Search

Local adaptation and genotype by environment (G×E) interactions affect the expression of phenotypes in crop species. An investigation on the interplay between adaptation and G×E on sorghum heterosis phenotypes is lacking. To address this question, a set of 112 diverse grain sorghum hybrids and their 22 inbred parents of local and exotic origins, representing the primary female and male heterotic groups, were tested in five contrasting sorghum‐growing environments across 2 years in Queensland, Australia. Plant height, days to flowering, seed yield, grain weight, and grain number were measured and used in the estimation of heterosis. Midparent heterosis for yield ranged from –25% to 217% and was highly influenced by grain number. In contrast to observations in maize, the magnitude of heterosis for yield was not associated with site mean. Striking differences were observed in heterosis in hybrids from locally developed inbred parents compared with hybrids that were developed from exotic inbred parents developed in other countries. Heterosis in the latter combination was higher on average across all the test environments for the majority of traits. We hypothesize maladaptive phenotypic plasticity in the exotic parents contributed to the observed differences in heterosis estimates. These data confirm that heterosis estimates in sorghum must be obtained and interpreted in relevant genetic and environmental contexts. Breeders in developing countries with low sorghum hybrid seed uptake will find these insights useful when selecting hybrids for broader adaptation, improving efficiency of their breeding programs. Core Ideas: Adaptation of sorghum inbred parents to test environment impacts the estimates of heterosis.Heterosis for yield in sorghum was not associated with mean site yields.Grain number in sorghum drives heterosis for yield. [ABSTRACT FROM AUTHOR]

Five years crossbreeding experiment was preformed involving two synthetic rabbit lines of APRI (A) and Moshtohor (M) where bucks of APRI line and does of Moshtohor line were used to produce F1 crossbreds (½A½M), followed by inter-se mating to obtain F2 crossbreds (½A½M)² . A total number of 263 sires, 445 dams and 1998 kits were used to estimate heritabilities and predicted breeding values (PBV) for post-weaning body weights (BW) and daily weight gains (DG). The variance components estimated by Gibbs Sampling were used to solve the mixed model equations using the PEST software, getting the solutions for genetic groups' effects along with the solutions for other fixed effects. The crossbreeding effects in terms of direct additive genetic effects (G I ), maternal effects (GM ), direct heterosis (HI ) and maternal heterosis (HM ) were obtained according to Dickerson model using the procedure of Generalized Least Squares (GLS). Heritability estimates were low to moderate, ranging from 0.17 to 0.36 for BW and 0.09 to 0.23 for DG. The ratios of common litter effects were low to moderate and ranging from 0.04 to 0.16 for BW and 0.03 to 0.26 for DG. The interse cross (½A½M)² had the lowest ranges in PBVs for BW and DG relative to the other three genetic groups. The percentages of GI were in favor of M line by 0.2 to 2.3 % for BW and by 0.5 to 3.2 % for DG. Also, the percentages of GM were in favor of M line by 2.1 to 4.6 % for BW and by 1.6 to 9.4 % for DG. The estimates of HI were mostly significantly positive and ranging from 15.1 to 20.9 % for BW and 5.0 to 32.3 % for DG. Also, the estimates of HM were significantly positive by 6.8 to 11.0 % for BW and 0.7 to 18.1 % for DG. In practice, new synthetic rabbit lines could be established in Egypt using the APRI line as a sire-group and the Moshtohor line as a dam-group. [ABSTRACT FROM AUTHOR]

Exploitation of heterosis is one of the potential means for improvement of sweet pepper (Capsicum annuum var. grossum L.) that can further be utilized for identification of desirable recombinants. Promising hybrids could be acceptable to growers of tropical and subtropical climates if it is a high yielder with attractive fruit colour and blocky shape. Seven diverse parents were selected through multivariate analysis and were crossed in half diallel mating design to determine the extent of heterosis, mode of gene action, combining ability effects, and dominance estimates for 18 quantitative characters. Expression of fruit colour and shape at physiological maturity stage in the F1 generation indicated the dominance of red coloured group over other fruit colour groups and dominance of blocky fruit shape over elongate and round fruit shape. Preponderance of non-additive gene action for most of the characters under study suggested the usefulness of exploitation of hybrid vigour. Three genotypes, 8/4, C/4, and Baby Bell were found most promising donors. The hybrids, Arya×Baby Bell, 8/4×Baby Bell and C/4×8/4 were identified as promising based on per se performance, heterosis manifested, and relevance of specific combining ability effects, for possible commercialization under low cost protected structure of tropical and subtropical climates after critical testing. Partial to over dominance response in inheritance of most traits contributed to the genetic basis of heterosis. Isolation of pure lines from the segregating generation of heterotic hybrids emerged as a promising approach to develop line-bred variety having improved fruit yield and quality. [ABSTRACT FROM AUTHOR]

Corn germplasm with different mesocotyl elongation was characterized for High Valleys in Mexico by estimating the general combinatory aptitude (GCA), specific combinatory aptitude (SCA), heterosis (H), inbreeding depression (ID) and principal component aptitude (PCA), with the purpose of directing the improvement for deep sowing. The hypothesis was that the parents and crosses of mesocotyl present variability in seedling and adult plant traits based on deep sowing. The 36 F1 and F2 crosses—derived from nine parents, three with short mesocotyl (S), three medium (M) and three long (L), obtained through Griffing diallel II—plus the parents were planted in sand beds and polyethylene bags in a greenhouse during the spring–summer cycles of 2021 and 2022. The following traits were measured: length of mesocotyl (LM), length of coleoptile, total seedling dry matter and 10 cob traits in addition to total dry matter. In 11 of the 14 traits, there was a positive and significant correlation (p ≤ 0.05) between the GCA of the parents and their LM. The highest SCA, H and ID (p ≤ 0.05) were for crosses L × L for all the traits measured. When comparing the GCA/SCA proportions, this relation varied from 0.76 to 0.97, which points to practically equal additive effects with those of dominance; however, in parents and L × L crosses, this relation was on average 0.94, 1.07 in M × M, 0.22 in S × S and 0.36 in L × S. In both F1 and F2, the variation was explained by two principal components: 89.5% for GCA and 73.4% for SCA. In both generations, the parents with higher GCA were H-48, HS-2 and Promesa, the three with long mesocotyl, while those with the highest GCA were crosses between these three hybrids. [ABSTRACT FROM AUTHOR]

Cowpea is an essential economic crop in underdeveloped and developing countries mainly grown by small farmers. In terms of seed yield and some agricultural characteristics, this study was carried out to determine the genetic structures and the general and specific adaptability of the genotypes. The trial, which included F1 hybrids and parents, was established under Konya ecological conditions with 3 replications in 2020 in the "Random Blocks Trial" design. Based on the results of the preliminary analysis of variance, it was determined that there was sufficient variation in the hybrid populations formed in terms of all traits examined. Nonadditive and dominant genes were found to be important in all traits examined. In the study, general adaptability was found to be important for the other traits examined, except the seed number per pod, seed number per plant, seed yield per plant, and protein yield per plant, and the effects of special adaptability were significant for all traits examined. Considering their general combining abilities, it was found that Ülkem, Sırma, and Pekşen cultivars should be used as rootstocks in breeding programs aimed at increasing yield and Pekşen and Ülkem cultivars in breeding programs to increase protein levels. When the specific combining abilities, heterosis and heterobeltiosis values are evaluated together, the hybrid combinations "Pekşen × Sırma", "Ülkem × Pekşen" and "Karagöz × Sırma" with the best performance in terms of, seed yield per plant and "Pekşen × Amazon", "Sırma × Pekşen", "Sırma × Karagöz" and "Ülkem × Pekşen" with the most outstanding give better performance in terms of protein ratio were found to be promising. [ABSTRACT FROM AUTHOR]

Simple Summary: Hybrid rice is produced by crossing a male sterile rice line (the A line) with a pollen doner that restores fertility (the restorer line). The consequential outbreeding can result in plant growth and yields that are above the average of the parental lines (a condition called heterosis). This gives rise to a normally higher productivity of hybrids compared to pure-line (inbred) rice varieties. However, hybrid rice has also been associated with higher herbivore damage compared to inbreds. In particular, susceptibility to the whitebacked planthopper (Sogatella furcifera) has been linked to the A line in early generation hybrids. We tested whether hybrids had heterosis for resistance to the whitebacked planthopper, brown planthopper (Nilaparvata lugens) and yellow stemborer (Scirpophaga incertulas) in a series of greenhouse and field experiments. In the field plots, heterosis resulted in relatively high hybrid yields. There were few cases of heterosis for resistance to herbivores in the greenhouse or field and only one of eight A lines was associated with susceptibility to planthoppers. Susceptibility to the yellow stemborer was largely due to plant physiology: larger, fast-growing and late-maturing varieties, including hybrids, were more vulnerable to stemborers. Therefore, susceptibility to stemborers was often a consequence of heterosis for plant biomass. We make a series of recommendations to improve screening and breeding for resistance to herbivores in hybrid rice. Three-line hybrid rice is produced by crossing male sterile (A line) rice with a fertility-restorer (R line). Fertile lines (B lines) are also required to maintain A line seed for breeding programs. We used a range of hybrids and their parental lines to assess the frequency and nature of heterosis for resistance to the whitebacked planthopper (Sogatella furcifera), brown planthopper (Nilaparvata lugens) and yellow stemborer (Scirpophaga incertulas). Heterosis is defined as trait improvement above the average of the parental lines as a result of outbreeding. Based on the results from a greenhouse study that challenged hybrids and their parental lines with each herbivore species, we found that susceptibility to planthoppers was associated with one of the eight A lines tested, but resistance was improved by crossing with a relatively resistant restorer. Higher frequencies of heterosis for susceptibility in comparisons between hybrids and their B lines suggest that susceptibility was not related to the cytoplasmic genomes of the associated sterile A lines. Furthermore, because none of the parental lines possessed currently effective resistance genes, improved resistance against planthoppers was probably due to quantitative resistance. In a related field trial, hybrids had generally higher yields than their fertile parents and often produced larger grain; however, they were often more susceptible to stemborers, leaffolders (Cnaphalocrocis medinalis) and other caterpillars (Rivula atimeta). This was largely a consequence of hybrid heterosis for plant biomass and was strongly affected by crop duration. We make a series of recommendations to improve hybrid breeding to reduce the risks of herbivore damage. [ABSTRACT FROM AUTHOR]

Molecular markers are effective tools used to 'flag' the location of a specific gene or the inheritance of a definite trait. Markers are unique DNA fragments that can be identified inside the entire genome. The development of molecular markers combined with high throughput technologies have paved the way for achieving the desirable traits as well as induced biotic and abiotic stress tolerance in plant, which enhanced the crop breeding. Highly polymorphic molecular markers are developed for gene mapping, estimation of genetic diversity, finding out the evolution and phylogeny of crop, analysis of heterosis, assessment of diploid/haploid crops and genotyping of cultivars along with Marker Assisted Breeding (MAB)/Marker Assisted Selection (MAS). These are the most significant objectives for crop breeding. This review reveals about the role of various recently developed molecular markers in the improvement of crop. Molecular markers act as a "milestone" for the researchers who aim to enhance crop breeding. [ABSTRACT FROM AUTHOR]

Heterosis plays a significant role in enhancing variety, boosting yield, and raising economic value in crops, but the molecular mechanism is still unclear. We analyzed the transcriptomes and 3D genomes of a hybrid (F1) and its parents (w30 and 082). The analysis of the expression revealed a total of 485 specially expressed genes (SEGs), 173 differentially expressed genes (DEGs) above the parental expression level, more actively expressed genes, and up-regulated DEGs in the F1. Further study revealed that the DEGs detected in the F1 and its parents were mainly involved in the response to auxin, plant hormone signal transduction, DNA metabolic process, purine metabolism, starch, and sucrose metabolism, which suggested that these biological processes may play a crucial role in the heterosis of Brassica rapa. The analysis of 3D genome data revealed that hybrid F1 plants tend to contain more transcriptionally active A chromatin compartments after hybridization. Supplementaryly, the F1 had a smaller TAD (topologically associated domain) genome length, but the number was the highest, and the expression change in activated TAD was higher than that of repressed TAD. More specific TAD boundaries were detected between the parents and F1. Subsequently, 140 DEGs with genomic structural variants were selected as potential candidate genes. We found two DEGs with consistent expression changes in A/B compartments and TADs. Our findings suggested that genomic structural variants, such as TADs and A/B chromatin compartments, may affect gene expression and contribute to heterosis in Brassica rapa. This study provides further insight into the molecular mechanism of heterosis in Brassica rapa. [ABSTRACT FROM AUTHOR]

Context. Maize (Zea mays L.) is one of the most economically important plants of the cereal family; it has value as human food, livestock feed, and as a component of industrial products. Aims. This study focused on genetic diversity and existence of genetic divergence among promising maize inbred lines in Iran. Methods. A commercial maize 600K SNP (single-nucleotide polymorphism) array was used to inspect genetic variability among 93 maize inbred lines. Key results. The rate of transition mutation was twice as high as transversion mutation, and the density of detected SNPs was greater close to telomere regions of maize chromosomes. Considering the fluctuation of observed, expected and total heterozygosity and fixation index values across maize chromosomes, as well as polymorphism information content values, there is a high level of genetic variability among the studied maize panel. In addition, discriminant analysis of the principal components revealed four subpopulations in which the subpopulation 'Line' was distinct from other subpopulations and had no genomic overlap with them. Selection signature analysis revealed 177 regions harbouring 75 genes that differentiate among subgroups. Detected genes had a role in the mitogen-activated protein kinase signalling pathway, spliceosome, protein processing in endoplasmic reticulum, and hormone signal transduction. Conclusions. We conclude that remarkable genetic diversity and differentiation exists among the studied maize subpopulations. The most differentiated SNPs among the subpopulations were associated with important biological processing genes and pathways. Implications. The findings provide valuable insights for future maize breeding programs through exploitation of heterosis, as well as marker-assisted selection. [ABSTRACT FROM AUTHOR]

Body composition traits are complex traits controlled by minor genes and, in hybrid populations, are impacted by additive and nonadditive effects. We aimed to identify candidate genes and increase the accuracy of genomic prediction of body composition traits in crossbred pigs by including dominance genetic effects. Genomic selection (GS) and genome‐wide association studies were performed on seven body composition traits in 807 Yunong‐black pigs using additive genomic models (AM) and additive‐dominance genomic models (ADM) with an imputed high‐density single nucleotide polymorphism (SNP) array and the Illumina Porcine SNP50 BeadChip. The results revealed that the additive heritabilities estimated for AM and ADM using the 50 K SNP data ranged from 0.20 to 0.34 and 0.11 to 0.30, respectively. However, the ranges of additive heritability for AM and ADM in the imputed data ranged from 0.20 to 0.36 and 0.12 to 0.30, respectively. The dominance variance accounted for 23% and 27% of the total variance for the 50 K and imputed data, respectively. The accuracy of genomic prediction improved by 5% on average for 50 K and imputed data when dominance effect were considered. Without the dominance effect, the accuracies for 50 K and imputed data were 0.35 and 0.38, respectively, and 0.41 and 0.43, respectively, upon considering it. A total of 12 significant SNP and 16 genomic regions were identified in the AM, and 14 significant SNP and 21 genomic regions were identified in the ADM for both the 50 K and imputed data. There were five overlapping SNP in the 50 K and imputed data. In the AM, a significant SNP (CNC10041568) was found in both body length and backfat thickness traits, which was in the PLAG1 gene strongly and significantly associated with body length and backfat thickness in pigs. Moreover, a significant SNP (CNC10031356) with a heterozygous dominant genotype was present in the ADM. Furthermore, several functionally related genes were associated with body composition traits, including MOS, RPS20, LYN, TGS1, TMEM68, XKR4, SEMA4D and ARNT2. These findings provide insights into molecular markers and GS breeding for the Yunong‐black pigs. [ABSTRACT FROM AUTHOR]

Heterosis is widely used in crop production, but phenotypic dominance and its underlying causes in soybeans, a significant grain and oil crop, remain a crucial yet unexplored issue. Here, the phenotypes and transcriptome profiles of three inbred lines and their resulting F1 seedlings were analyzed. The results suggest that F1 seedlings with superior heterosis in leaf size and biomass exhibited a more extensive recompilation in their transcriptional network and activated a greater number of genes compared to the parental lines. Furthermore, the transcriptional reprogramming observed in the four hybrid combinations was primarily non-additive, with dominant effects being more prevalent. Enrichment analysis of sets of differentially expressed genes, coupled with a weighted gene co-expression network analysis, has shown that the emergence of heterosis in seedlings can be attributed to genes related to circadian rhythms, photosynthesis, and starch synthesis. In addition, we combined DNA methylation data from previous immature seeds and observed similar recompilation patterns between DNA methylation and gene expression. We also found significant correlations between methylation levels of gene region and gene expression levels, as well as the discovery of 12 hub genes that shared or conflicted with their remodeling patterns. This suggests that DNA methylation in contemporary hybrid seeds have an impact on both the F1 seedling phenotype and gene expression to some extent. In conclusion, our study provides valuable insights into the molecular mechanisms of heterosis in soybean seedlings and its practical implications for selecting superior soybean varieties. [ABSTRACT FROM AUTHOR]

Soil salinization is one of the most important abiotic stresses which can seriously affect the growth and development of rice, leading to the decrease in or even loss of a rice harvest. Increasing the rice yield of saline soil is a key issue for agricultural production. The utilization of heterosis could significantly increase crop biomass and yield, which might be an effective way to meet the demand for rice cultivation in saline soil. In this study, to elucidate the regulatory mechanisms of rice hybrids and their parents that respond to salt stress, we investigated the phenotypic characteristics, physiological and biochemical indexes, and expression level of salt-related genes at the seedling stage. In this study, two sets of materials, encapsulating the most significant differences between the rice hybrids and their parents, were screened using the salt damage index and a hybrid superiority analysis. Compared with their parents, the rice hybrids Guang-Ba-You-Hua-Zhan (BB1) and Y-Liang-You-900 (GD1) exhibited much better salt tolerance, including an increased fresh weight and higher survival rate, a better scavenging ability towards reactive oxygen species (ROS), better ionic homeostasis with lower content of Na+ in their Na+/K+ ratio, and a higher expression of salt-stress-responsive genes. These results indicated that rice hybrids developed complex regulatory mechanisms involving multiple pathways and genes to adapt to salt stress and provided a physiological basis for the utilization of heterosis for improving the yield of rice under salt stress. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Plant Production is the property of Egyptian National Agricultural Library (ENAL) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Potato genetic improvement begins with crossing cultivars or breeding clones which often have complementary characteristics for producing heritable variation in segregating offspring, in which phenotypic selection is used thereafter across various vegetative generations (Ti). The aim of this research was to determine whether tetrasomic genomic best linear unbiased predictors (GBLUPs) may facilitate selecting for tuber yield across early Ti within and across breeding sites in inbred (S1) and hybrid (F1) tetraploid potato offspring. This research used 858 breeding clones for a T1 trial at Umeå (Norrland, 63°49′30″ N 20°15′50″ E) in 2021, as well as 829 and 671 clones from the breeding population for T2 trials during 2022 at Umeå and Helgegården (Skåne, 56°01′46″ N 14°09′24″ E), respectively, along with their parents (S0) and check cultivars. The S1 and F1 were derived from selfing and crossing four S0. The experimental layout was an augmented design of four-plant plots across testing sites, where breeding clones were non-replicated, and the parents and cultivars were placed in all blocks between the former. The genomic prediction abilities (r) for tuber weight per plant were 0.5944 and 0.6776 in T2 at Helgegården and Umeå, respectively, when T1 at Umeå was used as the training population. On average, r was larger in inbred than in hybrid offspring at both breeding sites. The r was also estimated using multi-environment data (involving at least one S1 and one F1) for T2 performance at both breeding sites. The r was strongly influenced by the genotype in both S1 and F1 offspring irrespective of the breeding site. [ABSTRACT FROM AUTHOR]

Maize breeding is greatly affected by hybrid vigor, a phenomenon that hybrids exhibit superior performance than parental lines. The immortalized F2 population (IMF2) is ideal for the genetic dissection and prediction of hybrid performance. Here, in this study, we conducted the QTL mapping and genomic prediction of six traits related to plant architecture using an IMF2 population. Broad-sense heritability of these traits ranged from 0.85 to 0.94. Analysis of genetic effects showed that additive variance was the main contributor to phenotypic variations. The mapping of quantitative trait loci (QTLs) revealed 10 to 16 QTLs (including pleiotropic loci and epistatic QTLs) for the six traits. Additionally, we identified 15 fine-tuning QTLs for plant height (PH). For genomic prediction (GP), the model of additive and dominance (AD) exhibited higher prediction accuracy than those fitting general combining ability (GCA) and its combination with special combining ability (SCA) effects for all tested traits. And adding the epistasis (E) effect into the AD model did not significantly increase its prediction accuracy. Moreover, the identified 15 fine-tuning QTLs of PH, which exerted large genomic prediction effects, were verified by the marker effect of GP. Our results not only provide an approach for the fine-mapping of fine-tuning QTLs but also serve as references for GP breeding in crops. [ABSTRACT FROM AUTHOR]

Pearl Millet (Pennisetum glaucum L.) is one of the most important crops in arid and semi-arid regions that are cultivated for grain and forage. Due to cross pollination and high heterosis, the development of hybrid varieties is the most important breeding method of pearl millet. In order to study the preliminary yield comparison of hybrid cultivars and investigate the possibility of replacing openpollinated cultivars with hybrid cultivars, 11 promising pearl millet hybrid cultivars with a check variety (Mehran cultivar) were planted in the randomized complete block design with three replications in Karaj, Isfahan and Zabul. The days to 50% flowering, plant height, stem diameter, leaves number, panicle length, panicle thickness, tiller number, fresh fodder yield, dry matter yield, 1000 seed weight, and seed yield were evaluated. The results of combined variance analysis and mean comparisons showed that there is considerable genetic diversity for the studied traits. The results showed that the cultivars H294, H444, H504, H604, H824, and H794 had the highest grain yield compared to the total mean of the experiment. In addition, five cultivars H543, H333, H353, H563, and H604 were above of total average in terms of fodder production and had good potential to be used in the field as commercial cultivars with the aim of fodder and seed production. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Agricultural Chemistry & Biotechnology is the property of Egyptian National Agricultural Library (ENAL) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Motivation Utilizing both purebred and crossbred data in animal genetics is widely recognized as an optimal strategy for enhancing the predictive accuracy of breeding values. Practically, the different genetic background among several purebred populations and their crossbred offspring populations limits the application of traditional prediction methods. Several studies endeavor to predict the crossbred performance via the partial relationship, which divides the data into distinct sub-populations based on the common genetic background, such as one single purebred population and its corresponding crossbred descendant. However, this strategy makes prediction inaccurate due to ignoring half of the parental information of crossbreed animals. Furthermore, dominance effects, although playing a significant role in crossbreeding systems, cannot be modeled under such a prediction model. Results To overcome this weakness, we developed a novel multi-breed single-step model using metafounders to assess ancestral relationships across diverse breeds under a unified framework. We proposed to use multi-breed dominance combined relationship matrices to model additive and dominance effects simultaneously. Our method provides a straightforward way to evaluate the heterosis of crossbreeds and the breeding values of purebred parents efficiently and accurately. We performed simulation and real data analyses to verify the potential of our proposed method. Our proposed model improved prediction accuracy under all scenarios considered compared to commonly used methods. Availability and implementation The software for implementing our method is available at https://github.com/CAU-TeamLiuJF/MAGE. [ABSTRACT FROM AUTHOR]

Background: The development of superior hybrids is must to break the existing yield plateau (< 800 kg/ha) in pigeonpea and hence, the genetic mechanism governing the heterosis in pigeonpea must be decoded. Methods: The present study was laid down using randomized block design during kharif 2018-19 at GBPUAT, Pantnagar with 36 genotypes (8 parents and 28 F1 hybrids) of pigeonpea. The estimates of combining ability were evaluated by using the Griffing's, Method II, Model I. The observations recorded for yield and related traits were subjected to the estimation of genetic diversity (GD) using the D2 statistics. The correlation between heterosis and different parameters viz., parental mean (PM), specific combining ability (SCA), mean of general combining ability (MGCA) and genetic diversity (GD) were estimated by using Pearson's correlation. Result: High estimates of SCA variance and more than unity (>1) average degree of dominance for all the characters indicated the presence of over dominance. The SCA followed by MGCA were found to be most reliable parameters to predict the heterosis. The parents having high × low or high × high per se performance, good × poor GCA effects and with medium genetic diversity resulted in high frequency of heterotic hybrids. [ABSTRACT FROM AUTHOR]

Background: The productivity of chickpea needs to be increased significantly to exploit the maximum benefit from the increasing world market demand for this crop. Hence, the objective of this study was to find suitable heterotic cross combinations for yield and yield related traits in chickpea. Methods: The present study on chickpea was conducted at Norman E. Borlaug Crop Research Centre, GBPUAT, Pantnagar, Uttarakhand, during rabi season of 2018-2019. It comprised a half-diallel set of seven diverse parents viz. PG5 and PG170 and five ICRISAT chickpea collections viz. ICC13124, ICC14778, ICC14815, ICC16348 and ICC16349 and their 21 F1 crosses were used for heterosis studies through 7×7 diallel analysis with respect to seed yield and other yield contributing traits. Result: Variance components of combining ability revealed that both additive and non-additive gene actions were important for yield and yield related traits. The parent ICC13124 was best general combiner for yield and related traits. It was also one of the parents in best specific combinations for seed yield. The crosses viz. PG170×ICC16349 (7.15), ICC13124×ICC14815 (3.22) and ICC13124×ICC14778 (3.00) were the best specific cross combinations for seed yield. The highest heterosis for seed yield was observed in cross PG170×ICC16349 (73.14%) followed by ICC13124×ICC14815 (43.17%) and ICC13124×ICC14778 (41.09%). The results showed direct association between the specific combining abilities of the crosses and heterotic response indicating the involvement of additive × additive type of interactions causing heterosis. Hence, the GCA, SCA and per se performance of the crosses should be given equal importance while selecting for heterotic combinations. [ABSTRACT FROM AUTHOR]

In the past 60 years, China's hybrid rice has developed from a three‐line system to a two‐line system: This has enriched the knowledge of heterosis and crop breeding. At the same time, the large‐scale commercialization of hybrid rice has made great contributions to China's rice production. [ABSTRACT FROM AUTHOR]

Soil salinization and alkalization are important abiotic stresses that affect crop growth and yield. Development of salt and alkali tolerant varieties is still dominated by the following conventional breeding method: The salt and alkali tolerant traits from screened germplasm are introduced into elite varieties by means of hybridization and backcrossing. In recent years, the breeding of salt and alkali tolerant rice has also made great progress. For example, the yield of Chao‐You 1000, a two‐line rice hybrid, has reached 12.04 t/ha growing in fields with salinity between 0.2% and 0.6%. This review is an update on the progress of salt and alkali tolerant rice germplasm screening and new salt and alkali tolerant varieties in development. By reviewing the performance of current rice hybrids in China's National Regional Variety Trials of Saline‐Alkali Tolerant Rice, we proposed the technical approach of developing saline–alkali tolerant rice hybrids using the third‐generation hybrid rice technology and furthermore the trend of developing salt and alkali tolerant rice hybrids. [ABSTRACT FROM AUTHOR]

Impacts of immigration on micro‐evolution and population dynamics fundamentally depend on net rates and forms of resulting gene flow into recipient populations. Yet, the degrees to which observed rates and sex ratios of physical immigration translate into multi‐generational genetic legacies have not been explicitly quantified in natural meta‐populations, precluding inference on how movements translate into effective gene flow and eco‐evolutionary outcomes. Our analyses of three decades of complete song sparrow (Melospiza melodia) pedigree data show that multi‐generational genetic contributions from regular natural immigrants substantially exceeded those from contemporary natives, consistent with heterosis‐enhanced introgression. However, while contributions from female immigrants exceeded those from female natives by up to three‐fold, male immigrants' lineages typically went locally extinct soon after arriving. Both the overall magnitude, and the degree of female bias, of effective gene flow therefore greatly exceeded those which would be inferred from observed physical arrivals, altering multiple eco‐evolutionary implications of immigration. [ABSTRACT FROM AUTHOR]

The present study was undertaken during October, 2020-January, 2021 at Maize Research Centre, Professor Jayashankar Telangana State Agricultural University, Rajendranagar, Hyderabad, Telangana state, India to identify potential inbred lines and hybrids with early maturity and high yield through combining ability analysis and heterosis. Six lines and four testers were crossed in L×T design to obtain 24 crosses. Evaluation of these crosses and their parents for combining ability revealed significant differences due to lines, testers and their crosses indicating the existence of wider variability among the material used in the study. Maize line MGC 434 (91 days), two testers GP-170 and PFSR-56 (91 days), and one hybrid MGC-445×PFSR-132 (83 days) were identified as early duration genotypes. Four lines MGC-444 (-3.13), MGC-440 (-2.71), MGC-439 (-1.96) and MGC-445 (-0.46) with significant negative GCA effects were identified as best general combiners for early maturity. Eight hybrids, MGC-439×BML-14 (-4.99), MGC-445×PFSR-56 (-4.65), MGC-461×PFSR-56 (-3.65), MGC-445×PFSR-132 (-3.60), MGC-434×BML-14 (-2.32), MGC-439×GP-170 (-2.10), MGC-440×PFSR-56 (-2.07) and MGC-440×GP-170 (-1.01) with significant negative SCA effects were considered as best cross combinations with early maturity. The inbred parents and cross combinations with early maturity identified in the study can be utilized for development of hybrids suitable to drought prone environments. [ABSTRACT FROM AUTHOR]

In plants, the genome structure of hybrids changes compared with their parents, but the effects of these changes in hybrids remain elusive. Comparing reciprocal crosses between Col × C24 and C24 × Col in Arabidopsis using high‐throughput chromosome conformation capture assay (Hi‐C) analysis, we found that hybrid three‐dimensional (3D) chromatin organization had more long‐distance interactions relative to parents, and this was mainly located in promoter regions and enriched in genes with heterosis‐related pathways. The interactions between euchromatin and heterochromatin were increased, and the compartment strength decreased in hybrids. In compartment domain (CD) boundaries, the distal interactions were more in hybrids than their parents. In the hybrids of CURLY LEAF (clf) mutants clfCol × clfC24 and clfC24 × clfCol, the heterosis phenotype was damaged, and the long‐distance interactions in hybrids were fewer than in their parents with lower H3K27me3. ChIP‐seq data revealed higher levels of H3K27me3 in the region adjacent to the CD boundary and the same interactional homo‐trans sites in the wild‐type (WT) hybrids, which may have led to more long‐distance interactions. In addition, the differentially expressed genes (DEGs) located in the boundaries of CDs and loop regions changed obviously in WT, and the functional enrichment for DEGs was different between WT and clf in the long‐distance interactions and loop regions. Our findings may therefore propose a new epigenetic explanation of heterosis in the Arabidopsis hybrids and provide new insights into crop breeding and yield increase. [ABSTRACT FROM AUTHOR]

Background: Cowpea is an important pulse crop grown worldwide that fits well in a variety of cropping systems. Improvement in yield and related characters along with reduced duration are desirable traits in this crop. The study of heterosis reveals the type of gene action involved which enables the plant breeder to adopt suitable breeding methodology for its improvement. Methods: The present investigation was carried out with 10 parent partial diallel design to analyse the gene action and estimate of heterosis with respect to nine yield related traits in cowpea. Result: Highly significant variances observed for all the traits indicated that hybrids and parents were different from each other for the traits under study and that variability in the breeding materials was attributed to additive and non-additive gene effects. Perusal of the data revealed significant positive heterosis for all yield related traits and significant negative heterosis for days to 50% flowering indicating earliness. Among the twenty five crosses studied, VS9 x VS43, VS24 x VS45 and VS44 x VS47 had significant heterosis for maximum number of characters. Both gca and sca variances were significant for all the characters indicating both additive and non-additive gene actions controlling the various traits. The additive variance was much higher than dominance variance for the characters days to 50% flowering, pod length, pod breadth, pod weight, pods per plant and cluster, pod yield per plant, seeds per plant and length of harvest period suggesting the preponderance of additive gene action. [ABSTRACT FROM AUTHOR]

Combining ability and heterosis were studied on 15 F1 hybrids and their parents to understand the inheritance of yield, its components and some grain quality traits for selecting superior genotypes. A line x tester mating design was conducted during 2021and 2022rice seasons at the Experimental Farm, of Sakha Research Station Kafr El-Sheikh, Egypt. The results revealed that GCA and SCA were highly significant for all studied traits except grain shape under both conditions. 11 L236 genotype was the best general combiner for number of days to 50% heading, number of filled grains/panicle, sterility% and grain yield/plant under normal and water deficit conditions. Also Giza 178 was the best general combiner for number of panicles/plant, grain yield/plant and hulling % under both conditions while, IR6500-127, Giza 178 and GZ1368-S-5-4 for head rice % and for amylose content Lines 11 L236 and tester Nerica7 under both conditions were good combiners for this trait. Crosses IR 69432 x Nerica7, IR 69432 x GZ1368-S-5-4, IR 12G3213 x Giza178, IR 12G3222 x Giza178 and IR 12G3222 x Nerica7 had high and significant SCA in desirable direction for most studied traits under both condition. Crosses IR6500-127 x Nerica7, 11 L236 x GZ1368-S-5-4, IR69432 x Nerica7, IR 12G3213 x Nerica7, IR 12G3222 x GZ1368-S-5-4 and IR 12G3222 x Nerica7 exhibited highly significant and desirable estimates of heterosis as a deviation from mid and better parent for most studied traits under both conditions. [ABSTRACT FROM AUTHOR]

Purpose: This paper intends to analyse the free and forced vibration response of functionally graded material (FGM) plates with and without circular and square cut-outs. Heterosis finite element combined with first-order shear deformation theory (FSDT) for the vibration analysis is presented to predict dynamic behaviour. Methods: A powerful and versatile finite element (FE) formulation by MAT Lab environment using nine noded heterosis elements have been used for the analysis. The FE formulation considers the contributions of shear deformation and rotary inertia. The forced vibration analysis without damping is executed under sinusoidal harmonic loading using the Newmark Beta method. Results: From the analysis, it is noticed that in FGM plates with and with cut-outs, a critical plate length-to-thickness ratio exists above which the natural frequency no longer increases even if the plate becomes thinner. In FGM plates with various cut-outs, the normalized natural frequency of vibration decreases with an increase in the material volume fraction index(k)value. Displacement response is minimum for ceramic plates (k = 0) and maximum for a metal plate (k = ∞) with or without cut out. Conclusion: The model is precise and successful in explaining the dynamic behaviour of FGM plates with and without cut-outs. The influences of various parameters, such as volume fraction index, cut-out size, cut-out shape, boundary conditions and the length-to-thickness ratio of the plate, are examined in detail. The validity of the present approach is verified by numerical examples in the open literature and by comparing the results with the numerical simulation. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Plant Production is the property of Egyptian National Agricultural Library (ENAL) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Although hybrid catfish (Ictalurus punctatus × I. furcatus) now constitute about half of the industry production, few studies have assessed comparative growth and survival with other commercially important catfish. Growth assessment is particularly important at moderate to high temperatures because of the direct influence of temperature on ectothermic organisms and the increasing trend of warm to extreme environmental temperatures. Therefore, growth, condition factor, and survival of channel (I. punctatus), blue (I. furcatus), and hybrid catfish were compared following a 10‐week growth experiment at moderate (23°C) and high (33°C) temperatures in tanks. It was hypothesized that hybrid catfish would outperform channel and blue catfish in overall growth due of heterosis, and growth of all three fish types would be greater at moderate than high temperatures, which are above the range for optimal channel and blue catfish growth. Channel catfish had the greatest growth and were in better condition compared to blue and hybrid catfish over moderate and high temperatures. All treatments had an average survival over 89% other than blue catfish at 33°C, which had an average survival of 63%. Therefore, these results indicate growth and condition factor in channel, blue, and hybrid catfish diminish at high temperatures, and channel catfish may outgrow blue and hybrid catfish at moderate to high temperatures. [ABSTRACT FROM AUTHOR]

Heterosis has been exploited to enhance the yield and adaptability in various shellfish species; however, the molecular basis of it remains unclear. The Pacific oyster Crassostrea gigas is one of the most economically important aquaculture species, and its productive traits can be improved by hybridization. Here, an intraspecific cross between orange shell (O, 10th generation) and 'Haida No. 1' (H, 13th generation) of C. gigas was performed to assess the heterosis of survival trait. Survival rates of hybrid family (OH) and inbred families (HH and OO) were compared at larval stage, and eyed-pediveliger larvae of three families were subjected to transcriptome analysis. The analysis results of best-parent heterosis and mid-parent heterosis showed that the hybrid family exhibited a high heterosis in survival relative to the parental families. The OH-M (OH vs. OO) and OH-P (OH vs. HH) had 425 and 512 differentially expressed genes (DEGs), respectively. Functional enrichment analysis of these DEGs revealed that the significantly enriched genes function in virion binding, C-type lectin receptor signaling pathway, cellular defense response and other immune-related processes, which involves perlucin-like protein, CD209 antigen-like protein, ZNFX1, caspase-3 and acan genes. These differentially expressed genes in OH-M and OH-P, together with the immune-related processes mentioned above may play an important role in the larval survival of C. gigas. In addition, three genes (CYP450, fucolectin and perlucin-like) are associated with the orange shell and low survival of maternal oyster OO. These findings provide support for the application of hybrid with superior survival and will facilitate the understanding of heterosis formation in the Pacific oyster. [ABSTRACT FROM AUTHOR]

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 F 1 hybrids in okra. The additive genetic component (D) was significant in all studied traits except average pod weight. Nonadditive ( H 1 and H 2 ) components were found to be significant in all studied traits. However, the values of the dominant effect ( H 1 ) 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. [ABSTRACT FROM AUTHOR]

A total of 11 genotypes from the collection of 101 bread wheat genotypes, with desirable traits in terms of increased tolerance to drought, were chosen for parents and eight crosses were performed. Number of seminal roots (NSR), total root length (TRL), root dry mass (RDM), number of shoots per plant (NS), main shoot length (MSL), shoot dry mass (SDM), number of leaves per plant (NL), leaf area per plant (LA), leaf dry mass (LDM), aboveground dry mass (ADM), SDM/LDM, RDM/ADM were analysed at the boot stage (Z45). The F1 progeny had on average higher mean values (P < 0.001) than parents for four traits: RDM, NS, LA and RDM/ADM. The highest broad sense heritability values were determined for RDM (97.6%) and NSR (93.9%). Factor analysis indicated that a large root system, higher RDM and TRL are associated with higher NS, NL, LA and LDM. For Euclid x CHI-4 and WWBMC2 x Ingenio combinations the highest heterosis values were observed for TRL (34.1%) and SDM (23.7%), for RDM (28.6%) and LA (26.8%), respectively. PEG-induced drought stress in the seedling stage, in most of the new germplasm, caused an increased redistribution of dry matter in the root compared to the stem. [ABSTRACT FROM AUTHOR]

Simple Summary: Mitogen-activated protein kinases (MAPKs) are serine/threonine kinases that play a crucial role in regulating multiple processes, including protein degradation and localization, mRNA stability, endocytosis, apoptosis, cytoskeleton dynamics, and cell migration. To investigate the regulation of MAPKs' gene expression variation in hybrid tilapia (Oreochromis niloticus ♀ × O. aureus ♂), we focused on p38 mapk. Our study uncovered a compensatory interaction between cis- and trans-acting elements of the Nile tilapia and blue tilapia sub-genomes, resulting in a nonadditive expression pattern of p38 in hybrid tilapia. In addition, we identified eight specific single-nucleotide polymorphisms (SNPs) in transcription factor binding sites between Nile tilapia and blue tilapia and demonstrated that it is promoter differences that differentiate parental gene expression using a dual-luciferase reporting system. Overall, this study reveals the non-additive expression patterns of functionally important genes in hybrid fish, particularly in growth and immune responses. Hybridization is a widely used breeding technique in fish species that enhances desirable traits in cultured species through heterosis. However, the mechanism by which hybrids alter gene expression to form heterosis remains unclear. In this study, a group of hybrid tilapia was used to elucidate heterosis through interspecies crossing. Specifically, p38 was analyzed to describe the regulation of gene expression variation in hybrid tilapia. Transcripts from the Nile tilapia allele were found to be significantly higher than those from the blue tilapia allele in hybrid individuals, indicating that the expression of p38 was dominated by Nile tilapia sub-genomic alleles. The study also found a compensatory interaction of cis- and trans-acting elements of the Nile tilapia and blue tilapia sub-genomes, inducing a non-additive expression of p38 in hybrids. Eight specific SNPs were identified in the p38 promoter regions of Nile tilapia and blue tilapia, and were found to be promoter differences leading to differences in gene expression efficiencies between parental alleles using a dual-luciferase reporter system. This study provides insights into the non-additive expression patterns of key functional genes in fish hybrids related to growth and immunity response. [ABSTRACT FROM AUTHOR]

Improving sweet–waxy corn hybrids enriched in carotenoids via a hybrid breeding approach may provide an alternative cash crop for growers and provide health benefits for consumers. This study estimates the combining ability and heterosis of sweet–waxy corn hybrids for yield-related traits and carotenoids. Eight super sweet corn and three waxy corn lines were crossed to generate 24 F1 hybrids according to the North Carolina Design II scheme, and these hybrids were evaluated across two seasons of 2021/22. The results showed that both additive and non-additive genetic effects were involved in expressing the traits, but the additive genetic effect was more predominant. Most observed traits exhibited moderate to high narrow-sense heritability. Three parental lines, namely the ILS2 and ILS7 females and the ILW1 male, showed the highest positive GCA effects on yield-related traits, making them desirable for developing high-yielding hybrids. Meanwhile, five parental lines, namely the ILS3, ILS5, and ILS7 females and the ILW1 and ILW2 males, were favorable general combiners for high carotenoids. A tested hybrid, ILS2 × ILW1, was a candidate biofortified sweet–waxy corn hybrid possessing high yields and carotenoids. Heterosis and per se performance were more positively correlated with GCAsum than SCA, indicating that GCAsum can predict heterosis for improving biofortified sweet–waxy corn hybrid enriched in carotenoids. The breeding strategies of biofortified sweet–waxy corn hybrids with high yield and carotenoid content are discussed. [ABSTRACT FROM AUTHOR]

In sorghum [Sorghum bicolor (L.) Moench], combining ability and heterosis analysis are commonly used to evaluate superior parental lines and to screen for strongly heterotic hybrids, which helps in sorghum variety selection and breeding. In this context, combining ability and heterosis analysis were assessed using 14 restorer lines and seven cytoplasmic male sterile (CMS) lines in 2019 and 2020. The analysis of variance of all cross combinations had highly significant differences for all characters studied, which indicated a wide variation across the parents, lines, testers, and crosses. Combining ability analysis showed that the general combining ability (GCA) and specific combining ability (SCA) of the different parents were differed significantly among different traits. Most combinations with high SCA also showed high GCA in their parent lines. The heritability in the narrow sense of grain weight per panicle and grain yield was relatively low, indicating that the ability of these traits to be directly inherited by offspring was weak, that they were greatly affected by the environment. The better-parent heterosis for plant height, grain weight per panicle, panicle length, and 1000-grain weight was consistent with the order of mid-parent heterosis from strong to weak. The GCA effects of two lines 10480A, 3765A and three testers 0-30R, R111, and JY15R were significant for the majority of the agronomic traits including grain yield and might be used for improving the yield of grains in sorghum as parents of excellent specific combining ability. Seven strongly heterotic F1 hybrids were screened; of these, hybrids 3765A × R111, 1102A × L2R, and 3765A × JY15R showed significant increases in seed iristectorigenin A content and will feature into the creation of new sorghum varieties rich in iristectorigenin A. [ABSTRACT FROM AUTHOR]

Objective The purpose of this research is to investigate the efficiency of the ISSR molecular marker in distinguishing the studied watermelon populations, to determine the degree of similarity and genetic distance of the populations in order to use the phenomenon of heterosis and to select suitable parents in watermelon hybrid seed production programs. Materials and methods In this research, the genetic diversity of 24 different watermelon populations from all over Iran was investigated using 10 ISSR primers. DNA extraction was done using the CTAB method. After PCR, molecular data were scored as zero and one. Indexes related to markers include total number of bands, number of polymorphic bands, polymorphic percentage, marker index (MI), resolution strength index (RP) and polymorphic information content (PIC). It was measured. In order to perform cluster analysis, NTSYS and Excel software were used, and GenALEx software was used to analyze the molecular variance and to analyze the main coordinates. Results In this research, a total of 202 bands were produced, of which 184 were polymorphic bands. The average number of total bands and polymorphic bands in this study was 20.2 and 18.4, respectively. The highest percentage of polymorphism was related to the ISSR6 primer with 100% and the lowest polymorphism was related to the ISSR5 primer with 80%. The average percentage of polymorphism in this study was also 0.90. The value of PIC index in this research varied between 0.26 and 0.44 and the average PIC was 0.35. After cluster analysis, the studied populations were divided into five groups at a similarity level of 55%. The results of molecular variance analysis in the studied populations showed that 14% of the variation is between the studied populations and 86% of the variation is within the studied populations. The results of analysis to main coordinates also confirmed the results of cluster analysis. Conclusions According to the obtained results, the ISSR molecular marker has the necessary efficiency to distinguish the studied populations, and on the other hand, considering the considerable genetic diversity between and within the studied populations, the genotypes used in this research can be considered as the population The first one was used in watermelon hybrid seed production programs and also Faryab and Minab populations can be used as cross parents considering that they had the least genetic similarity in order to use heterosis in watermelon hybrid seed production projects. [ABSTRACT FROM AUTHOR]

Intermating between genetically diverse tomatoes could provide information on the underlying biology as a source of new alleles for phytonutrient contents and tomato leaf curl virus (ToLCV) disease tolerance in cherry tomato [Solanum lycopersicum var. cerasiforme (Dunnal) A. Gray]. The study determined combining ability effects, heterosis and gene action for conditioning 19 quantitative traits involving crosses between anthocyanin rich (Aft gene) tomato (Solanum lycopersicum L.) lines and 7 breeding lines of nutritionally rich cherry tomato [S. lycopersicum var. cerasiforme (Dunnal) A. Gray]. An overwhelming response of non-additive gene action in controlling expression of most traits was evident. Purple tomato line "Bidhan Purple" and the cherry tomato lines "Cherry Round Yellow Big Fruit" and "18/ToCVAR-2" could be potential genitors for cherry tomato breeding. Based on combining ability, average heterosis, and mean performance, the promising hybrids: "Alisha Craig Aft ×18/TOCVAR-2," "Bidhan Purple × 18/TOCVAR-2" and "Alisha Craig Aft × Cherry Round Yellow Big Fruit" were identified in terms of phytonutrient contents and ToLCV disease tolerance. Partial, to over-dominance, reaction in inheritance of most traits reflects the genetic basis of heterosis. Promising cherry tomato hybrids could be exploited following appropriate testing or could be used in segregating generations to produce line-bred cultivars that are ToLCV disease-tolerant and high in phytonutrient contents. [ABSTRACT FROM AUTHOR]

In a large portion of the tropics, there is a demand for the development of hybrid chilies (Capsicum annuum L.) with high pungency, antioxidant vitamins, and tolerance to chili leaf curl virus, and anthracnose. Six genetically diverse parents were crossed in half-diallel fashion to develop 15 F1 hybrids to assess the level of heterosis, combining ability and gene action for 17 quantitative traits. The inheritance of most traits was apparently controlled by non-additive gene action. "Bidhan Chili 4" recorded the maximum, significant, GCA effects in a desired direction for PDIs of leaf curl virus and anthracnose along with commercially important traits. The maximum extent of heterobeltiosis was for oleoresin content followed by ascorbic acid and capsaicin contents, PDIs of chili leaf curl virus and anthracnose, and fruit yield per plant. The hybrids "Bidhan Chili 4 × Chili 38-Ragi" and "Pant C 1 × Bidhan Chili 4" could be isolated on the basis of their average performance, heterosis manifested in them, and SCA effects. Such hybrids could make a difference by meeting the horticultural requirements, high yield, disease tolerance and pungency, of commercial chili growing zones in the tropics. Hybrid vigor is available for commercial production of chili hybrids. A different approach from hybrid vigor is to isolate pure lines from segregating generations of potential heterotic F1s to increase fruit yield, quality attributes, and resistance to the chili leaf curl virus and anthracnose disease. [ABSTRACT FROM AUTHOR]

SUMMARY: Heterosis, also known as hybrid vigor, is the phenomenon wherein a progeny exhibits superior traits relative to one or both parents. In terms of crop breeding, this usually refers to the yield advantage of F1 hybrids over both inbred parents. The development of high‐yielding hybrid cultivars across a wider range of crops is key to meeting future food demands. However, conventional hybrid breeding strategies are proving to be exceptionally challenging to apply commercially in many self‐pollinating crops, particularly wheat and barley. Currently in these crops, the relative performance advantage of hybrids over inbred line cultivars does not outweigh the cost of hybrid seed production. Here, we review the genetic basis of heterosis, discuss the challenges in hybrid breeding, and propose a strategy to recruit multiple heterosis‐associated genes to develop lines with improved agronomic characteristics. This strategy leverages modern genetic engineering tools to synthesize supergenes by fusing multiple heterotic alleles across multiple heterosis‐associated loci. We outline a plan to assess the feasibility of this approach to improve line performance using barley (Hordeum vulgare) as the model self‐pollinating crop species, and a few heterosis‐associated genes. The proposed method can be applied to all crops for which heterotic gene combinations can be identified. Significance Statement: This perspective summarizes key hypotheses on the genetic basis of heterosis, assesses challenges in hybrid breeding of self‐pollinating crops, and proposes an approach using synthetic supergenes to exploit heterosis. [ABSTRACT FROM AUTHOR]

Assisted gene flow is increasingly used to combat severe population declines. However, the associated risks, such as outbreeding depression, are often insufficiently assessed. Here, we studied the impact of assisted gene flow on the fitness of a highly endangered landlocked salmon population (Salmo salar m. sebago) from the lake Saimaa complex (Finland), using an anadromous Atlantic salmon population (S. salar) as donor. We released individuals of both parental populations and their hybrids into seminatural streams, monitoring their survival under predation risk from Northern pike (Esox lucius) and their growth on a natural diet. Before release, we exposed half of the salmon to the parasite Diplostomum pseudospathaceum to study whether assisted gene flow affects infection susceptibility, which could indirectly shape predation susceptibility and growth. The parental populations differed in both studied traits and the hybrids showed intermediate values. Relative to the target landlocked salmon population, hybrids experienced 21–26% lower survival, but 1.4–2.2% higher growth. They also carried 0.6–2.8 more parasites than the landlocked salmon, contributing to survival differences. These findings indicate that assisted gene flow can induce both negative and positive fitness effects. We propose that the overall net effects of this conservation tool need to be carefully evaluated before its implementation. [ABSTRACT FROM AUTHOR]

The two bay scallop subspecies, Argopecten irradians irradians (NN) and A. i. concentricus (SS), are fast growing and major cultured bivalves in China. However, their relatively small sizes and decreasing production traits caused by long-term inbreeding have been major concerns to the industry in the last two decades. Hybridization between the two bay scallop subspecies may provide a new approach to breed a new variety with superior production traits for the industry. For this end, in this study, we hybridized the two bay scallop subspecies in order to obtain a new strain that incorporates the genes of both subspecies. No significant difference was found in fertilization rate, hatching rate and metamorphosis rate between the purebred and crossbred cohorts (NN♀×SS♂, denoted as NS; SS♀×NN♂, denoted as SN). Both mating strategy (intra- vs. inter-population crosses) and egg origin had significant effects on growth and survival at the larval stage. Heterosis was observed in the crossbred and was more pronounced in older stages. Genetic diversity of the reciprocal hybrids, especially that of SN, was increased compared with the purebred cohorts. Almost all hybrids were completely fertile and able to reproduce by self-fertilization or by backcrossing with either parent. Apparently, male sterile individuals whose gonads were fully occupied by the ovary part at mature stage were found in the hybrids for the first time. The hybrids, especially SN, may provide precious germplasm resources for the production of ternary hybrids with the Peruvian scallop, A. purpuratus. [ABSTRACT FROM AUTHOR]

Diseases of field crops significantly reduce yield and the quality of agricultural products. Developing resistant varieties is one of the tasks for enhancing agroecosystem resilience. The creation of infectious material for the background pathogen and heterosis analysis of F1 hybrids of soft winter wheat for resistance against Fusarium graminearum Schwabe (F. graminearum) and elements of spike productivity was the goal of the conducted research. The analysis of F1 genotypes of wheat for resistance against F. graminearum was carried out in field infections and natural nurseries of the wheat breeding laboratory of The V.M. Remeslo Myronivka Institute of Wheat of the NAAS of Ukraine (located in the northern part of the Right-Bank Forest-Steppe of Ukraine) during 2021 and 2022. The most aggressive isolates of the F. graminearum fungus were identified for developing inoculum and creating an artificial infection background in field conditions. In terms of the inheritance of resistance and spike productivity traits, 29.4% of hybrid populations of the first generation were selected. Positive dominance for the complex of investigated traits was found in hybrid combinations where sources of resistance against Fusarium graminearum (MV 20-88 × Smuhlianka, (Mikon × ALMA) × Lehenda Myronivska and local winter wheat varieties MIP Knyazhna, MIP Vyshyvanka were involved in the crossbreeding. It was established that cytoplasmic genes enhance the dominance of genes for complex resistance in one crossbreeding group. The best combinations with positive dominance in resistance to fusarium can be utilized in the development of highly resistant varieties. [ABSTRACT FROM AUTHOR]

Ten melon accessions including eight resistant lines involving one snapmelon line (Cucumismelo var. momordica) and two susceptible lineswith one genetic male sterile line were crossed to generate 45 F1's through half-dialleldesign. These genotypes wereevaluated for yield, quality and disease resistance traits in randomized block design with three replication. Pooled ANOVA for experimental design revealed significant mean squares due to environments except for β-carotene and TSS of juice and, treatment × environment except for fruit shape index and TSS of juice. The GCA estimates showed that parentsPunjab Sunehri was a good combiner for seed cavity area (-8.80), flesh thickness (0.12), rind thickness (0.42), firmness (0.61), dry matter (1.02) and β carotene (0.80) while SM-2012-12 for fruit yield (4.74), number of fruits vine-1(3.43), average fruit weight (0.06) and fusarium wilt incidence (-0.51) whereas, KP4HM-15 was good for average fruit weight (0.01), days to first fruit ripening (-2.31), TSS (1.21), pH (0.13), titrable acidity (-3.13), ascorbic acid content (5.89) and β-carotene (0.06). The heterobeltosis ranged from -87.2 to 927.08% for the yield and quality traits whereas for fusarium wilt incidence has -100 to 69.23%. The study offers an opportunity for transferring fusarium wilt incidence into superior horticultural genotype. Hybrids KP4HM-15 × Kajri Sel.1, Kajri Sel.1 × MM-202 and MM-314 × KP4HM-15 were identified as promising on the basis of phenotypic performance, SCA effects and resistance to fusarium wilt disease. These hybrids can be evaluated further at multilocation to assess their suitability for commercial release. [ABSTRACT FROM AUTHOR]

This study evaluated the performance of various grape hybrids for yield and quality traits, and to identify hybrid vigor for specific traits that can be utilized in future breeding programs. The research involved evaluating 76 hybrids derived from two diverse parents i.e., Pinot Noir and Marselan, during 2021 and 2022. Multiple fruit yield and biochemical traits were examined and quality traits of peel, flesh, and seeds were recorded. Two-way analysis of variance for parents was performed for all the traits under study to understand the significance of these traits over two years. Likewise, statistical analysis, such as the coefficient of variation, combined transmissibility rate, heterosis, and heterobeltiosis were computed to compare the performance of the hybrids against mid and better parents. The highest CV and Ta values were observed for fruit yield and peel phenolic contents respectively, across both years. The two-year data suggested that certain hybrids displayed superior heterosis and heterobeltiosis for numerous individual traits. Hybrid number 7 exhibited negative hybrid vigor for most of the traits and must be avoided for general cultivation. while hybrid number 25 showed increased hybrid vigor fruit yield and total flavonoids in peel, flesh, and seeds as well as a higher concentration of tannins in seeds. This research underscores the potential of hybrid number 25 for grape farmers and the wine industry in China, hinting at the untapped potential of hybrid grapes in producing superior wines. The study's insights aim to aid the development of indigenous grape varieties, reducing China's reliance on imports and fostering a unique Chinese wine identity in the global market. The data derived from this two-year evaluation can guide future breeding programs and further exploration of grape hybrid vigor to optimize both yield and wine-making quality. [ABSTRACT FROM AUTHOR]

The objective of this work was to determine the importance of vigor during the initial establishment of the maize crop. The work was carried out using 8 lots of hybrid corn seed, in which four lots were characterized as high vigor and four lots characterized as low vigor. After obtaining the seeds, they were sown in the field to determine the association between vigor and seedling performance at 21 days after sowing. The experiment was carried out in a randomized block design with four replications. Seedling emergence was measured daily up to 21 days, and at the end of the period, the shoot length, root system length, total seedling length and their respective masses, root system volume and stem diameter were determined. Seed vigor was positively associated with all measured variables, except for root system length. All parameters evaluated were superior in the group of seeds characterized as having high vigor. It is concluded that the vigor of hybrid corn seeds is crucial for the higher speed and uniformity of emergence in the field, being essential to form seedlings with superior performance in field conditions. [ABSTRACT FROM AUTHOR]

The main purpose of this research is to compare the bio-morphological properties, fiber properties, technological quality indicators and net return levels of different cotton varieties, to include different varieties in hybridization and to use the obtained hybrids as a starting material in selection. The research was carried out in the experimental area of the Plant Protection and Technical Plants Scientific Research Institute in Samukh district in 2017-2020. Research material consisted of the local Ganja-110 cotton variety and some cotton varieties S-6524 (Uzbekistan), BA-440 (Turkey), Akala Beret (Israel), Selekt (Greece), Tashauz-68 (Turkmenistan) brought from cotton growing countries. The results of this research revealed that cotton varieties differ from each other in terms of raw cotton yield, this yield indicator was 4,380 kg/ha in Ganja-110 cotton variety against lower yields in the other varieties. The raw cotton mass of the Ganja-110 cotton variety was 6.3 g in a boll while it varied 5.2-6.0 g in a boll for the other different cotton varieties. It has been determined that the net return of other cotton varieties was also lower than Ganja-110 variety. It is recommended to use hybrids with enhanced heterosis effect obtained from crossbreeding between different cotton varieties. [ABSTRACT FROM AUTHOR]

The use of Solanum aethiopicum as the female parent with S. melongena led to the development of a cytoplasmic-genic male sterility system (CGMS) in eggplant. The male sterility was complete and expressed as rudimentary anthers with no pollen grains. Ten backcross progenies of male sterile lines in diverse genetic backgrounds of S. melongena were characterised after BC7 generation for 14 horticultural traits. It was observed that male sterile lines and their respective maintainer parents were isogenic for all the traits, except stamen size and days to 50% flowering. The fertility of male sterile lines was restored after hybridising with plants derived from an S. melongena × S. aethiopicum cross. The fertility restoration was governed by a single dominant gene. The maternal cytoplasm of S. aethiopicum in male sterile lines and of S. melongena in maintainers and restorers was confirmed with mitochondria and chloroplast DNA-specific molecular markers. Further, to assess the heterotic potential, 10 cytoplasmic male sterility lines were crossed with three restorers to develop 30 F1 hybrids, out of which D−67A × R−6 and D−104A × R−6 were found consistently better than the standard check for yield plant−1 over two years. In this manuscript a comprehensive study on development and utilisation of an alloplasmic CGMS system in eggplant has been discussed. [ABSTRACT FROM AUTHOR]

This article presents the findings of a study on the breeding of Indian Mustard, specifically focusing on heterosis and combining ability for seed yield and its component traits. The researchers evaluated 12 advanced lines/varieties of Indian Mustard and found significant differences among the treatments for various traits. Certain lines and cross combinations were identified as good combiners and showed high heterosis. The study provides valuable information for breeding programs aimed at improving seed yield and its component traits in Indian Mustard. [Extracted from the article]

Heterosis is a method of increasing productivity and is used in many crops. In cotton, heterosis is mainly related to yield and fiber length. Two male-sterile cotton lines ms 273 and ms 274 were included in crosses with five modern varieties: Chirpan-539, Natalia, Rumi, Helius and Nelina. Heterosis manifestations were found for productivity/plant (7.4-63.8%) and fiber length in the F1 hybrids. The cultivar Chirpan-539 and Rumi variety, with high GCA for fiber length and high variances of SCA, emerged as suitable for heterosis selection of this trait. The crosses 273 × Nelina and 274 × Nelina, with the highest productivity\plant (39.5-42.1 g) and the highest heterosis (61.9-63.8%), the second one with high SCA effects, are of interest for the heterosis selection of productivity. The crosses 274 × Chirpan-539 and 274 × Natalia, with the longest fibers (28.9-29.3 mm) and heterosis (2.1-3.5%), the first one manifested high SCA effects, are of interest for the heterosis selection of fiber length. The results obtained are encouraging for the development of heterotic selection and practical use of heterosis in cotton based on male sterility. [ABSTRACT FROM AUTHOR]