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Mixed hybridisation trials involving Clarias gariepinus (CG), Heterobranchus longifilis (HL), and Heterobranchus bidorsalis (HB) were carried out with success using Ovulin as inducing agent. The crossing was followed by an early growth trial using post-yolk sac larvae that lasted ten days. Latency periods in the two catfishes differ, with 11 hours in crosses involving female CG and 12 hours in crosses involving female HL. The fertilisation rates of eggs from the females of the two species indicate that there is no significant discernment in fertilisation (p>0.05), with values ranging from 68.38% (CG×HB) to 80.94% (HL×CG). However, rates <80% indicate egg quality problems. The hatching rate was significantly higher (p<0.05) in both C. gariepinus (62.12%) and Heterobranchus sp. (47.75%) line crosses than the hybrids. There is an additive genetic effect due to the combination of pure-line male and female gametes that elicit better growth as against survival in crosses involving C. gariepinus. The genotype for better survival is in the maternal line of H. longifilis. These culminate into heterosis for growth in hybrid CG×HB and survival in hybrid HL×CG. [ABSTRACT FROM AUTHOR]

The magnitude of heterosis for economic flower quality and yield traits in china aster (Callistephus chinensis (L.) Nees) was estimated from twenty seven F1 hybrids, which were developed by involving nine lines and three testers in line x tester mating design during the year 2021-23 at Floriculture unit, Department of Horticulture, University of Agricultural Sciences, GKVK, Bengaluru. The twenty seven F1 hybrids along with parents and standard check (Arka Kamini) were evaluated in RCBD design with two replications for different flower quality and yield traits. The results revealed that among twenty seven F1 hybrids, majority of them exhibited significant average heterosis and heterobeltiosis for flower quality and yield traits. For flower diameter, hybrid, Miraj Local × AAC-1 (32.14 %) recorded maximum positive significant heterosis over standard check which was followed by Phule Ganesh White × AAC-1 (31.46 %). Similarly, the hybrid, Arka Poornima × Phule Ganesh Purple (33.23%) recorded maximum positive standard heterosis for flower stalk length while, Local White × Arka Kamini (-24.13) has least performed for this trait. The hybrid, Miraj Local × AAC-1 exhibited significant positive standard heterosis for vase life (39.41%) and shelf life (30.41%) which was followed by Phule Ganesh Pink × Phule Ganesh Purple. The maximum significant positive standard heterosis for flower yield per plant was recorded in Phule Ganesh Pink × AAC-1 (80.90%). From this experiment Miraj Local × AAC-1, Arka Poornima × Phule Ganesh Purple, Phule Ganesh Pink × AAC-1 and Arka Poornima × AAC-1 were identified as elite hybrids for flower quality and yield traits. [ABSTRACT FROM AUTHOR]

Commercial exploitation of bitter gourd hybrids is primarily focused on yield, while limited research has been conducted on the quality aspects of this crop. The study was conducted during the Summer and Kharif seasons of 2022 to identify superior hybrids compared to the standard checks in terms of significant quality traits. A total of 21 crosses were produced by crossing seven genetically distinct parents in a half diallel mating pattern during the summer of 2022. A total of 7 parents, 21 F1 hybrids, and 2 checks were assessed using a randomized complete block design with three replications during the Kharif season of 2022. The crosses, viz., Kashi Mayuri x IC-44418 and IC-44418 x IC-68314 have shown better performance in terms of quality aspects such as TSS. On the other hand, Kashi Mayuri x Special Boldar and IC-44418 x Special Boldar were found to be superior than commercial checks, Pragathi and Monarch for vitamin-C. Significantly greater heterosis for iron content was observed in the crosses viz., Kashi Mayuri x IC-469512, IC-433630 x IC-469512, and Kashi Mayuri x Special Boldar. Charantin, known for its antidiabetic properties, is a significant quality character present in fruits. The hybrids viz., IC-44418 x IC-68314, IC-433630 x IC-68314, and IC-68314 x IC-469512 demonstrated a significant increase in charantin heterosis. The superior cross combinations identified in this study warrant further evaluation to assess their potentiality and stability for commercial release as hybrids or varieties. [ABSTRACT FROM AUTHOR]

An experiment was conducted on ridge gourd in six generations i.e., P1, P2, F1, F2, BC1 and BC2 of VRG-24 x VRG-13 and Swarna Manjari x Arka Prasan in Randomized Block Design with three replications. The main aim of the study was to investigate the genetic mechanisms controlling yield and quality traits through generation mean analysis. Epistatic gene effects were found to play a crucial role in regulating most of the traits studied, except for days to male flowering, days to female flowering, node of first female flower, average fruit weight, and rind thickness in various crosses. Duplicate epistasis was particularly prominent across the majority of traits, suggesting that these traits could be effectively exploited through heterosis breeding and reciprocal recurrent selection strategies. Additionally, complementary epistasis was observed in the cross VRG-24 x VRG-13 for traits such as node of first female flower, number of female flowers per vine, and number of fruits per vine. This highlights the potential of the VRG-24 x VRG-13 cross to produce desirable transgressive segregants with enhanced trait combinations. [ABSTRACT FROM AUTHOR]

The experiment was conducted using a randomized complete block design with three replications at Shah Abdul Latif Experimental Farm, Sindh Agriculture University, Tandojam. Following a line × tester mating design in upland cotton (Gossypium hirsutum L.), twenty-one cross combinations were obtained from seven females and three males. F1 and F2 generations, along with their parents, were sown in a randomized complete block design with three replications during 2012-13 and 2013-14. Studied traits included lint yield (g) per plant, G.O.T (%), staple length (mm), fiber fineness (mic.value), and fiber strength (g/tex). Throughout the growing period, recommended cultural practices were followed. Analysis of variance revealed high significance for genotypes, parents, crosses, and their interactions (P×C) for all traits. In the F1 generation, lint yield and staple length under line × tester (L×T) were highly significant. For the F2 generation, genotypes, parents, crosses, and P×C were highly significant for all traits except G.O.T%, where lines, testers, and L×T were highly significant for all traits except G.O.T%. Cross VH-292 × VH-291 excelled in lint yield per plant, while CRIS-342 × IR-3701 demonstrated superior fiber fineness and strength. VH-292 × VH-291 also displayed higher lint yield per plant, while CRIS-342 × FH-113 exhibited longer staple length with increased fiber fineness. Significant mean squares for genotypes (parents, crosses, and parents × crosses) indicate the data's utility for assessing parental performance, hybrid evaluation, heterotic effects, and inbreeding depression. [ABSTRACT FROM AUTHOR]

The extent of wheat heterosis was determined by synthesizing 45 hybrids in a 10x10 diallel method, eliminating reciprocals, to determine how widespread it is. The 57 entries that made up the experimental material--10 parents, 45 crosses and 2 checks (HD 3086 and UP 2628), were assessed over the course of rabi 2018-19 using a Randomized Block Design (RBD) with three replications, and observations were made for 12 characters. For yield and its component traits, analyses of heterosis over mid parent, better parent and two standard checks were conducted. ANOVA exposed that there was a high significance existed among all the genotypes for all the characters studied. Yield and its contributing traits have been evaluated for their maximum heterotic range. One cross i.e., CAL/NH//H567.71/3/SER1/4/CAL/NH//H567.71/5/2* KAU2/6/...xPBW 692 showed positive significance for relative heterosis, heterobeltiosis and standard heterosis over both checks for grain yield per plant. In terms of the number of productive tillers per plant and the number of grains per spike, UP 2901xQLD 73 was found to be a superior heterotic F1. By displaying a negative significant standard heterosis over both checks, the cross between CAL/NH//H567.71/3/SER1/4/CAL/NH//H567.71/5/2*KAU2/6/...xUP 2901 demonstrated its earliness. The desired significant relative heterosis, heterobeltiosis and standard heterosis for spike length were present in HD 3234xUP 2762. The finest heterotic cross combinations for harvest index were determined to be CAL/NH//H567.71/3/SER1/4/CAL /NH//H567.71/5/2* KAU2/6/...xUP 2762 and VORB/SOKOLLxQLD 73. Higher heterotic crossings may be used to identify transgressive segregants that will increase bread wheat production and yield-contributing characteristics. [ABSTRACT FROM AUTHOR]

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ABSTRACT: Currently, the demand is not only for more productive corn hybrids, but also for those with high physiological seed quality. Seed quality is considered the sum of genetic, physical, physiological and sanitary attributes that directly interfere in plant vigor. The objective of this study was to evaluate the physiological parameters of the seeds of parents and maize inter varietal hybrids obtained in a reciprocal recurrent selection program through physiological and image analysis techniques and either to study the feasibility of simultaneously selecting for seed physiological quality and grain yield. Two experiments were performed, one in the field and the other in the laboratory. The evaluated traits in the field were days of female flowering, days of male flowering, insertion of the 1st ear, plant height and grain yield. For the physiological quality, the attributes of germination at four days, germination at seven days, vigor by the cold test, emergence speed index, and the ratio of the root length to shoot length were obtained using GroundEye®. Heterosis was measured for the agronomic and physiological traits. Through the contrast between the inter varietal crosse hybrids and reciprocals we measured the maternal effect. The magnitudes of heterosis allowed us to infer that as greater as the number of selection and recombination cycles, on average, greater heterosis for the traits grain yield and seed germination. The correlated response indicated that, high yield intervarietal hybrids have better seed physiological quality.

Erucic acid, more than 2 %, in mustard seed oil is considered unhealthy as edible oil, and also anti-nutritional for human consumption. The existing mustard varieties of Bangladesh contain 40–48 % erucic acid, which is a big concern for the country's nutritional, and food security and safety. Hence, to improve the seed oil quality of the existing variety, six popular cultivars of Brassica juncea mustard were crossed with a canola-grade line in 7 × 7 half diallel fashion, and the developed 21 F1 hybrids were assessed for yield contributing traits, and fatty acids composition. Variables with significant variations were found, while days to siliquae maturity, plant height, days to first flowering, and seeds per siliquae have moderate narrow sense heritability. The estimated gene action indicated that dominant or over-dominant gene action was more prominent in governing the traits. The parents, P1, P3, and P4 were discovered the best general combiners for early maturity and short phenology, whereas P2 and P7 were found to be the best general combiners for yield-attributing traits. Moreover, the hybrids P1 × P4, P1 × P6, P2 × P7, P4 × P6 and P3 × P5 were chosen as the promising hybrids due to their best specific combining ability, and desired heterotic effects on yield contributing traits. In addition, a significant decrease, on average 30–40 %, in erucic acid, but an approximately 20–25 % increase of oleic acid was found among the hybrids, in which the hybrids P1 × P6–S1, P5 × P6–S2 and P5 × P6–S4 demonstrated a better stability index. Overall, the obtained findings suggested that the hybrids, viz. P1 × P5, P1 × P6, P2 × P3, P2 × P7, P4 × P6, P5 × P6, and P6 × P7 were promising based on their early maturity, high-yielding, reduced erucic acid, and high oleic acid contents.

Understanding the combining ability effects, heterosis, and genetic relationships between parental lines would be helpful in the maize breeding program to develop high-yielding and genetically stable maize varieties for various contrasting environments. Hence, the objective of this study was to estimate combining ability effects, heterosis, genetic distance (GD) and associations for grain yield and other agronomic traits. Forty-five F1 diallel crosses, four commercial checks, and ten inbred lines were evaluated at Bako and Jima Agricultural Research Centers, Ethiopia. Significant differences were observed among environments, genotypes and genotype by environment interaction for grain yield and almost all studied agronomic traits. Combining ability analysis showed both additive and non-additive gene effects significantly controlled grain yield and all other studied traits. The preponderance of general combining ability (GCA) effects indicates the importance of additive gene action inheriting most agronomic traits. Lines L2, L7, and L9 were the best combiners for grain yield, whereas lines L3 and L4 had desirable GCA values to improve days to flowering and plant height. Among the top ten crosses, L6 × L9, L6 × L7 and L4 × L9 were good specific combiners and had 18.8 %, 17.2 % and 16.2 % grain yield advantage over the best check, BH546. These hybrids also had high mid and better-parent heterosis compared with other crosses. The associations of GD with mean of F1 and SCA effects were positive and highly significant for grain yield and some other traits. In contrast, correlations of GD with mid and better parent heterosis were non-significant for grain yield and most other traits. The results of this study are particularly useful for breeders who envisage combining conventional and molecular methods.

IntroductionIn Iran, as in most poor and developing countries, wheat is the most important food in the diet of the people. Therefore, the field of study and research on various aspects of this important and strategic crop is still open to relevant researchers and experts. Given that the achievement of yield potential in crops, including wheat, is influenced by genetics, environmental conditions, their interaction and the application of proper management in the optimal use of available resources, so the genetic capacity of the existing germplasm should be used to produce suitable breeding lines in order to make the most of natural and climatic resources. Therefore, screening genotypes, selecting the proper parents, and modifying them through conventional and new methods can still be helpful. Estimating genetic effects and studying the inheritance pattern of important agronomic traits and in general knowledge of germplasm genetic information and knowledge of the genetic system of the studied trait is one of the most useful tools in designing breeding methods to improve target traits. This study aimed to estimate the genetic model controlling important agronomic traits and also to estimate heterosis and heritability in two bread wheat cross under normal and terminal drought stress conditions using generation mean analysis method and multivariate regression analysis.Materials and methodsA field investigation materials consisted of basic generations obtained from the crosses of a local cultivar “Marvdasht” (female parent) with two cultivars “Sistan” and “Norstar” (male parents). Both the crosses and resultant progenies were performed and developed under field conditions. All the six generations derived from the above two crosses were sown under two distinct conditions, normal (non-stress) and terminal drought stress in a randomized complete blocks design with three replicates at the Research Farm of Razi University, Kermanshah, Iran during the next cropping season (2015-2016). Terminal drought stress was imposed in Mid-May; while non-stress plots were irrigated whenever required. Weeds were controlled manually when necessary. The rainfall in 2015-2016 was 653 mm. Data from 10 plants in each of P1, P2 and F1 generations, 30 plants in F2 and 15 plants in each of BC1 and BC2 were randomly recorded per replication. Statistical analyses were done using different methods and software.Results and discussionSignificant differences between the generations were found for most of the traits which indicated the presence of genetic variation in the plant populations and scope of improvement through breeding methods such as selection and expression of heterosis. The scaling and joint scaling tests revealed that the simple additive-dominance model was not sufficient to explain the genetic variation in the crosses for all the studied traits apart from the number of spike per plant, main stem diameter and number of spikelet per spike at Marvdasht × Sistan, and hundred kernel weight and peduncle length at Marvdasht × Norstar. It could be concluded that the inheritance of these traits is governed by epistasis gene action. The results of analysis of variance obtained by regression method showed that fixable genetic effects had the highest relative contribution of the generation sum of squares for most of the traits in both crosses and under both normal and drought stress conditions. High estimates of broad-sense heritability for hundred kernel weight (0.67) in normal conditions at Marvdasht × Sistan cross and plant height (normal: 0.76 and stress: 0.67) and peduncle length (normal: 0.72 and stress: 0.67) at the Marvdasht × Norstar cross shows that the effects of dominance have a greater role in the inheritance pattern of these traits and therefore it is possible to produce hybrid varieties to improve these traits.ConclusionThe results of generation mean analysis showed that the type and action of genetic effects were variable in both crosses and for different traits and indicate the need to adopt a special breeding method to improve them. The presence of duplicate mode of gene interactions signified the involvement of epistatic effects for most of the traits. Based on the present investigation, it could be inferred that the genetic control model was somewhat similar for most of the traits under both conditions at both crosses, and it has not been largely affected by drought stress.

The success of hybrid breeding programs across the world depends on an understanding of the impacts of gene activity, combining ability, and heterosis on desired characteristics. This project's major goals included the identification of better-inbred lines and hybrids based on combining prowess and heterosis effects in genotypes of super-sweet maize (Zea mays L. Saccharate) and the research of genetic factors and gene activity influencing agronomic attributes. In 2021, three inbred lines (as female parents) were crossed with three testers (as male parents) using the line-to-tester mating design. In a Randomized Complete Block Design (RCBD) with three replications in 2022, nine F1 hybrids with six parental lines were assessed for thirteen agronomic variables, including tillering potential (TP), conservable grain yield (CGY), and yield components. The findings showed that for all the attributes under study, the genotype-related mean squares and their distributions to parents crosses, and parents' crosses were significant (P 0.05). Numerous agronomic characteristics, including TP, CGY, plant height, and tassel length, were considerably influenced by additive gene action, while others were influenced by non-additive gene action, according to the ratio of 2GCA / 2SCA and narrow-sense heritability (Hns2). For CGY and TP characteristics, the SSBas-1 and SSChall-5 combination showed positive specific combining ability (SCA) benefits. Most hybrids also showed positive heterosis and SCA effects, which explained the heterosis in the hybrid's performance. The best general combiners for the majority of the analyzed traits were the parents SBas-1 among the lines and Chal-3 among the testers, which might be employed in further research to create high-yielding super-sweet corn hybrids.

Okra is the most labour-intensive monsoon vegetable crop, and it faces significant threats from weather patterns. A total of sixteen F1 crossings were employed in this study, following a mating strategy of L × T, where four lines and four testers were used. The objective was to assess the combining ability and heterosis for nine variables related to pod yield quality. Additionally, the study aimed to identify the most promising combinations for future breeding endeavors. The results revealed statistically significant variations across all the variables examined, except for pod diameter in the lines. Significant values were observed for various traits in the case of tests, including plant height, days to first flowering, days to first fruit set, days to first fruit picking, number of pods per plant, pod length, average weight of pods, and pod yield per plant. The parental lines, namely EC 169470, IC 128024, Kashi Pragati, and Arka Anamika, were determined to be effective general combiners in terms of single plant yield. Therefore, it is possible to exploit these parents through the practice of pedigree breeding to achieve improved recombinants through selective breeding in subsequent generations. The hybrids IC 128024 × Kahi Lalima, IC 128024 Kashi Kranti, and IC 128028 × Kashi Pragati were determined to be the most favorable combiners based on the outcomes of standard heterosis, GCA and SCA effects. These hybrids exhibit promising potential for utilization in future breeding endeavors.

The biofortification of pearl millet, a prime staple crop around the world with increased grain iron (Fe) and zinc (Zn) concentrations is part of continuing attempts to fight micronutrient deficiency. The goal of the current study was to examine heterosis, heritability, genetic advancement and inbreeding depression (ID) for yield, and associated features in pearl millet or bajra [Pennisetum glaucum (L.) R. Br.]. The majority of crosses with days to 50% flowering, maturity, and plant height showed negligible inbreeding depression and significant heterosis in the desired direction. Yield and other associated characteristics demonstrated significant average heterosis and heterobeltiosis, along with severe inbreeding depression. The presence of additive gene effects for grain Fe and Zn content was shown by the lower value of better parent and relative heterosis in F1s and the absence of inbreeding depression in F2. Majority of the characteristics had moderate to high heritability and low to average genetic advance. Crosses, 30127 x J 2556 for maturity; 30725 x ICMB 05333, J 2454 x 30348 and 30843 x ICMB 98222 for height of plants; 30727 x J 2523, ICMB 99222 x ICMB 08222, 30127 x J 2556, and 30843 x ICMB 98222 for panicle diameter; 30727 x J 2523 and 30725 x ICMB 05333 for seed yield/plant; J 2372 x 30610, ICMB 99222 x ICMB 08222, and 30843 x ICMB 98222 for test weight/1000 grain weight; 30843 x ICMB 98222 and ICMB 99222 x ICMB 08222 for Fe content; 30727 x J 2523, J 2372 x 30610, J 2454 x 30348, 30127 x J 2556, 30843 x ICMB 98222, ICMB 99222 x ICMB 08222, and ICMB 10444 x ICMB 97222 for Zn content showed average to high heritability (broad sense) associated with high to medium genetic advance (GA) that can be improved through selection.

The current study involved the evaluation of 96 pearl millet hybrids synthesized by crossing eight lines with 12 testers using a Line x Tester mating design. The experiment was conducted during the Kharif season of 2022 with two replications and included standard checks COH10 and 86M38. Analysis of variance for combining ability revealed that, significant amount of variation was present in all hybrids for studied traits. The contribution of lines to the total variance in hybrid was greater than tester. The ratio between GCA and SCA variance was less than one for all traits and it showed that non additive gene action was predominant and highlighting the potential of heterosis breeding to exploit hybrid vigor. Among the parents, ICMB 02777 and PT 6679 were identified as good combiners, showing positive gca effects and high mean performance for grain yield, test weight, single earhead weight, and single earhead threshed weight. The other parents viz., ICMB 02444, ICMB 93222, PT 6067, and PT 6476 were also recognized as good combiners for grain yield. Out of the 96 hybrids, the cross ICMB 02777 x PT 6679 exhibited significant positive heterosis along with high standard heterosis over both checks for grain yield, test weight and single earhead threshed weight. Additionally, the crosses ICMB 02444 x PT 6679, ICMB 93222 x PT 6067 also recorded significant sca effect for grain yield per plant. These promising hybrid combinations hold great potential for heterosis breeding programs and may be suitable for commercial exploitation after thorough evaluation under multi-location trials.

Doubled haploid technology is a valuable biotechnological approach in plant breeding that enables one to quickly create new varieties through the single-stage production of homozygous lines. The aim of this study was to assess the indicators of in vitro androgenesis in the anther culture of the initial breeding material of varieties and combinations of F1 and F2 and to identify promising accessions with good responsiveness. For that purpose, the plant material that proved promising for the breeding programs of Siberian Research Institute of Plant Production and Breeding (SibRIPP&B) was used. Ten cultivars of common wheat and the F1 and F2 hybrids of nine combinations were evaluated for the main parameters of in vitro androgenesis such as the number of new formations, albino, green and all regenerated plants. Induction of androgenesis in vitro was carried out in anther culture in growth medium Chu (N6) containing 1 mg/l of growth regulator 2,4-D. The studied samples showed different responses to induction. The maximum level of new formations was found in F2 hybrids Novosibirskaya 15 × Lutescens ShT-335. The largest number of green plants was found in F1 Novosibirskaya 15 × Lutescens ShT-335. According to the results of variance analysis, a significant ( p < 0.01) influence of genotype on the studied traits was established. Varieties with good responsiveness to anther culture (Novosibirskaya 15) and lack of responsiveness to in vitro androgenesis (Novosibirskaya 31) were identified. Novosibirskaya 16 was characterized by a low regeneration capacity of new formations. A significant heterotic effect was revealed considering the number of new formations per 100 anthers among the hybrids of such combinations as Novosibirskaya 15 × Lutescens ShT-335, Novosibirskaya 15 × Lutescens 111/09, and Zagora Novosibirskaya × Obskaya 2. Novosibirskaya 15 was recommended for inclusion in crossings as a parental form that provides high hybrid responsiveness during in vitro androgenesis. The use of doubled haploid technology made it possible to quickly create DH-lines based on the breeding material.

Parental selection is important for heterosis formation during crossbreeding of Populus. However, in poplar hybrids, the effect of parents on vegetative growth heterosis is not well understood. In this study, one female parent (P. simonii XY4) and two male parents (P. nigra OH and P. deltoides × P. nigra BJLY3#) were used to produce two progenies (Hyb1 and Hyb2). Vegetative growth investigation showed that both Hyb1 and Hyb2 performed heterosis in plant growth and ground diameter. The vegetative growth of hybrids was strongly correlated with the male parents but not with the female parents. The gene expression levels in the hybrids were more biased toward the male parents. In Hyb1 and Hyb2, 51.93% and 45.03% of the expressed genes showed the non-additive effect, respectively, and over 65% of the non-additively expressed genes showed the dominant effect. It is noteworthy that genes of paternal expression dominant effect (ELD_♂) account for the majority of dominantly expressed genes, suggesting the paternal contribution to heterosis. KEGG enrichment analysis indicated that a large number of non-additively expressed genes were enriched in the plant hormone signal transduction pathway. WGCNA analysis showed that MEcyan was significantly correlated with the traits of hybrids, and 12 plant hormone signal transduction pathway genes were enriched in this module. Transcription factors (TFs) MYB88, LHY, and TCP4 may be involved in the regulation of these pathway genes. This finding supported that the male parents play an important role in the formation of vegetative growth heterosis of Populus. In addition, the non-additively expressed genes of the signal transduction pathway and the regulation of TFs related to these pathway genes may be one of the reasons for the generation of heterosis.

The application of heterosis can not only effectively improve the disease resistance and meat quality of livestock, but also significantly enhance the reproduction and growth of livestock and poultry. We conducted genome-wide association studies using data from F2 crossbred meat rabbits to screen out candidate genes with significant dominant effects associated with economic trait variation. High-throughput sequencing technology was used to obtain SNPs covering the whole genome to evaluate the homozygosity of the population genome, and analyze the number, length, frequency, and distribution of ROHs in the population. Candidate genes related to economic traits of meat rabbits were searched based on high-frequency ROH regions. After quality control filtering of genotype data, 380 F2 crossbred rabbits were identified with 78,579 SNPs and 42,018 ROHs on the autosomes. The fitting of the Logistic growth curve model showed that 49-day-old rabbits were a growth inflection point. Then, through genome-wide association studies, 10 SNP loci and seven growth trait candidate genes were found to be significantly related to body weight in meat rabbits at 84 days of age. In addition, we revealed the functional roles and locations of 20 candidate genes in the high-frequency ROH region associated with economic traits in meat rabbits. This study identified potential genes associated with growth and development in the high-frequency ROH region of meat rabbits. In this study, the identified candidate genes can be used as molecular markers for assisted selection in meat rabbits. At the same time, the inbreeding situation based on ROH assessment can provide reference for breeding and breeding preservation of meat rabbits.

TGF-β1/Smads is a classic signaling pathway, which plays important roles in the development process of organisms. Black porgy Acanthopagrus schlegelii and red porgy Pagrus major are valuable economic fishes, and their hybrid offspring show excellent heterosis traits. Yet the molecular regulation mechanism of the heterosis traits is less clear. Here, we explored the TGF-β1/Smads pathway’s molecular genetic information for heterosis in A. schlegelii ♂ × P. major ♀ (AP) and A. schlegelii ♀ × P. major ♂ (PA) in terms of growth and development. The mRNA expression levels of TGF-β1, TβR-I, TβR-II, and Smad2 genes in different developmental stages of A. schlegelii were detected. Furthermore, the expression levels of TGF-β1, TβR-I, TβR-II, and Smad2 genes in different tissues of adult (mRNA level) and larva (mRNA and protein level) of A. schlegelii, P. major, and their hybrids were determined by both real-time quantitative PCR and Western blot techniques. The results indicated the ubiquitous expression of these genes in all developmental stages of A. schlegelii and in all tested tissues of A. schlegelii, P. major, and its hybrids. Among them, the mRNA of TGF-β1, TβR-I, and TβR-II genes is highly expressed in the liver, gill, kidney, and muscle of black porgy, red porgy, and their hybrid offspring. There are significant changes in gene and protein expression levels in hybrid offspring, which indirectly reflect hybrid advantage. In addition, there was no correlation between protein and mRNA expression levels of Smad2 protein. The results provide novel data for the differential expression of growth and development genes between the reciprocal hybridization generation of black porgy and red porgy and its parents, which is conducive to further explaining the molecular regulation mechanism of heterosis in the growth and development of hybrid porgy.

A half-diallel cross study of seven melon inbred lines was carried out. The seven parents and their 21 F1 hybrids were evaluated for precocity of maturity, average weight per fruit, and fruit quality (fruit size, rind thickness, and soluble solids). The Diallel analysis was investigated for breeding values of these melon genotypes via general and specific combining ability, relationships between general and specific combining ability, and heterosis for the evaluated traits. The analysis of variance of the traits evaluated indicated highly significant differences among genotypes, suggesting the presence of adequate genetic variation for breeding. Additive genetic effects were most important with respect to fruit weight, while genetic dominance and epistasis effects mainly controlled fruit quality traits (fruit size, rind thickness, and TSS). Parent 1 (P1) and parent 3 (P3) had significant positive general combining ability effects for fruit weight. Also, P3 had positive general combining ability effects for fruit length and diameter, and cavity diameter. P3 was found to show maximum significant GCA in the desirable direction for all the traits except for TSS. Evaluation of heterosis (%) revealed that hybrid P1 × P3 can be considered as the best-performing hybrid for average fruit weight, TSS, and precocity, which also exhibited the highest positive and significant SCA effect for these traits. These results suggested that, among the melon genotypes studied, there is the potential to generate superior new varieties in hybrid production.

A simple crossbreeding experiment between Gabali (G) bucks and Hyplus (H) does was performed to estimate crossbreeding effects for post-weaning growth traits (body weight at 5 (BW5), 7 (BW7), 9 (BW9), 11 (BW11), and 13 (BW13) weeks of age and daily weight gains (DG) during (DG5-7), (DG7-9), (DG9-11), (DG11-13) and (DG5-13), weeks of age). Estimates of heritability were mostly low or moderate for growth traits and ranged from 0.12 to 0.35 for body weights and 0.05 to 0.66 for daily weight gains. The percentages of direct additive genetic effects on body weights favored (p ≤ 0.01) the Gabali breed by 22.1, 31.2, 32.8, 31.1, and 25.2% at 5, 7, 9, 11, and 13 weeks and by 35.4, 38.1, 21.9, 3.7, and 27% for DG5-7, DG7-9, DG9-11, DG11-13, and DG5-13, respectively. The percentages of maternal effects ranged from 22 to 34.8% for body weights and ranged from 4.7 to 43.4% for daily weight gains. The percentages of direct heterosis were significantly positive by 11, 19.1, 20.3, 19.7, and 16.5% for body weights at 5, 7, 9, 11, and 13 weeks and by 25.6, 27.2, 17.3, 3.5, and 17.9% for DG5-7, DG7-9, DG9-11, DG11-13, and DG5-13, respectively. These results suggest that the Gabali breed could be used as a sire-group and the Hyplus line could be used as a dam-group to create new high growth rabbit lines in Egypt. [ABSTRACT FROM AUTHOR]

Background: Non-additive genetic effects are often ignored in livestock genetic evaluations. However, fitting them in the models could improve the accuracy of genomic breeding values. Furthermore, non-additive genetic effects contribute to heterosis, which could be optimized through mating designs. Traits related to fitness and adaptation, such as heat tolerance, tend to be more influenced by non-additive genetic effects. In this context, the primary objectives of this study were to estimate variance components and assess the predictive performance of genomic prediction of breeding values based on alternative models and two independent datasets, including performance records from a purebred pig population and heat tolerance indicators recorded in crossbred lactating sows. Results: Including non-additive genetic effects when modelling performance traits in purebred pigs had no effect on the residual variance estimates for most of the traits, but lower additive genetic variances were observed, especially when additive-by-additive epistasis was included in the models. Furthermore, including non-additive genetic effects did not improve the prediction accuracy of genomic breeding values, but there was animal re-ranking across the models. For the heat tolerance indicators recorded in a crossbred population, most traits had small non-additive genetic variance with large standard error estimates. Nevertheless, panting score and hair density presented substantial additive-by-additive epistatic variance. Panting score had an epistatic variance estimate of 0.1379, which accounted for 82.22% of the total genetic variance. For hair density, the epistatic variance estimates ranged from 0.1745 to 0.1845, which represent 64.95–69.59% of the total genetic variance. Conclusions: Including non-additive genetic effects in the models did not improve the accuracy of genomic breeding values for performance traits in purebred pigs, but there was substantial re-ranking of selection candidates depending on the model fitted. Except for panting score and hair density, low non-additive genetic variance estimates were observed for heat tolerance indicators in crossbred pigs. [ABSTRACT FROM AUTHOR]

Background: Egg-laying performance is economically important in poultry breeding programs. Crossbreeding between indigenous and elite commercial lines to exploit heterosis has been an upward trend in traditional layer breeding for niche markets. The objective of this study was to analyse the genetic background and to estimate the heterosis of longitudinal egg-laying traits in reciprocal crosses between an indigenous Beijing-You and an elite commercial White Leghorn layer line. Egg weights were measured for the first three eggs, monthly from 28 to 76 weeks of age, and at 86 and 100 weeks of age. Egg quality traits were measured at 32, 54, 72, 86, and 100 weeks of age. Egg production traits were measured from the start of lay until 43, 72, and 100 weeks of age. Heritabilities and phenotypic and genetic correlations were estimated. Heterosis was estimated as the percentage difference of performance of a crossbred from that of the parental average. Reciprocal cross differences were estimated as the difference between the reciprocal crossbreds as a percentage of the parental average. Results: Estimates of heritability of egg weights ranged from 0.29 to 0.75. Estimates of genetic correlations between egg weights at different ages ranged from 0.72 to 1.00. Estimates of heritability for cumulative egg numbers until 43, 72, and 100 weeks of age were around 0.15. Estimates of heterosis for egg weight and cumulative egg number increased with age, ranging from 1.0 to 9.0% and from 1.4 to 11.6%, respectively. From 72 to 100 weeks of age, crossbreds produced more eggs per week than the superior parent White Leghorn (3.5 eggs for White Leghorn, 3.8 and 3.9 eggs for crossbreds). Heterosis for eggshell thickness ranged from 2.7 to 6.6% when using Beijing-You as the sire breed. No significant difference between reciprocal crosses was observed for the investigated traits, except for eggshell strength at 54 weeks of age. Conclusions: The heterosis was substantial for egg weight and cumulative egg number, and increased with age, suggesting that non-additive genetic effects are important in crossbreds between the indigenous and elite breeds. Generally, the crossbreds performed similar to or even outperformed the commercial White Leghorns for egg production persistency. [ABSTRACT FROM AUTHOR]

Objective: This study was to estimate heritabilities, additive genetic correlations, and phenotypic correlations between number of piglets born alive (NBA), litter birth weight (LTBW), number of piglets weaned (NPW) and litter weaning weight (LTWW) in different parities of Landrace (L), Yorkshire (Y), Landrace×Yorkshire (LY), and Yorkshire×Landrace (YL) sows in a commercial swine operation in Northern Thailand. Methods: Two models were utilized, a single trait repeatability model (RM) and a multiple trait animal model (MTM). The RM assumed reproductive records from different parities to be repeated values of the same trait, whereas the MTM assumed these records to be different traits. The two models accounted for the fixed effects of farrowing year-season, genetic group of the sow, heterosis, and age at first farrowing, and the random effects of sow, boar, and residual. Results: Heritability estimates from RM were 0.02±0.01 for NBA, 0.10±0.01 for LTBW, 0.04±0.01 for NPW, and 0.11±0.01 for LTWW. Heritability estimates from MTM fluctuated across parities, ranging from 0.04±0.01 in parity 2 to 0.09±0.02 in parity 4 for NBA, 0.07± 0.02 in parity 2 to 0.16±0.02 in parity 3 for LTBW, 0.04±0.02 in parity 4 to 0.08±0.01 in parity 1 for NPW, and 0.16±0.02 in parity 1 to 0.20±0.02 in parity 2 for LTWW. Additive genetic correlation estimates from MTM were also variable, ranging from 0.29±0.24 between NBA in parity 1 and NBA in parity 2 to 0.99±0.05 between LTWW in parity 3 and LTWW in parity 4. Conclusion: The findings of this study highlight the advantage of using MTM for the genetic improvement of reproductive traits in swine and contribute to the development of sustainable swine breeding programs in Thailand. [ABSTRACT FROM AUTHOR]

FOXO1 (FKHR) gene, as a transcription factor, plays a vital role in animal growth and development, participating in many biological processes. The aim of this study was to ascertain Insertion/deletions (Indels) polymorphism within bovine FoxO1 gene in 679 Chinese adult cows and associate them with stature traits. Two Indels (named as Indel-3 and Indel-4, recorded as rs383545622 and rs525318770 in NCBI, respectively) were successfully genotyped by the Once PCR method, which was reliable, rapid and cost effective for simultaneous detection of two or more Indels. Indel-3 and Indel-4 were located at the second intron. All four different haplotypes (H1: D3D4, H2: I3D4, H3: D3I4, H4: I3I4) could be identified, and the D (del-) allele, DD (del-/del-) genotype and D3D4 haplotype retained the highest frequency. However, individuals with DI (D3I3, D4I4 or H1H4/H2H3 genotype) showed significantly better phenotypic traits than those with the other genotypes in Nanyang cattle, showing a hybrid vigor. The results implied that this DI genotype can be applied to early selective breeding to improve the productivity of Nanyang cattle. Our results suggested that these two Indels within the bovine FoxO1 gene might be used as genetic markers for marker-assisted selection (MAS) in cattle breeding and genetics. [ABSTRACT FROM AUTHOR]

Morphological and molecular diversity was studied in a population of 20 rice genotypes, comprising mainly traditional aromatic non-basmati rice. Morphological diversity based on 13 yield traits using D2 statistics and molecular diversity from 17 polymorphic SSR markers resulted in six and five clusters, respectively with minor changes in cluster composition. The D² values ranged from 17.32 to 2521.56. The highest average intra- and inter-cluster distance (√D²) was 12.3 in Cluster I and 46 between Cluster III and IV. Cluster - I and VI played critical role in inter-cluster distance. Relative contribution of days to flowering to the divergence was highest, followed by secondary panicle branches, panicle exertion and test weight. Molecular analysis revealed 50 alleles with a range of 2 - 4 alleles and PIC values ranging from 0.095 to 0.685 with mean of 0.402. RM390 appeared as the potential marker for polymorphism investigations. Considering genetic divergence, crosses have been suggested for exploitation of heterosis in the F1 generation and isolation of transgressive segregates in advanced segregating generations. [ABSTRACT FROM AUTHOR]