Non-additive Components Research Articles

Genetic Analysis for the Improvement of Grain Yield, Yield Contributing Traits and Quality in Rabi sorghum [Sorghum bicolor (L.) Moench

An experiment was conducted, the hybrids and their parents were evaluated using thirty F1 hybrids of rabi sorghum (Sorghum bicolor (L.) Moench) developed by crossing three lines and ten testers in line × tester fashion. for their combining ability and also to check the superiority of hybrids (heterosis) over parents with respect to quality traits, grain yield and its components. Among thirty hybrids, two potential hybrids M-35-2A x RSV 2388 and 104A x Phule Vasudha were found to be good specific combiners with highest standard heterosis and per se performance for grain yield over checks CSH 15R. AKMS-66-2A and 104A were the good general combiner with males viz. Phule Vasudha, RSV 2388, Phule Revati and RSV 1910. The estimates of general combing ability and specific combining ability revealed the presence of both additive and non-additive genetic components for most of the traits under study.

Combining ability for grain yield and low-N tolerance of intermediate/late maturing maize (Zea mays) inbred lines

ABSTRACT Low soil nitrogen (N) is a significant challenge to maize (Zea mays L.) production in Sub-Saharan Africa, particularly for small-scale farmers. Developing maize hybrids tolerant to low N is crucial for improving yields under such conditions. This study examined the genetic basis of agronomic traits in intermediate/late maturing maize inbred lines under contrasting N conditions, focusing on general combining ability (GCA) and specific combining ability (SCA) effects. Two hundred and thirty-seven F1 hybrids from 79 inbred lines crossed with three testers in a line x tester mating design, were evaluated across eight environments in Nigeria. Line x tester analysis revealed that GCA effects, primarily from lines, predominantly influenced grain yield and other traits across both N conditions, except for ear height and plant aspect under low N, where SCA effects also had significant impact. A significant (p ≤ 0.01) positive correlation was observed between GCA and SCA effects, suggesting a positive relationship between additive and non-additive genetic components. Lines SMLW146 and SMLW147 were identified as valuable resources for breeding low-N tolerant hybrids. Additionally, considering non-additive effects, hybrids SMLW22 × SAM50M and SMLW106 × SAM50M (under low-N) and SMLW3 × IITA1876, SMLW84 × IITA1876, and SMLW165 × IITA1876 (under optimum-N) were promising combinations for high grain yield. Morphological traits like plant height and ear height, phenological traits like days to anthesis and silking, and qualitative traits like ear aspect and plant aspect were identified as important for selecting genotypes with improved grain yield under low-N conditions.

Genetics of Fruit Yield and Its Traits in Okra [Abelmoschus esculentus (L.) Moench

A Half-diallel mating design involving nine okra genotypes was used to study the inheritance of fruit yield and its component characters in okra. Data from the F1 generation and parents were analysed using Hayman's (1954) method of diallel analysis. The estimated component of genetic variation revealed that additive component (D) was significant for number of branches per plant and fruit girth in E1 and fruit girth in E3 environment. However, additive component was non-significant in all three environments for fruit yield per plant. The dominant components (H1 and H2) were significant for all the characters in all the environments. These results revealed the importance of both additive and non-additive component of gene action in the expression of traits under study. The relative magnitude of dominant component (H1 and H2) was higher than additive component for most of the traits indicating that dominance gene action involved in expression of most of the characters under studied. The average degree of dominance for fruit yield per plant and most of the traits was more than unity in all the three environments which suggested over dominance effect in expression of all the traits. The proportion of genes with positive and negative effects in parents was deviated from 0.25 in all three environments suggesting asymmetrical distribution of positive as well as negative alleles among the parents for fruit yield per plant. The ratio of dominant and recessive genes in the parents were also greater than unity in all the three environments, indicated excess of dominant genes were present in the parents for fruit yield per plant. In the presence of overdominance for yield, reciprocal recurrent selection is the best recurrent scheme to develop hybrids.

A Comprehensive study of wheat genotypes for combining ability and heritability in drought tolerance

A major challenge in wheat cultivation is the negative impact of water scarcity on growth and yield. Therefore, it is crucial to develop wheat varieties with both high productivity and resilience to drought stress to support food production and improve global food security. The study aims to identify general and specific combining abilities and to understand the genetic mechanisms responsible for key traits by employing half-diallel analysis. In the current study, a half-diallel set comprising 10 x 10 wheat genotypes was subjected to crosses in all feasible combinations, excluding reciprocals, under drought stress conditions. Significant mean squares were observed for both General Combining Ability (GCA) and Specific Combining Ability (SCA) components among the 10 parents and 45 F1 progenies across eleven traits. Assessment of variance components (s2g and s2s), narrow-sense heritability (Hn), broad-sense heritability (Hb) and the GCA/SCA ratio allowed for the determination of the relative contributions of additive and non-additive genetic components. High narrow-sense heritability was noted for traits such as days to 75 % flowering, spike length and biological yield, indicating their predominantly additive genetic control. Conversely, the remaining eight traits exhibited low narrow-sense heritability, suggesting their inheritance is primarily governed by non-additive genetic factors, thus indicating the potential benefits of heterosis breeding. Based on GCA effects, P5 demonstrated superior general combining ability across traits, except for biological yield. P1, P3, P8 and P9 exhibited better combining ability for grain yield per plant. Specific cross combinations including P7×P10, P3×P4 and P5×P6 displayed notable specific combining ability and could be leveraged to develop superior pure lines in subsequent breeding endeavors.

Combining Ability Analysis and Association of Yield and Yield Components among Selected Rajmash (Phaseolus vulgaris L.) Lines

Background: Rajmash (Phaseolus vulgaris L.) is a significant leguminous crop known for its high protein content and dietary value. As global demand for nutritious food sources rises, enhancing the productivity and nutritional quality of Rajmash has become imperative. This research paper aims to investigate the combining ability and character associations in rajmash to facilitate the development of improved varieties with superior agronomic traits. Methods: An experiment was carried out in Rajmash using line × tester mating design to estimate the gca effect of parents and sca effect of 21 hybrids for yield and its traits using 7 lines and 3 testers. Hybrids along with ten parents were studied for combining ability and phenotypic correlations for seed yield and nine yield related traits. Result: The result indicated that the general combining ability (GCA) and specific combining ability (SCA) were significant for most characters indicating the importance of both additive and non-additive genetic components. This implies that a comprehensive understanding of both types of genetic effects is crucial for effective breeding programs. Among parent TRCR 3, SKAU-R-19, RR-21-01 and RKR 1033 were found to be good general combiners for seed yield per plant. This indicates their potential to consistently impart favorable traits to their progeny. The identification of such strong general combiners is valuable information for breeders aiming to enhance overall seed yield. The most promising specific combiners for seed yield were from crosses including SKAU-R-19 × RKR 1033, IPR-205-19 × HUR, RR-21-01 × RKR 1033, RR-21-12 × GR 1 and RR-21-01 × HUR. Significant desirable phenotypic correlations were observed between seed yield with days to flowering, days maturity, number of pods per plant, pod length and 100 seed weight these characters can act as indirect selection criteria in yield that could be used in rajmash breeding programs. The identification of strong general combiners, promising specific crosses and meaningful phenotypic correlations offers practical guidance for future breeding efforts, contributing to the development of improved varieties with enhanced yield potential and desirable agronomic traits.

Genetic Components Derived Parameters and Heterosis in Okra under Saudi Arabia Conditions.

Four parental genotypes of okra were crossed in complete diallel design to study the direction and extent of relative heterosis and heterobeltiosis for yield and its associated traits for utilization of existing genetic diversity to develop heterotic F1 hybrids in okra. The additive genetic component (D) was significant in all studied traits except average pod weight. Nonadditive (H1 and H2) components were found to be significant in all studied traits. However, the values of the dominant effect (H1) were smaller than the D components for no. of nodes/plant, no. of pods/plant, weight of medium pods, weight of large pods, and total fresh pod yield. The maximum significant MP heterosis in the desirable direction (149.9%) was recorded for the weight of large pods/plot. The maximum significant heterobeltiosis in the desirable direction (120.1%) was recorded for the weight of small pods/plot followed by total fresh pod yield (107.4%), the weight of large pods/plot (104.9%), weight of medium pods/plot (92.1%), average pod weight (51.8%), number of pods/plant (38.4%), and plant height (34.3%). It could be concluded that plant height, average pod weight, and the number of branches could be considered for the development of elite hybrids (heterosis breeding) or inbred lines (pure line selection) in succeeding generations. Therefore, these parameters can be considered for selecting genotypes to improve the pod yield of okra. The superior crosses identified through heterosis analysis were Egyptian Balady × Line 4.1.18 (30.8 ton/ha), Line 4.1.18 × Egyptian Balady (29.8 ton/ha), Dwarf Green Long Pod × Line 4.1.18 (28.3 ton/ha), and Egyptian Balady × Dwarf Green Long Pod (27.6 ton/ha) as these crosses had high performance as well as significant and higher estimates of heterobeltiosis for fruit yield per plant and yield attributing other characters.

Exploration of Diallel Method for Assessing Heterosis and Combining Ability in Maize (Zea mays L.)

During the Kharif season of 2018 and Rabi season of 2018-19, an experimental study was conducted. The selection of seven maize genotypes was based on quantitative traits, growth duration, suitability for the Kharif season, and yield. These genotypes were then crossed in a half diallel mating design, resulting in the production of 21 single-cross hybrids. The cultivation of these hybrids, along with the seven parental inbred lines, totaling 28 genotypes, followed a randomized block design. Each plot had dimensions of 23.10m by 1.0m and maintained a plant density of 240 plants per plot. To assess the quantitative traits, observations were recorded from five randomly selected plants per plot. The analysis of variance indicated significant genetic variability among the genotypes, particularly in traits such as days to 50% germination, silking, maturity, plant height, number of leaves per plant, biological yield, cob ear weight, number of rows per cob, and number of seeds per cob. This variability was attributed to both additive and non-additive genetic components, as evident from significant variances due to general combining ability (GCA) and specific combining ability (SCA). The GCA/SCA ratio was less than unity for most traits. For most traits, parental lines P1, P2, and P4 exhibited high GCA effects. Additionally, F1 hybrids P4x P3, P3x P1, P5x P3, and P7 x P5 were found to be desirable in terms of yield and related traits. In terms of yield, seven crosses (P1 x P6, P2 x P7, P2x P5, P1 x P2, P3x P4, P5 x P7, and P3 x P5) outperformed the check hybrid, demonstrating their potential for future breeding programs aimed at enhancing maize yield.

Non-additive genetic components contribute significantly to population-wide gene expression variation

Gene expression variation, an essential step between genotype and phenotype, is collectively controlled by local (cis) and distant (trans) regulatory changes. Nevertheless, how these regulatory elements differentially influence gene expression variation remains unclear. Here, we bridge this gap by analyzing the transcriptomes of a large diallel panel consisting of 323 unique hybrids originating from genetically divergent Saccharomyces cerevisiae isolates. Our analysis across 5,087 transcript abundance traits showed that non-additive components account for 36% of the gene expression variance on average. By comparing allele-specific read counts in parent-hybrid trios, we found that trans-regulatory changes underlie the majority of gene expression variation in the population. Remarkably, most cis-regulatory variations are also exaggerated or attenuated by additional trans effects. Overall, we showed that the transcriptome is globally buffered at the genetic level mainly due to trans-regulatory variation in the population.

Genetic Variability in Garden Pea (Pisum sativum L.): A Review

The estimation of variability parameters, particularly heritability and genetic gain, holds significant importance in assessing the potential for character improvement through selection. It is observed that selection based on highly heritable traits tends to yield more successful outcomes. Hence, the utilization of heritability, in conjunction with other measures of variability, enables the prediction of gains under specific selection intensities. Additionally, the concept of predicted genetic gain provides insight into the degree of change achievable in a trait through simple selection. However, the process of selecting for features related to yield and quality can be enhanced by having access to information regarding the correlation between these traits. This can be further improved by doing a path coefficient analysis to gain a deeper knowledge of the relationship between the important characteristics. In order to enhance the traits that did not exhibit a favorable response to selection, it becomes necessary to divide the non-additive component of genetic variance through the process of hybridization, which can be accomplished by conducting genetic divergence studies.

Study on gene action, heterosis and inbreeding depression for yield and quality traits in castor (Ricinus communis L.)

Gene action, heterosis and inbreeding depression study for yield and quality traits in castor (Ricinus communis L.) was carried out through six parameter generation mean analysis at Main Castor-Mustard Research Station, Sardarkrushinagar Dantiwada Agricultural University (SDAU), Sardarkrushinagar (SK Nagar). The experimental material included six families (P1, P2,F1,F2, BC1, BC2) of six crosses SH 72 x PRT 44, SKI 215 x SKI 166, PCS 124 x 37504, PCS 124 x JH 118, SKI 1 x JH 118 and HC 8 x JH 118. The charactersstudied were daysto flowering, daysto maturity,stemlength, number of nodes onmain stem, effective length of primary raceme, number of capsules on primary raceme, number of effective branches/plant, seed yield/plant, 100-seed weight, oil content in seed, endosperm content, oil content in endosperm, palmatic acid content, oleic acid content, linoleic acid content, linolenic acid content and ricinoleic acid content. The analysis of variance showed significant differences between all the generationsin majority ofthe characters ofthe crosses. The estimation ofscaling testsshowed that non-allelic interactions played an important role in the genetic control of all the characters. All the generations differed significantly for their mean(m) performance of all the traits. The estimates of gene effectsrevealed that both additive and non-additive gene actions were important for days to flowering, days to maturity, stem length, number of nodes on main stem, effective length of primary raceme, number of capsules on primary raceme, number of effective branches/plant, endosperm content, 100-seed weight, seed yield/plant, oil content in seed, linoleic acid content, linolenic acid content and ricinoleic acid content. Whereas, non-additive as well as epistatic gene actions were important for oil content in endosperm, palmatic acid content and oleic acid content. Crosses showing low heterobeltiosis effects also displayed high inbreeding depression for seed yield/plant in general. Utilization ofbiparental mating and reciprocal recurrent selection schemes which has the virtue of effectively exploiting, both additive and non-additive components, was suggested for exploiting present set of materials for obtaining high yielding genotypes of castor.

Incorporating the pedigree information in multi-environment trial analyses for improving common vetch.

Common vetch is one of the most profitable forage legumes due to its versatility in end-use which includes grain, hay, green manure, and silage. Furthermore, common vetch is one of the best crops to rotate with cereals as it can increase soil fertility which results in higher yield in cereal crops. The National Vetch Breeding Program located in South Australia is focused on developing new vetch varieties with higher grain and dry matter yields, better resistance to major diseases, and wider adaptability to Australian cropping environments. As part of this program, a study was conducted with 35 field trials from 2015 to 2021 in South Australia, Western Australia, Victoria, and New South Wales with the objective of determining the best parents for future crosses and the vetch lines with highest commercial value in terms of grain yield production. A total of 392 varieties were evaluated. The individual field trials were combined in a multi-environment trial data, where each trial is identified as an environment. Multiplicative mixed models were used to analyze the data and a factor analytic approach to model the genetic by environment interaction effects. The pedigree of the lines was then assembled and incorporated into the analysis. This approach allowed to partition the total effects into additive and non-additive components. The total and additive genetic effects were inspected across and within environments for broad and specific selections of the lines with the best commercial value and the best parents. Summary measures of overall performance and stability were used to aid with selection of parents. To the best of our knowledge, this is the first study which used the pedigree information to breed common vetch. In this paper, the application of this statistical methodology has been successfully implemented with the inclusion of the pedigree improving the fit of the models to the data with most of the total genetic variation explained by the additive heritable component. The results of this study have shown the importance of including the pedigree information for common vetch breeding programs and have improved the ability of breeders to select superior commercial lines and parents.

Genetic studies on yield and yield attributing traits in sesame (Sesamum indicum L.)

Six diverse parents were crossed in a half diallel fashion to study the heterosis and combining ability in sesame. Parents, 15 F1s with one check was planted in RBD design at College Farm, NAU, Campus Bharuch during kharif-2021. The mean sum of squares due to genotypes and hybrids were significant for all the traits while, due to parents were significant for most of the traits. The mean sum of squares due to parents vs. hybrids were found to be significant for some traits. The gca and sca ratio was less than unity indicated that non-additive components play a greater role in the inheritance of most of the traits. Parents, Ingorala 5 and DC 4 had high per se and also good general combiner for seed yield and its traits, while hybrids AT 476 x Ingorala 5 and AT 332 x Ingorala 5 had the highest standard heterosis and sca effects for seed yield and some of its traits. Keywords: Sesame, Heterosis, Combining ability, Gene action

Heritability and variance components of seed size in wild species: influences of breeding design and the number of genotypes tested.

Seed size affects individual fitness in wild plant populations, but its ability to evolve may be limited by low narrow-sense heritability (h2). h2 is estimated as the proportion of total phenotypic variance (σ2P) attributable to additive genetic variance (σ2A), so low values of h2 may be due to low σ2A (potentially eroded by natural selection) or to high values of the other factors that contribute to σ2P, such as extranuclear maternal effects (m2) and environmental variance effects (e2). Here, we reviewed the published literature and performed a meta-analysis to determine whether h2 of seed size is routinely low in wild populations and, if so, which components of σ2P contribute most strongly to total phenotypic variance. We analyzed available estimates of narrow-sense heritability (h2) of seed size, as well as the variance components contributing to these parameters. Maternal and environmental components of σ2P were significantly greater than σ2A, dominance, paternal, and epistatic components. These results suggest that low h2 of seed size in wild populations (the mean value observed in this study was 0.13) is due to both high values of maternally derived and environmental (residual) σ2, and low values of σ2A in seed size. The type of breeding design used to estimate h2 and m2 also influenced their values, with studies using diallel designs generating lower variance ratios than nested and other designs. e2 was not influenced by breeding design. For some breeding designs, the number of genotypes included in a study also influenced the resulting h2 and e2 estimates, but not m2. Our data support the view that a diallel design is better suited than the alternatives for the accurate estimation of σ2A in seed size due to its factorial design and the inclusion of reciprocal crosses, which allows the independent estimation of both additive and non-additive components of variance.

Understanding Gene Action, Combining Ability, and Heterosis to Identify Superior Aromatic Rice Hybrids Using Artificial Neural Network

The aromatic rice represents a smaller but independent rice collection, the quality of which is considered to be highly acceptable. Farmers are interested in growing aromatic rice due to high premium market price. The prime objective of this study was to enhance genetic improvement of aromatic rice. Combining ability analysis (GCA and SCA) and gene action are studied in a set of 7 × 7 half-diallel crosses. Twenty-one hybrids along with their seven parents were assessed in randomized complete block design. Different quantitative characters were used to estimate the magnitude of heterosis. GCA and SCA significance for all traits revealed the importance of both additive and nonadditive genetic components. Several genes determine quantitative traits, with each gene having very little impacts and being easily influenced by environmental factors. Pusa Basmati-1 and Govindobhog were the best combiners among the seven parents. In terms of per se performance, heterosis, and SCA effects on seed yield per plant and important yield qualities, the crosses BM-24 Deharadun Pahari, Baskota × Tulaipanji, and Pusa Basmati-1 × Tulaipanji may be of interest. Because of its interconnected processing properties, ANN can play a critical role in this experiment. As a result, the current study was carried out to collect data and validate it using an artificial neural network (ANN) on the combining ability, gene action, and heterosis involved in the expression of diverse fragrant rice features. Using ANN, the validation of the result was done and it was found that the overall efficiency was approximately 99%.

Genomic dissection of repeatability considering additive and nonadditive genetic effects for semen production traits in beef and dairy bulls.

The low heritability and moderate repeatability of semen production traits in beef and dairy bulls suggest that nonadditive genetic effects, such as dominance and epistatic effects, play an important role in semen production and should therefore be considered in genetic improvement programs. In this study, the repeatability of semen production traits in Japanese Black bulls (JB) as beef bulls and Holstein bulls (HOL) as dairy bulls was evaluated by considering additive and nonadditive genetic effects using the Illumina BovineSNP50 BeadChip. We also evaluated the advantage of using more complete models that include nonadditive genetic effects by comparing the rank of genotyped animals and the phenotype prediction ability of each model. In total, 65,463 records for 615 genotyped JB and 48,653 records for 845 genotyped HOL were used to estimate additive and nonadditive (dominance and epistatic) variance components for semen volume (VOL), sperm concentration (CON), sperm motility (MOT), MOT after freeze-thawing (aMOT), and sperm number (NUM). In the model including both additive and nonadditive genetic effects, the broad-sense heritability (0.17 to 0.43) was more than twice as high as the narrow-sense heritability (0.04 to 0.11) for all traits and breeds, and the differences between the broad-sense heritability and repeatability were very small for VOL, NUM, and CON in both breeds. A large proportion of permanent environmental variance was explained by epistatic variance. The epistatic variance as a proportion of total phenotypic variance was 0.07 to 0.33 for all traits and breeds. In addition, heterozygosity showed significant positive relationships with NUM, MOT, and aMOT in JB and NUM in HOL, when the heterozygosity rate was included as a covariate. In a comparison of models, the inclusion of nonadditive genetic effects resulted in a re-ranking of the top genotyped bulls for the additive effects. Adjusting for nonadditive genetic effects could be expected to produce a more accurate breeding value, even if the models have similar fitting. However, including nonadditive genetic effects did not improve the ability of any model to predict phenotypic values for any trait or breed compared with the predictive ability of a model that includes only additive effects. Consequently, although nonadditive genetic effects, especially epistatic effects, play an important role in semen production traits, they do not improve prediction accuracy in beef and dairy bulls.

Combining NDVI and Bacterial Blight Score to Predict Grain Yield in Field Pea.

Field pea is the most commonly grown temperate pulse crop, with close to 15 million tons produced globally in 2020. Varieties improved through breeding are important to ensure ongoing improvements in yield and disease resistance. Genomic selection (GS) is a modern breeding approach that could substantially improve the rate of genetic gain for grain yield, and its deployment depends on the prediction accuracy (PA) that can be achieved. In our study, four yield trials representing breeding lines' advancement stages of the breeding program (S0, S1, S2, and S3) were assessed with grain yield, aerial high-throughput phenotyping (normalized difference vegetation index, NDVI), and bacterial blight disease scores (BBSC). Low-to-moderate broad-sense heritability (0.31–0.71) and narrow-sense heritability (0.13–0.71) were observed, as the estimated additive and non-additive genetic components for the three traits varied with the different models fitted. The genetic correlations among the three traits were high, particularly in the S0–S2 stages. NDVI and BBSC were combined to investigate the PA for grain yield by univariate and multivariate GS models, and multivariate models showed higher PA than univariate models in both cross-validation and forward prediction methods. A 6–50% improvement in PA was achieved when multivariate models were deployed. The highest PA was indicated in the forward prediction scenario when the training population consisted of early generation breeding stages with the multivariate models. Both NDVI and BBSC are commonly used traits that could be measured in the early growth stage; however, our study suggested that NDVI is a more useful trait to predict grain yield with high accuracy in the field pea breeding program, especially in diseased trials, through its incorporation into multivariate models.

Heterosis and combining ability for yield traits and its relationship with gene action in muskmelon (Cucumis melo)

Twenty-one F1 hybrids were developed from seven diverse parental lines of muskmelon (Cucumis melo L.) from two horticultural groups, viz. inodorous and cantalupensis through half-diallel mating system and evaluated at ICARIndian Agricultural Research Institute, New Delhi, during 2017 and 2018. The component of variance for sca (σ2s) was higher than gca component of variance (σ2g) for all the characters, except average fruit weight, which indicated the importance of non-additive gene action for improvement of many traits. The predictability ratio and average degree of dominance was less than 0.5 and more than 1 for all the yield related traits, except average fruit weight, which further confirmed the predominant role of non-additive component of variance. The parent DHM-163 (P1) was identified as good general combiner for earliness, whereas parent DCM-31 (P4) for fruit length, average fruit weight and yield per plant. The parent Pusa Madhuras (P5) also exhibited highest gca effects for number of fruits per plant, number ofprimary branches per plant, fruit diameter and negative gca effects for days to first fruit harvest. The hybrid DCM-31 × Kashi Madhu (P4 × P6) exhibited highest heterotic value for days to first male flower anthesis, days to first female flower anthesis and days to first fruit harvest. Three crosses, DMM-159 × Pusa Madhuras (P3 × P5), DHM-163 × Kashi Madhu (P1 × P6) and DMM-159 × DCM-31 (P3 × P4) were found to be best heterotic combinations for yield related traits. These promising heterotic hybrid combinations may be tested under multi-location trials to assess their potential as commercial hybrids.

Genetic analysis of parental lines and identification of heterotic hybrid combinations in rice (Oryza sativa L.)

Thirty hybrids along with their parents (B and R lines) and standard checks viz., MTU 1001 and 27P63 were evaluated for grain yield and related traits to study combining ability and heterosis in rice. The mean performance of the hybrids for most of the characters was found higher than that of parents. The analysis of variance revealed significant differences among lines, testers and hybrids for most of the characters studied. SCA variances were found lower than GCA variances for most of the characters and average degree of dominance was far from unity indicating the predominance of additive gene action for these traits. However, for effective bearing tillers and spikelet fertility the average degree of dominance was very near to unity inferring the predominance of non-additive genetic components for these traits. The gca effects revealed that the lines, RNR 25783 and RP 5980-109-12-9-27 had significant gca effects in desired direction for yield and yield attributing traits whereas the tester, CMS 59A was a good general combiner. SCA effects showed that the hybrid, JMS 13A × RNR 19361 was found to be good specific combiner for grain yield per plant and spikelet fertility. Similarly, the hybrids, CMS 59A × SYE 503-78-34-2, CMS 46A × WGL 347 and JMS 13A × RP 5980-109-12-9-27 were identified as good specific combiner for grain yield and yield contributing characters. Based on heterotic estimates, five hybrids viz., CMS 59A × RNR 25783, CMS 59A × WGL 14, JMS 13A × RNR 25783, CMS 59A × RNR 25776, JMS 13A × RP 5980-109-12-9-27 were identified as promising with more than 5% and 20% yield advantage over hybrid and varietal checks, respectively.

Supramolecular Approach to Tuning the Photophysical Properties of Quadrupolar Squaraines.

In the present study, the influence of the hydrogen bonding for the one- and two-photon absorption of the prototypical squaraine dye is investigated with quantum chemistry tools. The central squaraine unit is bound by strong hydrogen bonds with 4-substituted N,N′-diphenylurea and, alternatively, N,N′-diphenylthiourea molecules, which affects to a high extend the properties of the squaraine electron accepting moiety, thus shifting its maximum absorption wavelength and enhancing the TPA cross section. The replacement of oxygen by sulfur atoms in the squaraine central ring, known to affect its photophysical behavior, is considered here as the way of modifying the strength and nature of the intermolecular contacts. Additionally, the influence of the oxygen-by-sulfur replacement is also considered in the N,N′-diphenylurea moiety, as the factor affecting the acidity of the N–H protons. The introduction of the sequence of the substituents of varying electron-donating or electron-withdrawing characters in the position 4 of N,N′-diphenyl(thio)urea subsystems allows to finely tune the hydrogen bonding with the central squaraine unit by further modification of the N–H bond characteristics. All of these structural modifications lead to the controlled adjustment of the electron density distribution, and thus, the properties affected such as transition moments and absorption intensity. Ab initio calculations provide strong support for this way of tailoring of one- or two-photon absorption due to the obtained strong hypsochromic shift of the maximum one-photon absorption wavelength observed particularly for thiosquaraine complexes and an increase in the TPA wavelength together with the increase in the TPA cross section. Moreover, the source of the strong modification of the thiosquaraine OPA in contrast to the pristine oxosquaraine upon N,N′-diphenyl(thio)urea substitution is determined. Furthermore, for the first time, the linear dependence of the non-additivity in the interaction energy on the Hammett substituent constant is reported. The stronger the electron-donating character of the substituent, the larger the three-body non-additive components and the larger their percentage to the total interaction energy.

Study of combining ability analysis on half diallel crosses in water stress of wheat (triticum aestivum L.)

Combining ability analysis was performed in a 10 x 10 half diallel cross of ten bread wheat genotypes for yield and its contributing traits. The experiment was conducted in 2013–2014 and 2014–2015 at Crop Research Centre, Sardar Vallabhbhai Patel University of Agriculture & Technology, Modipuram, Meerut, UP. Combining ability revealed that both general and specific combining ability variances were responsible for all the traits. Thus, additive and non-additive gene action was important in controlling the inheritance of all the traits. The variance due to gca was equal to that part of genetic variance which is due to additive and additive x additive effects, while variances due to sca was ascribed to non-additive components of variance that include dominance and epistatic variance. On the basis of overall gca effects, the best general combiners were WH-147, RAJ-3765, WH-730, NP-846, HUW-468, UP-2382 for maximum number of characters under normal and water stress condition. On the basis specific combining ability effects, five crosses viz., HUW-234 x RAJ-3765, HUW-234 x HUW468, WH-730 x C-306, C-306 x HD-2967 and DBW-17 x UP-2382 in normal condition, and WH-147 x WH-730, WH-147 x HD-2967, RAJ-3765 x HUW-468, RAJ-3765 x WH-730 and WH-730 x UP-2382 in water stress condition were found as good specific combiner for grain yield per plant.