Performance Of F1 Hybrids Research Articles

Performance of Different Pumpkin (Cucurbita moschata) Hybrids for Growth, Yield and Quality under Prayagraj Agro-Climatic Condition

An experimental material comprised of 10 hybrid of pumpkin viz., SADABAHAR, PK-2507 F1hybrid, P6 F1 hybrid, P6 Gold F1hybrid, SS-76 F1 hybrid, SURAJ F1hybrid, SIPRA F1 hybrid, PRITVI F1hybrid, LHP-SINGHAM F1hybrid, SW-1001 F1hybrid.The investigation was carried out in a Randomized Block Design with three replications. Main Experiment Station of the Department of Vegetable Science at Sam Higginbottom University of Agriculture, Technology and Sciences Prayagraj (U.P) during the spring season. Present investigation reveuled that pumpkin hybrids viz, vine length cm (SW-1001 F1hybrid), no of braches (PK-2507 F1hybrid) performance best in term of growth. Two hybrids namely LHP-SINGHAM F1hybrid and SW-1001 F1hybrid performance best in term of yield. For the maximum number of fruit per plant and minimum node number for the first staminate flower anthesis was observed in the case of LHP-SINGHAM F1hybrid which is promoted to earliness and high yielding. Two hybrids namely P6 Gold F1hybrid TSS (°Brix), LHP-SINGHAM F1hybrid Vitamin c /100gm.

To assess the performance of F1 hybrids and their parents of rice (Oryza sativa L.) at different levels of salt stress under the hydroponic condition

To assess the performance of F1 hybrids and their parents of rice (Oryza sativa L.) at different levels of salt stress under the hydroponic condition

Single-parent expression complementation contributes to phenotypic heterosis in maize hybrids.

The dominance model of heterosis explains the superior performance of F1-hybrids via the complementation of deleterious alleles by beneficial alleles in many genes. Genes active in one parent but inactive in the second lead to single-parent expression (SPE) complementation in maize (Zea mays L.) hybrids. In this study, SPE complementation resulted in approximately 700 additionally active genes in different tissues of genetically diverse maize hybrids on average. We established that the number of SPE genes is significantly associated with mid-parent heterosis (MPH) for all surveyed phenotypic traits. In addition, we highlighted that maternally (SPE_B) and paternally (SPE_X) active SPE genes enriched in gene co-expression modules are highly correlated within each SPE type but separated between these two SPE types. While SPE_B-enriched co-expression modules are positively correlated with phenotypic traits, SPE_X-enriched modules displayed a negative correlation. Gene ontology term enrichment analyses indicated that SPE_B patterns are associated with growth and development, whereas SPE_X patterns are enriched in defense and stress response. In summary, these results link the degree of phenotypic MPH to the prevalence of gene expression complementation observed by SPE, supporting the notion that hybrids benefit from SPE complementation via its role in coordinating maize development in fluctuating environments.

Adding genome‐wide genotypic information to a tobacco (Nicotiana tabacum) breeding programme

AbstractLarge‐scale genotypic information can be used to increase genetic gain in plant breeding programmes. In this research, we evaluated the following: (i) statistical models that could be useful in selection of superior tobacco genotypes in absence of phenotypic information; (ii) the applicability of genome‐wide selection (GWS) for predicting tobacco hybrid performance, and (iii) correlations between genetic divergence of parental lines and F1 hybrid performance. We crossed 13 inbred lines of flue‐cured Virginia tobacco crossed in a diallel scheme to generate 72 hybrid combinations and evaluated them in two field environments. Genotype by sequencing was used for single nucleotide polymorphism (SNP) marker generation, and prediction model validation was performed with different levels of missing information. Hybrid performance was predicted using only the genotypic and phenotypic information. We found genetic divergence among lines to be uncorrelated with hybrid performance or heterosis. Genotype × environment interaction affects GWS efficiency, however, and an index that incorporates both genotypic and phenotypic information improves selection accuracy. Tobacco hybrid prediction utilizing GWS data can be used as additional information to increase the response to selection.

Diallelic Analysis of Tropical Maize Germplasm Response to Spontaneous Chromosomal Doubling.

Chromosome doubling is an important step in the production of maize doubled haploid (DH) lines to induce fertility in the male and female reproductive organs of haploid plants. Chromosomal doubling is routinely accomplished by treating haploid seedlings with mitosis-inhibiting chemicals. However, chromosomal doubling involves several labor-intensive steps and toxic chemicals. Spontaneous chromosomal doubling without any chemical treatments occurs at high frequency in haploids from a few maize genotypes. This study focused on elucidating the genetic components of two traits important for using spontaneous doubling in maize-breeding programs, namely, haploid male fertility (HMF) and haploid fertility (HF). In two different sets of diallel crosses, haploids were derived and assessed for HMF and HF in two environments in replicated trials. The results revealed significant genotypic variations for both traits. The general combining ability (GCA) and specific combining (SCA) were significant for both traits. Significant and positive GCA effects of up to 14% and 9% were found for HMF and HF, respectively. No significant reciprocal effects and genotype-by-environment (G×E) interactions were found for HF in both experiments, but HMF showed significant effects for both in one of the experiments. The GCA effects were more important than the SCA effects for HMF and HF across environments, implying that selection could facilitate their improvement. The high correlations between F1-hybrid performance and mid-parent values, as well as that between F1-hybrid performance and GCA effects, also supports the assumption that these traits are controlled by a few genes. SCA effects also played a role, especially when lines with low spontaneous doubling were used as parents. Overall, spontaneous doubling can be introgressed and improved in elite germplasm with selection, and it has the potential to be employed in DH pipelines.

In silico simulation of future hybrid performance to evaluate heterotic pool formation in a self-pollinating crop

Hybrid vigour has the potential to substantially increase the yield of self-pollinating crops such as wheat and rice, but future hybrid performance may depend on the initial strategy to form heterotic pools. We used in silico stochastic simulation of future hybrid performance in a self-pollinating crop to evaluate three strategies of forming heterotic pools in the founder population. The model included either 500, 2000 or 8000 quantitative trait nucleotides (QTN) across 10 chromosomes that contributed to a quantitative trait with population mean 100 and variance 10. The average degree of dominance at each QTN was either 0.2, 0.4 or 0.8 with variance 0.2. Three strategies for splitting the founder population into two heterotic pools were compared: (i) random split; (ii) split based on genetic distance according to principal component analysis of SNP genotypes; and (iii) optimized split based on F1 hybrid performance in a diallel cross among the founders. Future hybrid performance was stochastically simulated over 30 cycles of reciprocal recurrent selection based on true genetic values for additive and dominance effects. The three strategies of forming heterotic pools produced similar future hybrid performance, and superior future hybrids to a control population selected on inbred line performance when the number of quantitative trait nucleotides was ≥2000 and/or the average degree of dominance was ≥0.4.

Estimation of heterosis for yield and its components under normal and sodic soil in barley (Hordeum vulgare L.)

Manipulation of heterosis is considered to be a vital approach to enhance the yield potential of barley and is as accepted to be a safe strategy to overcome barriers in barley yield. Thirteen diverse Indian genotypes were crossed to obtain a series of crosses to estimate the level of heterosis and heterobeltiosis among F1 hybrids along with their parents under two contrasting environments: normal and sodic soil. Estimates revealed a significant relationship between the mean performance of F1 hybrids and their parents under sodic stress regime only. The presence of significant heterosis for grain yield was also accompanied by heterosis for yield components, such as days to 50% flowering, plant height, number of effective tillers /plant, number of spikelets /spike, number of grains/ spike, days to maturity,1000- grain weight, biological yield / plant, grain yield / plant and harvest index. The cross NDB 1245 X NDB 943 was an elite cultivar and showed significant heterobeltiosis. The study suggests that the obtained hybrids surpassed their better parents’ effects, indicative of commercial heterosis, and are thus candidates for the commercial production of hybrid barley.

Ploidy variation and agronomic performance of F1 hybrids of tetraploid and diploid forms of Humulus lupulus L.

Humulus lupulus (2n = 2x = 20) as a source of hop resins, essential oils and polyphenols has value in brewing, pharmacy and cosmetology. Conventional crossing between tetraploids of ‘Sybilla’ and diploid males were performed to obtain F1 hybrids. Cytological studies revealed that 83.8% of the hybrids were triploids (2n = 3x = 30), 15.2% were aneuploids in which the chromosome number ranged from 28–32. Tetraploids (2n = 4x = 40) and diploids were also observed, which indicates numerous disturbances of gametogenesis of the parental forms. STS markers specific for male plants showed that females outnumbered male individuals among the F1 hybrids, which is in accordance with the distribution of sex ratio characteristic for diploid hybrids of H. lupulus. Female triploids were compared to the control ‘Sybilla’ with regard to their functional characteristics and alpha acids content in cones. A two year-long experiment showed that most of the triploids had a significantly higher position of fructiferous branches and shoot twist index compared to diploids of ‘Sybilla’. There was also a significantly extended time for them to reach technological maturity of cones. Triploids were distinguished by a significantly lower seed content compared to ‘Sybilla’, therefore the raw material obtained from them is more suitable for the production of hop pellets and extracts.

Reproductive Cold Stress Tolerance in Sorghum F1 Hybrids is a Heterotic Trait

The sensitivity of sorghum to pre-flowering cold stress, resulting in reduced pollen viability and poor seed set, is a major constraint for expanding growing areas into higher altitudes and latitudes. Nevertheless, compared to juvenile cold tolerance, reproductive cold tolerance in sorghum has received much less attention so far, and very little is known about its inheritance in F1-hybrids. We have composed a representative factorial (n = 49 experimental F1-hybrids) for a comprehensive study on heterosis and combining ability for crucial tolerance traits as spikelet fertility (panicle harvest index), seed yield and pollen viability, using field trials in stress- and control environments in Germany and Mexico as well as climate chamber experiments. Our results indicate a heterotic and rather dominant inheritance of reproductive cold tolerance in sorghum, with strong effects of female general combining ability (GCA) on F1-hybrid performance in our material. These findings, together with the comparatively low contribution of specific combining ability (SCA) effects and high heritability estimates, suggest that robust and efficient enhancement of reproductive cold tolerance is feasible via hybrid breeding.

Heterotic patterns of primary and secondary metabolites in the oilseed crop Brassica juncea.

Heterosis refers to the superior performance of F1 hybrids over their respective parental inbred lines. Although the genetic and expression basis of heterosis have been previously investigated, the metabolic basis for this phenomenon is poorly understood. In a preliminary morphological study in Brassica juncea, we observed significant heterosis at the 50% flowering stage, wherein both the growth and reproduction of F1 reciprocal hybrids were greater than that of their parents. To identify the possible metabolic causes or consequences of this heterosis, we carried out targeted LC-MS analysis of 48 primary (amino acids and sugars) and secondary metabolites (phytohormones, glucosinolates, flavonoids, and phenolic esters) in five developmental tissues at 50% flowering in hybrids and inbred parents. Principal component analysis (PCA) of metabolites clearly separated inbred lines from their hybrids, particularly in the bud tissues. In general, secondary metabolites displayed more negative heterosis values in comparison to primary metabolites. The tested primary and secondary metabolites displayed both additive and non-additive modes of inheritance in F1 hybrids, wherein the number of metabolites showing an additive mode of inheritance were higher in buds and siliques (52.77-97.14%) compared to leaf tissues (47.37-80%). Partial least regression (PLS) analysis further showed that primary metabolites, in general, displayed higher association with morphological parameters in F1 hybrids. Overall, our results are consistent with a resource-cost model for heterosis in B. juncea, where metabolite allocation in hybrids appears to favor growth, at the expense of secondary metabolism.

Variability and Performance of F1 hybrids Tomatoes Crossing Between Tropical Tomatoes Cultivars and Ethylene Insensitive Mutants

Variability and Performance of F1 hybrids Tomatoes Crossing Between Tropical Tomatoes Cultivars and Ethylene Insensitive Mutants

Genome-wide regression models considering general and specific combining ability predict hybrid performance in oilseed rape with similar accuracy regardless of trait architecture.

Genomic prediction using the Brassica 60k genotyping array is efficient in oilseed rape hybrids. Prediction accuracy is more dependent on trait complexity than on the prediction model. In oilseed rape breeding programs, performance prediction of parental combinations is of fundamental importance. Due to the phenomenon of heterosis, per se performance is not a reliable indicator for F1-hybrid performance, and selection of well-paired parents requires the testing of large quantities of hybrid combinations in extensive field trials. However, the number of potential hybrids, in general, dramatically exceeds breeding capacity and budget. Integration of genomic selection (GS) could substantially increase the number of potential combinations that can be evaluated. GS models can be used to predict the performance of untested individuals based only on their genotypic profiles, using marker effects previously predicted in a training population. This allows for a preselection of promising genotypes, enabling a more efficient allocation of resources. In this study, we evaluated the usefulness of the Illumina Brassica 60k SNP array for genomic prediction and compared three alternative approaches based on a homoscedastic ridge regression BLUP and three Bayesian prediction models that considered general and specific combining ability (GCA and SCA, respectively). A total of 448 hybrids were produced in a commercial breeding program from unbalanced crosses between 220 paternal doubled haploid lines and five male-sterile testers. Predictive ability was evaluated for seven agronomic traits. We demonstrate that the Brassica 60k genotyping array is an adequate and highly valuable platform to implement genomic prediction of hybrid performance in oilseed rape. Furthermore, we present first insights into the application of established statistical models for prediction of important agronomical traits with contrasting patterns of polygenic control.

Accumulation Profiles of Embryonic Salt-Soluble Proteins in Maize Hybrids and Parental Lines Indicate Matroclinous Inheritance: A Proteomic Analysis.

Maize is one of the most widely cultivated crops. It accumulates a large quantity of seed storage proteins, which are important for seed development and germination, and contribute to the nutritional quality of seeds. Based on solubility, the storage proteins are divided into albumins (water-soluble), globulins (salt-soluble), prolamins (alcohol-soluble), and glutelins (acid- or alkali-soluble). Maize hybrids are cultivated due to the superior performance of F1 hybrids than that of their parents, a phenomenon known as heterosis. However, the accumulation patterns of seed storage proteins in maize embryos between the hybrids and their parental inbred lines have not been compared. In the present study, two elite inbred lines of China, Zheng 58 and Chang 7-2, and their reciprocal hybrids (Zheng 58 × Chang 7-2 and Chang 7-2 × Zheng 58) were used to explore parental influences on the accumulation patterns of seed storage proteins in maize embryos. For this purpose, we focused on seed salt-soluble proteins (SSPs) in our experiments. The SSPs were selectively extracted from maize mature embryos after extensive removal of water-soluble albumin and separated using two-dimensional gel electrophoresis (2-DE), followed by mass spectrometry analysis. Our results indicated that the 2-DE SSP profiles of hybrids closely resembled those of their maternal parent rather than the paternal parent. In other words, 2-DE SSP profiles of Zheng 58 × Chang 7-2 were more similar those of Zheng 58 whereas such profiles of Chang 7-2 × Zheng 58 were more similar to those of Chang 7-2 although the 2-DE profiles of all four maize types were quite similar. In total, 12 relatively abundant SSPs spots representing five kinds of proteins were identified, of which nine protein spots displayed non-additive accumulation in at least one hybrid. This study provided additional data on dominance and partial dominance effects on maize hybrids embryos. Besides, earlier studies on accumulation profiles of globulin-1 (also known as vicilin), which is one of the most abundant globulins in maize embryos, also support the above results. This study would be helpful in revealing the mechanisms underlying SSPs accumulation patterns in the hybrids.

Stability of Single-Parent Gene Expression Complementation in Maize Hybrids upon Water Deficit Stress.

Heterosis is the superior performance of F1 hybrids compared with their homozygous, genetically distinct parents. In this study, we monitored the transcriptomic divergence of the maize (Zea mays) inbred lines B73 and Mo17 and their reciprocal F1 hybrid progeny in primary roots under control and water deficit conditions simulated by polyethylene glycol treatment. Single-parent expression (SPE) of genes is an extreme instance of gene expression complementation, in which genes are active in only one of two parents but are expressed in both reciprocal hybrids. In this study, 1,997 genes only expressed in B73 and 2,024 genes only expressed in Mo17 displayed SPE complementation under control and water deficit conditions. As a consequence, the number of active genes in hybrids exceeded the number of active genes in the parental inbred lines significantly independent of treatment. SPE patterns were substantially more stable to expression changes by water deficit treatment than other genotype-specific expression profiles. While, on average, 75% of all SPE patterns were not altered in response to polyethylene glycol treatment, only 17% of the remaining genotype-specific expression patterns were not changed by water deficit. Nonsyntenic genes that lack syntenic orthologs in other grass species, and thus evolved late in the grass lineage, were significantly overrepresented among SPE genes. Hence, the significant overrepresentation of nonsyntenic genes among SPE patterns and their stability under water limitation might suggest a function of these genes during the early developmental manifestation of heterosis under fluctuating environmental conditions in hybrid progeny of the inbred lines B73 and Mo17.

Komplementation von Genexpressionsmustern in Maishybriden

Heterosis describes the superior performance of F1-hybrids compared to their genetically distinct parents, a phenomenon which is extensively exploited in maize breeding. To better understand the molecular basis of heterosis in maize, we analyzed how the genetic diversity of parental inbred lines affects the root transcriptome of their F1-progeny. We discovered complementation of activity in evolutionary younger genes and as a consequence more active genes in hybrids than in parental inbred lines.

Interspecific hybridization between cultivated and wild species of genus Passiflora L.

The genus Passiflora L. has about 80 species with edible fruits and desirable agronomic characteristics which can be transferred to commercial species for further breeding by artificial hybridization. The aim of this study is to determine the self-fertility (SF) and interspecific compatibility of six commercially cultivated species and six wild species as a resource for future breeding programs. Reciprocal interspecific pollinations were carried out involving twelve species for a total of 144 hybrids combinations. The test of SF showed that seven species display no more than 5 % of fruit set, indicating self-incompatibility (P. cincinnata, P. maliformis, P. caerulea, P. mucronata and P. vitifolia, P.alata and P. edulis f. flavicarpa). Percentage of formed fruits in a fruit set ranged from 2.1 to 60 % and results showed significant differences in the effectiveness of some species in crosses when acting as the female parent. The highest fruit set was obtained when the female parent was P. vitifolia, P. mucronata and P. edulis f. edulis and P. edulis f. flavicarpa ranging from 22.2 to 60 %. Regarding fruit production, 48.1 % of the successful crosses reached physiological maturity giving a total of 21 fruits with similar sizes and number of seeds, as compared to the ones obtained by natural pollination. Post-zygotic barriers were detected in 53.8 % of the crosses where a fruit was formed due to failure in seed endosperm development or low germination. The highest percentage of germination was obtained in crosses of P. mucronata × P. alata and P. edulis f. flavicarpa × P. vitifolia with 87.5 and 100 %, respectively. The finding of high compatibility of some hybrid combinations in this study is promising. However, the performance of F1 hybrids needs to be determined in field evaluations to assess the real potential for further breeding.

Morphological characteristics and growth performance of F1 hybrids of red junglefowl cocks crossed with Fayoumi or H’mong Hens

Red Junglefowl (Gallus gallus) is considered as the direct ancestor of domesticated chickens. There is a wide speculation on the on-going gene flow between Red Junglefowls in the wild and some neigbouring native chicken populations in South and Southeast Asia. This may challenge the reliability of specific morphological markers to differentiate them and may have implications on the utility value of Red Junglefowls in the genetic improvement for disease resistance and adaptive traits of domestic chickens. The intensive monitoring and measurements of morphological and morphometric characteristics of 100 F1 hybrid birds each from two mating groups involving Red Junglefowl cocks crossing with Fayoumi or H'mong hens were performed from day-old chicks to 12-week-old pullets in this study. The morphological data showed that the typical down feather pattern in striped phenotype as for camouflage, that is critical to the survival of Red Junglefowls in the wild, was not observed in any hybrid chick, suggesting that this specific phenotype is likely controlled by a recessive allele and thus a morphological marker for the identification of true Red Junglefowls in their early development stages or life. The high survival rate and improved growth performance of the two F1 hybrid groups demonstrated the potential value of Red Junglefowls in reconstituting the genetic diversity and possibly improving the adaptability of domestic chickens. Therefore the unique wild relative resources that are able to survive in the increasingly fragmented jungles in South and Southeast Asia warrant further exploration and great attention for in situ conservation and sustainable exploitation.

Characterization of a new temperature-sensitive male sterile line SP2S in rapeseed (Brassica napus L.)

Photoperiod and/or temperature-sensitive male sterility is an economically effective pollination control system for hybrid crops production. This study reports some characteristics of a temperature-sensitive genic male sterile (TGMS) in Brassica napus line, SP2S, which is a spontaneous mutation found in 2007. The fertility alteration in response to temperature was investigated under controlled environment conditions. The pollen abortion was observed under light and electron microscopes to investigate structural and cellular changes associated with male sterility. The results showed that the fertility of SP2S line was greatly influenced by temperature change 12–14 days prior to flowering while photoperiod had no obvious effect on it. The SP2S line became male sterile when daily maximum temperature was above 20 °C and nearly fertile when lower than 15 °C. The size of petal and stamen reduced while the pistil and nectary was normal with good seed set after open-pollination. Microscopic observation in this study revealed the extremely vacuolated and enlarged tapetal cells of PMC during meiosis, which was associated with pollen abortion. The microspores were bonded together and hardly released from tetrads due to the persistence of callose layer covering them. The cytoplasm of degenerated microspores was accompanied by early degraded tapetum. The fertility of SP2S was controlled by at least two recessive nuclear genes and all cultivars could restore the fertility of SP2S. Commercially valuable traits such as seed yield, seed quality, sclerotinia-resistance, lodging, and other agronomical traits of four F1 hybrids of SP2S were as good as their counterparts from near isogenic line, SP2F. The recessive TGMS genes showed no adverse effect on the performance of F1 hybrids. Thus, SP2S line is a promising TGMS for hybrid production in rapeseed and canola. This characterization study helped understanding the process of male sterility and producing super hybrids through this two-line pollination control system.

Evaluation of F1 Hybrids and their Parents for Growth, Yield and Quality in Cherry Tomato (Solanum lycopersicum Var. cerasiforme)

The present study was carried out to estimate the performance of F1 hybrids and their parents for various yield and yield-attributing traits in cherry tomato, at Division of Vegetable Crops, Indian Institute of Horticultural Research (IIHR), Bengaluru, during the year 2010-11. Among the seven parents used, three parents, namely, IIHR-2866 (yielding 3.03kg/plant), IIHR-2864 (2.87kg/plant) and IIHR-2865 (2.73kg/plant) were found to be high-yielding. Among the 21 F1 hybrids evaluated, three hybrids, namely, IIHR-2754 x IIHR-2860 (4.27kg/plant), followed by IIHR- 2754 x IIHR-2865 (3.97kg/plant) and IIHR-2864 x IIHR-2865 (3.40kg/plant) recorded higher yield than the Check varieties, whereas, three hybrids, viz, IIHR-2754 x IIHR-2865 (54.38t/ha), succeeded by IIHR-2863 x IIHR-2866 (46.46t/ha) and IIHR-2858 x IIHR-2866 (44.79t/ha), recorded higher estimated yield per hectare than the Check varieties. Hybrid IIHR-2754 x IIHR-2860 was found promising for most of the traits studied. The best performing parents can be used for breeding further while, the hybrids can be exploited commercially.

Heterosis and Combing Ability in F1 Population of Hexaploid Wheat (<i>Triticum Aestivum</i> L.)

The heterosis, heterobeltiosis, general combining ability (GCA) and specific combining ability (SCA) were examined during Rabi (crop season) of 2013-2014 in hexaploid wheat genotypes. The experiment for this study was conducted at the Botanical Garden, Department of Plant Breeding & Genetics, Sindh Agriculture University Tandojam, Pakistan. The breeding material was comprised of four parents (Imdad, TD-1, SKD-1, and Moomal). These parents were crossed in half partial mating fashion; thus, six possible cross combinations (F1s) were obtained (Imdad × TD-1, Imdad × SKD-1, Imdad × Moomal, TD-1 × SKD-1, TD-1 × Moomal, and SKD-1 × Moomal). A three-replicated RCB Design was used. The mean squares corresponding to different traits of various hexaploid wheat genotypes indicated significant (P F1 hybrids) effects for the characters (plant height, tillers plant-1, spike length, spikelets spike-1, seeds spike-1, seed index, and grain yield plant-1). The mean performance of F1 hybrids differed significantly (P < 0.01) for all the traits studied. Among the parents, Imdad and TD-1 proved to be better general combiners for almost all the studied traits. In regards to SCA effects, the F1 hybrids Imdad × TD-1 and Imdad × SKD-1 expressed higher SCA and heterotic effects for most of the studied traits.