Non-allelic Interaction Research Articles

Analyzing Genetic Variation and Graphical Representation (Wr-Vr) in Brinjal (Solanum melongena L.) using the Hayman Approach in the Northwestern Region of India

Background: Brinjal, also known as eggplant, is a resilient and widely cultivated vegetable crop in the Solanaceae family. It plays a crucial role in diets due to its rich supply of vitamins, minerals and dietary fiber, helping address the deficit in vegetable consumption recommended by the World Health Organization (WHO), which advises a daily intake of at least 400 grams of fruits and vegetables. Estimating genetic parameters is essential for understanding the genetic architecture of yield and its determining factors. Hayman’s diallel cross analysis method is extensively utilized in plant breeding due to its capacity to provide comprehensive insights into diverse genetic parameters, including gene action, degree of dominance and heritability. Methods: Nine parents with thirty six F1 hybrids of brinjal derived using a half diallel mating design with nine brinjal genotypes, namely JBL-1, JBR-1, JBR-2, JBR-3, JBL-2, JBL-3, JBR-4, JBR-5 and JBR-6 were evaluated for yield and other yield attributing traits during kharif season 2023) using randomized block design (RBD) with three replications. Result: The dominance effect (H1) was significant and displayed a greater magnitude, indicating dominance gene action for yield per plant. The regression coefficient slope showed a significant deviation from zero, but not from unity, indicating the absence of non-allelic interaction. Furthermore, the regression line intersected the Wr axis below the origin, suggesting the presence of over-dominance for days to 50% flowering, fruit length (cm), number of primary branches per plant, plant height (cm), total fruit yield per plant (kg) and fruit borer infestation (%). The mean degree of dominance exceeding one indicated the prevalence of over-dominance for all traits except days to first picking, average fruit weight (gm), fruit girth (cm) and number of fruits per plant. These findings emphasize the importance of dominance variation in eggplant improvement, enabling successful heterosis breeding for advancing these populations and development of hybrids.

Generation Mean Analysis for Estimating Gene Action, Heterosis and Inbreeding Depression in Yield and Foliar Disease Resistance in Three Faba Bean (Vicia faba L.) Crosses

This study was conducted at the Sakha Agricultural Research Station farm over three growing seasons (2019/20, 2020/21, and 2021/22) to introduce new faba bean genotypes possessing high yield potential and increased resistance to foliar diseases. The research involved six populations (P1, P2, F1, F2, BC1, and BC2) from three crosses (Cross-1: Santamora x Foal Sbai Labiade, Cross-2: Santamora x Misr 3, and Cross-3: Cairo 4 x Misr 3), analyzed using a randomized complete block design with three replications. Generation mean analysis revealed significant mid and better parent heterosis for most traits, indicating over-dominance. Inbreeding depression manifested negatively for chocolate spot and rust diseases but positively for seed count and seed yield per plant across all crosses. Non-allelic interactions were present for all traits, and dominance gene effects were more influential than additive gene effects for most traits. Mean performance analysis showed that F1 populations had lower disease reactions, but higher yields compared to the better parent, while F2 populations displayed greater genetic variability due to segregation. Heterosis was significant for yield and its components across all crosses but less beneficial for disease resistance. Inbreeding depression was significant and negative for disease reactions but positive for yield traits. The study found high broad-sense heritability for all traits, suggesting potential for phenotypic selection. Narrow-sense heritability values were moderate for qualitative traits and lower for quantitative traits. Genetic advance under selection indicated the highest gains were associated with moderate heritability values. Significant non-allelic interactions suggested the need for specific breeding strategies, with dominance gene effects more pronounced than additive effects. These findings support the feasibility of selecting high-yielding, disease-resistant faba bean genotypes through targeted breeding methods, aligning with previous research on the genetic inheritance of these traits.

Epistasis and pleiotropy-induced variation for plant breeding.

Epistasis refers to nonallelic interaction between genes that cause bias in estimates of genetic parameters for a phenotype with interactions of two or more genes affecting the same trait. Partitioning of epistatic effects allows true estimation of the genetic parameters affecting phenotypes. Multigenic variation plays a central role in the evolution of complex characteristics, among which pleiotropy, where a single gene affects several phenotypic characters, has a large influence. While pleiotropic interactions provide functional specificity, they increase the challenge of gene discovery and functional analysis. Overcoming pleiotropy-based phenotypic trade-offs offers potential for assisting breeding for complex traits. Modelling higher order nonallelic epistatic interaction, pleiotropy and non-pleiotropy-induced variation, and genotype × environment interaction in genomic selection may provide new paths to increase the productivity and stress tolerance for next generation of crop cultivars. Advances in statistical models, software and algorithm developments, and genomic research have facilitated dissecting the nature and extent of pleiotropy and epistasis. We overview emerging approaches to exploit positive (and avoid negative) epistatic and pleiotropic interactions in a plant breeding context, including developing avenues of artificial intelligence, novel exploitation of large-scale genomics and phenomics data, and involvement of genes with minor effects to analyse epistatic interactions and pleiotropic quantitative trait loci, including missing heritability.

Generation mean analysis of unadapted landraces and wild relatives of cucumber (Cucumis sativus L.) for earliness and downy mildew

The choice of breeding method for the genetic improvement of any crop largely depends on understanding the genetics and inheritance patterns of the traits involved. The knowledge pertaining to gene actions and interactions is likely to direct and strengthen the crop breeding programmes. With this objective the present investigation aims to elucidate the nature and magnitude of gene action associated for various earliness and disease trait through generation mean analysis (GMA) with six generations (P1, P2, F1, F2, B1 and B2) of two crosses involving three diverse parents of cucumber. The studies were undertaken at Experimental Research Farm of the Department of Vegetable Science, Dr YSP and UH&F Nauni, Solan, HP (India) under open field conditions. Experimental results revealed that non-allelic interactions were present for all the traits considered in both the crosses as evident from individual scaling and joint scaling test. In the inheritance of most of traits except a few, both additive and non-additive gene actions contribute significantly therefore, the breeding methods reciprocal recurrent selection/ bi-parental mating could be exploited for the improvements of the traits. Earliness traits viz., node number bearing first female flower and days to first fruit set was mainly governed by dominance (h) and hence these characters can be improved through heterosis breeding. The duplicate type of epistasis influenced all traits in both cross-combinations; indicating the mild selection intensity in the earlier generations while intense in later generations.

Genetic Component and Character Association for Yield and Yield Component Traits in Bread Wheat (Triticum aestivum L.)

The current research involves the implementation of half diallel crosses between ten genotypes of bread wheat in 2018-2019. The parents and their F1 generation, excluding reciprocals, were then cultivated in the 2019-2020 growing season at the agriculture research farm, School of Agricultural Sciences and Engineering, IFTM University, Lodhipur Rajput, Moradabad (U.P.) and R.B. (PG) College, Mudi, Agra, using a randomized complete block design with three replications. Knowledge of type of gene action controlling target traits and genetic behaviour is a basic principle for designing an appropriate breeding procedure for the purpose of genetic improvement. Hence, the success of any selection or hybridization breeding program for developing varieties depends on precise estimates of genetic variation components for traits of interest which may be additive, dominant and non-allelic interaction effects. Significant genotype means squares and its components (parents and crosses) were obtained for all traits in both locations. Genetic components analysis found that additive (D) and Dominance (H1) was significant in all the traits. The value of mean degree of dominance was greater than additive, indicating availability of over dominance for all the traits. The present investigation revealed that grain yield was positively correlated with days to maturity, plant height, number of effective tillers per plant spike length, number of spikelets per spike, days to 50% heading and yield (q ha-1). Hence, more importance should be given to these traits while exercising selection. Based on the correlation and path studies it was reported that days to ear head emergence, days to maturity, plant height, number of effective tillers per plant, number of spikelets per spike, number of grains per spike, grain yield per plant and 1000 grain weight could be used as important selection traits in order of merit to improve productivity during designing a suitable breeding programme in wheat.

Generation Mean Analysis for quantitative traits in the population of AKDRMS 21-54 x YH3 cross of rice (Oryza sativa L.)

Aim: To study the genetic components of inheritance for 12 quantitative traits which leads into genetic improvement by identification of gene actions for yield and yield related traits. Methodology: Twelve quantitative traits for yield and yield attributing traits were studied at Agricultural College, Bapatla during Rabi 2021-22 deploying Hayman's five parameter model generation mean analysis in estimating the gene effects in the population (P1, P2, F1, F2 and F3) generated from the cross AKDRMS 21-54 x YH3. Estimated mean effects affirm the existence of significant variation in the traits studied. Significance of either one or both, scales C or D inferred the existence of epistatic interaction for the traits studied. Digenic non-allelic interaction model explained the gene action of the traits studied in the present investigation. Results: The generation mean for all the traits showed the importance of both additive and dominance type of gene effects. Among the epistatic gene effects, the additive x additive gene interaction was reported predominant for shoot length, plant height, flag leaf length, spikelet fertility and flag test weight. The gene interaction is associated with homozygosity, therefore, pedigree method of breeding may be adopted for isolation of desirable lines, while for all other traits, along with grain yield per plant, dominance x dominance gene interaction was found to be pre-dominant. The gene interaction is not fixable, hence, population improvement approaches, would be effective. Interpretation: Dominance x dominance gene interaction was predominant for grain yield per plant and majority of yield component traits studied coupled with duplicate epistasis, infers to takeup population improvement approaches, such as bi-parental mating and recurrent selection, followed by isolation of purelines in later generations for competent improvement. Key words: Epistasis, Five parameter model, Generation Mean Analysis, Quantitative traits, Rice

Effects of Non-Allelic Interactions of O2 and SU2 Mutant Genes on Grain Biochemical Composition in Various Corn Inbreds

The use of combinations of non-allelic mutant genes of the maize endosperm structure creates opportunities for improving the quality of corn grain in comparison not only with forms of the common type but also with monogenic endospermic mutants. In this study, the effect of a combination of mutant genes O2 (Opaque-2) and SU2 (Sugary-2) according to the biochemical composition of the grain was studied. For the research, a series of inbreds - carriers of a combination of mutant genes O2SU2, inbreds - carriers of monogenic mutations O2 and SU2, as well as maize inbreds of the common type of two-year reproduction were used. In the experiments, the content of protein, starch, and oil and the main characteristics of their quality were studied. It was found that the inbred carriers of the O2SU2 combination are superior to the inbred carriers of monogenic mutations O2 and SU2 in terms of complex biochemical characteristics. In comparison with mutants O2 they were distinguished by an increased content of protein (by 12.3% on average), amylose in starch (by 38.9% on average), starch digestibility (by 24.4% on average), oil content (by 18.4% on average) and oleate content in oil (by 29.9% on average). In comparison with the carriers of SU2 mutation, they had a higher content of lysine and tryptophan in the total grain protein (on average, by 19.4% & 14.3%, respectively). The main characteristics of grain quality in carriers of a combination of mutant genes O2SU2 were characterized by quantitative variability, which can modify the effect of non–allelic interaction of mutant genes O2 and SU2. The obtained results indicate the effectiveness of using non-allelic interactions between the O2 and SU2 mutant genes to improve the quality of corn grain.

Understanding the genetics of important quality traits in maize (Zea mays L.) using diverse germplasm by generation mean analysis

The information about gene actions and interactions would most likely to direct and reinforce the crop breeding programs. With this objective, the present investigation was undertaken by using six generations P1, P2, F1, F2, BC1, and BC2 derived from six different crosses in maize, evaluated at CCS Haryana Agricultural University, Regional Research Station Karnal from Kharif 2015 to 2016. The study underscores the significance of additive–dominance model, gene action involved in the inheritance of grain yield and quality traits. Both the scaling test and the joint scaling test detected nonallelic interactions affecting the traits, showing the inadequacy of the additive–dominance model alone in describing the manifestation of complex traits like yield and quality traits except for oil content in cross HKI 325-17AN × HKI 1128. Both additive genetic effects and dominance effects were found significant with positive and negative magnitude in all the crosses. On the note, different types of interallelic interactions (i, j, l) contributed to the inheritance of traits in the given crosses. And among them, the dominance × dominance component (l) gene effect also played a major role in the inheritance of the studied traits. Duplicate epistasis was prevalent in all the crosses for grain yield and also for protein, tryptophan, oil, and starch content in some crosses whereas a complementary type of interaction was reported for protein content in cross HKI 325-17AN x HKI 1128 and oil content in cross HKI 209 x HKI 163. In view of the diverse gene actions, i.e. additive, dominant, and epistasis, playing important roles in the manifestation of complex traits like yield and quality traits, we advocate the implementation of population improvement techniques in particular reciprocal recurrent selection to improve productivity gains in maize in terms of both yield and quality. It is concluded that crosses, where dominant gene action was found predominant, should be effectively utilized in hybrid maize programs for improved grain yield and quality traits.

Genetic elucidations of grain iron, zinc and agronomic traits by generation mean analysis in pearl millet [Pennisetum glaucum (L.) R. Br.

Pearl millet is endowed with important nutritional attributes and climate resilience and has been identified as potential staple food crop to address nutritional and food security. Gene action studies for different traits will assist in devising suitable breeding strategies. The present study was conducted to determine gene actions for grain iron and zinc concentrations and agro-morphological traits using generation mean analysis for biofortified pearl millet breeding. Six generations P1, P2, F1, F2, BC1 and BC2 were evaluated during South-west monsoon season 2021 and 2022. Analysis of variance showed significant variability for all the traits in both seasons. Six parameter models revealed the predominance of additive and dominant gene effects and non-allelic interactions for plant height, spike length, spike girth 1000- seed weight, iron and zinc content. Seed yield per spike was predominantly under non-additive gene control (maximum in cross I where d was 29.53 and l was −49.53); however, additive genetic control also contributed significantly. Likewise, for day to 50% flowering, days to maturity and number of productive tillers, dominant and additive × dominance type of gene effects were substantial. These findings provide deeper insights for strategizing breeding methods to increase iron and zinc content as well as yield potentially.

Gene Effects of Quantitative Traits through Six Parameter Model of Generation Mean Analysis in Black Gram [Vigna mungo (L.) Hepper

Background: Yellow mosaic disease (YMD) caused by Mungbean Yellow Mosaic Virus (MYMV) is one of the most destructive biotic constraints for production in urdbean. Development and introduction of resistant cultivars with high seed yield is considered as the most economical and eco-friendly option to manage YMD, for which understanding the gene action controlling the inheritance of different traits along with YMD resistance is an important requirement. Methods: Material comprised of four diverse genotypes (TU 94-2, PU 31, IPU 94-1 and LBG 623), six F1s, six BC1s and six BC2s and six F2s. These six generations of all the six crosses were evaluated for various yield related traits in rabi, 2020-21 and phenotyped for YMD in summer, 2021 at Lam, Guntur, Andhra Pradesh which is hotspot for YMD. Result: Inadequacy of additive-dominant model for all most all traits including YMD except for test weight was observed. It was found that, [l] type of non-allelic interaction was observed to be predominant for majority of the traits. Further, the existence of duplicate type of epistasis in the inheritance was evident at least in few crosses for all the traits (except days to maturity). The duplicate epistasis will reduce the variation in F2 and subsequent generations, thereby hinder the pace of the progress through selection.

Genetic dissection of embryo size and weight related traits for enhancement of kernel oil in maize

Embryo is a key determinant of kernel-oil in maize. Higher calorific value of maize kernel is attributed to increment in kernel-oil and it stores in specialised structure called embryo. Understanding the genetic behaviour of embryo size and weight related-traits is inevitable task for genetic improvement of kernel-oil. Here, the six-basic generations (P1, P2, F1, F2, BC1P1 and BC1P2) of three crosses (CRPBIO-962 × EC932601, CRPBIO-973 × CRPBIO-966 and CRPBIO-966 × CRPBIO-979) between contrasting embryo-sized maize inbreds were field evaluated at three locations to decipher the genetics of twenty embryo, kernel and embryo-to-kernel related-traits through generation-mean-analysis (GMA). Combined ANOVA revealed the significance of all the traits among generations; however, location and generation × location were found to be non-significant (P > 0.05) for most of the traits. Significance (P < 0.05) of scaling and joint-scaling tests revealed the presence of non-allelic interactions. Elucidation of six-parameters disclosed the predominance of dominance main-effect (h) and dominance × dominance interaction-effect (l) for most of traits. The signs of (h) and (l) indicated the prevalence of duplicate-epistasis type across crosses and locations. Thus, the population improvement approaches along with heterosis breeding method could be effective for improvement of these traits. Quantitative inheritance pattern was observed for all the traits with high broad-sense heritability and better-stability across locations. The study also predicted one to three major-gene blocks/QTLs for embryo-traits and up to 11 major-gene blocks/QTLs for embryo-to-kernel traits. These findings could provide deep insights to strategize extensive breeding methods to improve embryo traits for enhancing kernel-oil in sustainable manner.

Mendelian inheritance revisited: dominance and recessiveness in medical genetics.

Understanding the consequences of genotype for phenotype (which ranges from molecule-level effects to whole-organism traits) is at the core of genetic diagnostics in medicine. Many measures of the deleteriousness of individual alleles exist, but these have limitations for predicting the clinical consequences. Various mechanisms can protect the organism from the adverse effects of functional variants, especially when the variant is paired with a wild type allele. Understanding why some alleles are harmful in the heterozygous state - representing dominant inheritance - but others only with the biallelic presence of pathogenic variants - representing recessive inheritance - is particularly important when faced with the deluge of rare genetic alterations identified by high throughput DNA sequencing. Both awareness of the specific quantitative and/or qualitativeeffects of individual variants and the elucidation of allelic and non-allelic interactions are essential to optimize genetic diagnosis and counselling.

Gene effects for begomovirus resistance and plant architecture attributes in pumpkin (Cucurbita moschata Duchesne)

Knowledge of gene actions governing begomovirus resistance and plant architectural traits is a prerequisite for a successful hybrid breeding programme. Therefore, the gene actions associated with these traits were studied in two intervarietal crosses of Cucurbita moschata (C1: Punjab Nawab × MVSR-6711 and C2: Punjab Nawab × P-135). We used the generation mean analysis of six generations for this purpose. Significant differences between the generation means were observed for all the traits in both crosses. The parental lines differed significantly in most of the studied traits. The nature and magnitude of the gene effects of seventeen traits varied by trait and cross. A simple additive dominance model was adequate for the internode number, leaf length and width, petiole length, fruit weight and cavity diameter in C1 and the number of fruits/plant in C2. The non-allelic interaction was found to be significant for a majority of the traits including the per cent disease index of the squash leaf curl China virus, tomato leaf curl New Delhi virus and their mixed infections, which indicated, that recurrent selection in biparental progeny might be useful for the accumulation of genes with additive effects. Duplicate epistasis was observed for the vine, internodal and peduncle length in C1 and the internode number, petiole and peduncle length, peduncle and fruit polar diameter in C2. This information will help to establish a breeding program for the simultaneous improvement of virus resistance and yield traits in pumpkins.

Non-allelic interaction of some quantitative traits in chickpea

In the present study five generations viz. P1, P2, F1, F2 and F3 of chickpea were taken for the analysis of non-allelic interaction considering five yield and yield contributing characters like as date of first flower (DFF), number of primary branches at first flower (NPBFF), plant height at first flower (PHFF), number of pods per plant (NPd/P) and number of seeds per plant (NS/P). At first Mather’s scaling test was done where scales C and D found to be significant and non-significant for all the traits, respectively. Potence was non-significant for all the characters, which revealed that there was no dominance. In the Cavalli’s joint scaling test, the χ2 values were found to be significant for all the characters, which confirm that additive-dominance model was inadequate and except additive and dominance effects there are other effects like non-allelic interaction, linkage, genotype × environment (G×E) interaction etc. are involved either individually or in combination in the inheritance of the studied traits.

Non-allelic interaction of some quantitative traits in chickpea

Non-allelic interaction of some quantitative traits in chickpea

Identification of mutant gene for Black crystal coat and non-allelic gene interactions in Neogale vison

Sable (Martes zibellina) and American mink (Neogale vison) are valuable species characterized by a variety of coat colour produced on fur farms. Black crystal fur phenotype is Mendelian codominant trait: heterozygous animals (Cr/ +) have white guard hairs scattered predominantly on the spine and the head, while homozygous (Cr/Cr) minks have coats resembling the Himalayan (ch/ch) or white Hedlund (h/h) types. It is one of the most recent of more than 35 currently known phenotypic traits of fur colour in American mink. Black crystal fur phenotype was first described in 1984 in the Russian population of mink, which had undergone selection for domestic defensive response to humans. Here, we performed whole-genome sequencing of American mink with Cr/Cr phenotype. We identified a missense mutation in the gene encoding the α-COP subunit of the COPI complex (COPA). The COPI complex mediates retrograde trafficking from the Golgi system to the endoplasmic reticulum and sorting of transmembrane proteins. We observed an interaction between a newly identified mutation in the COPA gene and a mutation in the microphthalmia-associated transcription factor (MITF), the latter mutation led to the formation of the white Hedlund (h/h) phenotype. Double heterozygotes for these mutations have an entirely white coat and a black-eyed phenotype similar to the phenotype of Cr/Cr or h/h minks. Our data could be useful for tracking economically valuable fur traits in mink breeding programs to contribute to global fur production.

Elucidation of gene action and combining ability for productive tillering in spring barley

The purpose of the present study is to identify breeding and genetic peculiarities for productive tillering in spring barley genotypes of different origin, purposes of usage and botanical affiliation, as well as to identify effective genetic sources to further improving of the trait. There were created two complete (6 × 6) diallel crossing schemes. Into the Scheme I elite Ukrainian (MIP Tytul and Avhur) and Western European (Datcha, Quench, Gladys, and Beatrix) malting spring barley varieties were involved. Scheme II included awnless covered barley varieties Kozyr and Vitrazh bred at the Plant Production Institute named after V. Y. Yuriev of NAAS of Ukraine, naked barley varieties Condor and CDC Rattan from Canada, as well as awned feed barley variety MIP Myroslav created at MIW and malting barley variety Sebastian from Denmark. For more reliable and informative characterization of barley varieties and their progeny for productive tillering in terms of inheritance, parameters of genetic variation and general combining ability (GCA) statistical analyses of experimental data from different (2019 and 2020) growing seasons were conducted. Accordingly to the indicator of phenotypic dominance all possible modes of inheritance were detected, except for negative dominance in the Scheme I in 2020. The degree of phenotypic dominance significantly varied depending on both varieties involved in crossing schemes and conditions of the years of trials. There was overdominance in loci in both schemes in both years. The other parameters of genetic variation showed significant differences in gene action for productive tillering between crossing Schemes. In Scheme I in both years the dominance was mainly unidirectional and due to dominant effects. In the Scheme II in both years there was multidirectional dominance. In Scheme I compliance with the additive-dominant system was revealed in 2019, but in 2020 there was a strong epistasis. In Scheme II in both years non-allelic interaction was identified. In general, the mode of gene action showed a very complex gene action for productive tillering in barley and a significant role of non-genetic factors in phenotypic manifestation of the trait. Despite this, the level of heritability in the narrow sense in both Schemes pointed to the possibility of the successful selection of individuals with genetically determined increased productive tillering in the splitting generations. In Scheme I the final selection for productive tillering will be more effective in later generations, when dominant alleles become homozygous. In Scheme II it is theoretically possible to select plants with high productive tillering on both recessive and dominant basis. In both schemes the non-allelic interaction should be taken into consideration. Spring barley varieties Beatrix, Datcha, MIP Myroslav and Kozyr can be used as effective genetic sources for involvement in crossings aimed at improving the productive tillering. The results of present study contribute to further development of studies devoted to evaluation of gene action for yield-related traits in spring barley, as well as identification of new genetic sources for plant improvement.

Deciphering higher order non-allelic interactions for quantitative characters through twelve generation mean analysis in castor (Ricinus communis L.)

The genetic architecture of oil content, seed yield and its related biometric traits in castor was investigated through generation mean analysis in four crosses viz., JP 104 × JI 433, SKP 84 × JI 433, SKP 84 × JI 437 and SKP 84 × JI 441 in twelve generations (P1, P2, F1, F2, B1, B2, B11, B12, B21, B22, B1s and B2s). Significance of simple scaling tests and Cavali’s joint scaling test in all the crosses for one or more traits indicated the presence of digenic and trigenic gene interactions. Further, the significant χ2(2) value at six degrees of freedom based on six- parameter model of Hill (1966), depicted the presence of trigenic or higher order epistasis in all the crosses for all the characters. The trigenic ten-parameter model was found to be adequate in cross JP 104 × JI 433 for effective length of primary raceme; in crosses JP 104 × JI 433 and SKP 84 × JI 437 for number of capsules on primary raceme; and in cross SKP 84 × JI 441 for number of effective branches per plant. On the other hand, χ2(3) with two degrees of freedom was found significant for remaining traits in all the four crosses showing the presence of higher order epistasis and/or linkage. All the ten-parameters were significant for shelling out turn percentage in three crosses SKP 84 × JI 433, SKP 84 × JI 437 and SKP 84 × JI 441 and for days to maturity of primary raceme in cross SKP 84 × JI 433. Moreover, the duplicate epistasis was reported for the inheritance of oil content, seed yield and its component traits. This information can be utilized in developing castor lines with high seed yield and oil content.

Understanding the Genetic Architecture and Gene Actions Involved in the Inheritance of Yellow Mosaic Disease and Other Yield Related Traits in Mungbean [Vigna radiata (L.) Wilczek

Background: Yellow mosaic disease (YMD) transmitted by white fly, Bemisia tabaci is the most persistent and devastating biotic stress worldwide and in India resulting the reduced productivity of mungbean. At the same time the yield levels in mungbean reached a plateau, which emphasizes the importance of varieties with improved productivity. Methods: In the present investigation, to address this urgent requirement of YMD resistant high yielding varieties, six-parameter model of generation mean analysis was employed for proper understanding of the genetic architecture and gene actions. Susceptible genotype MGG 385 was crossed with four resistant genotypes (LGG 607, LGG 630, WGG 42 and PM 5) to produce respective F1s (during rabi, 2018-19), BC1s, BC2s (during summer, 2019) and F2s (during kharif, 2019). These generations of the four crosses were evaluated for various yield related traits in rabi, 2019-20 and phenotyped for YMD in summer, 2020 at Lam, Guntur, Andhra Pradesh which is hotspot for YMD. Result: The scaling tests and joint scaling test indicated the inadequacy of Additive-dominant model for all most all traits including YMD except for branches per plant and pods per cluster. The study revealed the importance of non-allelic interactions in the inheritance of majority of traits including YMD. Among the non-allelic interactions, [l] type of interaction is predominant. Further, the control of duplicate type of epistasis in the inheritance is evident at least in few crosses for all the traits (except grain yield per plant) that had inadequacy for additive-dominant model, which hinders the pace of the progress through selection. In presence of inter-allelic interaction with such duplicate type of epistasis, population approach in self-pollinated crops, which is similar to recurrent selection in cross pollinated crops or biparental mating followed by conventional selection in the later generations should be adopted for identifying desirable segregants.

Partial Results Regarding the Genetic Determinism of Growth Process in a Native Horse Breed using Wither’s Height

Study of variability in domestic animal populations is the foundation of quantitative genetics. Based on statistical methods, the weights of the total phenotype variation that belong to its different fractions (causal components) are quantified: variation due to gene additive effect, variation due to allelic and non-allelic interactions, variation due to environment (general and special), variation due to genotype-environment interaction and possibly variation due to the association between genotype and environment. In this study, during 2017-2020, we used the method of analysis of variance with two sources of variation. The material was represented by 538 individuals from Hucul horse breed analyzed at 18, 30 and 42 months old). The heritability of character was 0.3402±0.1546 (18 months), 0.5549±0.2225 (30 months), 0.4506±0.1895 (42 months), suggest that this is a hereditary condition that follows a quantitative model of inheritance, where the influence of additive genetic factors is moderate to intense. We can conclude that, in this native breed and for this character, a significant share of the phenotypic value is due to the additive effect of genes.