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ThesisItem Open Access FULL DIALLEL ANALISYS IN PEARL MILLET (PENNISETUM GLAUCUM (L.) R.BR.)(JAU,JUNAGADH, 2011-07) A.S. BHADALIA; H.J. JOSHIThesisItem Open Access MORFOLOGICAL AND MONECULAR GENETICS DIVERSITY ANYLISYS IN DURUM WHEAT(JAU,JUNAGADH, 2010-05) TAMBE ASHWINI EKNATHRAO; V.P. CHOVATIYAThesisItem Open Access GENETICS STUDIES IN BOTTLE GOURD(JAU,JUNAGADH, 2010-06) P.M. VEGAD; M.A. VADDORIAThesisItem Open Access FULL DIALLEL ANALYSIS IN PEARL MILLET (Pennisetum glaucum (L.) R. Br.)(jau,junagadh, 2011-08) A. S. Bhadalia; Dr. H. J. JoshiThe present investigation was undertaken on pearl millet in order to estimate heterosis, combining ability and nature of gene action involved in the inheritance of grain yield and its component characters, viz., days to 50% flowering, days to maturity, number of effective tillers per plant, earhead length (cm), earhead girth (cm), earhead weight (g), plant height (cm), number of grains per square cm, grain yield per plant (g), 1000-grains weight (g), dry fodder yield per plant (g) and harvest index (%). The crosses were attempted by adopting diallel analysis (including reciprocals) involving eight elite inbreds during summer-2009. The resultant 56 hybrids along with their parents and one standard check hybrid (GHB-744) were evaluated in randomized block design with three replications during kharif-2009 at Main Pearl Millet Research Station, Junagadh Agricultural University, Jamnagar (Gujarat), India. The analysis of variance for experimental design revealed that mean square differences among genotypes, parents and hybrids and reciprocals were significant for all the traits indicating sufficient amount of genetic variability for the twelve traits under study. The mean square due to parents Vs hybrids and F1 Vs reciprocals were significant for all the traits. On the basis of per se performance revealed among the crosses, J-2454 x J-2467 (69.07g) and among the parents, J-2467 (65.21g) gave the highest grain yield per plant. Considerable degree of heterosis over better parent and standard check was observed in different hybrids for most of the traits. The magnitude of heterotic effects was high for grain yield per plant, number of effective tillers per plant, ear head weight and harvest index; and it was moderate to low for rest of the traits. The highest significant positive standard heterosis for grain yield per plant and some of its component traits were recorded in the crosses viz, J2454 x J2467, J2454 x J2511, H77/833-2 x J2405 and J2340 x J2511. The crosses exhibited high heterosis for grain yield also expressed high heterosis for at least one or more component traits. The general and specific combining ability variances were highly significant for all the characters indicating both additive and non-additive gene effects played a vital role in the inheritance of all the traits. However, the gca:sca variance ratio less than unity confirmed the preponderance of non-additive gene action for the traits under studies and emphasized the utility of hybrid breeding approach to exploit existing heterosis in pearl millet. The estimate of GCA effects indicated that it was difficult to pick good general combiner parents for all the traits. However, the parents J2405, J2467 and J2511 were found good general combiners for grain yield per plant and some of its component traits. Hence, these parents were considered to be good source of imparting favorable genes for grain yield per plant and its components. Considerable harmony was observed between per se performance of parents and their GCA effects for grain yield and most of component traits. The best crosses on the basis of SCA effects for grain yield per plant were J2467 x J2454, J2511 x J2454 and J2511 x J2340. The estimate of SCA effects revealed that crosses showing high SCA effects for grain yield also depicted high SCA effects for one or more yield components. The cross J2467 x J2454 had also high SCA effects for ear head weight, ear head length, number of grains per square cm and harvest index. The cross displaying high SCA effects did not always involve parents with high GCA effects, suggesting that interallelic interactions were also important for the characters. The per se performance of crosses for various traits was not related with their SCA effects. Average degree of dominance revealed over dominance for all the traits except, number of effective tillers per plant, ear head girth and number of grains per square cm. Asymmetrical distribution of positive and negative genes in the parents was observed for most of the traits and nearly symmetrical distribution for days to 50% flowering, days to maturity and ear head girth. Inheritance of most of the characters including grain yield per plant was generally governed by a few genes or group of genes. The estimate of narrow sense heritability was found high for ear head weight, number of grains per square cm, grain yield per plant, dry fodder yield per plant and harvest index. Ear head length manifested moderate heritability whereas, rest of the traits displayed low heritability. Considering the overall performance, three best promising crosses viz., J2454 x J2467 (poor x good), J2454 x J2511 (poor x good) and J2340 x J2511 (average x good) exhibited the highest per se performance as well as high positive significant standard heterosis, heterobeltiosis and SCA effects for grain yield per plant. These crosses also registered significant heterosis and SCA effects in desired direction for yield and its component traits. Therefore, these crosses to be segregate the favorable good sergeants in later generations for selection of superior inbred lines in pearl millet. These crosses also recorded 14.29, 13.09 and 12.37 per cent higher grain yield over standard check hybrid (GHB-744) respectively. Therefore, these crosses could also be exploited for heterosis breeding programme to boost the grain yield in pearl millet. Overall results of present investigation suggested that reciprocal recurrent selection procedure make up the additive gene effects and would also allow dissiparation of non-additive gene effects. Bi-parental 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. Due to the preponderance of non-additive gene effects of grain yield and most of its component traits, heterosis breeding would also be practically feasible in crop like pearl millet.ThesisItem Open Access GENETIC VARIABILITY, CORRELATION AND PATH COEFFICIENT ANALYSIS IN GROUNDNUT (Arachis hypogaea L.)(jau,junagadh, 2011-08) Ekshinge K. S.; Dr. V. J. BhatiyaThe present investigation was carried-out to assess the genetic variability, correlation coefficients, path coefficients, selection indices and genetic divergence in 54 genotypes of groundnut (Arachis hypogaea L.). The experiment was layed-out in a randomized block design with three replications at the Main Oilseed Research Station, Junagadh Agricultural University, Junagadh during kharif-2010. The observations were recorded on 18 characters viz., days to 50% flowering, days to maturity, plant height, number of primary branches per plant, number of secondary branches per plant, number of undeveloped pods per plant, kernel yield per plant, pod yield per plant, number of pegs per plant, number of mature pods per plant, sound mature kernels, 100-kernel weight, 100-pod weight, shelling out turn, protein content, oil content, biological yield per plant and harvest index. Analysis of variance revealed significant differences among the genotypes for all the characters studied except number of primary branches per plant. A wide range of variation was observed for most of the important yield components. High estimates of genotypic coefficient of variation was observed for number of secondary branches per plant, number of undeveloped pods per plant, number of pegs per plant, harvest index, number of mature pods per plant, kernel yield per plant, biological yield per plant and pod yield per plant. High heritability coupled with high genetic advance as per cent of mean was observed for number of pegs per plant, harvest index, number of mature pods per plant, biological yield per plant, 100- pod weight and number of secondary branches per plant, pod yield per plant, kernel yield per plant and 100-kernel weight. The analysis of correlation coefficients suggested that the magnitude of genotypic correlations were higher than the corresponding phenotypic correlations for the most of the pairs. The pod yield per plant showed significant and positive genotypic and phenotypic correlations with kernel yield per plant, harvest index, shelling out-turn, oil content and 100-pod weight. While its association with protein content was significant but negative at genotypic level only. The path coefficient analysis revealed the high and positive direct effects of days to maturity, kernel yield per plant, biological yield per plant and harvest index towards pod yield. The most of the characters contributed indirectly to pod yield through biological yield per plant and harvest index. Based on correlation and path analysis, harvest index, biological yield per plant, number of mature pods per plant and 100-seed weight were identified as the most important components of pod yield. The selection indices forming 31 combinations involving pod yield and four yield components were constructed using the discriminant function technique. In a single character index, the maximum efficiency was exhibited by harvest index followed by biological yield per plant, shelling out-turn and kernel yield per plant. The efficiency of selection increased with the inclusion of more number of characters in the index. The highest relative efficiency was exhibited by a selection index involving two component characters viz., shelling out-turn and biological yield per plant (X3. X4) followed by an index based on four characters. i.e., included pod yield per plant, kernel yield per, shelling out-turn and harvest index (X1 .X2. X3. X5). The 54 genotypes were grouped into 14 clusters by Mahalanobis’s D2-statistic. The clustering pattern of the genotypes did not confirm to the geographical distribution. The maximum inter cluster distance was found between clusters XII and XI followed by that between IX and XII and XI and X. The cluster III was superior for pod yield per plant, kernel yield per plant, shelling out-turn and harvest index, while Cluster VII was the best for days to 50% flowering, days to maturity and 100-kernel weight. Cluster V was the best for protein content. The cluster IX was good for number of secondary branches per plant, number of undeveloped pods per plant and sound mature kernels per plant. The cluster X was good for plant height and biological yield per plant. The cluster XII was good for days to mature, number of pods per plant, sound mature kernels per plant and oil content. The cluster VI was the good for 100-pod weight, while cluster XIV was good for number of primary branches per plant and number of pegs per plant. Therefore, in the present investigation, bases on high yielding genotypes and large inter cluster distances, it is advisable to attempt crossing of the genotypes from cluster XII , of cluster IX, X and XI which may lead to broad spectrum of favourable genetic variability for yield improvement in groundnut. Overall, it can be concluded from the study of variability, correlation, path coefficient analysis, selection indices and genetic diversity that days to maturity, kernel yield per plant, shelling out-turn, biological yield per plant and harvest index were most important yield contributes and the emphasis should be given to these traits for pod yield improvement in groundnut. Selection index based on either two traits (X3.X4) or four traits (X1X2X3X5) would be useful for indirect selection.ThesisItem Open Access HETEROSIS, COMBINING ABILITY AND GENETIC ARCHITECTURE IN SUMMER GROUNDNUT [Arachis hypogaea L.](jau,junagadh, 2011-05) Mr. H. K. GOR; Dr. L. K. DHADUKAn 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 CHARACTER ASSOCIATION, SELECTION INDICES AND GENETIC DIVERGENCE IN GROUNDNUT (Arachis hypogaea L.)(jau,junagadh, 2011-06) Bhosale Sharmila D.; Dr. K. L. DobariyaAn investigation was carried out using 108 genotypes of groundnut to find out the genetic variability, correlation coefficients, path coefficients, selection indices and genetic divergence. The material was evaluated in a randomized block design with three replications at the Main Oilseeds Research Station, J. A. U., Junagadh during kharif 2010. The observations were recorded on 19 characters viz., days to 50% flowering, days to maturity, plant height (cm), number of primary branches per plant, number of secondary branches per plant, number of pods per plant, kernel yield per plant (g), pod yield per plant (g), haulm yield per plant (g), number of pegs per plant, number of mature pods per plant, sound mature kernels (%), 100-pod weight (g), 100-kernel weight (g), shelling out-turn (%), oil content (%), protein content (%), biological yield per plant (g) and harvest index (%). Analysis of variance revealed significant differences among the genotypes for all the 19 characters studied. The highest range of variation was observed for harvest index followed by biological yield per plant, haulm yield per plant, plant height, sound mature kernels, 100-pod weight, days to maturity, shelling out-turn and number of secondary branches per plant. The highest genotypic coefficient of variation was observed for number of secondary branches per plant followed by haulm yield per plant, harvest index, number of mature pods per plant, number of pegs per plant, number of primary branches per plant, number of pods per plant, kernel yield per plant, plant height and biological yield per plant. The values were observed to be moderate for pod yield per plant, 100-kernel weight, 100-pod weight, sound mature kernels and days to maturity. High heritability along with high genetic advance was observed for number of primary branches per plants, number of secondary branches per plants, number of pods per plant, haulm yield per plant, number of pegs per plant, number of mature pods per plant, biological yield per plant and harvest index. The values of genotypic correlation were higher than their corresponding phenotypic correlations in the present study. The pod yield per plant exhibited significant positive association with number of pods per plant, kernel yield per plant, number of pegs per plant, number of mature pods per plant, 100-pod weight, 100-kernel weight and harvest index at both genotypic and phenotypic levels, while pod yield per plant exhibited highly significant and negative correlation with days to maturity, plant height, number of secondary branches per plant and haulm yield per plant at both the genotypic and phenotypic levels. The pod yield per plant also showed positive and highly significant correlation with days to 50% flowering and shelling out-turn at genotypic level. The analysis of path coefficient was observed the highest positive direct effects for days to 50% flowering, number of pods per plant, kernel yield per plant, haulm yield per plant and harvest index towards pod yield per plant. The indirect effects through days to 50% flowering, numbers of pegs per plant and harvest index were higher and positive for most of the characters. Based on correlation and path analysis, days to 50% flowering, number of pegs per plant, harvest index, kernel yield per plant, number of pods per plant, number of mature pods per plant, 100-pod weight and 100-kernel weight identified as the most important components of pod yield. The selection indices forming 63 combinations involving pod yield and five yield components were constructed using the discriminant function technique. In a single character index, the maximum efficiency was exhibited by harvest index followed by haulm yield per plant, number of pods per plant and kernel yield per plant. The efficiency of selection increased with the inclusion of more number of characters in the index. The highest relative efficiency was exhibited by a selection index involving five component characters viz., pod yield per plant, days to 50% flowering, number of pods per plant, kernel yield per plant and harvest index followed by an index based on four characters viz., pod yield per plant, number of pods per plant, kernel yield per plant and harvest index. The 108 genotypes were grouped into 13 clusters by Mahalanobis’s D2-statistic. The clustering pattern of the genotypes did not confirm to the geographical distribution. The maximum inter-cluster distance was found between clusters VIII and XII followed by that between clusters IV and XII, VIII and XI, XI and XIII, XII and XIII, V and VIII, IV and XI and VI and XII. The cluster XI was superior for haulm yield per plant, number of pegs per plant, 100-pod weight and protein content, while Cluster I was the best for number of pods per plant, number of mature pods per plant and harvest index. Cluster XII was good for plant height and sound mature kernel. The cluster II was good for pod yield per plant and kernel yield per plant. The cluster XIII was good for number of primary branches per plant and secondary branches per plant. The cluster IV was good for days to 50% flowering, while the cluster X had greater mean for days to maturity. The cluster VI was good for shelling out-turn. The cluster IX had higher mean for oil content and the cluster V was good for 100-kernel weight. Therefore, in the present investigation, bases on high yielding genotypes and large inter-cluster distances, it is advisable to attempt crossing of the genotypes from cluster XI with the genotypes of cluster XII and I, which may lead to broad spectrum of favourable genetic variability for yield improvement in groundnut.ThesisItem Open Access GENETIC ANALYSIS IN CASTOR (Ricinus communis L.)(jau,junagadh, 2011-06) Mr. Hardik P. Virani; Dr. H. L. DhadukIn the present investigation entitled “Genetic analysis in castor (Ricinus communis L.)” was undertaken with a view to generate genetic information on gene effects, heterosis, inbreeding depression, and genetic correlation for seed yield and its components. The experimental material consisted of six generations, namely P1, P2, F1, F2, BC1 and BC2 of five crosses of castor viz., JP 96 x JI 368 (cross 1), JP 96 x JI 372 (cross 2), JP 101 x SKI 215 (cross 3), JP 101 x SKI 291 (cross 4) and JP 102 x JI 372 (cross 5) grown at Main oilseeds Research Station, Junagadh Agricultural University, Junagadh. 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 twelve characters. The analysis of variance between families (crosses) revealed that the mean squares due to crosses were significant for all the characters except plant height up to main raceme and number of effective branches per plant. 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 number of nodes up to main raceme in cross 1, and number of effective branches per plant in cross 1, cross 2 and cross 5. 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 days to flowering of main raceme in cross 1; days to maturity of main raceme, shelling out turn and oil content in cross 4. For remaining crosses either all the three or any one or two individual scaling test A, B or C were found significant. This was also confirmed by joint scaling test showing significant chi-square values for these cases, indicating involvement of digenic interaction parameters in the inheritance of the characters. On the basis of perfect fit solution of six parameter model, all the six parameters viz., m, (d), (h), (i), (j) and (l) were significant for plant height up to main raceme, shilling out turn and oil content in cross 5; for number of node up to main raceme in cross 4; for length of main raceme and effective length of main raceme in cross 1 and for 100-seed weight in cross 2 and cross 4, indicated the involvement of additive, dominance as well as epistasis gene interaction for controlling these traits. For the characters where evidence of digenic epistatic interaction was obtained, both additive and non-additive effects were significant for days to maturity of main raceme, plant height up to main raceme, shelling out turn, 100-seed weight in cross 1; days to maturity of main raceme, plant height up to main raceme, shelling out turn and seed yield per plant in cross 2; days to flowering of main raceme, days to maturity of main raceme, length of main raceme, effective length of main raceme, number of capsule on main raceme and shelling out turn in cross 3; plant height up to main raceme in cross 4 and days to maturity of main raceme, number of nodes up to main raceme, length of main raceme, effective length of main raceme and 100-seed weight in cross 5. Only additive (d) component was found significant for number of capsule on main raceme cross 1, oil content in cross 1 and cross 2; plant height up to main raceme, number of nodes up to main raceme, 100-seed weight, oil content and seed yield per plant in cross 3; length of main raceme, effective length of main raceme and number of capsule on main raceme in cross 4 and seed yield per plant in cross 5. While only dominance (h) component was found significant for seed yield per plant in cross 1; length of main raceme, effective length of main raceme, number of capsule on main raceme in cross 2; number of effective branches per plant in cross 3; days to flowering of main raceme in cross 4 and number of capsule on main raceme in cross 5.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 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. Breeding procedures involving multiple crosses, biparental crosses may be restored to get transgressive segregants. This is especially important to develop inbred lines having superiority in different characters. Such lines can give better hybrids. While in case of complementary type of epistasis, material can be utilized directly in breeding programme. The magnitude of heterotic effects was high for plant height up to main raceme, number of nodes up to main raceme, 100-seed weight and seed yield per plant; moderate for days to flowering of main raceme, days to maturity of main raceme, shelling out turn and oil content and low for length of main raceme, effective length of main raceme and number of effective branches per plant. The cross JP 96 x JI 368 exhibited highest standard heterosis for seed yield per plant along with high to moderate heterotic effect for majority of trait in desirable direction. Either low or moderate amount of inbreeding depression in desired direction was found for most of the traits. It is desirable to have high, significant and positive heterosis with low inbreeding depression for characters like seed yield and its components. As observed in cross JP 96 x JI 372 for seed yield per plant, cross JP 101 x SKI 291for shelling out turn and cross JP 96 x JI 368 in oil content. Significant and positive correlation coefficient of seed yield per plant was exhibited in hybrid JP 96 x JI 368 and JP 96 x JI 372 with number of effective branches per plant; in JP 101 x SKI 215 with number of effective branches per plant and shelling out turn, in JP 101 x JI 291 with shelling out turn, 100-seed weight and oil content and in JP 102 x JI 372 with length of main raceme and effective length of main raceme.ThesisItem Open Access GENETIC ANALYSIS OF GRAIN YIELD AND ITS COMPONENTS IN WHEAT (Triticum aestivum L.) UNDER DIVERSE ENVIRONMENTS(jau,junagadh, 2011-01) L.G. Vanpariya; Dr. M.S. PithiaSix 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. 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 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) 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 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 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.
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