Heterosis For Yield Research Articles

Combining Ability and Heterosis for Earliness, Growth and Biological Yield of Some Flax Genotypes at Normal-irrigation and Water-Shortage Environments

Combining Ability and Heterosis for Earliness, Growth and Biological Yield of Some Flax Genotypes at Normal-irrigation and Water-Shortage Environments

Standard heterosis and heterotic grouping of highland adapted maize (Zea Mays L.) inbred lines in Ethiopia

The current study was initiated to estimate the magnitude of standard heterosis for grain yield and yield related traits in a line x tester hybrids and to classify the inbred lines into different heterotic groups. Fifty entries consisting of 48 testcrosses developed from 12 inbred lines and 4 testers using line x tester design and two commercial check hybrids used in the study. The experiment was conducted using alpha lattice design with two replications at Ambo and Holeta Agricultural Research Center in 2018 cropping season. Analysis of variance revealed highly significant mean squares due to genotypes for all traits. Site variance showed highly significant mean squares for all traits except ear height. Genotype x site interaction was significant for grain yield, days to silking, bad husk cover and ear aspect. Cross L11 x T4 exhibited maximum standard heterosis over the checks (Kolba and Jibat) for grain yield followed by L9 x T4. In addition, these hybrids showed negative standard heterosis for plant height and ear aspect. The study also proposed eight inbred lines to be assigned to one of the different heterotic groups (A and B). The current study revealed that extensive works needs to be done in broadening the genetic base for highland maize breeding program to develop higher yielding varieties for the target areas. Key words: Heterotic grouping, Inbreed lines, standard heterosis, testers.

Combinations of Ghd7, Ghd8, and Hd1 determine strong heterosis of commercial rice hybrids in diverse ecological regions.

Heterosis of grain yield is closely associated with heading date in crops. Gene combinations of the major heading date genes Ghd7, Ghd8, and Hd1 play important roles in enhancing grain yield and adaptation to ecological regions in rice. However, the predominant three-gene combinations for a specific ecological region remain unclear in both three-line and two-line hybrids. In this study, we sequenced these three genes of 50 cytoplasmic male sterile/maintainer lines, 31 photo-thermo-sensitive genic male sterile lines, and 109 restorer lines. Sequence analysis showed that hybrids carrying strong functional alleles of Ghd7 and Hd1 and non-functional Ghd8 are predominant in three-line hybrids and are recommended for rice production in the subtropics around 30°N/S. Hybrids carrying strong functional Ghd7 and Ghd8 and non-functional Hd1 are predominant in two-line hybrids and are recommended for low latitude areas around 23.5°N/S rich in photothermal resources. Hybrids carrying strong functional Ghd7 and Ghd8 and functional Hd1 were not identified in commercial hybrids in the middle and lower reaches of the Yangtze River, but they have high yield potential in tropical regions because they have the strongest photoperiod sensitivity. Based on these findings, two genic sterile lines, Xiangling 628S and C815S, whose hybrids often head very late, were diagnosed with these three genes, and Hd1 was targeted to be knocked out in Xiangling 628S and replaced with hd1 in C815S. The hybrids developed from both modified sterile lines in turn had appropriate heading dates and significantly improved grain yield. This study provides new insights for breeding design to develop hybrids for various regions.

Heterosis for Biomass-Related Traits in Interspecific Triploid Hybrids of Willow (Salix spp.)

Species hybridization is key for the improvement of shrub willow (Salix spp.) bioenergy crops because hybrids often display heterosis for yield. The development of high-yielding genotypes requires numerous broad attempts at hybridization followed by field evaluation and selection for stable performance. Selection of improved shrub willow varieties for use as a bioenergy crop involves evaluation of full-sib progeny in family-based selection trials. Improving the accuracy of evaluation through the use of components of yield would greatly improve the efficiency of selection. Heterosis for biomass yield in intra- and interspecific F1 and F2 shrub willow crosses, made between Salix sections and ploidy, was examined by utilizing a suite of morphological, physiological, and chemical composition traits collected over the course of 12 weeks in the greenhouse and over 3 years in the field. Triploid families generated from diploid S. viminalis and tetraploid S. miyabeana displayed the greatest levels of heterosis for harvestable biomass and biomass-related growth traits in the greenhouse and in the field. While intraspecific S. purpurea diploids exhibited low levels of heterosis for these traits, interspecific diploids produced moderate levels of heterosis in greenhouse experiments. Differences between greenhouse and field trial results can largely be explained by pest damage, which negatively impacted interspecific diploids. Heterosis for the traits that form the basis for biomass yield, including stem growth, foliar, and physiological traits, was quantified, and family-level differences are discussed.

Genomic Prediction of Yield Traits in Single-Cross Hybrid Rice (Oryza sativa L.).

Hybrid rice varieties can outyield the best inbred varieties by 15 – 30% with appropriate management. However, hybrid rice requires more inputs and management than inbred rice to realize a yield advantage in high-yielding environments. The development of stress-tolerant hybrid rice with lowered input requirements could increase hybrid rice yield relative to production costs. We used genomic prediction to evaluate the combining abilities of 564 stress-tolerant lines used to develop Green Super Rice with 13 male sterile lines of the International Rice Research Institute for yield-related traits. We also evaluated the performance of their F1 hybrids. We identified male sterile lines with good combining ability as well as F1 hybrids with potential further use in product development. For yield per plant, accuracies of genomic predictions of hybrid genetic values ranged from 0.490 to 0.822 in cross-validation if neither parent or up to both parents were included in the training set, and both general and specific combining abilities were modeled. The accuracy of phenotypic selection for hybrid yield per plant was 0.682. The accuracy of genomic predictions of male GCA for yield per plant was 0.241, while the accuracy of phenotypic selection was 0.562. At the observed accuracies, genomic prediction of hybrid genetic value could allow improved identification of high-performing single crosses. In a reciprocal recurrent genomic selection program with an accelerated breeding cycle, observed male GCA genomic prediction accuracies would lead to similar rates of genetic gain as phenotypic selection. It is likely that prediction accuracies of male GCA could be improved further by targeted expansion of the training set. Additionally, we tested the correlation of parental genetic distance with mid-parent heterosis in the phenotyped hybrids. We found the average mid-parent heterosis for yield per plant to be consistent with existing literature values at 32.0%. In the overall population of study, parental genetic distance was significantly negatively correlated with mid-parent heterosis for yield per plant (r = −0.131) and potential yield (r = −0.092), but within female families the correlations were non-significant and near zero. As such, positive parental genetic distance was not reliably associated with positive mid-parent heterosis.

Heterosis for yield and yield attributing traits in tomato (Solanum lycopersicum L.)

Six diverse lines of tomato were crossed with four testers inline x tester (L×T) cross design to investigate the extent ofheterosis for yield and its contributing traits in tomato. Thepresent investigation was carried out under AICRP onVegetable Crops at Horticultural Research cum InstructionalFarm, Department of Vegetable Science, IGKV, Raipur (C.G.)during rabi 2017-18. A high degree of heterosis wasobserved for most of the characters under investigation.High per se performance with remarkable heterosis wereexpressed by PR x 14/TLCV-3, KA x 15/TLCV-2, H-86 x 14/TLCV-3, KA x 14/TLCV-3 and H-24 x 14/TLCV-1 for higherfruit yield, however, a high degree of heterosis for othertraits in desired direction was also observed

Estimation of economic heterosis for seed and oil yield in sunflower (Helianthus annuus L.) hybrids for coastal saline belt

Present investigation was carried out to identify the best hybrid combinations giving high degree of useful heterosis for economic traits like seed and oil yield in sunflower under high saline soil in coastal saline belts of West Bengal. The standard heterosis for seed yield ranged from -12.7 to 17.9, -3.4 to 30.5 and -10.5 to 20.8 per cent over LFSH -171, DRSH-1 and KBSH-44, respectively. The maximum hybrid vigor for seed yield was reported in the CMS-234A x EC-273009, followed by CMS-853A x EC 623023, CMS-234A X RHA-1-1, CMS-852 A x EC-601725 and CMS-852A x EC-601751. The range of economic heterosis for oil yield varied from 0.3 to 27.2 per cent over LSFH-171, from -10.2 to 13.9 per cent over DRSH-1 and from 5.2 to 33.4 per cent over KBSH-44. The maximum hybrid vigor for oil yield was reported in the CMS-234 A x EC-273009, followed by CMS-853 A x EC 623023, CMS-103 A x EC-601978, CMS-850 A x EC-601978, CMS-852 A x EC-601725, CMS-207 A X CSFI-99, CMS-234A X RHA-1-1 and PET-2-7-1A x R-138-2 . The study revealed that out of 32 new sunflower hybrids, only hybrids viz., CMS-234 A x EC-273009, CMS-853 A x EC 623023, CMS-234A X RHA-1-1, CMS-852 A x EC-601725 CMS-850 A x EC-601978 and CMS-207 A X CSFI-99 manifested significant economic heterosis for seed and oil yield over national checks LSFH-171, DRSH-1 and KBSH-44. From the study it may be concluded that the sunflower hybrids viz. CMS-234 A x EC-273009, CMS-853 A x EC 623023, CMS-234A X RHA-1-1, CMS-852 A x EC-601725, CMS-207 A X CSFI-99 and CMS-850 A x EC-601978 might be promoted for further evaluation and commercialization. Key wordEconomic heterosis, Sunflower, Seed Yield, Oil Yield.

The magic of genomics in creating hybrid potato

The magic of genomics in creating hybrid potato

Studies on heterosis for fruit yield and quality attributing characters in in okra [Abelmoschus esculentus (L.) Moench

The present investigation was conducted on heterosis for fruit yield quality attributing characters in okra. Fifteen F1 hybrids were generated by half diallel (excluding reciprocals) mating design. These F1 hybrids along with six parents were evaluated in Randomized Block Design with three replications during late Rabi season of 2018 at three locations HRS, Lam; KVK, V.R.Gudem and KVK, Vonipenta, Andhra Pradesh. Observations were recorded for five randomly selected and tagged plants from each treatment for fruit yield and quality attributing characters viz., number of fruits per plant, fruit length (cm), fruit girth (cm), fruit weight (g), number of seeds per fruit, test weight (g/100), fruit yield per plant (g), fruit yield per hectare (t), fibre content (%), ascorbic acid content (mg/100g) and shelf life (days). The values of F1 hybrids averaged over three replications were used for estimating heterosis and pooled data was obtained. The top five heterotic cross combinations viz., 440-10-1 x HRB-9-2, VRO-6 x HRB-9-2, TCR-1674 x HRB-9-2, VRO-6 x JPM-20-16-39 and VRO-3 x HRB-9-2 were identified as stable with desirable heterosis for fruit yield and other important traits.

The metabolomic landscape of rice heterosis highlights pathway biomarkers for predicting complex phenotypes.

Understanding the molecular mechanisms underlying complex phenotypes requires systematic analyses of complicated metabolic networks and contributes to improvements in the breeding efficiency of staple cereal crops and diagnostic accuracy for human diseases. Here, we selected rice (Oryza sativa) heterosis as a complex phenotype and investigated the mechanisms of both vegetative and reproductive traits using an untargeted metabolomics strategy. Heterosis-associated analytes were identified, and the overlapping analytes were shown to underlie the association patterns for six agronomic traits. The heterosis-associated analytes of four yield components and plant height collectively contributed to yield heterosis, and the degree of contribution differed among the five traits. We performed dysregulated network analyses of the high- and low-better parent heterosis hybrids and found multiple types of metabolic pathways involved in heterosis. The metabolite levels of the significantly enriched pathways (especially those from amino acid and carbohydrate metabolism) were predictive of yield heterosis (area under the curve = 0.907 with 10 features), and the predictability of these pathway biomarkers was validated with hybrids across environments and populations. Our findings elucidate the metabolomic landscape of rice heterosis and highlight the potential application of pathway biomarkers in achieving accurate predictions of complex phenotypes.

Heterotic pools in African and Asian origin populations of pearl millet [Pennisetum glaucum (L.) R. Br.

Forty-five African or Asian origin pearl millet populations bred either in Africa or Asia were investigated to generate information on heterotic pools. They were clustered into seven groups (G1 to G7) when genotyped, using 29 highly polymorphic SSRs. Fourteen parental populations representing these seven marker-based groups were crossed in diallel mating design to generate 91 population hybrids. The hybrids evaluated at three locations in India showed mean panmictic mid-parent heterosis (PMPH) and better-parent heterosis (PBPH) for grain yield ranging from − 21.7 to 62.08% and − 32.51 to 42.99%, respectively. Higher grain yield and heterosis were observed in G2 × G6 (2462 kg ha−1, 43.2%) and G2 × G5 (2455 kg ha−1, 42.8%) marker group crosses compared to the most popular Indian open-pollinated variety (OPV) ICTP 8203. Two heterotic groups, Pearl millet Population Heterotic Pool-1 (PMPHP-1) comprising G2 populations and Pearl millet Population Heterotic Pool-2 (PMPHP-2) comprising G5 and G6 populations, were identified based on hybrid performance, heterosis and combining ability among marker group crosses. Population hybrids from two heterotic groups, PMPHP-1 × PMPHP-2 demonstrated PMPH of 14.75% and PBPH of 6.8%. Populations of PMPHP-1 had linkages with either African or Asian origin populations, whereas PMPHP-2 composed of populations originating in Africa and later bred for Asian environments. Results indicated that parental populations from the two opposite heterotic groups can be used as base populations to derive superior inbred lines to develop high yielding hybrids/cultivars.

Underground heterosis for yield improvement in melon.

Heterosis, the superiority of hybrids over their parents, is a major genetic force associated with plant fitness and crop yield enhancement. We investigated root-mediated yield heterosis in melons (Cucumis melo) by characterizing a common variety grafted onto 190 hybrid rootstocks, resulting from crossing 20 diverse inbreds in a diallel-mating scheme. Hybrid rootstocks improved yield by more than 40% compared with their parents, and the best hybrid yield outperformed the reference commercial variety by 65% under both optimal and minimal irrigation treatments. To characterize the genetics of underground heterosis we conducted whole genome re-sequencing of the 20 founder lines, and showed that parental genetic distance was no predictor for the level of heterosis. Through inference of the 190 hybrid genotypes from their parental genomes, followed by genome-wide association analysis, we mapped multiple quantitative trait loci for root-mediated yield. Yield enhancement of the four best-performing hybrid rootstocks was validated in multiple experiments with four different scion varieties. Our grafting approach is complementary to the common roots genetic approach that focuses mainly on variation in root system architecture, and is a step towards discovery of candidate genes involved in root function and yield enhancement.

The genetic mechanism of heterosis utilization in maize improvement

BackgroundIn maize hybrid breeding, complementary pools of parental lines with reshuffled genetic variants are established for superior hybrid performance. To comprehensively decipher the genetics of heterosis, we present a new design of multiple linked F1 populations with 42,840 F1 maize hybrids, generated by crossing a synthetic population of 1428 maternal lines with 30 elite testers from diverse genetic backgrounds and phenotyped for agronomic traits.ResultsWe show that, although yield heterosis is correlated with the widespread, minor-effect epistatic QTLs, it may be resulted from a few major-effect additive and dominant QTLs in early developmental stages. Floral transition is probably one critical stage for heterosis formation, in which epistatic QTLs are activated by paternal contributions of alleles that counteract the recessive, deleterious maternal alleles. These deleterious alleles, while rare, epistatically repress other favorable QTLs. We demonstrate this with one example, showing that Brachytic2 represses the Ubiquitin3 locus in the maternal lines; in hybrids, the paternal allele alleviates this repression, which in turn recovers the height of the plant and enhances the weight of the ear. Finally, we propose a molecular design breeding by manipulating key genes underlying the transition from vegetative-to-reproductive growth.ConclusionThe new population design is used to dissect the genetic basis of heterosis which accelerates maize molecular design breeding by diminishing deleterious epistatic interactions.

English

English

Analysis of Re-Heterosis for Yield and Fruit Quality in Restructured Hybrids, Generated from Crossings among Tomato Recombinant Lines

Randomized complete block design was used, with three replications. Heterosis for yield and fruit quality characteristics was studied, and expressed as Relative heterosis, heterobeltiosis and Standard heterosis. It would be expected, according to the dominance model, that the heterosis recorded after crossing the recombinant lines, having only a small portion of recessive deleterious alleles, would be minimal. The results showed that the elite recombinant inbred lines became the parents of elite restructured hybrids, with increased levels of re-heterosis for all characters measured. This may prove that dominance is not the only case in explaining heterosis in tomato for yield components and fruit quality characteristics. Several recombinant lines, and most of the new reconstructed F1 hybrids, showed excellent productivity under a low input farming system. The evaluation and selection of the different types of cultivars (recombinant pure lines or reconstructed hybrids) under low input conditions could point towards the most suitable/ideal genotype for organic cultivation.

COMBINING ABILITY IN RELATION TO HETEROSIS EFFECTS AND GENETIC DIVERSITY IN COTTON USING LINE X TESTER MATING DESIGN

The aim of this study was to investigate the relationship between specific combining ability, genetic diversity of parents and heterosis over better parent effects. This research, having eighteen F1 crosses derived from crossing between six lines and three testers, was conducted in order to estimate combining ability, to determine the nature of gene action and heterosis for yield and fiber quality traits and to detect the appropriate crosses for cotton breeding program. The experiment was conducted on randomized complete block design with three replications. The analyses of variance showed significant differences among the genotypes, parents (lines and testers) and crosses for all the studied traits. Estimates of both general and specific combining ability effects were significant for most traits, indicating the importance of both additive and non-additive gene effects for these traits. While, specific was higher than general combining ability variances, for all traits, showing non-additive gene action controlling and therefore, heterosis breeding may be rewarding. The heterosis value varied from cross to cross and from trait to trait. This dissimilarity coefficient was ranged from 3.234 between Giza 85 and Giza 80 to 71.002 between Giza 96 and 10229. Association between heterosis over better parent and specific combining ability was positive and significant for all the studied traits except lint yield / plant. No correlations were found between SCA and GD for all the studied traits. Similarly, heterosis effects was negatively significantly correlated with GD only in the case of boll weight, lint yield / plant and uniformity ratio %, while showed positive and significant correlation for fiber strength and micronaire value. Four crosses showed both positive and significant heterosis and specific combining ability for most yield traits. The parents of these crosses belong to different clusters. Crossing diverse parents could produce high heterotic performance in hybri

PARENTAL SELECTIONS IN SORGHUM (SORGHUM BICOLOR L.) ON THE BASIS OF HETEROSIS AND COMBINING ABILITY IN ASSOCIATION WITH SSR DIVERSITY IN SUB-TROPICAL PLAINS OF UTTARAKHAND, INDIA

Selection of genetically diverse and complementary parents for important key traits is most difficult task in any hybrid breeding programme. The objective of this study was to estimate heterosis and relative combining abilities with associated SSR diversity for identification of unique sorghum genotypes. A total of forty crosses and thirteen parental lines including five cytoplasmic male sterile (CMS) lines and eight pollinator lines with two standard check varieties were phenotyped using six agro-morphological traits and genetic diversity was estimated by using five polymorphic SSR markers. Sorghum genotypes were crossed with CMS lines using a line × tester mating design and 40 hybrids, 13 parents and two check varieties were field-evaluated using alpha lattice design with three replications. General combining ability (GCA), specific combining ability (SCA) and heterosis for grain yield and other associated attributes were determined. SSR diversity estimates were ranged from 0.54 to 0.90. Among CMS lines, 11A2 and MR750A2 and among pollinators, UPC2 and M35-1 were reported as best general combiners. A2 cytoplasm was found to be more efficient to produce more heterotic combination with experimental lines. Cross, 11A2 x UPC2 gave best results of heterosis for most of the characters. MR750 A2 x UPC2, 11A2 x UPC2, ICSA467 x UPC2, ICSA467 x CS3541, ICSA 467 x RS29, ICSA 467 x M35-1 and 11A2 x M35-1 revealed significant and positive values of heterosis, SCA and GCA. However, no direct correlation was detected with heterosis and molecular diversity for most of the characters. These results may be used for the exploitation of hybrid vigor in sorghum breeding programmes

An enhanced photosynthesis and carbohydrate metabolic capability contributes to heterosis of the cotton (Gossypium hirsutum) hybrid \u2018Huaza Mian H318\u2019, as revealed by genome-wide gene expression analysis

BackgroundHeterosis has been exploited for decades in different crops due to resulting in dramatic increases in yield, but relatively little molecular evidence on this topic was reported in cotton.ResultsThe elite cotton hybrid variety ‘Huaza Mian H318’ (H318) and its parental lines were used to explore the source of its yield heterosis. A four-year investigation of yield-related traits showed that the boll number of H318 showed higher stability than that of its two parents, both in suitable and unsuitable climate years. In addition, the hybrid H318 grew faster and showed higher fresh and dry weights than its parental lines at the seedling stage. Transcriptome analysis of seedlings identified 17,308 differentially expressed genes (DEGs) between H318 and its parental lines, and 3490 extremely changed DEGs were screened out for later analysis. Most DEGs (3472/3490) were gathered between H318 and its paternal line (4–5), and only 64 DEGs were found between H318 and its maternal line (B0011), which implied that H318 displays more similar transcriptional patterns to its maternal parent at the seedling stage. GO and KEGG analyses showed that these DEGs were highly enriched in photosynthesis, lipid metabolic, carbohydrate metabolic and oxidation-reduction processes, and the expression level of these DEGs was significantly higher in H318 relative to its parental lines, which implied that photosynthesis, metabolism and stress resistances were enhanced in H318.ConclusionThe enhanced photosynthesis, lipid and carbohydrate metabolic capabilities contribute to the heterosis of H318 at the seedling stage, and establishes a material foundation for subsequent higher boll-setting rates in complex field environments.

Gene Action and Heterosis for growth and yield in bread wheat (triticum aestivum l.)

Gene Action and Heterosis for growth and yield in bread wheat (triticum aestivum l.)

Assessment of genetic diversity of Turkish maize landraces for phytic acid and total phenolic contents

Assessment of genetic diversity of Turkish maize landraces for phytic acid and total phenolic contents