Development Of Interspecific Hybrids Research Articles

Development of inter-specific hybrids between Solanum melongena L. and Solanum sisymbriifolium Lam. through embryo rescue

In present investigation, inter-specific hybridization between two species was carried out using a three-way cross with the aim to study the response of heterotic hybrids for cross-compatibility and to improve the fertility traits of interspecific cross such as pollen viability and density for further introgression of agronomically important traits. The present investigation highlights genotypic variation of for cross-compatibility between S. melongena hybrids and Solanum sisymbriifolium. Among three hybrids, H3 x Solanum sisymbriifolium (4%) and H4 x Solanum sisymbriifolium (1.5%) showed compatibility for fruit set and developed immature seeds only. The embryo rescue from 25 day-old fruits and in vitro culture on ½ MS medium supplemented with 2mg/L–1BAP showed germination. H5 x S. sisymbriifolium showed 49.4% embryo germination and produced four complete plantlets. Furthermore, all plants were morphologically variable for the presence or absence of spines, flower clustering, slightly curved/straight stigma tip, and flower color. The regenerated plantlets were intermediate to cultivated and wild parents for the quantitative traits. Two SSR markers viz., emg01A17, emh11001 and emb01E03 also confirmed the hybridity of three-way cross plants. Among four interspecific plants, one established high pollen viability (78.5%), while others were partial-fertile (62.8%) and all carried low pollen density (69-299 pollen/ 1cm2) at anthesis. Inbreeding and backcrossing of these plants to both cultivated and wild parents remained unsuccessful. This is the first report of developing a partially-fertile three-way cross between S. melongena and S. sisymbrifollium via embryo rescue.

Development of interspecific hybrids through embryo rescue for heat-stable nematode resistance (Mi-9 gene) from Solanum arcanum in tomato

Development of interspecific hybrids through embryo rescue for heat-stable nematode resistance (Mi-9 gene) from Solanum arcanum in tomato

Development of interspecific hybrids between urdbean & mungbean

Interspecific hybridization was performed between five genotypes of urdbean & three genotypes of mungbean to check the crossability relationship. Thirteen cross combinations of urdbean x mungbean were successfully developed. Interspecific seeds showed no germination under soil conditions so various growth media were used for germination. Interspecific seeds germinated only on the salt solution. F1 seeds of cross UG-218 x Suketi exhibited highest crossability and showed maximum response on salt solution. The study put emphasis on the different kinds of fertilization barriers. In future genetic improvement studies can be carried out with the genotypes showing substantially high percent of crossability.

Morphoanatomic and histochemical aspects of Elaeis oleifera (Kunth) Cortés seed

Abstract: Elaeis oleifera is an oleaginous palm tree native to America. The fruit contains unsaturated fatty acid extracted from the mesocarp. The species is mainly used in breeding programs of E. guineensis in development of interspecific hybrids with higher oil yield and resistance to lethal yellowing. E. oleifera is propagated by seed, which requires the adoption of methods for breaking dormancy and increasing the germination rate. However, there are no studies on the morphology and anatomy of the seed and its ergastic substances; knowing its structure makes it possible to improve planting methods and make them more effective. The aim of the present study was to describe the morpho-anatomy and histochemistry of the seed, characterizing it and contributing information that assists in understanding dormancy. In seeds collected in the experimental area of Embrapa Amazônia Ocidental (Amazonas), morpho-anatomical and histochemical analysis was conducted to detect metabolites (starch, protein, lipids, carbohydrates, and phenolic compounds). The seeds vary in shape, oblong and ovate. The embryo has an oblique embryonic axis, composed of root apical meristem and shoot apical meristem with three leaf primordia. Phenolic compounds were found throughout the seed coat; there are lipids, protein, and pectin in the embryo and endosperm.

Optimizing pollen germination and pollen viability estimates for Hydrangea macrophylla, Dichroa febrifuga, and their hybrids

The genus Hydrangea L. is comprised of some of the most popular ornamental plants in the world. The development of interspecific hybrids between Hydrangea species and within the family Hydrangeaceae would increase genetic diversity in the Hydrangea breeding pool and lead to unique combinations of desirable traits. Protocols to estimate Hydrangea pollen viability need to be optimized in order to perform basic studies on self- and cross-incompatibility, fertility of hybrids, formation of unreduced gametes, and pollen storage. Our goal is to quantify pollen production in Dichroa, Hydrangea, and their hybrids, determine the optimal media for pollen germination, and develop a series of correlations between staining and germinating that can be applied to stained pollen for a rapid, precise estimate of viability. Production of round versus oblong pollen grains was heavily influenced by species (F = 335.8, p < 0.001). Dichroa accessions produced an average of 86% round grains while Hydrangea accessions produced 65% round grains. Dichroa x Hydrangea hybrids averaged only 39% round grains. The optimal media composition for all accessions based on iterative test was 7.5% sucrose, 0.01% Ca(NO3)2, and 0.025% H3BO3, and 10 mM 2-(N-morpholino)ethanesulfonic acid pH 5.5. Aniline blue-lactophenol staining overestimated viability by an average of 2.3x for Hydrangea and Dichroa, and an average of 4.1x for hybrids as compared to in vitro germination. The results from this experiment will provide more consistent results within and between laboratories and will easily fit into existing Hydrangea breeding programs.

Interspecific compatibility barriers, development of interspecific hybrids through embryo rescue and lineage of Trifolium alexandrinum (Egyptian clover)—important tropical forage legume

AbstractGenetic improvement of Trifolium alexandrinum L. is hampered because of narrow genetic base and lack of interspecies compatibility information. The study was envisaged to understand the interspecies incompatibility and the affinity between T. alexandrinum and 22 species of the genus representing different sections and to develop interspecific crosses. Development of interspecific hybrids with T. resupinatum, T. lappaceum, T. subterraneum, T. vesiculosum and T. echinatum, through embryo rescue, revealed their affinity with T. alexandrinum. Failure of pollen germination or restricted pollen tube growth showed its distant relatedness with T. clypeatum, T. balansae, T. purpureum, T. leucanthum, T. hirtum, T. pilulare and T. hybridum. Pollen tubes reached up to ovule among the crosses with T. alpestre, T. repens and T. nigrescens, whereas it travelled up to ovary among the crosses with T. angustifolium, T. grandiflorum and T. dasyurum indicating need of manipulation to overcome barrier. Thus, incompatibility of T. alexandrinum with many Trifolium species could be overcome through embryo rescue with intensive crossing. Egyptian clover ecotype ‘Fahli’ was more compatible with other species than ‘Mescavi’.

Development of interspecific hybrids of cassava and paternity analysis with molecular markers

SUMMARYThe present paper demonstrates the development of interspecific hybrids between Manihot esculenta Crantz ssp. esculenta (Mee) and M. esculenta Crantz ssp. flabellifolia (Mef) and paternity analysis using microsatellite markers [simple sequence repeat (SSR)]. Three Mef accessions (FLA005, FLA025V and FLA029V) were used for crosses with varieties of Mee: Saracura, Aipim Bravo, COL 1725, Aipim Rosa, Abóbora, Paraná and PER334. The paternity of the interspecific hybrids was investigated using 24 SSRs. The observed heterozygosity (Ho), polymorphic information content (PIC), probability of identity (PI) and paternity exclusion (PE) were evaluated. The rate of breeding success varied from 17 to 92%, and an average of two pollinations were required for each generated hybrid plant. The Ho value ranged from 0·11 to 0·92, and the PIC value ranged from 0·12 to 0·59. The uneven distribution of allele frequencies was accompanied by a high PI average (0·56). However, the combined PE for 21 loci was 0·99, which allows for the determination of the paternity of the hybrids with good discriminatory power. Of the 74 hybrids evaluated, 0·82 had their paternity confirmed using microsatellite markers. Discriminant analysis of principal components (DAPC) indicated the presence of eight clusters, of which, one was composed of only Mef varieties and the supposed hybrid Fla52Sar-H7, which was a product of apomixis. The parent Mee and hybrids were allocated in the other seven clusters. The data obtained demonstrate that SSR markers can be routinely used in breeding programmes to verify the paternity of interspecific crosses of cassava.

Recent advances and future perspectives in resistance breeding against Puccinia graminis f. sp. tritici, strain UG99

The new stem rust strain, Puccinia graminis f. sp. tritici — Ug99, has been a rising threat since the alarm was rung in Uganda in 1998. The genetic and breeding dimensions of research against this disease include the development of vigorous molecular markers, the identification and introgression of multiple resistance genes, the translocation of alien chromosomes, the enrichment of breeding lines with crossability alleles and the development of interspecific hybrids. Resistance genes have been identified in the primary wheat gene pool and in alien sources such as Aegilops spp., Dasypyrum villosum, Secale cereale, Hordeum vulgare and Oryza spp. and some of these sources have been used to confer resistance as a function of single or multiple gene effects. Realizing the potential disaster if Ug99 and related variants break out in other regions, wheat-producing countries are characterizing their germplasm and improving their stem rust race tracking systems. Equally important is “appropriate genetic management”, i.e. the use of currently effective resistance genes in such a way that the evolution and adaptation of new virulence will be deterred. This review will summarize the recent research advances and future perspectives in setting effective genetic barriers vis-à-vis the seemingly intractable spread and evolution of Ug99.

Genetic Variation of Fatty Acid Components in &lt;I&gt;Arachis&lt;/I&gt; Species and Development of Interspecific Hybrids with High Oleic and Low Palmitic Acids

Genetic Variation of Fatty Acid Components in &lt;I&gt;Arachis&lt;/I&gt; Species and Development of Interspecific Hybrids with High Oleic and Low Palmitic Acids

Trifolium alexandrinum × T. resupinatum – Interspecific Hybrids Developed through Embryo Rescue

This is the first report on the development of interspecific hybrids between T. alexandrinum and T. resupinatum, using embryo rescue. T. resupinatum is an important donor species for traits such as resistance to root and stem rot diseases, and tolerance to alkalinity for the potential improvement of T. alexandrinum. T. alexandrinum, as female parent, was crossed with T. resupinatum and embryos were excised 10–12 days after pollination and cultured in vitro on EC3 medium. Of the recovered embryos, 23.08% showed plumule emergence. For subculturing, shoot-induction medium LSP3 was used. Roots were induced on RL1 medium. Regenerants were hardened and inoculated with Rhizobium before transfer to the field. Morphological appearance of the hybrids was intermediate to both the parents. The hybrids were erect, leafy with short internodes and possessed distinct dwarf bushy compact appearance and were profusely branched. The plants were late flowering with pollen fertility more than 90%. Three out of five hybrid plants set seed following selfing. Hybridity of the plants was also confirmed through Est, PRX, SOD, GOT isozymes and protein banding patterns.

Development and characterization of interspecific hybrids of Trifolium alexandrinum×T. apertum using embryo rescue

AbstractThis is the first report on the development of interspecific hybrids between Trifolium alexandrinum and T. apertum using embryo rescue and characterization of F1 plants. T. apertum was used as the male parent and T. alexandrinum as the female parent. Development of interspecific hybrids under natural conditions is not successful and so embryo rescue was attempted. Of the several combinations tried, pollination 2 days after emasculation and embryos rescued 11 days after pollination was found to be the best. For embryo culture, EC3 medium consisting of MS basal supplemented with 2.3 μM kinetin and 3% sucrose was used. Germinated embryos were transferred to LSP3 medium 25 days after inoculation wherein most of the cultures showed multiple shoots that were split and subcultured on RL1 medium for rooting. After hardening, about 75% of hybrids were successfully transferred to the field. The hybrids, in general, showed morphological traits intermediate between the two parents; however, a few hybrids showed better growth than either parent. Some F1 plants were almost 3 weeks later in flowering than the female parent. Pollen fertility among these plants ranged from 78 to approximately 100%. Chromosomal associations at diakinesis and isozyme banding patterns for acid phosphatase (ACP), superoxide dismutase (SOD) and peroxidase also confirmed the hybrid nature of the plants.

Phylogenetic relationships among the Anopheles hyrcanus species group based on the degree of hybrid development and comparison with phylogenies by other methods.

Phylogenetic relationships among 7 members of the Anopheles hyrcanus species group of East Asia which contains vectors of human parasitic diseases were studied based on the development of interspecific hybrids; they were compared with phylogenetic relationships obtained from morphological and biochemical works. A study of Takai et al. (1984) on postmating reproductive isolation between 7 members of the An. Hyrcanus species group demonstrated various degrees of development among hybrids. It is proposed in this study that hybrid development is correlated with phylogenetic relationship. An index of hybrid development was introduced and was applied to classification of the parental members. It was compared with a classification based on the morphological data of Harrison (1972) which were reanalyzed in this study. The data for polypeptide differences disclosed by two-dimensional gel electrophoresis conducted by Imajoh (1981) were reanalyzed to construct a classification, which was compared with the present results. A common clustering among the three classifications was a grouping of An. Argyropus, An. nigerrimus, and An. Nitidus. Laboratory colonies of this subgroup were difficult in free-mating in cages and preferred to feed on man, whereas colonies of the other species freely mated in cages and preferred to blood-feed on mice, except that An. crawfordi did not freely mate in cages. Relation of the vector members to the classification is discussed. A revision in the UPGMA method is also presented.