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ThesisItem Open Access GENETIC ANALYSIS FOR POD YIELD AND STEM ROT RESISTANCE IN PEANUT [Arachis hypogaea (L.)](Acharya N G Ranga Agricultural University, 2024-04-26) K. AMARNATH; Dr. M. REDDI SEKHARThe present experiment entitled “Genetic analysis for pod yield and stem rot resistance in peanut (Arachis hypogaea L.)” was carried out in both stress (sick plot) and control condition at Dry land farm, S.V. Agricultural College, Tirupati, Andhra Pradesh. Five lines viz., Kadiri-6, Narayani, TAG-24, ICGV 07262 and four testers viz., TCGS-1862, TCGS-2149, J-11 and CS-19 were hybridized in a Line x Tester design during kharif, 2019. The resulting 20 F1 crosses along with their parents were evaluated during rabi, 2019 under both sick plot and control condition simultaneously. The analysis of variance revealed the existence of substantial variation among lines, testers and F1 crosses for all the 23 traits. Based on mean performance and gca effects, the line i.e., ICGV-07262 and the testers viz., J-11 and CS-19 were identified as the best parents for yield and yield attributing traits in both sick plot and control condition. Hence, these parents and their crosses could be exploited for improvement of pod yield and its attributes in groundnut. The estimates of mean sum of squares due to lines, testers, crosses and their interaction showed significant variation for all the characters. The magnitude of SCA variance was higher than GCA variance for all the characters indicating the preponderance of non-additive gene action in the expression of these traits. On the basis of per se performance and sca effects, the F1 crosses viz., Kadiri-6 x CS-19, Narayani x J-11, ICGV-07262 x TCGS-1862 and ICGV 07262 x TCGS-2149 were found as superior crosses for yield, yield components and percent disease incidence (PDI) at maturity in sick plot and control condition and could be exploited to obtain desirable transgressive segregants in advanced generations with increased pod yield coupled with stem rot resistance. Based on heterosis ICGV-07262 x TCGS-1862 was adjudged as the best heterotic cross for pod yield plant-1 and percent disease incidence (PDI) at maturity among 20 F1 crosses. In overall, Narayani x J-11, Kadiri-6 x CS-19, xxii ICGV-07262 x TCGS-1862 and ICGV-07262 x TCGS-2149 were selected as desirable heterotic cross combinations for pod yield and its components coupled with stem rot resistance. Generation mean analysis of four crosses viz., Narayani x J-11, Kadiri-6 x CS-19, ICGV-07262 x TCGS-1862 and ICGV-07262 x TCGS-2149 for 20 yield and yield components deciphered the importance of epistatic effects in all the crosses for all the traits. Predominance of dominance gene effects were expressed for pod yield plant-1 in ICGV-07262 x TCGS-1862 and for kernel yield plant-1 in Narayani x J-11 under both sick plot and control condition. Significant additive x additive [i] gene effects were exhibited in the crosses viz., Narayani x J-11 and ICGV-07262 x TCGS-1862 in both sick plot and control condition for pod yield plant-1 while additive x dominance [j] gene effects were displayed in the crosses, Narayani x J-11 in sick plot and Kadiri-6 x CS-19 in control condition for yield and its attributes. Duplicate type of epistasis was involved in expression of pod yield and its components in all four crosses in both sick plot and control condition. Hence, biparental mating in early generations followed by selection in advance generations of all four crosses is advocated to isolate high yielding purelines in groundnut. On contrary, complementary type of epitasis was predominant in the cross, Narayani x J-11 for SLA at 60DAS, number of flowers plant-1 from 25 to 50 DAS and hundred kernel weight in both sick plot and control condition. Similarly, the cross ICGV-07262 x TCGS-2149 showed complementary epitasis for hundred kernel weight and dry haulm weight plant -1 in both sick and control condition while, ICGV-07262 x TCGS-1862 also displayed complementary epitasis for hundred kernel weight in both sick plot and control condition. Two or three cycles of intermating of selects followed by selection in later generation is suggested for exploitation of superior transgressive segregants in these crosses. The monogenic inheritance of stem rot resistance was confirmed in F2 generation of the crosses viz., Kadiri-6 x CS-19 and Narayani x J-11. Duplicate type of gene action involving two major genes was evident in inheritance of stem rot resistance in the F2 generation of crosses viz., ICGV-07262 x TCGS-1862 and ICGV-07262 x TCGS-2149, respectively. Significant and positive heterosis over mid parent, better parent and standard parent was displayed in the cross, ICGV-07262 x TCGS- 1862 with high inbreeding depression for pod yield plant-1 and kernel yield plant-1 in both sick plot and control condition indicating non additive gene action on trait governance and could be exploited through heterosis breeding. However, the cross ICGV-07262 x TCGS- 2149 exhibited significant mid parent heterosis, better parent heterosis and standard heterosis with low inbreeding depression in control condition suggesting the preponderance of additive gene action governing the trait expression and preceeding its suitability for advancement through recombination breeding. High frequency of transgressive segregants were obtained in F2 populations of ICGV-07262 x TCGS- 2149 (42.77%) followed by Narayani x J 11 (25.55%), Kadiri-6 x CS-19 (21.66%) and ICGV-07262 x TCGS-1862 (19.44%) for pod yield and its attributes. These crosses could be selected for xxiii recovery of transgressive segregants, which could be advanced in single plant progenies through later generations in pedigree breeding for development of high yielding purelines for yield and its attributes in groundnut. Disease reaction of genotypes to stem rot identified ten genotypes as immune (TCGS-1862, TCGS-2149, J-11, CS-19, Abhaya, TCGS-2018, TCGS 2197, TCGS-2196, TCGS-1877, TCGS-2015), one genotype as highly resistant (TCGS-2122), two genotypes as resistant (TCGS-2198 and TCGS-2015), 13 genotypes as moderately susceptible (Kadiri -6, TAG-24, ICGV-07262, ICGV 91114, ICGV-00350, Prasuna, JL-24, Kadiri -9, Kadiri Amaravathi, Bheema, TCGS-2160, TCGS-2200 and TCGS-1399) and four genotypes as highly susceptible (Narayani, Kadiri-7, Greeshma and TCGS-1522), respectively and could be further utilized in resistance breeding programme. Three SSR markers viz., DGR 294, DGR-470 and DGR-510 displayed 60.00 % of polymorphism among 30 groundnut genotypes. Among the polymorphic primers, DGR-294 was found as informative marker with PIC value of 0.24 and Heterozygosity value of 0.3. Hence, the primer DGR-294 could be employed as a reliable marker for marker assisted breeding programmes in groundnut.ThesisItem Open Access GENETIC STUDIES FOR EARLY MATURITY, YIELD AND YIELD ATTRIBUTES IN GROUNDNUT (Arachis hypogaea L.)(Acharya N G Ranga Agricultural University, 2024-04-26) GUMMA VINEELA NEEHARIKA; Dr. C. KIRAN KUMAR REDDYBreeding for earliness in groundnut is always a significant part of the objectives in many crop improvement programs across the globe. However, limited studies were available on sources of earliness and its contributing traits coupled with yield and yield components. No coherent character association studies were available for early maturity and its contributing traits. Therefore, the present study was conducted to estimate the extent of genetic variability, genetic divergence and trait associations for high yield, earliness and their contributing traits in groundnut where thirty six groundnut genotypes were evaluated in alpha lattice design with two replications at Regional Agricultural Research Station, Tirupati, during Rabi, 2021-22. Variability among all the 36 genotypes is highly significant for all the traits studied. Of all the thirty six entries tested, TAG 24, TCGS 2339, TCGS 2326, UBEK 21-40, UBEK 21-43 and UBEK 21-74 were noteworthy early maturing entries (90 days) with superior agronomic characters. All these genotypes were visualized with 100 pod weight below 90g, 100 kernel weight below 40g and harvest index below 50%. These characters are to be confirmed in future studies and in designing ideal plant type for early maturity. Study of genetic variability revealed high PCV and GCV for characters viz., days from opening of 1st flower to opening of 25 number of flowers and number of primary and secondary branches per plant. High heritability coupled with high genetic advance as per cent of mean were recorded for days from opening of 1st flower to opening of 25, 40, 50 number of flowers, plant height, number of primary and secondary branches per plant, number of mature pods per plant, harvest index, 100 pod weight and 100 kernel weight. Genetic divergence studies revealed the diversity among 36 genotypes by grouping them into 6 clusters. Maximum inter cluster distance was observed between cluster VI and III followed by cluster V and III, cluster II and III, cluster IV and VI and cluster I and VI. Genotypes from cluster III and genotype (UBEK 21-67) from cluster IV can be selected for developing early maturing genotypes. To develop genotypes with higher pod yields, genotypes from cluster II and V are to be utilized in hybridization programs. Character association studies revealed two phenological traits viz., days to accumulation of 25 and 40 flowers from emergence contributed significantly to days to maturity. Even though other traits exhibited significant inter-se correlations among them, their association with days to maturity was negligible. Therefore, for developing early maturing genotypes, selection for early accumulation of 25 and 40 flowers from emergence would be advantageous. For pod yield plant-1, significant positive correlations were observed with days to maturity, seed yield plant-1, number of mature pods plant-1, 100 pod weight, 100 kernel weight and harvest index but number of immature pods plant-1 was observed to be negatively correlated. Thus, for developing high yielders, selection should be focused on number of mature pods plant-1, days to maturity, harvest index, 100 pod weight, 100 kernel weight and seed yield plant-1. For developing early maturing genotypes with optimum yield levels, selection criteria could be days to accumulation of 25 flowers and 40 flowers from emergence with optimal number of ripened pods at 90 days duration with a harvest index (<50%), 100 pod weight (90g) and 100 kernel weight (<40g).ThesisItem Open Access CHARACTERIZATION AND GENETIC DIVERGENCE STUDIES IN INDIGENOUS FINGER MILLET [Eleusine coracana (L.) Gaertn] GERMPLASM(Acharya N G Ranga Agricultural University, 2024-04-26) POOLA SOUMYA; Dr. L. MADHAVILATHAThe present investigation was conducted at Agricultural Research Station (ARS), Perumallapalle, Tirupati during kharif, 2021 to characterize indigenous germplasm lines for DUS traits and to identify potential germplasm lines by estimating genetic parameters (variability, heritability and genetic advance), genetic divergence, character association and path coefficient. Morphological characterization of 60 finger millet genotypes using 26 DUS traits highlighted the existence of sufficient variability for the characters studied. In the present study for plant growth habit erect was predominant, for plant pigmentation at leaf juncture, non-pigmented was predominant, for leaf sheath pubescence, absence was predominant, for days to 50% flowering, late duration was predominant, for glumes colour, light green was predominant, for stem culm branching, absence was predominant, for flag leaf blade length, long blade length was predominant, for flag leaf blade width, narrow blade width was predominant, for peduncle length, medium type was predominant, for ear shape, compact type was predominant, for finger branching, absent type was predominant, for finger position of branching, at thumb finger, was predominant, for multiple whorl, absence was predominant, for ear head length, finger length, finger width and plant height medium length genotypes was predominant, for character finger number on main ear, medium number was predominant, for number of productive tillers, low number was predominant, for seed shattering, absence was predominant, for seed covering by glumes, enclosed was predominant, for seed colour, light brown was predominant, for seed shape, round type was xiv predominant, for seed surface, smooth was predominant, for pericarp after threshing, non-persistent type was predominant and for 1000 grain weight, medium weight was predominant. The analysis of variance carried out among 60 germplasm lines for 13 yield and yield attributes revealed significant differences for all the characters indicating the presence of considerable amount of genetic variability for the characters in the studied material. The characters such as finger length, number of productive tillers plant-1 , 1000 grain weight, grain yield plant-1 and fodder yield plant-1 showed higher estimates of PCV and GCV indicating ample amount of variation among indigenous germplasm lines for these traits. Thus, direct selection for these traits would result in further improvement of grain yield. High heritability coupled with high genetic advance as per cent of mean was observed for days to 50% flowering, peduncle length, ear head length, finger length, finger width, number of productive tillers plant-1 , 1000 grain weight, grain yield plant-1 and fodder yield plant-1 indicating the predominance of additive gene action and direct selection would be effective for improvement of these traits. D2 analysis grouped 60 germplasm lines into six clusters. Among all the characters studied, days to 50% flowering (80.00%), 1000 grain weight (10.51%) and fodder yield plant-1 (3.62%) contributed relatively maximum towards the total genetic divergence. Inter cluster distance was observed maximum between cluster II and VI followed by cluster II and IV, cluster V and VI, cluster II and III and cluster I and VI representing that germplasm lines belonging to these clusters are more divergent. Based on divergence analysis, the crosses IC00622007 × IC00622057 (cluster II x cluster VI) and IC00622007 × EN 70 (cluster II x cluster IV) could be recommended for crop improvement. Character association analysis revealed that the traits viz., flag leaf blade length, finger number on main ear, finger width, number of productive tillers plant-1 , flag leaf blade width and fodder yield plant-1 had significant positive association with grain yield plant-1 indicating simultaneous selection of these traits would result in improvement of grain yield. Further, path analysis estimates in the present investigation revealed that finger number on main ear, fodder yield plant-1 and finger width had true relationship with grain yield plant-1 by establishing significant positive association and high positive direct effect on grain yield plant-1 . Days to 50% flowering exhibited negative direct effect and had negative association with grain yield plant-1 indicating that negative association of this trait would be more rewarding for selection of early maturing germplasm lines. xv Evaluation of 60 indigenous finger millet germplasm resulted in identification of trait specific germplasm lines viz., early maturing germplasm lines IC00622057 (1 genotype); long flag leaf blade germplasm lines (47 genotypes); lengthy ear heads (6 genotypes), IC0478442 (13.13 cm); lengthy fingers (19 genotypes), IC0478442 (13.10 cm); wide fingers (2 genotypes), high finger number on main ear (9 genotypes), EN 46 (9.70 cm); tall germplasm lines (4 genotypes), IC00622031 (135.99 cm); high 1000 grain weight (5 genotypes), EN 70 (3.50 g), IC0478656 (3.10 g) and IC0007954 (3.05 g); high grain yield plant-1 EN 70 (19.36 g), IC0478640 (17.00 g), IC0478543 (16.94 g); high fodder yield plant-1 , EN 70 (145.90 g), IC00622053 (145.60 g), IC0475386 (137.40 g). Germplasm line EN 70 exhibited superior performance when compared with Standard varieties GPU 48, GPU 67, VL376 and PR 202.ThesisItem Open Access DUS CHARACTERIZATION AND DIVERSITY ANALYSIS OF INBRED LINES IN PEARL MILLET (Pennisetum glaucum (L.) R. Br.)(Acharya N G Ranga Agricultural University, 2024-04-24) INUKOLLU PRAVEEN KUMAR; Dr. M. SHANTHI PRIYAThe present investigation was conducted at Agricultural Research Station (ARS), Perumallapalle, Tirupati during rabi, 2021 to characterize pearl millet inbred lines for DUS traits and to identify potential germplasm lines by estimating genetic parameters (variability, heritability and genetic advance), genetic divergence, character association and path coefficient. DUS characterization of 70 pearl millet genotypes using 28 DUS traits revealed existence of abundant diversity for these characters. In the present studied pearl millet inbred lines appreciable differences were observed for the traits viz., anthocyanin pigmentation, leaf sheath length, leaf blade length, leaf blade width, spike stigma pigmentation, anther colour, plant node pubescence, number of nodes plant-1, node pigmentation, internode pigmentation, spike length, anthocyanin pigmentation of glume, spike bristle, spike bristle colour, bristle appearance, spike girth, number of productive tillers plant-1, plant height, spike shape, spike-density, seed color, seed shape and 1000 seed weight. Based on the DUS descriptors inbred lines were characterized effectively which would be useful for their documentation and registration. These descriptors would aid in explicit identity of inbred lines and help in maintenance of their purity in field for use in future breeding programmes. The analysis of variance carried out among 70 germplasm lines for 21 yield and yield attributes revealed significant differences for all the characters indicating the presence of considerable amount of genetic variability for the characters in the studied material. The characters such as grain yield plant-1, 1000 grain weight panicle weight, green fodder yield plant-1, dry fodder yield plant-1 and harvest index showed higher estimates of PCV and GCV indicating ample amount of variation among germplasm lines for these traits. Thus, direct selection for these traits would result in further improvement of grain yield. High xix heritability coupled with high genetic advance as per cent of mean was observed for days to 50 % flowering, spike length, spike girth, number of productive tillers plant-1, plant height, 1000 grain, panicle weight, green fodder yield plant-1, dry fodder yield plant-1, threshing percentage, harvest index and grain yield plant-1 indicating the predominance of additive gene action and direct selection would be effective for improvement of these traits. D2 analysis grouped 70 inbred lines into 12 clusters. Among all the characters studied, 1000 grain weight, days to 50% flowering and number of productive tillers plant-1 contributed relatively maximum towards the total genetic divergence. Inter cluster distance was observed maximum between cluster VI and XII followed by cluster X and XII, cluster III and XII and cluster IV and XII representing that germplasm lines belonging to these clusters are more divergent. Correlation studies revealed that characters viz., panicle weight followed by green fodder yield plant-1, dry fodder yield plant-1, number of productive tillers plant-1, spike girth, plant height, leaf blade length, number of nodes plant-1, 1000 grain weight, spike length, harvest index, threshing percentage, leaf blade width and specific leaf area at 45 DAS had significant positive association with grain yield plant-1 indicating simultaneous selection of these traits would result in improvement of grain yield. Further, path analysis estimates in the present investigation revealed that panicle weight followed by threshing percentage, green fodder yield plant-1 had true relationship with grain yield plant-1 by establishing significant positive association and high positive direct effect on grain yield plant-1. Low residual effects at both phenotypic and genotypic level demonstrated that choice of traits in the present study were able to explain most of the effects on grain yield. Superior inbred lines PPBi-3, PPBi-46, PPBi-47, PPBi-50 and PPBi-59 identified in the present study could be utilized for the development of composites.ThesisItem Open Access STUDIES ON GENETIC VARIABILITY FOR YIELD AND YIELD ATTRIBUTING TRAITS IN GROUNDNUT (Arachis hypogaea L.)(Acharya N G Ranga Agricultural University, 2024-04-24) RAGIRI PAVAN KUMAR; Dr. K. JOHNThe present investigation was conducted at Regional Agricultural Research Station (RARS), Tirupati, during kharif, 2021 to assess variability, genetic parameters, genetic divergence, character association and path analysis among 30 advanced breeding lines of groundnut under rainfed conditions. Analysis of variance carried out among 17 physiological, yield attributes and quality traits revealed that highly significant differences among the genotypes for all the characters studied indicating the presence of ample amount of variability among the genotypes. Based on per se performance, the genotypes viz., TCGS-2443, TCGS-2198, TCGS-2442, TCGS-2440 and TCGS-2108 were found as promising genotypes and these genotypes could be exploited for improvement of yield and its contributing characters in the breeding programme as donors. The characters, pod yield plant-1, kernel yield plant-1, dry haulms yield plant-1 and number of mature pods plant-1 exhibited high GCV and PCV indicating ample amount of variation among the genotypes and simple selection may be sufficient for these characters to bring genetic improvement in desired direction due to preponderance of fixable additive gene action. High heritability coupled with high genetic advance as per cent of mean was recorded for characters viz., plant height, hundred pod weight, dry haulms yield plant-1, number of mature pods plant-1, harvest index, pod yield plant-1 , number of primary branches plant-1, kernel yield plant-1 and hundred kernel xvi weight indicating preponderance of additive gene action in expression of these characters and selection would be effective for improvement of these characters. Using D2 analysis, thirty genotypes of groundnut were grouped into six clusters. Cluster III is observed as the largest cluster with eleven genotypes. Cluster II contain ten genotypes and cluster I contain six genotypes and remaining clusters (IV, V and VI) are monogenotypic clusters Based on inter cluster distances, the clusters IV × V, IV × VI, III × IV, I x IV and I × V were found to be more divergent in decreasing order of their magnitude. Hence, the genotypes from these clusters can be utilized as potential parents. The characters viz., protein content, hundred kernel weight, plant height, oil content, number of mature pods plant-1, dry haulms yield plant-1, hundred pod weight were the major contributors towards genetic divergence. A perusal of character association indicated highly significant positive association of kernel yield plant-1, number of mature pods plant-1, number of primary branches plant-1, harvest index, hundred pod weight, hundred kernel weight and dry haulms yield plant-1 with pod yield plant-1 as well as among themselves at both phenotypic and genotypic levels. Hence, these characters could be used in the further selection programme for improvement of pod yield plant-1 . Path analysis revealed that kernel yield plant-1 had high magnitude of positive direct effect on pod yield plant-1 followed by harvest index, dry haulms yield plant-1 and hundred pod weight. This infers the importance of these component traits in selection of superior genotypes for higher pod yield in groundnut.ThesisItem Open Access HAPLOTYPE ANALYSIS OF MOLECULAR MARKERS LINKED TO EARLY SEEDLING VIGOUR RELATED TRAITS IN A SET OF RICE (Oryza sativa L.) GENOTYPES(Acharya N G Ranga Agricultural University, 2024-04-24) YAMASANI MOUNIKA REDDY; Dr. R.P. VASANTHIRice is the most important and staple food crop in the world. The eventual shifting of cultivation from puddle transplanted rice (PTR) to direct seeded rice (DSR) to save water prompted breeders to identify the donor parents, genes, haplotypes and cross combinations suitable to develop varieties for dry DSR conditions. The present investigation was carried out on haplotype analysis of molecular markers linked to early seedling vigour-related traits using 40 rice genotypes. From the mean performance, the genotypes SM211, BMF536, BMF517, BMF574 and 81C were found superior with higher grain yield plant-1. The genotypes, Lalanakanda, Varalu, BMF536, BMF517 and MM129 registered desirable performance under dry DSR conditions for most of the characters studied. The characters, number of chaffy grains panicle-1, 1000-grain weight, grain yield plant-1, number of filled grains panicle-1 and seedling vigour index – II recorded high PCV, GCV, heritability (broad sense) and genetic advance as per cent of mean indicating these characters are amenable for simple phenotypic selection for further improvement. Mahalanobis’s D2 analysis grouped 40 genotypes into eight clusters based on yield, yield attributes and early seedling vigour-related traits. A perusal of the results revealed Cluster I to be the largest comprising of 23 genotypes followed by cluster II comprising of 7 genotypes and Cluster III with 5 genotypes. Whereas, clusters IV, V, VI, VII and VIII had single genotype. Among all the traits studied, seedling vigour index-I followed by seedling vigour index-II and days to maturity contributed relatively maximum towards total genetic divergence. Molecular diversity analysis with markers related to early seedling xv vigour traits using DARwin software grouped the 40 rice genotypes into 3 clusters. From character association studies, grain yield plant-1 was found to possess significant positive association with traits viz., days to 50% flowering, days to maturity, plant height, panicle length, number of panicles plant-1, number of filled grains panicle-1, number of chaffy grains panicle-1, 1000 grain weight, grain breadth and seedling height whereas spikelet fertility exhibited negative significant association with grain yield plant-1 . Haplotype analysis of molecular markers linked to early seedling vigour related traits was carried out using flanking markers of three QTLs viz., qSV-6a (RM204 and RM402) for root length; qVI (RM20429 and RM3) for seedling vigour index; qGP-6 (RM528 and RM400) for germination percentage on chromosome 6. Haplotype analysis of these molecular markers grouped the 40 rice genotypes into different haplotypes which were significantly different according to students’s t-test and this helped in the identification of rice genotypes with superior and novel haplotypes. These could be utilized to develop rice varieties suitable for dry DSR conditions.ThesisItem Open Access GT BIPLOT ANALYSIS FOR YIELD TRAITS AND MOLECULAR PROFILING OF SELECTED LINES IN BLACKGRAM [Vigna mungo (L.) Hepper](Acharya N G Ranga Agricultural University, 2024-04-24) DIGUMARTHI LAKSHMI VINEESHA; Dr. D. BHARATHIThe present investigation was carried out at dryland farm of Sri Venkateswara Agricultural College, Tirupati during Rabi, 2021-22 to study genetic parameters, genetic diversity, genotype by trait biplot analysis for twelve traits and to develop molecular profiles of 35 blackgram genotypes. Moderate estimates of GCV and higher estimates of PCV were observed for the traits plant height, number of pods per plant, number of clusters per plant and harvest index. High heritability coupled with high genetic advance as per cent of mean was recorded for number of primary branches per plant. Genetic divergence analysis using Mahalanobis D2 statistics grouped 35 genotypes into eight clusters. Among the clusters, cluster III had the maximum intra cluster distance followed by cluster I and cluster V. The maximum inter cluster distance was recorded between cluster IV and V followed by cluster V and VIII, cluster I and V, cluster V and VII and cluster VII and VIII. Hence, the crosses viz., LBG 645 × P 112, LBG 645 × IP4-10-4, LBG 645 × PU 31, LBG 645 × P 1032 and P 1032 × IPU-10-4 could be suggested for the exploitation of transgressive segregants for yield. Based on genotype by trait biplot analysis, the seed yield was positively correlated with number of pods per plant, number of clusters per plant, number of primary branches per plant, number of seeds per pod, plant height, days to maturity, pod length, number of pods per cluster and harvest index. The trait number of primary branches per plant was considered as best, similarly, the genotype LGG 645 was identified as ideal cultivar. Molecular profiling disclosed, out of 16 SSR markers, ten were polymorphic and generated unique DNA profiles for 35 blackgram genotypes studied. Based on the level of polymorphism detected by individual marker, four SSR markers (CEDG 20, CEDG 44, CEDG 243 and BM 170) were most informative and this set of markers had the enormous potential to identify most of the blackgram genotypes studiedThesisItem Open Access GENETIC STUDIES IN F2 POPULATIONS OF GROUNDNUT (Arachis hypogaea L.) FOR YIELD, YIELD ATTRIBUTES AND STEM ROT RESISTANCE(Acharya N G Ranga Agricultural University, 2024-04-24) Y. V. S. JYOTHIRMAI; Dr. M. SREEVALLI DEVIThe experimental material used for the research included six F2 populations viz., Kadiri 6 × TCGS 1862, Kadiri 6 × J 11, Narayani × TCGS 1862, Narayani × CS 19, TAG 24 × TCGS 1862 and TAG 24 × CS 19 derived from six parents involved viz., Kadiri 6, Narayani, TAG 24, TCGS 1862, J 11 and CS 19. The crop was grown in unreplicated plots during kharif, 2021 in dryland farm of S. V. Agricultural College, Tirupati. Estimates of genetic parameters i.e., phenotypic co-efficient of variation, genotypic co-efficient of variation were high for number of secondary branches plant-1 , number of immature pods plant-1, number of mature pods plant-1, harvest index, dry haulm yield plant-1, kernel yield plant-1 and pod yield plant-1 in all the crosses. High heritability coupled with high genetic advance as percent of mean were observed in plant height, number of mature pods plant-1, shelling per cent, harvest index, dry haulm yield plant-1, kernel yield plant-1 and pod yield plant-1 indicating that these are predominantly governed by additive genetic variance. Hence, simple phenotypic selection would be effective in early generations in all the six crosses. Among six crosses studied, two crosses namely, Kadiri 6 × TCGS 1862 and TAG 24 × CS 19 showed positive significance for all the ten characters considered under character association. In these two crosses, all the characters studied might be considered for selection for the improvement of pod yield plant -1. In the remaining crosses, pod yield plant-1 showed positive significant association with number of mature pods plant-1 , harvest index and kernel yield plant-1 indicating that these characters would be considered while selecting individual plants. Based on the path coefficient analysis, kernel yield plant-1 exhibited high positive direct effect with pod yield plant-1 in all six crosses; hence importance should be given in selection process for the improvement of pod yield in groundnut. In TAG 24 × CS 19, two genes appeared to be involved in the inheritance of stem rot with one of genes acting in inhibitory manner. In Narayani × TCGS 1862, Narayani × CS 19, it showed monogenically dominant with single gene difference. In other three crosses viz., Kadiri 6 × TCGS 1862, Kadiri 6 × J 11 and TAG 24 × TCGS 1862, two genes were involved and showed complementary gene interactions.ThesisItem Open Access DEVELOPMENT OF miRNA-SSR MARKERS AND THEIR CHARACTERIZATION IN RICE (Oryza sativa L.)(Acharya N G Ranga Agricultural University, 2024-04-24) BAVISETTI HEMA SAI; Dr. B. RUPESH KUMAR REDDYThe present investigation was conducted at Wetland Farm, S.V. Agricultural College, Tirupati during kharif, 2021 to develop SSR markers derived from microRNAs and their target genes related to yield component traits and their characterization in 60 diverse rice genotypes. In this study, 70 miRNAs from 16 miRNA families which were responsive to yield and yield attributing characters in rice (Oryza sativa L.) were surveyed. Out of these, 29 miRNA sequences were selected for SSR mining based on expression analysis in surveyed literature. Eight miRNA SSRs from the 29 yield responsive miRNA genes of rice from the present study and other ten miRNA target gene-SSRs from targets of these 29 yield responsive miRNA genes were found to possess ≥7 repeats which were used for primer designing with default parameters. Out of total 18 miRNA and target SSRs, 5 miRNA-SSRs and 8 miRNA target gene SSRs were randomly chosen for characterization of 60 rice genotypes in the present study. The analysis of variance carried out among 60 rice genotypes for 15 yield and yield attributes revealed significant differences for all the characters indicating the presence of considerable amount of genetic variability for the characters in the studied material. The characters such as number of chaffy grains panicle-1 , number of filled grains panicle-1 , number of spikelets panicle-1 , grain yield plant-1 and thousand grain weight showed higher estimates of PCV and GCV indicating ample amount of variation among 60 rice genotypes for these traits. Thus, direct selection for these traits would result in further improvement of grain yield. High heritability coupled with high genetic advance as per cent of mean was observed for days to 50% flowering, days to maturity, thousand grain xvi weight, number of chaffy grains panicle-1 , grain L/B ratio, grain width, plant height, number of spikelets panicle-1 , number of filled grains panicle-1 and grain yield plant-1 indicating the predominance of additive gene action and direct selection would be effective for improvement of these traits. Character association analysis revealed that the characters viz., plant height, panicle length, number of effective tillers plant-1 , number of filled grains panicle-1 and spikelet fertility% had significant positive association with grain yield plant-1 indicating simultaneous selection of these characters would result in improvement of grain yield. D2 analysis grouped 60 rice genotypes into nine clusters. Among all the characters studied, days to maturity (78.81%) and 1000 grain weight (19.49%) contributed relatively maximum towards the total genetic divergence. Inter cluster distance was observed maximum between cluster IV and IX followed by cluster VI and IX, cluster I and IX, cluster V and IX and cluster II and IX representing that rice genotypes belonging to these clusters are more divergent. Based on divergence analysis, the cross between SMB3 (cluster VIII) and Juma (cluster IV) could be recommended for recombination breeding to get superior transgressive segregants for earliness and desirable yield attributing characters. Similarly, the crosses viz., IC455374 (cluster I) x Juma (cluster IV), SMB3 (cluster VIII) x MTU1153 (cluster VI) and Ranjith (cluster III) x Juma (cluster IV) were also divergent for molecular diversity which was identified in the current study. Out of 13 markers designed in the current study, four markers showed polymorphism. Among four polymorphic markers, the marker miR408-SSR exhibited highest PIC value of 0.747 followed by miR396f-SSR (0.599) and miR172b-SSR (0.526). The marker miR408-SSR produced maximum of seven alleles with maximum number of effective alleles and high Shannon’s information index. High PIC markers are more informative and can effectively distinguish the genotypes. The molecular diversity studies by Unweighted Neighbour Joining method revealed that all the 60 genotypes were grouped into three major clusters. Cluster II was the largest cluster which was further separated into three sub-clusters IIA with 25 genotypes, IIB with seven genotypes and IIC with four genotypes followed by cluster I further divided into two sub-clusters IA and IB with nine genotypes each. Whereas, cluster III was the smallest cluster with two sub-clusters comprised of three genotypes in each sub cluster. The population structure analysis indicates that the population consists of three subgroups. Based on the membership fractions, the genotypes with score >0.80 were considered as pure while <0.80 considered as admixture. Among three subpopulations, subpopulation1 consists of 18 pure types and 1 admixed type, subpopulation2 with 10 pure types and 6 admixed types while, subpopulation 3 has 14 pure types and 11 admixed types. The presence of admixtures was perhaps due to the fact that the loci involved in this study xvii revealed only a small part of the genotype/phenotype association of otherwise complex traits or acquisition of a few spontaneous mutations in the genotypes or the admixtures sharing ancestries greatly with two other groups. The association analysis studies showed three significant marker-trait associations (SMTAs) by GLM method. OsARF18-SSR for grain yield plant-1 and miR408-SSR for grain thickness and grain L/B ratio. Whereas, two SMTAs were detected by the MLM method, days to 50% flowering and days to maturity with marker miR172b-SSR which indicate these marker miR172b SSR could be used for discriminating rice genotypes for earliness. Similarly, miR408-SSR could be used for characterizing rice genotypes for grain size which will aid the selection of parents and subsequent generation for these characters in marker-assisted breeding (MAB)
