Journal of Plant Breeding and Genetics: Thesis Abstracts
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<p>Journal of Plant Breeding and Genetics is an open-access, peer-reviewed, international journal devoted to providing opportunities for original as well as extended versions of published researches. Journal of Plant Breeding and Genetics publishes original and review articles by internationally recognized researchers, covering all areas of plant genetics, genetics and related interface. The journal focuses on crop plants and is therefore of interest to seed companies and the plant breeding industry as well as to researchers and teachers in this field. Journal publishes original research covering all areas of theoretical and applied plant breeding and genetics. Journal is a periodical for the publication of records of original research in all branches of genetics, plant breeding and cytology, including molecular biology, biotechnology and other related sciences of sufficient importance and of such a character as to be of the primary interest to the geneticist and plant breeders.</p>en-USDROUGHT TOLERANCE ASSESSMENT OF CASSAVA GENOTYPES IN A SEMI-ARID ENVIRONMENT IN CENTRAL TANZANIA
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Crop Science, Sokoine University of Agriculture<br />October, 2014<br /><br />Drought tolerance is an increasingly important trait in cassava due to globally dwindling water resources, a shift in production areas and increasing input costs. This study was conducted to evaluate eighteen cassava genotypes for drought tolerance to counteract frequent shortages of rainfall. An experiment was set in Dodoma, Tanzania which is a drought-stricken environment where cassava genotypes were grown under-watered and water stressed conditions. Identification of drought-tolerant genotypes that also had good yield potential was facilitated by the stress treatments used on the farm. Morphological (leaf length, leaf width, plant height), physiological (leaf retention, chlorophyll content), biochemical (Catalase and Peroxidase enzymes activities) and yield (number of roots per plant, yield in tons per hectare, above-ground biomass, percentage dry matter content and harvest index) attributes were used to assess tolerance of the tested genotypes to drought stress. During harvesting, on-farm farmers participatory evaluation and organoleptic test were also conducted to enable farmers to select the best genotypes based on consumers criteria. It was found during the study that water stress had a profound effect on growth, physio-chemical and yield performance of cassava genotypes. All attributes measured were significantly influenced by drought except leaf length at180 DAP, plant height at 120 and 150 DAP, number of roots per plant, the weight of above-ground biomass and harvest index (P≤0.05). Generally, water stress suppressed both growth and yield of the crop. Through the study, superior drought promising cassava genotypes identified were 92B/00073, KBH 2006/363, KBH 2006/12 and KBH 2006/18. These genotypes performed well under stress and well-watered conditions and thus may serve as parents for drought stress improvement and genetic analysis.Journal of Plant Breeding and Genetics2020-08-03GENE ACTION AND COMBINING ABILITY ANALYSIS FOR YIELD AND YIELD ATTRIBUTES IN RICE (ORYZA SATIVA L.)
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Department of Genetics and Plant Breeding, Narendra Deva University of Agriculture and Technology<br />April, 2014<br /><br />The present study was conducted to determine the gene action and combining ability analysis for yield and yield attributes in rice (Oryza sativa L.). The present study was carried out during kharif, 2013, at the Genetics and Plant Breeding farm of Narendra Deva University of Agriculture and Technology, Narendra Nagar, (kumarganj) Faizabad (U.P.) The experiment was based on evaluation of a line x tester set of 36 hybrids (F1’s) and their 15 parents along with 2 checks, for thirteen characters under normal sown and irrigated condition in randomized block design with three replications during Kharif, 2013. The 36 F1’s were generated by crossing 3 testers with 12 lines during Kharif, 20012. The observations were recorded on days to 50% flowering, flag leaf area (cm2), panicle length (cm), plant height (cm), panicle bearing tillers plant-1, spikelets panicle-1, spikelet fertility (%),biological yield plant-1 (g), grain yield plant-1(g), harvest index (%), test weight (g), L/ B ratio, and chlorophyll content (spad value). The analysis of variance for treatments, parents and crosses was highly significant for all the traits indicating the existence of sufficient variability in the treatments, parents and crosses for all the traits. The variation due to parent’s vs crosses was significant for all traits except parent’s vs crosses for L/B ratio, that indicating the presence of heterosis in the crosses. The dominance variance > additive variance, degree of dominance >1 except days to 50% flowering, spikelets panicle-1 and L/B Ratio, indicating selection is ineffective as it is non fixable; and general predictability ratio less than one for all the character the, indicating the involvement of non-additive gene action and heterosis was mainly governed by over dominance for majority of the traits. The non-significance of mean squares due to testers (males) for all the characters except days to 50% flowering and L/B ratio and lines (females) significant for panicle length, spikelets panicle-1 and test weight except all the character indicated non-significant prevalence of additive effects in expression of the related traits. The significance of mean squares due to lines × testers for all the traits provides a direct test indicating that (i) non-additive variance was important for all of the characters; and (ii) combining ability contributed heavily in the expression of these traits. In general, maximum contribution to the total variance was due to females higher than due to males for all the traits except days to 50% flowering and L/B ratio. Among the parents, best five genotypes were IR55179-3B-11-3, IR 11T159, Jaya, IR 58025 B and NDRK 50026 exhibited significant GCA effects, for grain yield plant-1, indicating the involvement of additive gene action for yield and component traits. Among the crosses, best five hybrids were Narendra Usar Dhan 2009 x NDRK 50026, Jaya x Narendra Usar Dhan 2008, IR11T164 x Narendra Usar Dhan 2008, CSR 28 x NDRK 50026 and Jaya x Narendra Usar Dhan 3 exhibited significant SCA effects for grain yield plant-1, indicating the preponderance of non-additive gene action for yield and component. Majority of the desirable heterotic cross combinations possessed at least one of the high general combiner. IR55179-3B-11-3, IR 11T159 and Jaya were found to be the best parental lines based on per se performance and GCA effects for grain yield plant-1 which may be utilized as a donor in hybridization programme. arendra Usar Dhan 2009 x NDRK 50026 and Jaya x Narendra Usar Dhan 2008 were found to be best crosses based on per se performance and sca effects for grain yield plant-1, indicated the exploitation of heterosis to enhance yield potential.Journal of Plant Breeding and Genetics2014-04-22HETEROSIS AND COMBINING ABILITY ESTIMATES FOR YIELD AND YIELD COMPONENTS IN MAIZE (ZEA MAYS L.)
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Department of Genetics and Plant Breeding, Sri Venkateshwara Agricultural College Tirupati, AP, India<br />October, 2011<br /><br />Eight parents and 28 F1 cross combinations of maize were evaluated in a RBD with three replications during rabi, 2010-2011 so as to identify the best parental genotypes and cross combinations with higher grain yield. Based on both per se performance and gca effects, the inbred lines CM 209, CM 149 and BML 15 were recognized as the best general combiners for most of the traits and hence, could be used in crossing programme for obtaining transgressive segregants for yield and yield components. The highly significant sca effects in addition to high per se performance were identified for most of the traits in the crosses viz., CM 149 x BML 6 (cob length, cob girth, grain yield per plant and 100-seed weight) and CM 132 x BML 7 (days to 50 per cent tasseling and days to 50 per cent silking).These cross combinations showing high sca effects besides high per se performance for yield and yield components could be utilized in recombinant breeding programme. The estimates of components of variance revealed predominance of non-additive gene action for all the traits. In such cases where non-additive gene action played a predominant role in association with additive component, the recurrent selection and reciprocal recurrent selection can be used to exploit simultaneously both the components. The estimates of heterosis obtained in hybrid combinations revealed considerable genetic divergence among eight parents. The cross combinations CM 149 x BML 6 and CM 148 x BML 15, which recorded high heterobeltiosis for most of the traits could be utilized in heterosis breeding programme to exploit heterotic vigour. Further, based on highly significant heterobeltiosis, standard heterosis and sca effects for grain yield per plant, the promising cross combinations were CM 149 x BML 6, CM 149 x BML 15, CM 148 x BML 15 and CM 133 x BML 7. Correlation analysis revealed that, number of kernels per row followed by cob length, cob girth and 100-seed weight exhibited maximum positive association with grain yield per plant. Further, the inter-se association among these traits was also highly significant and positive. Path coefficient analysis revealed that, cob length followed by cob girth, number of kernels per row and 100-seed weight exerted highest positive direct effects on grain yield per plant. Hence these characters may be given due emphasis in formulating selection indices in order to evolve high yielding genotypes in maize.Journal of Plant Breeding and Genetics2013-09-04CYTOMORPHOLOGICAL STUDIES IN INDUCED POLYPLOIDY OF LABLAB PURPUREUS L.VAR. TYPICUS PRAIN.
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Department of Botany, University of Rajasthan, Jaipur<br />April, 2013<br /><br />The present investigation entitled “Cytomorphological studies in induced polyploids of Lablab purpureus syn. Dolichos lablab L. var. typicus Prain” was conducted at department of Botany, Rajasthan University, Jaipur during (2006-2009) and (2010-2012). The pure seeds of field bean (Lablab purpureus L. Sweet var. typicus prain) were used in the present investigation. Three methods viz. seed treatment, seedling treatment and both seed and seedling treatment had been implemented for inducing polyploidy in Dolichos lablab L. var. typicus, using different concentration of colchicine. The findings conclude that seeds treated with colchicine had negative impact on seed germination. Thus seed treatment with colchicine was not successful method for the induction of polyploidy in Dolichos lablab L. var. typicus. The chief cause of failure appeared to be the drastic effect of the drug on roots, which failed to produce lateral roots or to show any appreciable development after treatments. After failure of seed treatment, another method seedling treatment with colchicine using cotton swab was followed for the induction of polyploidy in Dolichos lablab L. var. typicus. Plants were treated with different concentration and duration of colchicine i.e. from 0.2 and 0.3% colchicine for 6 hrs., 9 and 12 hrs duration, and 0.4 and 0.5% colchicine for 6 and 9 hrs duration. In seedling treatment method colchicine was added drop wise on the apical tip of the plant with the help of cotton swab and syringe at cotyledonary stage. Fifty plants were used for each concentration and duration of treatment. In C1 generation morphologically variable plants among the treated plants were selected and tagged. Different morphological variable data were recorded and analyzed statically. Different type of morphological variation in, plant, stem, leaf, flower, pod and seed were recorded. In C1 generation four different plant types viz. dwarf, giant, climber and bushy were observed. Generally plant height decreased with the increase in concentration of colchicine. However plants were, giant in size when treated with 0.2 and 0.3 % colchicine for 9 and 12 hrs of duration and bushy when treated with 0.2 and 0.3 % colchicine for 6 hrs. Climbers were also observed when treated with 0.2 % colchicine for 6 and 12 hrs of duration.Plant suspected as tetraploid was observed when seedlings were treated with 0.5 % colchicine for 6 and 9 hrs. duration. The height of such plant was less (29.00 ± 0.85) than diploid plant (71.68 ± 0.72). Stem diameter also increased at higher concentration and duration of colchicine treatments. The maximum 12 % and minimum 6 % value of thick stem plant was calculated when seedlings were treated with 0.5% colchicine for 6hrs. duration and 0.2 % colchicine for 9hrs. duration, respectively. In suspected tetraploid plant the stem diameter was more (4.40 ± 0.62) than diploid (3.40 ± 0.16) plant. Treatment with Different concentration and duration of colchicine altered the normal branching (alternate) to zig- zag and basal branching pattern. Maximum percentage (14% plants) of zig-zag branching was observed only with 0.2 % colchicine treatment for 6 hrs duration, whereas basal branching was observed with all the treatments in range of 10 - 14 %. In suspected tetraploid plant branching pattern was basal. The mean number of nodes per branch was also reduced in most of the treatments. In suspected tetraploid plant, mean number of nodes per branch was 10.50 ± 1.41 as compare to 30.20 ± 0.44 in diploid plant. Treatment of colchicine affected the leaf shape, size, serration, colour and texture in C1 generation. In treated plants leaves were altered, dark green, leathery, deeply serrated. Highest number of leaf variants (89) were recorded with 0.4 % colchicine treatments (6 hrs. duration), while lowest value of leaf variants was observed with 0.2 % colchicine treatments for 6 hrs duration. In suspected tetraploid plant number of branches/plant, number of leaves/plant, length of petiole (cm), length of odd and even leaflet was 35.00 ± 0.89, 75.00 ± 0.13, 6.20 ± 1.24, and 5.60 ± 0.47 respectively. In contrast to these values were higher in diploid plant and was 47.00 ± 0.95, 141.00 ± 1.18, 11.9 ± 0.84, 3.98 ± 0.28 and 0.40 ± 0.06 respectively. In suspected tetraploid plant leaf was dark green, leathery, deeply serrated, and of altered shaped. Rough, leathery and shiny textured of leaves increased along with the increase in concentration and duration of colchicine treatments. Colchicine affected the normal morphology of flower. Maximum flower variants (15) were found at 0.2 % colchicine treatment for 12 hrs. duration and minimum (6) floral variants were observed at 0.3 % colchicine treatment for 6 hrs duration. Flower size and leathery texture increases with the increase concentration and duration of colchicine treatment. In suspected tetraploid plant flower was terminal in position, leathery in texture and larger (7.01 ± 0.724), than diploid plant where flower size was (5.90 ± 0.51). In suspected tetraploid plant number of flowers per inflorescence was 4.80 ± 0.24 as compare to 9.20 ± 0.49 in diploid plant. Pod variants were normally observed with higher dose of colchicine. Maximum number (41) of pod variant was obtained with 0.3 % colchicine (9hrs. duration) followed by 35 variant with 0.5 % (9 hrs duration) and 30 variant each with 0.4 % (6 hrs duration) and 0.5 % (6 hrs duration) of colchicine treatment. While in rest of the treatments, these variants were not observed. Pod size reduced with the increase in concentration of colchicine. In suspected tetraploid plant pod were flat, curved, dark green, and rough. The pod size was 4.10 ± 0.51 in treated plant as compare to 3.90 ± 0.31 in diploid plant. Seed variants were generated at higher dose of colchicine treatments. Maximum (Seed shape, size, colour) seed variants (12) was observed with 0.4% colchicine treatment for 6 hrs duration followed by 11 seed variants each with 0.5 % for 6 and 9 hrs duration and 9 with 0.4 % colchicine treatment for 9 hrs duration. Number of seeds/pod in suspected tetraploid was 4.10 ± 0.15, whereas in diploid plant it was 6.60 ± 0. 25. In suspected tetraploid plant seeds were round, altered, dark and light brown in colour and larger (0.71 ± 0.72) than diploid (0.53 ±.018).Number of seeds per plant (16.00 ± 0.87) was less in suspected tetraploid than diploid plant (125.0 ± 0.51).Highest guard cell index and highest mean values (19.80), (17.20) and (15.14) for guard cell index, was observed in 0.2 % (6 hrs), 0.2 % (9 & 12 hrs). 0.3 % (6 hrs) colchicine respectively. Lowest mean value (6.80) for the same was depicted by 0.5% colchicine treatment (9 hrs duration). In suspected tetraploid plant number of epidermal cell (22.90 1.09), epidermal cell length (19.40 ± 0.31µm), stomatal length (6.80 ± 0.37) increased by increasing the concentration and duration of colchicine treatment. The number of stomata in suspected tetraploid reduced to 12.20± 0.37 from 35.90 ± 0.44 in diploids at higher concentration. Stomatal studies showed that increased concentration and duration of colchicine treatment increased wavy behavior of epidermal cell. Maximum mean value for stomata length (6.80 µm) was depicted by treatment 0.5 % colchicine (9 hrs. duration). Paracytic type of stomata was observed in all treatments expect 0.2 % (12hrs) and 0.3 % (6hrs) colchicine treatment. Diacytic type of stomata was found at 0.2 % (9hrs duration) and above concentration of colchicine, while anomosytic type of stomata was observed in 0.2 and 0.5 % (6hrs duration) and 0.4 % (9hrs duration) concentration and duration of colchicine. Stomata of suspected tetraploid were large and diacytic type with altered and wavy epidermal cell wall whereas stomata of diploid were anomocytic, diacytic and paracytic types with straight epidermal cell. Maximum mean value of stomatal index (39.00) was investigated with 0.2 % (6 hrs). Whereas, minimum mean value (13.10) for the same was expressed by 0.5 % colchicine treatment (9 hrs). In suspected tetraploid plant stomatal index (13.10 ± 0.48), guard cell index (6.80 ± 1.73), pore area index (129.00 ± 1.63) were lesser than diploid plant (42.18 ± 0.09, 21.73 ±1.17, 153.00 ± 1.06), while total pore index (0.26 ± 0.003) in suspected tetraploid plant was higher than diploid plant (0.07 ± 0.48).Highest mean value (131.30) for pore area index was found with colchicine dose 0.5% (9 hrs) followed by 129.10 at 0.5% (6 hrs) and 119.00 at 0.4% (9 hrs). It was minimum (97.60) at 0.2% (6 hrs) of colchicine treatment.Maximum mean value of total pore index (0.30) was shown by treatment 0.2% (12 hrs duration), whiles minimum (0.01) by 0.2% (6 hrs) and 0.3% (6, 9 hrs) of colchicine treatment. Buds of morphological variable plants were collected between 4.00am- 5.00 am for the cytological studies. After the cytological studies four suspected tetraploid plant was found in 0.5 % colchicine treatment for 6 and 9 hrs. duration. Plants of other concentration and duration showed meiotic abnormality. Multinuclei formation was observed at 0.2 % (9, 12hrs), 0.3% (9, 12 hrs),0.4% (6, 9 hrs) and 0.5% (6, 9 hrs) concentration and duration of colchicine treatment. Suspected tetraploid plants were obtained in 0.5 % (6,9hrs) treatments. Suspected tetraploid plants showed doubling of chromosome from (2x=24) in diploid to (4x=48) in tetraploid at metaphase and diakinesis phase. Bivalents were higher than tetravalents in suspected tetraploid plants. Chiasmata were not apparently seen. Equal separation (24:24) and unequal separation (24:23) with laggards was observed during anaphasic separation. Pollen viability decreased generally with the increase in concentration of colchicine. Pollen shape and size varies in different concentration and duration of treatment. Viable, uneven and unequal size of pollen was observed at 0.2% colchicine treatment for 6 hrs. duration while altered and viable pollen were observed in 0.2% colchicine ( 9,12 hrs duration) treatment as well as in 0.3% colchicine treatment for 6 hrs., 9 and 12 hrs duration. At 0.4% colchicine treatment for 9, 12 hrs duration, pollen was altered shaped and unequal in size. In treated plant maximum number of pollen fertility was observed in 0.2 % concentration of colchicine at 6 hrs duration of treatment while minimum in 0.5% colchicine at 9 hrs duration of treatment. i.e. 92.18 ± 0.03 and 48.58 ± 0.58 respectively. Size of pollen grain and tetrad was maximum in 0.5 % at 9 hrs duration of treatment i.e. (12.8 ± 0.37 x 13.4 ± 0.24, 12.99 ± 0.23×14.87 ± 0.23) and minimum in diploid plant (9.2 ± 0.37x5.4 ± 0.24, 8.9 ± 0.37×12.1 ± 7.12). At different concentration and duration of treatment tetrads showed slight variation, While in suspected tetraploid pollen grain and tetrads were larger (11.2 ± 0.63×15.2 ± 0.77) than diploid (9.2± 0.83×14.2 ± 0.83). The Pollen fertility was 97.1 ± 12.87 % in diploid as compare to 34.3 ± 13.7 in tetraploids plants. Diad, triad, polyyad type of tetrad were observed in suspected tetraploid plant. Crossing has been done in between diploids and relatively fertile suspected tetraploids. Eight seeds were obtained from one hundred crosses. Six seeds were deformed and failed to germinate. Out of remaining two seeds, one died after germination and another showed little flowering with few flowers. Cytological studies could not be performed due to lack of sufficient buds.Ten seeds from four suspected tetraploid plant collected in C1 generation was sown for the next C2 generation. Five seeds were shrunken and did not germinate, but other five germinated. Out of five plants one plant was suspected triploid and another plant was suspected monosomic. Rest of plants was diploids in C2 generation. Quantitative and qualitative traits of suspected triploid, monosomic and morphologically variable plants were studied. Seeds from suspected monosomic and triploid plants were collected, which failed to germinate.Plants of C2 generation were dwarf, light green in colour with shiny leaves and large pods. The height was maximum (54.87 cm.) and minimum (46.01 cm) in 0.2 % colchicine (6 hrs. treatment) and 0.5 % colchicine (9 hrs. treatment) respectively. Stem of plants was weak and light green in colour. Maximum stem diameter 2.94 cm. was measured at 0.5 % concentration of colchicine (6 hrs. treatment) followed by 2.93 and 2.92 cm at treatment of 0.4 % concentration of colchicine for 6 and 9 hrs respectively. Maximum pod length (7.90cm) was measured at 0.2 % colchicine (6hrs treatment) and minimum (5.78cm) at 0.5% colchicine (9hrs treatment). Maximum seed size (0.38cm) was found at 0.2 % colchicine (9hrs treatment), while minimum (0.21cm.) at 0.5% colchicine (5hrs treatment). Two variable plants were obtained from the seeds of suspected tetraploid. These plants were suspected as triploid and monosomic plant. Morphological characters of suspected triploid plant were similar to triploid plants. Suspected tetraploid plant had reduced flower and fruit setting, and seeds were altered, shrunken, large and light brown in colour and failed to germinate. Flower size was slightly larger than control. Pollen sterility was high in this plant. During cytological observations, in diakinesis, 3x=36 chromosome were observed. Chiasmata ring and rods formation was not clear. Suspected monosomic plant was week, light green in colour; pods and seeds were altered, flat or round. Cytologically (2n-1=23) chromosome were observed at metaphasic plate. Anaphasic separation and diakinesis was not found.Journal of Plant Breeding and Genetics2013-09-04GENOMIC STUDIES AND IDENTIFICATION OF SEX AT SEEDLING STAGE IN SOME DIOECIOUS PLANTS THROUGH PCR BASED DNA MARKERS
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Department of Botany, KARNATAK UNIVERSITY, DHARWAD<br />November, 2011<br /><br />In dioecious plants sex identification is challenging task for the plant breeder. As the sex of the plant cannot be identified in many dioecious plants at pre-flowering stage, because of absence of morphological markers. In the absence of morphological markers, molecular markers like RAPD (Random Amplified Polymorphic DNA), SCAR (Sequence Characterized Amplified Region) play an important role for sex identification at pre-flowering stage. Therefore development of an ideal tool to identify the sex at seedling stage is worth exploring. Two dioecious plants namely Momordica dioica Roxb. (Cucurbitaceae) and Simarouba glauca DC. (Simaroubaceae) were studied during my Ph.D. work as both the taxa have sex specific economic value. The main objectives of my Ph.D work are; to assess the existence of heteromorphic chromosomes in these two taxa, development of sex linked RAPD marker, Sex specific SCAR marker in both the taxa and probable role of these markers in sex determination. Present investigation revealed that both taxa exhibited homomorphic chromosomes, which reveals that, in these two plants sex cannot be identified based on karyomorphological analysis. In S. glauca chromosome number was found to be 2n=30 in both male and female accessions. Present study was the first report of chromosome number in S. glauca. In M. dioica RAPD marker OPA-151500 was developed to identify male sex at pre-flowering stage. Based on RAPD analysis, further SCAR marker named as SCAR-SDSM was developed to identify male sex at pre-flowering stage. It was submitted to GenBank (Accession number: GQ980260). Similarly in S. glauca RAPD marker OPA-181100 was developed to identify male sex at pre-flowering stage. Based on RAPD analysis, further SCAR marker named as SCAR-MSSMS was developed to identify male sex at pre-flowering stage. It was submitted to GenBank (Accession number: HM240852). Both SCAR-SDSM and SCAR-MSSMS genomic sequences exhibit homology with these two repetitive sequences RAYSI and RAE180 of Rumex acetosa. Existence of repetitive sequences is the key information as it helps for designing probes for identification of sex chromosomes in both M. dioica and S. gluaca as both taxa exhibit homomorphic chromosomes.Journal of Plant Breeding and Genetics2013-03-05STUDIES ON VARIABILITY AND STABILITY UNDER DIFFERENT POPULATION DENSITY LEVELS IN GRAIN AMARANTHUS (Amaranthus hypochondriacus L.)
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Horticulture, Tamilnadu Agricultural University<br />July, 2008<br /><br /><a href="http://www.sfu.ca/path/to/thesis.pdf">Full text (external site)</a><br /><br />In grain amaranthus (Amaranthus hypochondriacus L.) ten genotypes were evaluated for thirteen characters under four plant density levels viz., very high (D1), high (D2), normal (D3) and low plant density (D4) levels to study the variability parameters, character association and stability. The study was conducted at Pandit Jawaharlal Nehru College of Agriculture and Research Institute, Karaikal during rabi 2007. Grain yield per plant was reduced in very high and low plant density levels mainly because of reduction in length of the primary inflorescence, fresh weight of the inflorescence, number of secondary branches per inflorescence and leaf area at 50 per cent flowering when compared to high and normal plant densities. The high plant density produced the highest grain yield per plot which was mainly due to the number of plants per unit area was higher under this density level than normal and low plant density levels which could increase the grain yield per plot. Based on the mean performance, Annapurna was identified as ideal genotype performing superior under all the four plant density levels followed by the genotype EC 519554 for most of the yield and yield attributing characters. Plant densities altered the estimates of genetic variability, heritability and genetic advance as per cent of mean. The characters viz., leaf area at 50 per cent flowering, fresh weight of the inflorescence, number of secondary branches per inflorescence and total carbohydrates registered high genetic variability in combination with high heritability and genetic advance in all the plant density levels, revealing the possibility of improvement of these traits through a simple selection programme. Correlation and direct effect of component traits on grain yield were, in general, highly influenced by the plant densities both in direction and magnitude. The fresh weight of the inflorescence, length of the primary inflorescence and number of secondary branches per inflorescence recorded strong positive correlation with grain yield as well as strong inter correlations among themselves, indicating that improvement of grain yield in amaranthus could be achieved by exercising selection for these component traits. The path analysis revealed that fresh weight of the inflorescence, leaf area at 50 per cent flowering, length of the primary inflorescence and number of secondary branches per inflorescence had direct positive effects on grain yield. Based on the stability analysis, the genotype Annapurna was identified as stable genotype for grain yield in all the four plant density levels. The genotypes BGA 2, GA 2 and IC 415290 recorded stable performance for total carbohydrates and protein content and could be utilized for improvement of these traits in breeding programme. The genotype GA 2 showed stable performance for fresh weight of the inflorescence, an important trait influencing the grain yield in all the four plant density levels. Similarly, SKNA 601 can be chosen as stable genotype for leaf area at 50 per cent flowering, an important selection parameter for yield improvement in all the plant density levels. Among the characters studied, length of the rachis per inflorescence, total carbohydrates and protein content were found to be relatively stable in all the four plant density levels.Journal of Plant Breeding and Genetics2013-02-20GENETIC IMPROVEMENT OF LOCAL BRINJAL TYPES FOR YIELD AND QUALITY (Solanum melongena L.)
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Horticulture, Tamilnadu agricultural university<br />May, 2012<br /><br /><a href="http://www.sfu.ca/path/to/thesis.pdf">Full text (external site)</a><br /><br />Research work was undertaken in brinjal (Solanum melongena L.) to develop F1 hybrids/hybrid derivatives with high yield and quality traits through L x T crossing. Variability and genetic diversity in parents, heterosis, combining ability, gene action, correlation and path analysis in F1 generation, variability, heritability and genetic advance, correlation, path analysis and frequency distribution in F2 generations were analysed for growth, yield and quality traits. A relatively high estimate of phenotypic and genotypic co-efficient of variation was observed among the parents for fruit length, calyx length, number of fruits per plant, little leaf incidence, total phenol content and fruit yield per plant. The characters viz., fruit length, calyx length, number of fruits per plant, little leaf incidence, total phenol content and fruit yield per plant recorded high amount of genetic variability along with heritability and genetic advance. Based on diversity analysis, the genotypes belonging to clusters V and III could have greater genetic divergence and hence intermating between the genotypes belonging to them would give more transgressive segregates in advanced generations. The analysis of combining ability estimates revealed that the predominance of non-additive gene action was observed for all the characters studied. The combining ability and per se performance indicated that the line Palamedu Local (L5) possessed high mean value and gca effects for seven characters viz., days to first flowering, fruit circumference, average fruit weight, shoot borer infestation, little leaf incidence and fruit yield per plant. It was followed by Alavayal local (L1) and Keerikai Local (L7) and the tester Annamalai (T1) were good general combiners since they had high gca and mean values for yield and other related characters. Based on per se, sca effects and magnitude of heterosis, four hybrids viz., Alagarkovil Local x Annamalai (L4xT1), Palamedu Local x Punjab Sadabahar (L5xT3), Palamedu Local x EP 65 (L5xT4) and Keerikai Local x KKM 1 (L7xT2) were identified for heterosis breeding. The hybrid L5xT2 can be effectively used for improving number of branches per plant, number of fruits per plant and fruit yield per plant through recombination breeding. Correlation in F1 generation indicated that number of fruits per plant, number of branches per plant and average fruit weight recorded significant association with fruit yield both at phenotypic and genotypic levels. Path analysis revealed that plant height, number of branches per plant, fruit length, fruit pedicel length, number of fruits per plant, average fruit weight and little leaf incidence registered positive direct effect on yield. Among the 40 hybrids, ten crosses were selected based on mean yield and other desirable traits. In F2 generation, the crosses L5xT4 and L4xT1 showed high mean, variability, heritability and genetic advance as per cent of mean for individual fruit weight and fruit yield per plant thereby offering good scope for selection for the improvement of above characters. Association analysis in F2 revealed that yield per plant had significant positive association with number of fruits per plant, average fruit weight and fruit circumference. Path analysis showed that number of branches per plant, average fruit weight and number of fruits per plant had positive direct effect on fruit yield. From the frequency distribution analysis, wide range of variation was observed with regarding to fruit yield per plant among the ten crosses. In three crosses L4xT2 (3 plants), L5xT4 (3 plants) and L7xT2 (1 plant) were produced the fruit yield more than 3.00 kg per plant. The fruit yield per plant was more than 2.00 kg were observed in all the crosses except L1xT1, L6xT2 and L8xT1.Journal of Plant Breeding and Genetics2013-01-26