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ThesisItem Open Access PHENOTYPIC STABILITY FOR GRAIN YIELD AND ITS CONTRIBUTING CHARACTERS USING DIFFERENT STABILITY MODELS IN BREAD WHEAT (Triticum aestivum L. em. Thell(2015-04) ODEDRA RAMA KANA; Pithia M.S.Key words: Bread wheat, genotype x environment interaction, stability, regression The genotype x environment interaction is of major concern in plant breeding programmes. Number of statistical methods have been developed to analyse G x E interaction and thereby to evaluate phenotypic stability of genotypes. However, the literature on comparison of stability analysis model is very scanty. The present study was undertaken to compare some stability analysis models. For this purpose eighty genotype of bread wheat were evaluated at two different locations viz., Wheat Research Station and Krishi Vigyan Kendra, Khapat (Porbandar), Junagadh Agricultural University, Junagadh during the Rabi 2009-10 in a randomized complete block design with three replication. Four environments were created by sowing crop in two different dates of sowing at two locations i.e. E1 (normal sowing at Khapat), E2 (late sowing at Khapat), E3 (normal sowing at Junagadh), E4 (late sowing at Junagadh). The data on days to 50% flowering, days to maturity, plant height (cm), number of effective tillers per plant, peduncle length (cm), flag leaf area (cm2), length of main spike (cm), number of spikelets per spike, number of grains per spike, 1000- grain weight (g), biological yield per plant (g), harvest index (%) and grain yield per plant (g) were recorded and analysed. Three stability analysis models proposed by Eberhart and Russell (1966), Perkins and Jinks (1968) and Freeman and Perkins (1971) were compared empirically for their efficiency. Additive main effects and multiplicative interaction (AMMI) analysis was also attempted in this study to evaluate 80 bread wheat genotypes established in four environments using grain yield data in order to determine the magnitude of G x E interaction and to identify stable and adaptable genotypes. Differential relative response to different genotypes to different environments were observed for grain yield and other characters under study. The ranking of genotypes for grain yield per plant showed that none of the genotype had same rank in all the environments. The genotype MACS 2496, GW 322, PBN 4456 and J 24 ranked first in E1, E2, E3 and E4 environments respectively. Analysis showed in general, that none of the genotype remained constant at first position in all the environments. Ranking pattern of genotypes based on stability parameters viz., regression was similar in all three models of stability indicating that there was similarity in prediction of performance and prediction of stability in all the three models. There was non-significant correlation between mean and deviation from regression of ER model indication that prediction of stability performance was easy. Thus on the basis of correlation among mean regression values (bEi, Bi and bFi) and deviation from regression (S2di (E) and S2di (F)), it could be concluded that the prediction was moreover similar in all the three models. The stability analysis by using Eberhart and Russell (1966) model for all the characters under study revealed that none the genotypes found stable for all the characters. However genotypes J 91-10 and P 11616 looked promising as they produced high grain yield per plant under four environmental conditions. It means these two genotypes can be designated for timely and late sowing conditions at Junagadh and Khapat locations. But still there is a need to evaluate them for more years. As per Perkins and Jinks (1968) model, 14 genotypes were found promising in giving stable performance for grain yield per plant across the environments. Most of the genotypes were found common in both models. Twenty five genotypes produced stable grain yield as per the model of Freeman and Perkins (1971). The AMMI analysis for grain yield data shows that model was found not multiplicative hence the environments had the lowest effects. All the three principal component were non-significant genotype or environments situated on the same parallel line reactive to the ordinate has same yield capacity, while those located on the right side of the midpoint of the axis has slightly higher grain yield in few genotypes only than those on the left side. Therefore, biplot showed solitary group of genotypes.ThesisItem Open Access EARLY GENERATION SELECTION FOR YIELD AND ITS COMPONENTS IN CHICKPEA (Cicer arietinum L.)(2012-06) TA LAPADA MANSUKHLA L MOHANBHAI; Monpara . B. A.For maximum efficiency and progress in breeding for chickpea, it would be advantageous if effective selection could be carried out in as early a generation as possible so that only best lines would be retained for further testing. Five populations of chickpea were formed by involving seven parents. Ten F2 plants from each of these crosses were selected for high as well as for low expression of pods per plant, seeds per plant, harvest index and seed yield per plant. The F3 lines from 226 selected F2 plants were grown in randomized block design with three replications. Results revealed that selection for high level had maintained their higher expression for pods per plant, seeds per plant and seed yield. Increasing of CV values in F3 as compared to F2 generation usually not expected, may be due to the predominant repulsion phase linkage. Correlations among pods per plant, seeds per plant and seed yield from F2 generation to derived F3 lines of them were increased as the generation was advanced. Realized heritability estimates were inconsistent and cross dependent. Low heritability coupled with low genetic advance and inconsistent correlations of F2/F3 generations for the selection criterion indicated the influence of environment on the effectiveness of selection. Selection for improvement of seed yield using pods per plant was found effective as significant yield difference between high and low level of this trait was observed in all the crosses. However, its effectiveness may be considered as moderately successful because of 40% of high yielding F3 progenies were derived from F2 plants with high pod number. In contrast, selection for other components and seed yield itself showed significant yield advantage in certain situations, however, it could not be recommended as routine procedure. There was no definite pattern for identification of superior yielding lines through selection of yield and its components. Some superior yielding lines were identified by selection for all the traits, whereas, some superior progenies were obtained even in the absence of high expression of all the traits. It is concluded that while gain in yield can be achieved by selecting for high pod number in early generation, a foremost consideration needs to be the influence of environment on the effectiveness of selection.ThesisItem Open Access GENETIC ARCHITECTURE OF GRAIN YIELD AND ITS COMPONENTS IN BREAD WHEAT (Triticum aestivum L.) UNDER DIFFERENT DATES OF SOWING(2013-06) PANSURIYA ASHWINKUMAR GOVINDBHAI; Dhaduk L. K.The present investigation entitled “genetic architecture of grain yield and its components in bread wheat (Triticum aestivum L.) under different dates of sowing” was carried out with a view to estimate heterosis, combining ability and gene action, genotype x environment interaction and stability parameters for grain yield and its component traits along with biochemical parameters in bread wheat. The experimental materials comprised of ten parents (LOK 1, GW 366, GW 173, HD 2932, DL 788-2, WH 1059, K 9906, KRL 213, RAJ 3765 and WR 885), their fortyfive F1 hybrids and one standard check variety GW 496. This material was evaluated in three different environments( three dates of sowing) in randomized block design with three replications during rabi 2011-12 at Wheat Research Station, Junagadh Agricultural University, Junagadh. The observations on five randomly selected plants were recorded for 15 characters viz., days to heading, days to maturity, plant height (cm), number of effective tillers per plant, length of main spike (cm), number of spikelets per main spike, peduncle length of main spike (cm), number of grains per main spike, 1000-grain weight (g), grain yield per plant (g), biological yield per plant (g), harvest index (%) and biochemical parameters like protein content (%), wet gluten content (%) and water absorption (ml). The data were analyzed for heterosis and combining ability (Method-II, model-I of Griffing, 1956a). The genetic components of variation were estimated according to Hayman (1954) while, G x E interaction and stability parameters were calculated following the model of Eberhart and Russell (1966). The mean squares due to parents and hybrids (F1s) exhibited highly significant differences among themselves for grain yield per plant and all its component traits in all the three environments which indicated the existence of considerable amount of genetic variability amongst parents and hybrids for all the traits under study. Similarly mean squares due to parents vs. hybrids were found to be significant for all the traits under all the three environments except days to heading, number of grains per main spike and water absorption in E1, length of main spike in E2 and plant height, peduncle length of main spike, number of grains per main spike and harvest index in E3 indicating that the performance of parents was different from that of crosses thereby suggesting the presence of mean heterosis for all these characters. No specific consistency was observed with regard to heterosis for grain yield and yield components in different crosses. This may be due to interacting effects of different component traits in manifestation of heterosis for grain yield. This reflected that in different crosses, path-way for releasing heterotic effects varied from cross to cross. Eleven hybrids over better parent and 17 hybrids over standard check variety (GW496) exhibited significant and positive heterosis. The crosses K 9906 X WR 885, K 9906 X RAJ 3765, GW 173 X WH 1059, GW 366 X GW 173, GW 366 X K 9906, HD 2932 X RAJ 3765, GW 366 X HD 2932, GW 366 X RAJ 3765, GW 173 X DL 788-2 and WH 1059 X RAJ 3765 manifested significant and desirable standard heterosis for grain yield per plant and important yield components therefore, such crosses could be exploited further for yield advancement in bread wheat. The general as well as specific combining ability variances were found to be significant for all the traits evaluated in individual environment as well as pooled over environments indicating the role of both fixable and non-fixable variances in the expression of all the traits studied. However, the potence ratio (σ2 GCA/ σ2 SCA < 1) less than unity revealed the preponderance of non-additive gene action for all the traits studied. The parents GW 366, K 9906, WR 885 and HD 2932 were found to be good general combiners for grain yield per plant. LOK 1, GW 173, HD 2932, DL 788- 2 and RAJ 3765 were emerged as good general combiners for early maturity. The parents Dl 788-2, K 9906 and WR 885 for protein content; LOK 1, DL 788-2 and WR 885 for wet gluten content and GW 173, HD 2932, WH 1059 and WR 885 for water absorption were observed to good general combiners. The estimates of SCA effects revealed that none of the top ten crosses for SCA with respect to grain yield per plant was simultaneously superior for all the traits. The cross K9906 x WR 885 with highest grain yield per plant had high SCA effect for grain yield per plant, which involved good x good general combiners. Other two superior cross combinations, (GW 366 x GW 173 and K 9906 x RAJ 3765) with respect grain yield per plant involved good x average combining parents. The cross combinations involving good x poor or average x poor general combiners besides exhibiting favourable additive effect of good or average combining parents, manifest complementary interaction effect and thus result in higher SCA effects. In the present study, such combinations for grain yield per plant were GW 173 X DL 788-2, LOK 1 X RAJ 3765, LOK 1 X GW 173, DL 788- 2 X WR 885 and DL 788-2 X RAJ 3765. The relative magnitude of additive components (D) was higher than both/ either of dominance components (H1, H2) for days to heading, days to maturity, plant height, number of spikelets per main spike and number of grains per main spike suggesting predominance of additive genetic variance for these characters. For rest of the characters, magnitude of dominance components (H1, H2) was higher than additive component (D). The average degree of dominance (H1/D)1/2 indicated over dominance for all the traits evaluated except days to maturity, plant height, number of spikelets per main spike and number of grains per main spike. The distribution of genes with positive and negative effects (H2/4H1) in the parents was observed nearly symmetrical for all the traits except days to maturity and number of spikelets per main spike. The value of h2/H2 was very low in case of days to heading, plant height, number of spikelets per main spike, number of grains per main spike, 1000 grain weight, protein content, wet gluten content and water absorption indicating that number of gene groups which exhibited dominance could not be estimated properly. The estimates of ratio h2/H2 for number of effective tillers per plant, length of main spike, peduncle length of main spike, grain yield per plant, biological yield per plant and harvest index suggested the involvement few genes, normally one gene group for the control of inheritance. In general narrow sense heritability was found to be less than 50 per cent for all the traits indicating comparatively, more role of dominance gene effect in the expression of grain yield and its attributes. The stability analysis revealed the presence of significant genotype x environment interactions (G x E) for days to maturity, number of spikelets per main spike, number of grains per spike, grain yield per plant, biological yield per plant and wet gluten content when tested against the pooled error. This suggested that genotypes interacted significantly in different environments for these traits. Among the parents, GW 366, WR 885 and HD 2932 were found to be stable for high yield. Sixteen hybrids recorded high mean grain yield with unit regression and non-significant deviation from regression among which top five stable hybrids were K9906 X RAJ 3765, GW 173 X WH 1059, HD 2932 X RAJ 3765, WH 1059 X KRL 213 and LOK 1 X RAJ 3765. The hybrids GW 366 X K 9906 and K 9906 X WR 885 found to be stable for grain yield per plant under better environmental condition.ThesisItem Open Access GENETIC ANALYSIS OF GRAIN YIELD AND ITS COMPONENTS IN WHEAT (Triticum aestivum L.) UNDER DIVERSE ENVIRONMENTS(2011-01) VANPARIYA LALITKUMAR GORDHANBHAI; Pithia M.S.Six generations, namely P1, P2, F1, F2, BC1 and BC2 of eight crosses of bread wheat viz., AKW 770 x MP 4010 ( cross 1) , AKAW 2862-1 x MACS 2496 (cross 2), CLN 1 x GW 273 (cross 3), CLN 5 x GW 322 (cross 4), GW 9715 x K 9102 (cross 5), NWL 1 x GW 496 (cross 6), P 11616 x PBW 524 (cross 7) and RWP 2002-2 x LOK 1 (cross 8) were grown under timely (E1) and late (E2) sowing conditions at Wheat Research Station, Junagadh Agricultural University, Junagadh to study the gene effects, heterosis, inbreeding depression, heritability, genetic advance and genetic correlation for grain yield and its components. Experiment was laid-out in Compact Family Block Design with three replications. The observations were recorded on five randomly selected plants from P1, P2 and F1, forty plants from F2 and twenty plants from BC1 and BC2 generations in each replication for thirteen characters viz., days to heading, days to maturity, plant height, number of effective tillers per plant, length of main spike, number of grains per spike, flag leaf area, grain filling period, peduncle length of main spike, grain yield per plant, 1000-grain weight, biological yield per plant and harvest index. 57 The analysis of variance between families revealed that the mean squares due to crosses were significant for all the characters under both the environments. The analysis of variance among progenies within each family indicated significant differences among six generation means for all the characters studied in all the crosses except plant height in cross 8, length of main spike in cross 1 and cross 5 and grain filling period in cross 1 and cross 4 under timely sown condition and length of main spike in cross 4 and cross 6, grain filling period in cross 1 and cross 6 and harvest index in cross 1, cross 3 and cross 6 under late sown condition. This indicates the sufficient variability in the material under study. On the basis of individual scaling test A, B and C and joint scaling test, the additive-dominance model was found adequate for description of variation in generation means for number of effective tillers per plant in cross 6, number of grains per spike in cross 1 and cross 6, grain filling period in cross 7, grain yield per plant and biological yield per plant in crosses 3, 6 and 7 and harvest index in cross 6 and cross 7 under timely sown condition and days to maturity in cross 8, number of effective tillers per plant in cross 5, flag leaf area in cross 1 and cross 8 and biological yield per plant in cross 4 under late sown condition. For remaining cases, either all or the three or any of the individual scaling test A, B or C were found significant. The application of joint scaling test also expressed significant Chi-square values for these cases confirming the involvement of digenic interaction parameters in the inheritance of these characters. On the basis of perfect fit solution of six parameter model, main effects m, (d), (h) and all the three digenic interactions (i), (j) and (l) were significant for days to heading in crosses 2, 3, 4 and 6, for days to maturity in crosses 2, 4, 5 and 8, for plant height in crosses 1, 2 and 4, for number of effective tillers per plant in cross 1, for length of main spike in 58 crosses 2, 3 and 6, for number of grains per spike in crosses 2, 7 and 8, for flag leaf area in cross 2, for peduncle length of main spike in crosses 3, 4, 7 and 8, for grain yield per plant in cross 4 and for 1000-grain weight in crosses 3 and 6 under timely sowing. While under late sowing, these all the six parameters were significant for days to heading in crosses 1, 2, 4 and 8, days to maturity in crosses 4 and 7, for plant height in crosses 2, 3, 6, 7 and 8, for number of effective tillers per plant in crosses 1, 2 and 4, for number of grains per spike in crosses 1 and 4, for grain filling period in crosses 7 and 8, for peduncle length of main spike in crosses 4 and 5, for grain yield per plant in cross 5 and for 1000-grain weight in crosses 1 and 8. These indicated the involvement of additive, dominance as well as epistatic gene interaction for controlling the traits. For the characters where evidence of digenic epistatic interaction was obtained under timely sowing, only additive (d) component was found significant for length of main spike in cross 7, flag leaf area in cross 4, while only dominance (h) component was found significant for plant height in crosses 6 and 7, number of effective tillers per plant in cross 8, peduncle length of main spike in cross 6 and harvest index in crosses 1 and 5. Both additive (d) and dominance (h) effects were significant in all the remaining crosses for all the remaining traits. While In case of late sowing, Only additive (d) effect was found significant for days to maturity and 1000-grain weight in cross 2, for days to heading and days to maturity in cross 3, for grain filling period in cross 4 and for number of grains per spike and 1000-grain weight in cross 7, while only dominance (h) effect was significant for peduncle length of main spike and grain yield per plant in cross 2, for harvest index in cross 5, for grain yield per plant and biological yield per plant in cross 6 and for number of effective tillers per plant in cross 8. Both additive (d) and dominance (h) 59 components were significant for all the remaining crosses for all the remaining traits. Looking to the interaction components, all the three or any one or any two interaction parameters were found significant for most of the traits in most of the crosses under both the environments indicating interaction parameters also played important role in the inheritance of majority of the character in almost all the crosses. The classification of gene action showed importance of duplicate type of gene action for most of the characters in most of the crosses under both the environments. Under a situation of this type, it would be difficult for the breeder to get promising segregants better than parents involved through conventional breeding methods. Magnitude of heterotic effects was high for length of main spike and number of grains per spike under both the sowing conditions. Though, high magnitude of heterotic effect was also registered for biological yield per plant and grain yield per plant under late sowing. The cross GW 9715 x K 9102 exhibited the highest standard heterosis followed by CLN 1 x GW 273 and RWP 2002-2 x LOK 1 for grain yield per plant under timely sowing. While in case of late sowing, the maximum standard heterosis was displayed by hybrid CLN 1 x GW 273 followed by RWP 2002-2 x LOK 1 and CLN 5 x GW 322. It was observed that crosses CLN 1 x GW 273 and RWP 2002-2 x LOK 1 were heterotic for grain yield per plant and majority of important traits in desirable direction under both the environments. Either low or moderate amount of inbreeding depression in desired direction was found for developmental traits like days to heading, days to maturity and plant height. While either moderate or low inbreeding depression in undesirable direction was observed for most of the 60 characters under both sowing conditions. The cross RWP 2002-2 x Lok 1 had significant standard heterosis and negative significant inbreeding depression. The highest significant and positive inbreeding depression for grain yield per plant under E1 was found in cross RWP 2002-2 x Lok 1 followed by CLN 5 x GW 322 and AKAW 2862-1 x MACS 2496. While in case of E2, cross CLN 5 x GW 322 showed maximum and significant inbreeding depression which was followed by CLN 1 x GW 273. The plant height, number of effective tillers per plant, number of grains per spike, flag leaf area, peduncle length of main spike and biological yield per plant displayed moderate to higher estimates of narrow sense heritability and genetic advance expressed as percentage of mean in all the crosses under timely sowing. While in case of late sown condition, plant height, number of effective tillers per plant, number of grains per spike, flag leaf area and peduncle length of main spike showed the high values of heritability as well as genetic advance. Therefore, these characters are of great importance for the improvement of grain yield. Under timely sowing, negative and significant association with grain yield per plant was found in hybrid RWP 2002-2 x LOK 1 for days to heading, in GW 9715 x K 9102 for days to maturity and in AKAW 2862-2 x MACS 2496 for plant height. However, significant and positive relationship was displayed between grain yield per plant with number of effective tillers per plant in all the crosses except crosses CLN 5 x GW 322 and GW 9715 x K 9102, length of main spike in AKW 770 x MP 4010 and GW 9715 x K 9102, number of grains per spike in CLN 1 x GW 273 and GW 9715 x K 9102, flag leaf area in AKW 770 x MP 4010, AKAW 2862-1 x MACS 2496, CLN 5 x GW 322 and RWP 2002-2 x LOK 1, grain filling period in AKAW 2862-1 x MACS 2496, CLN 1 x GW 273 and CLN 5 x GW 322, peduncle length of main spike in GW 61 9715 x K 9102, NWL 1 x GW 496, P 11616 x PBW 524 and RWP 2002-2 x LOK 1, 1000-grain weight in RWP 2002-2 x LOK 1. Positive and significant association of grain yield per plant with biological yield per plant and harvest index was observed in all the crosses except cross 3 and crosses 3 and 7, respectively. In case of late sowing, significant and negative genetic association for developmental traits was found for days to maturity in cross RWP 2002-2 x LOK 1 and for plant height in AKAW 2862-1 x MACS 2496, CLN 1 x GW 273 and P 11616 x PBW 524. While positive and significant association of grain yield per plant with number of effective tillers per plant, length of main spike, number of grains per spike, grain filling period and biological yield per plant was observed in all the crosses except cross 3 for length of main spike and cross 2 for number of grains per spike under late sowing. Further significant and positive genetic association was observed for peduncle length of main spike in AKW 770 x MP 4010 and RWP 2002-2 x LOK 1, 1000-grain weight in AKW 770 x MP 4010, P 11616 x PBW 524 and RWP 2002-2 x LOK 1 and for harvest index in P 11616 x PBW 524 and RWP 2002-2 x LOK 1. Above said yield contributing characters are useful for the indirect selection for the improvement of grain yield per plant under respective environment in bread wheat.ThesisItem Open Access HETEROSIS, COMBINING ABILITY AND GENETIC ARCHITECTURE IN SUMMER GROUNDNUT [Arachis hypogaea L.](2011-05) GOR HARSUKH KESHAV; Dhaduk L. K.An experiment was conducted in a randomized block design with three replications at Instructional Farm, Junagadh Agricultural University, Junagadh during summer, 2010 with a view to estimate heterosis, inbreeding depression, combining ability and nature of gene action involved in the inheritance of pod yield, its components and quality traits in groundnut (Arachis hypogaea L.) using diallel mating design (excluding reciprocals) involving eight different Spanish bunch and one Virginia bunch genotypes in F1 and F2 generations. The analysis of variance revealed highly significant differences among parents, F1’s and F2’s for all the traits studied except for days to number of primary branches per plant in parents vs. F1 and days to 50 per cent flowering and sound mature kernel per cent in F1’s vs. F2’s, indicating considerable amount of genetic variability present in the material studied. Low to medium magnitude of heterobeltiosis, high magnitude of standard heterosis and low to moderate inbreeding depression were observed in case of pod yield per plant (g), kernel yield per plant (g), 100-kernel weight (g), number of mature pods per plant, shelling outturn (%), total soluble sugar and harvest index (%). The highest heterobeltiosis and standard heterosis for pod yield per plant was recorded in the cross, TPG 41 x AK 303. The estimate of variance components due to general and specific combining ability indicated that both additive as well as non-additive gene action played an important role in the expression of all the characters. However, additive gene action was predominant in the expression of most of the traits. The combining ability analysis revealed that the parents, TPG 41, JB HPS K 08-1 and AK 303 were observed to be the best general combiners for pod yield per plant, kernel yield per plant and 100-kernel weight (g) in both generations. While the parents, NRCG 10389 was also a good general combiner for days to 50 per cent flowering, days to maturity, number of mature pods, sound mature kernel, shelling outturn, protein content, harvest index and biological yield in both F1 and F2 generations. The parent, J 11 was a good general combiner for days to 50 per cent flowering, days to maturity, plant height, number of immature and mature pods, shelling outturn, total soluble sugar content, and biological yield. These parents could be used in the hybridization programme to isolate superior segregants. The per se performance of the parents and hybrids could be a good indicator for predicting general combining ability (gca) and specific combining ability (sca) effects, respectively. The cross, TPG 41 x AK 303 was found to be best specific combiner for pod yield per plant, kernel yield per plant, number of mature pods per plant and total soluble sugar content with best per se performance for pod and kernel yield per plant which could be expected to throw good transgressive segregants in later generations. The cross, NRCG 10389 x TPG 41 was found to be the best specific combiner for pod yield and kernel yield per plant in both generations followed by two cross combinations, J 11 x AK 303 and NRCG 115 x JB HPS K 08-1. Estimation of variance due to additive and dominance components revealed that additive as well as dominance gene actions were involved in the inheritance of most of the traits studied with preponderance of additive gene action for most of the traits. These findings were also confirmed by estimates of GCA/SCA variance ratios. Average degree of dominance was found in the range of over dominance for all the characters in both the generations except for the traits like, days to 50 per cent flowering, days to maturity, 100- kernel weight, sound mature kernels, pod and kernel yield per plant and biological yield in which partial dominance was observed. Asymmetrical distribution of positive and negative genes and unequal frequency of dominant and recessive genes in the parents were observed for all the traits except for sound mature kernels in both the generations. Heritability estimates in narrow sense in both the generations, was high for days to 50 per cent flowering, days to maturity, 100-kernel weight, sound mature kernel, pod yield per plant, kernel yield per plant, and biological yield; moderate for number of mature pods per plant, oil content, protein content, total soluble sugar content and harvest index and low for plant height, number of primary branches per plant and number of immature pods per plant. On other hand, shelling outturn (%) exhibited high heritability in F1 and moderate heritability in F2 generation. The results of present investigation suggested that reciprocal recurrent selection procedure would mop up the additive gene effects and would also allow dissipation of non-additive gene effects. Biparental mating may also be used in the segregating generations to break the undesirable linkages and to exploit both additive and non-additive gene effects simultaneously for isolating superior transgressive segregants in later segregating generations.ThesisItem Open Access GENETIC ARCHITECTURE OF SEED YIELD AND ITS COMPONENTS IN CASTOR (Ricinus communis L.) UNDER DIVERSE ENVIRONMENTS(2010-05) MONPARA BABULAL ARJANBHAI; Pithia M.S.Six generations, namely P1, P2, F1, F2, BC1 and BC2 of six crosses of castor viz., Geeta x JI 263 ( cross 1) , JP 84 x JI 263 (cross 2), JP 86 x JI 273 (cross 3), JP 90 x JI 258 (cross 4), SKP 42 x SKI 215 (cross 5) and SKP 106 x PCS 124 (cross 6) were grown under diverse environmental conditions (pre-rabi and rabi seasons) at Instructional Farm, College of Agriculture, Junagadh Agricultural University, Junagadh to study the gene effects, heterosis, inbreeding depression, heritability, genetic advance and genetic correlation for seed yield and its components. Experiment was layed-out in Compact Family Block Design with three replications. The observations were recorded on five plants from P1, P2 and F1, forty plants from F2 and thirty plants from BC1 and BC2 generations in each replication for twelve characters viz., days to flowering of main raceme, days to maturity of main raceme, plant height up to main raceme, number of nodes up to main raceme, total length of main raceme, effective length of main raceme, number of effective branches per plant, number of capsules on main raceme, shelling out turn, 100-seeds weight, oil content and seed yield per plant. ii The analysis of variance between families revealed that the mean squares due to crosses were significant for all the characters under both the environments. The analysis of variance among progenies within each family indicated significant differences among six generation means for all the characters studied under both the seasons in all the crosses except oil content in case of JP 84 x JI 263 cross in pre-rabi season. This indicates the sufficient genetic variability in the material under study. All the three or any of the individual scaling tests A, B or C were significant for all the character in all the six crosses under both seasons indicating the presence of epistasis. The application of joint scaling test expressed significant chi-square values for all the traits in all the six crosses under both the environments confirming involvement of digenic interaction parameters in the inheritance of all the characters. On the basis of perfect fit solution of six parameter model, main effects m, (d), (h) and all the three digenic interactions (i), (j) and (l) were significant for majority of the characters in most of the crosses under both the seasons indicating involvement of additive, dominance as well as epistatic gene effects. In case of pre-rabi sowing condition, only additive (d) effect was significant for days to flowering of main raceme in cross 3, days to maturity of main raceme in cross 1, total length of main raceme in cross 6, number of effective branches per plant in cross 2 and 100-seeds weight in cross 1 and 6. While only dominance (h) component was significant for days to flowering of main raceme in cross 1 and 4, plant height up to main raceme in cross 4, number of nodes up to main raceme in cross 6, number of effective branches per plant in cross 1, number of capsules on main raceme in cross 3, shelling out turn in cross 1 and 2, oil content in cross 4 and seed yield per plant in cross 3. Both additive (d) and dominance (h) effects were significant in all the remaining crosses iii for all the remaining traits. Significance of only additive (d) parameter under rabi sowing was observed for days to maturity of main raceme in cross 5, number of effective branches per plant in cross 3 and oil content in cross 6 while, only dominance (h) component was significant for days to flowering of main raceme in cross 1, number of nodes up to main raceme in cross 6, number of effective branches per plant in cross 4, shelling out turn in cross 3 and 5 and oil content in cross 4. Both main effects were found significant for remaining traits in rest of the crosses. Such situation indicated role of both additive as well as dominance gene effects for controlling the characters. Looking to the interaction components, all the three or any one or any two interaction parameters were found significant for all the traits in all the six crosses under both the environments indicating interaction parameters also played important role in the inheritance of all the character in all the six crosses. The classification of gene action showed importance of duplicate type of gene action for most of the characters in most of the crosses under both the environments. Under a situation of this type, it would be difficult for the breeder to get promising segregants better than parents involved through conventional breeding methods. While in case of complementary type of epistasis, material can be utilized directly in breeding programme. Magnitude of heterotic effects was high for number of effective branches per plant, seed yield per plant, number of capsules on main raceme, plant height up to main raceme, number of nodes up to main raceme and days to flowering of main raceme, moderate for 100-seeds weight, shelling out turn, days to maturity of main raceme and low for oil content under both the environments. The cross Geeta x JI 263 exhibited the highest standard heterosis followed by JP 90 x JI 258 and JP 86 x JI 273 for seed yield per plant under pre-rabi season. While in case of iv rabi season, the maximum standard heterosis was displayed by hybrid SKP 42 x SKI 215 followed by Geeta x JI 263 and JP 90 x JI 258. It was observed that crosses Geeta x JI 263 and JP 90 x JI 258 were heterotic for seed yield per plant and majority of traits in desirable direction under both the environments. Either low or moderate amount of inbreeding depression in desired direction was found for most of the traits. The Highest significant and positive inbreeding depression for seed yield per plant under pre-rabi sowing was found in cross SKP 106 x PCS 124 followed by JP 84 x JI 263 and Geeta x JI 263. While in case of rabi season, cross Geeta x JI 263 showed maximum and significant inbreeding depression which was followed by SKP 42 x SKI 215 and SKP 106 x PCS 124. The days to flowering of main raceme and seed yield per plant displayed the higher estimates of narrow sense heritability and genetic advance in all the crosses under pre-rabi season, while, plant height up to main raceme, total length of main raceme, effective length of main raceme and number of effective branches per plant had higher values of genetic advance for most of the crosses. While, in case of rabi sowing condition, the number of nodes up to main raceme and plant height up to main raceme showed the high values of heritability as well as genetic advance. Therefore, these characters are of great importance for the improvement of seed yield. Under pre-rabi season, significant and positive relationship was displayed between seed yield per plant with total length of main raceme, effective length of main raceme and shelling out turn in cross Geeta x JI 263; total and effective length of main raceme in crosses JP 84 x JI 263 and SKP 42 x SKI 215; number of capsules on main raceme, shelling out turn, 100-seeds weight and oil content in JP 86 x JI 273; shelling out turn and 100-seeds weight in JP 90 x JI 258 and number of effective branches v per plant, shelling out turn, 100-seeds weight and oil content in SKP 106 x PCS 124. In case of rabi season, yield components like effective length of main raceme in cross JP 86 x JI 273, number of effective branches per plant in JP 84 x JI 263, number of capsules on main raceme in JP 86 x JI 273 and shelling out turn in cross Geeta x JI 263 were positively associated with seed yield per plant. Above said yield contributing characters are useful for the indirect selection for the improvement of seed yield per plant under respective environment in castor.ThesisItem Open Access GENETIC ARCHITECTURE OF SEED YIELD AND YIELD ATTRIBUTING TRAITS IN CASTOR (Ricinus communis L.) UNDER DIVERSE ENVIRONMENTS(2010-03) SODAVADIYA PARESH RAMESHBHAI; Dhaduk L. K.In the present investigation entitled “Genetic architecture of seed yield and yield attributing traits in castor (Ricinus communis L.) under diverse environments” was undertaken with a view to generate genetic information on heterosis, combining ability, gene action, genotype x environment interaction and stability parameters for seed yield and yield attributing traits. The experimental material consisted of ten diverse genotypes of castor (SKP-42, Geeta, JI-244, JI-342, JI-353, JI-357, JI-371, DCS-89, PCS-124 and JI-338), their F1‟s derived by crossing these parents in a diallel fashion excluding reciprocals and GCH-6 as standard check. The experiment was laid out in kharif 2008 under three environments, created by three different date of sowing in randomize block design with three replications in each environment. Observations were recorded on days to flowering of main raceme, days to maturity of main raceme, plant height up to main raceme (cm), number of nodes up to main raceme, total length of main raceme (cm), effective length of main raceme (cm), effective branches per plant, number of capsules on main raceme, shelling out turn (%), 100-seeds weight (g), oil content (%) and seed yield per plant (g). The data were analyzed for heterosis and combining ability (Method II, Model I of Griffing, 1956). The genetic components of variation were analyzed following the method of Hayman (1954a) while, stability analysis was carried out as per model suggested by Eberhart and Russel (1966). Analysis of variance in individual as well as pooled over environments revealed significant differences among genotypes and existance of overall heterosis for seed yield per plant and yield attributes. The magnitude of heterosis over better parent was considerable for seed yield per plant; moderate to high for total and effective length of main raceme, number of capsules on main raceme, effective branches per plant; low to moderate for plant height, number of nodes per plant, 100-seed weight, shelling outturn and oil content. The magnitude of heterosis over standard check GCH-6 was low for seed yield per plant, 100-seed weight, oil content, shelling outturn, days to 50 per cent flowering and days to maturity, while it was moderate to high for plant height, number of nodes per plant, number of capsules on main raceme, effective branches per plant and total and effective length of main raceme. Among 45 hybrids, DCS-89 x PCS-124, JI-353 x PCS-124 and Geeta x PCS-124 recorded the significant and positive (desirable) heterosis over GCH-6. The cross SKP-42 x JI-371 followed by DCS-89 x PCS-124 and SKP-42 x JI-338 recorded the highest heterobeltiosis for seed yield per plant. The high heterosis in these hybrids was mainly due to high heterosis in one or more of their component traits. The combining ability analysis revealed significant general and specific combining ability variances for all the characters across the environments and these variances were largely influenced by environments. The specific combining ability variance were found more important compared to general combining ability for seed yield and all other characters except days to 50 per cent flowering, plant height up to main raceme, number of nodes up to main raceme and 100-seed weight. Parents JI-353, DCS-89 and PCS-124 were good general combiners for seed yield per plant. Among ten parents, PCS-124 and DCS-89 recorded the good general combining ability for all the yield attributing traits studied. The hybrids DCS-89 x PCS-124, JI-353 x PCS-124 and Geeta x PCS-124 recorded the highest sca effects for seed yield per plant along with high and desirable sca effects for most of the traits directly related to seed yield. As per Hayman diallel analysis the value of H1/D indicated over dominance for all the traits evaluated except for days to flowering of main raceme, plant height up to main raceme and number of nodes up to main raceme and 100-seed weight. The distribution of genes with positive and negative effects in the parents were nearly symmetrical for the traits like days to flowering of main raceme, plant height up to main raceme, total length of main raceme, effective length of main raceme, effective branches per plant, number of capsules on main raceme, shelling outturn, 100-seed weight, oil content and seed yield per plant indicating considerable degree of gene symmetry over all the loci. The estimates of KD/KR ratio was more than unity for all the characters except for days to flowering of main raceme, shelling outturn, 100-seed weight and seed yield per plant indicating high proportion of dominant genes in the parents for these traits. The estimates of ratio h2/H2 suggested the involvement of one group of genes showing dominance in all the traits except for total and effective length of main raceme, effective branches per plant, number of capsules on main raceme and seed yield per plant. Griffing and Hayman analysis revealed importance of additive as well as non-additive gene effects with high relative magnitude of non-additive gene effects for seed yield per plant as well as components directly related to seed yield. This situation suggested heterosis breeding for evolving highly productive hybrids. For overall improvement, biparental mating with reciprocal recurrent selection could offer the best promise. Alternatively, intermating and selfing or intermating between F2‟s showing transgressive segregation would also be helpful in isolating superior genotypes. The genotype x environment interactions were substantial for all the characters except days to 50 per cent flowering and oil content. The linear components were accounted for major portion of total G x E interactions for all the traits except total length of main raceme, effective length of main raceme and oil content. Among parents DCS-89 and JI-353 and among hybrids Geeta x PCS-124, Geeta x DCS-89, JI-353 x DCS-89, Geeta x JI-353 and JI-244 x PCS-124 were the best combinations due to their good stability coupled with high seed yield per plant. Good stability of these superior genotypes for seed yield per plant were synchronized with their stability for yield attributes. On the basis of per se performance, heterosis, combining ability as well as stability over the environments, the cross Geeta x PCS-124 was the most promising for exploitation of heterosis on commercial scale whereas, the hybrids DCS-89 x PCS-124, JI-353 x PCS-124, Geeta x DCS-89, JI-353 x DCS-89 and JI-342 x DCS-89 may be utilized for isolation of high yielding genotypes /inbred lines in the later segregating generation. ABBREVIATIONS USED BP = Better parent Cap = Number of capsules on main raceme DF = Days to flowering of main raceme DM = Days to maturity of main raceme EB = Number of effective branches per plant EL = Effective length of main raceme G x E = Genotype x Environment gca = General combining ability ND = Number of nodes up to main raceme No. = Number Pht = Plant height up to main raceme SC = Standard check sca = Specific combining ability SW = 100-seed weight TL = Total length of main raceme