Hybrid Pair Research Articles

Chromosomal constitutions of five wheat – Elytrigia elongata partial amphiploids as revealed by GISH, multicolor GISH and FISH

A combination of meiotic pairing analysis and in situ hybridization (genomic in situ hybridization [GISH], multicolor GISH [mcGISH] and fluorescence in situ hybridization [FISH]) of five Triticum aestivum (Linnaeus, 1753) - Elytrigia elongata (Podpěra, 1902) (2n = 10x = 70) amphiploids was employed to investigate the genomic constitution and relationships between wheat and alien chromosomes. GISH, multicolor GISH and FISH patterns of mitotic chromosomes indicate that the genomic constitution of the five partial amphiploids (XY693, XY7430, SN19, SN20 and SN122) are 14A + 12B + 14D + 8Js + 8J, 12A + 16B + 14D + 2St + 8Js + 2J + 2 W-E, 14A + 14B + 14D + 4St + 8Js, 14A + 14B + 14D + 2St + 10Js + 2J, and 14A + 14B + 14D + 2St + 8Js + 4J, respectively. Analysis of meiotic chromosome pairing in the F1 hybrids between these five partial amphiploids suggests that SN20 and SN122 are the most closely related amphiploids and are somewhat related with XY693 and XY7430. However, the alien chromosome constitutions of SN19 differed from the other four amphiploids. In addition, a new pairing between wheat and E. elongata chromosomes was distinguished in some cells of the hybrids SN19 × XY7430, SN20 × XY7430 and SN122 × XY7430.

A General Coincidence and Fixed Point Theorem for Hybrid Pairs of Mappings Satisfying a Common Coincidence Range Property

AbstractIn this paper the notion of common coincidence range property is introduced and a general coincidence and fixed point theorem is proved. As applications, new results for mappings satisfying a contractive condition of integral type and for mappings satisfying a φ-contractive condition are obtained.

On coupled coincidence and common fixed point theorems for different types of mappings satisfying rational type contractions in b−metric spaces

In this paper, we study the existence and uniqueness of coupled coincidence and common xed points for single valued and fuzzy mappings under contraction condition of rational type in b-metric spaces and obtain the corresponding results for hybrid pair of single-valued and multi-valued mappings. We consider b-metric space with partial order and prove the existence coupled coincidence and common xed points for two single valued mappings.

ON EXISTENCE OF STRICT COINCIDENCE AND COMMON STRICT FIXED POINT OF A FAINTLY COMPATIBLE HYBRID PAIR OF MAPS Vol. 5(2) July 2017, No. 29, pp. 298-305 ANITA TOMAR, SHIVANGI UPADHYAY AND RITU SHARMA

ON EXISTENCE OF STRICT COINCIDENCE AND COMMON STRICT FIXED POINT OF A FAINTLY COMPATIBLE HYBRID PAIR OF MAPS Vol. 5(2) July 2017, No. 29, pp. 298-305 ANITA TOMAR, SHIVANGI UPADHYAY AND RITU SHARMA

Pairing analysis and in situ Hybridisation reveal autopolyploid-like behaviour in Solanum commersonii\xa0\xd7\xa0S. tuberosum (potato) interspecific hybrids

Wild potato relatives are rich sources of desirable traits for introgressive hybridisation into cultivated potato. One of them, Solanum commersonii (2n = 2x = 24, 1EBN, endosperm balance number), is an important species belonging to the potato tertiary genepool. It can be used in potato breeding through bridge crosses and 2n gamete production. Triploid F1 hybrids between S. commersonii (through spontaneous 2n egg formation) and diploid 2EBN Solanum tuberosum Group Phureja were crossed with S. tuberosum Group Tuberosum, resulting in successive backcross 1, 2 and 3 progenies. The main aim of this study was to determine if there are any barriers to homoeologous pairing and recombination in the allotriploid (S. commersonii × potato) hybrids and their backcrosses, and so to predict if S. commersonii chromosomes can be transmitted to the next generation and introgressed into their recipient potato chromosomes. Microscopic observations of spread pollen mother cells suggested no preferential pairing in the triploid hybrids, while chromosome transmission and segregation in further meiotic stages were fairly balanced. Fluorescent in situ hybridisation with BAC probes (BAC FISH) was used to obtain markers to trace the meiotic behaviour of specific chromosome pairs. Moreover, genomic in situ hybridisation (GISH) demonstrated no obvious differences in fluorescence signals between the homoeologues suggesting that repetitive sequences did not diverge much between the parental species. As a consequence, we were not able to trace the course of the S. commersonii chromosomes in the successive introgressive hybridisation backcross generations. Our results strongly point at a high genomic similarity between the homoeologous chromosomes promising high suitability of S. commersonii in introgressive hybridisation breeding of potato.

Proximal Point Algorithms for a Hybrid Pair of Nonexpansive Single-Valued and Multi-Valued Mappings in Geodesic Metric Spaces

In this paper, we propose a new proximal point algorithm for finding a common element of the set of fixed points of nonexpansive single-valued mappings, the set of fixed points of nonexpansive multi-valued mappings, and the set of minimizers of convex and lower semi-continuous functions. We obtain \(\Delta \)-convergence and strong convergence of the proposed algorithm to a common element of the three sets in CAT(0) spaces. Furthermore, we apply our convergence results to obtain in a special space of CAT(0) spaces, so-called \(\mathbb {R}\)-tree, under the gate condition. A numerical example to support our main results is also given.

The Effect of Homoeologous Meiotic Pairing in Tetraploid Hordeum bulbosum L. × H. vulgare L. Hybrids on Alien Introgressions in Offspring

The pairing behaviour of the individual chromosome arms of Hordeum vulgare (Hv) with their homoeologous arms of H. bulbosum (Hb) at metaphase I of meiosis in tetraploid Hb × Hv hybrids and the frequencies of recombined Hv chromosome arms in selfed offspring were studied on differentially visualized chromosomes after fluorescent in situ hybridisation. The frequencies of paired Hv-Hb arms in the F₂ and F₃ hybrids were correlated with the frequencies of recombined Hv chromosomes in progenies. Self-generation of hybrids, the number of Hv and Hb chromosomes, and the number of recombined Hv chromosomes of the hybrids strongly influenced the Hv-Hb pairing frequency in meiosis. Within the offspring of F₂ and F₃ hybrids both Hv plants and hybrids were detected. In contrast, all progenies of the F₄ hybrid were hybrids which exhibited centromere misdivisions. The highest frequencies of homoeologous pairing in hybrids and most recombinants were obtained for the barley chromosome 1HL. Recombinants for 4HL, 5HS, 6HS, and 7HS were rarely found. Meiotic pairing and recombinants involving chromosome 1HS were never observed. The results of this study demonstrate that fertile tetraploid interspecific hybrids with a high intergenomic pairing at meiosis are valuable basic material for introgression breeding in barley.

Use of a synthetic form Avrodes for transfer of leaf rust resistance from Aegilops speltoides to common wheat

Diploid wild relative of wheat – Aegilops speltoides – is a valuable source of genes for resistance to diseases. The synthetic form Avrodes (BBAASS) was used as a bridge to transfer leaf rust resistance genes from Ae. speltoides to common wheat. Introgression lines obtained from crosses of Avrodes and susceptible common wheat cultivars were evaluated in a field leaf rust nursery. Resistance levels varied from high to moderate. Testing of lines with the use of molecular markers has shown that some lines have the Lr28 and Lr35 genes inherited from synthetic form Avrodes. The majority of resistance lines have not been found to carry these genes. The Lr47 and Lr51 genes were not identified in the Avrodes and introgression lines. The analysis of chromosome pairing in F1 hybrids showed that the transfer of a genetic material from Avrodes to common wheat basically occurs through translocations. Lines with translocations on chromosomes 2D and 5D were identified by C-banding and FISH. The translocations differed in chromosomal location from known leaf resistance genes transferred to common wheat from Ae. speltoides. Hence it was assumed that new genes were introduced into the common wheat genome from Ae. speltoides. Introgression lines have been studied for productivity and technological qualities of grain. Lines AA60n9 and D37n10 combine high resistance to leaf rust with good characteristics of productivity and technological qualities of grain. The received results demonstrate a genetic diversity and a value of the investigated introgression lines for breeding of common wheat.

Common fixed point theorems for hybrid pair of mappings

In this paper we define the concept of conditionally commuting mappings and establish some common fixed point theorems for hybrid pair of mappings satisfying a nonexpansive type condition.

A general fixed point theorem for two hybrid pairs of mappings satisfying a mixed implicit relation and applications

A general fixed point theorem for two hybrid pairs of mappings satisfying a mixed implicit relation and applications

Strict common fixed points of nonlinear mappings via δ-distances and an application

The purpose of this paper is to prove some strict common fixed point theorems for weakly compatible hybrid pairs of nonlinear mappings defined on semi-metric spaces employing implicit relations which unify, extend and generalize several results from the literature. As an application, we prove a general common fixed point theorem for integral type contractive conditions. Finally, we give an example to demonstrate the main result of the paper.

A coincidence and common fixed point theorem for subsequentially continuous hybrid pairs of maps satisfying an implicit relation

In this paper, we introduce the notion of subsequential continuity for a hybrid pair of maps and combine this concept with compatibility, to establish a coincidence and common fixed point theorem for a hybrid quadruple of maps. Our main result also demonstrates that several fixed point theorems can be unified using implicit relations. We also give two examples in support our results.

An iterative process for a hybrid pair of a Bregman strongly nonexpansive single-valued mapping and a finite family of Bregman relative nonexpansive multi-valued mappings in Banach spaces

In this paper, we construct an iterative process involving a hybrid pair of a Bregman strongly nonexpansive single-valued mapping and a finite family of Bregman relative nonexpansive multi-valued mappings and prove strong convergence theorems of the proposed iterative process in reflexive Banach spaces under appropriate conditions. Our main results can be viewed as an improvement and extension of the several results in the literature.

Multiple and asymmetrical origin of polyploid dog rose hybrids (Rosa L. sect. Caninae (DC.) Ser.) involving unreduced gametes.

Polyploidy and hybridization are important factors for generating diversity in plants. The species-rich dog roses ( Rosa sect. Caninae ) originated by allopolyploidy and are characterized by unbalanced meiosis producing polyploid egg cells (usually 4 x ) and haploid sperm cells (1 x ). In extant natural stands species hybridize spontaneously, but the extent of natural hybridization is unknown. The aim of the study was to document the frequency of reciprocal hybridization between the subsections Rubigineae and Caninae with special reference to the contribution of unreduced egg cells (5 x ) producing 6 x offspring after fertilization with reduced (1 x ) sperm cells. We tested whether hybrids arose by independent multiple events or via a single or few incidences followed by a subsequent spread of hybrids. Population genetics of 45 mixed stands of dog roses across central and south-eastern Europe were analysed using microsatellite markers and flow cytometry. Hybrids were recognized by the presence of diagnostic alleles and multivariate statistics were used to display the relationships between parental species and hybrids. Among plants classified to subsect. Rubigineae , 32 % hybridogenic individuals were detected but only 8 % hybrids were found in plants assigned to subsect. Caninae . This bias between reciprocal crossings was accompanied by a higher ploidy level in Rubigineae hybrids, which originated more frequently by unreduced egg cells. Genetic patterns of hybrids were strongly geographically structured, supporting their independent origin. The biased crossing barriers between subsections are explained by the facilitated production of unreduced gametes in subsect. Rubigineae . Unreduced egg cells probably provide the highly homologous chromosome sets required for correct chromosome pairing in hybrids. Furthermore, the higher frequency of Rubigineae hybrids is probably influenced by abundance effects because the plants of subsect. Caninae are much more abundant and thus provide large quantities of pollen. Hybrids are formed spontaneously, leading to highly diverse mixed stands, which are insufficiently characterized by the actual taxonomy.

Drought-Tolerant Corn Hybrids Yield More in Drought-Stressed Environments with No Penalty in Non-stressed Environments.

The potential benefit of drought-tolerant (DT) corn (Zea mays L.) hybrids may depend on drought intensity, duration, crop growth stage (timing), and the array of drought tolerance mechanisms present in selected hybrids. We hypothesized that corn hybrids containing DT traits would produce more consistent yields compared to non-DT hybrids in the presence of drought stress. The objective of this study was to define types of production environments where DT hybrids have a yield advantage compared to non-DT hybrids. Drought tolerant and non-DT hybrid pairs of similar maturity were planted in six site-years with different soil types, seasonal evapotranspiration (ET), and vapor pressure deficit (VPD), representing a range of macro-environments. Irrigation regimes and seeding rates were used to create several micro-environments within each macro-environment. Hybrid response to the range of macro and micro-environmental stresses were characterized in terms of water use efficiency, grain yield, and environmental index. Yield advantage of DT hybrids was positively correlated with environment ET and VPD. Drought tolerant hybrids yielded 5 to 7% more than non-DT hybrids in high and medium ET environments (>430 mm ET), corresponding to seasonal VPD greater than 1200 Pa. Environmental index analysis confirmed that DT hybrids were superior in stressful environments. Yield advantage for DT hybrids appeared as yield dropped below 10.8 Mg ha-1 and averaged as much as 0.6–1 Mg ha-1 at the low yield range. Hybrids with DT technology can offer a degree of buffering against drought stress by minimizing yield reduction, but also maintaining a comparable yield potential in high yielding environments. Further studies should focus on the physiological mechanisms presented in the commercially available corn drought tolerant hybrids.

Unifying Some Implicit Common Fixed Point Theorems for Hybrid Pairs of Mappings in G-Metric Spaces through Altering Distance Function

Unifying Some Implicit Common Fixed Point Theorems for Hybrid Pairs of Mappings in G-Metric Spaces through Altering Distance Function

A previously undocumented hybrid New World Warbler (Setophaga pensylvanicaxS. magnolia) captured at Long Point, Ontario

ABSTRACT New World Warblers represent a complex and closely related family, with a high propensity to hybridize. With more than 73 known hybrid pairings of Parulidae documented, we report a previously undocumented hybrid: a Chestnut-sided (Setophaga pensylvanica) × Magnolia Warbler (S. magnolia). The parentage of the hybrid individual and its identity are supported by morphological and genetic evidence. DNA sequencing of a fragment of cytochrome oxidase c subunit I (COI) supports the female parent as Chestnut-sided, while strong morphological features support Magnolia Warbler as the father.

Resistance of Bt-maize (MON810) against the stem borers Busseola fusca (Fuller) and Chilo partellus (Swinhoe) and its yield performance in Kenya

A study was conducted to assess the performance of maize hybrids with Bt event MON810 (Bt-hybrids) against the maize stem borer Busseola fusca (Fuller) in a biosafety greenhouse (BGH) and against the spotted stem borer Chilo partellus (Swinhoe) under confined field trials (CFT) in Kenya for three seasons during 2013–2014. The study comprised 14 non-commercialized hybrids (seven pairs of near-isogenic Bt and non-Bt hybrids) and four non-Bt commercial hybrids. Each plant was artificially infested twice with 10 first instar larvae. In CFT, plants were infested with C. partellus 14 and 24 days after planting; in BGH, plants were infested with B. fusca 21 and 31 days after planting. In CFT, the seven Bt hybrids significantly differed from their non-Bt counterparts for leaf damage, number of exit holes, percent tunnel length, and grain yield. When averaged over three seasons, Bt-hybrids gave the highest grain yield (9.7 t ha−1), followed by non-Bt hybrids (6.9 t ha−1) and commercial checks (6 t ha−1). Bt-hybrids had the least number of exit holes and percent tunnel length in all the seasons as compared to the non-Bt hybrids and commercial checks. In BGH trials, Bt-hybrids consistently suffered less leaf damage than their non-Bt near isolines. The study demonstrated that MON810 was effective in controlling B. fusca and C. partellus. Bt-maize, therefore, has great potential to reduce the risk of maize grain losses in Africa due to stem borers, and will enable the smallholder farmers to produce high-quality grain with increased yield, reduced insecticide inputs, and improved food security.

STRICT COMMON FIXED POINT THEOREMS FOR HYBRID PAIRS OF MAPPINGS VIA ALTERING DISTANCES AND AN APPLICATION

In this paper, we utilize an implicit relation to improve and extend some strict common fixed point results of the existing literature to two pairs of hybrid mappings in 2-metric spaces via altering distances. As an application, we also prove some strict common fixed point theorems for hybrid pairs of mappings satisfy- ing a contractive condition of integral type in 2-metric spaces.

Fuzzy fixed points of generalized F-2-Geraghty type fuzzy mappings and complementary results

The aim of this paper is to introduce generalized F2-Geraghty type fuzzy mappings on a metric space for establishing the existence of fuzzy fixed points of such mappings. As an application of our result, we obtain the existence of common fuzzy fixed point for a generalized F2-Geraghty type fuzzy hybrid pair. These results unify, generalize and complement various known comparable results in the literature. An example and an application to theoretical computer science are presented to support the theory proved herein. Also, to suggest further research on fuzzy mappings, a Feng–Liu type theorem is proved.