devastating pests of brinjal. It is a major bottle neck in the cultivation of egg plant. Identification of resistant sources and transfer of these genes into the high yielding varieties is an important step in mitigating the damage caused by this pest. Keeping the above facts in view, the present investigation entitled “Breeding brinjal (Solanum melongena L.) for resistance to brinjal shoot and fruit borer” was taken up in the Department of Plant Breeding and Genetics from Sept 2017- April 2021. Thirty one accessions belonging to eight different species of Solanum were evaluated in the field for resistance to brinjal shoot and fruit borer during Aug- Nov 2018. The treatments showed significant difference for all the characters studied. The highest number of primary branches was observed in IC618034 belonging to S. virginianum and the lowest number was observed in IC618035 belonging to Solanum melongena. Infestation of shoots by borer started nearly 7th week after transplanting. The number of damaged shoots was highest in Surya. The per cent shoot infestation ranged from 0 to 75 per cent. The wild accessions were resistant to brinjal shoot and fruit borer and only the melongena lines exhibited considerable damage. The extent of per cent fruit damage ranged from 0 per cent in the wild accessions to 64.67 per cent in Arka Neelkanth. Yield per plant and marketable yield per plant was highest in Vengeri. Based on the observation from the screening experiment conducted during August –November 2018, eleven accessions were evaluated further for a confirmatory screening during March- July 2020. As there was considerable infestation by borer, artificial inoculation was not carried out. There was significant difference among the treatments for the characters studied. Highest yield per plant and marketable yield per plant was observed in Vengeri. Lowest yield was observed in IC624241 and IC624239. Yield loss was highest in Ponni and lowest in IC624239. The resistance index developed by Mishra et al. (1988) was followed to classify the accessions. The accessions IC618035, IC618044, IC624241, Arka Kusumkar and Vengeri were graded as resistant (1-10 %) with respect to per cent shoot damage. Based on the extent the of fruit damage, the accessions IC618035, IC618044 and IC624239 and Arka Kusumkar were graded as moderately resistant (11-20%). IC624241 and Vengeri were graded as resistant (0-10%). Haritha, Surya, Arka Keshav, Ponni and Arka Neelkanth were graded as highly susceptible (>40 %). The biophysical, anatomical and biochemical basis of resistance was elucidated in the selected accessions. Trichomes in Solanum sps. were stellate in shape with six trichome strands forming one asterisk. Trichome density on calyx was negatively and significantly correlated with shoot damage while trichome density on leaf was positively and significantly correlated with shoot damage. Pericarp thickness, fruit breadth, total sugar content and total nitrogen content were positively and significantly correlated with per cent fruit damage. Total phenol content showed a significant negative correlation with the per cent fruit infestation. The resistant lines IC618035, IC618044, IC624241, Arka Kusumkar and Vengeri were characterized by thick epidermis and cuticle, dense and compact cortex and cambium, well developed vascular bundles and small pith. IC618044, IC624241, IC618035, Arka Kusumkar and Vengeri falling under the resistant and moderately resistant category were selected as testers to cross with highly susceptible lines Haritha, Ponni and Arka Neelkanth. The twelve hybrids and parents were screened in the field along with the hybrid ‘Neelima’ as check during Dec 2020- April 2021 to check the per cent infestation of brinjal shoot and fruit borer. On the basis of per cent fruit infestation the hybrids Haritha x JRPH IC624241 and Ponni x IC624241 were graded as immune. Haritha x IC618044, Haritha x IC618035, Ponni x IC618035 and Ponni x Vengeri were graded as resistant. The hybrids Haritha x Vengeri , Haritha x Arka Kusumkar, Ponni x IC618044 and Neelima were graded as moderately resistant. Ponni x Arka Kusumkar was graded as tolerant. The hybrid Arka Neelkanth x IC618035 Arka Neelkanth x IC618044 were graded as highly susceptible. L x T analysis revealed that Vengeri can be considered as a good combiner with respect to per cent shoot damage, yield per plant and marketable yield per plant. While Arka Kusumkar is a good combiner with respect to number of fruits per plant, number of damaged fruits and per cent fruit damage. Among the lines, Ponni can be considered as a good combiner in terms of yield and marketable yield. Ponni x Vengeri can be considered to be superior as it exhibited high positive heterosis over the mid parent, better parent as well as the commercial check for yield as well as marketable yield and high negative heterosis for per cent shoot and fruit damage. Almost all the hybrids exhibited negative heterosis for per cent shoot and fruit damage. Ponni x Vengeri was ranked as ‘one’ on the basis of organoleptic evaluation conducted with a panel of ten judges. DNA fingerprinting of the superior F1 hybrids and the respective parents done using nineteen ISSR markers revealed that Arka Neelkanth was unique in a way that it produced 10 bands for UBC 836. Comparing other hybrids highest number of bands for UBC 868, UBC 816, UBC 836 and ISSR 08 were produced by Arka Neelkanth. UBC 826 was used to identify bands common in hybrids and parents in Haritha x IC618044, Haritha x Arka Kusumkar, Ponni x Arka Kusumkar and Arka Neelkanth x IC618044. The bands similar in parents and hybrids were identified in all the hybrids except Ponni x IC624241. Superior hybrids viz., Ponni x Vengeri, Ponni x Arka Kusumkar and Haritha x Vengeri can be evaluated further. Mapping populations can be developed from the segregating generations to develop functional markers for resistance to brinjal fruit and shoot borer.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.
