Production of Intergeneric Hybrids Between <Emphasis Type="Italic">Sinapis alba</Emphasis> and <Emphasis Type="Italic">Brassica carinata</Emphasis>

Reciprocal crosses were made between Brassica carinata and its related species Sinapis alba. Pollen germination studies indicated the presence post-fertilization barriers in both ways. Sequential ovary–ovule culture helped to realize the intergeneric hybrids from the cross S. alba × B. carinata. The F₁ obtained was confirmed as a hybrid based on morphology, cytology and isozyme studies. The hybrid was backcrossed to its male parent and obtained BC₁ seeds, which were used to raise BC₁ generation. The BC₁ generation plants were further backcrossed to B. carinata in order to develop alloplasmic lines.     

Trait inheritance,fertility, and genomic relationships of some n = 9 Brassica species

Summary Karyotypic differences among n = 9 Brassica species, as well as the inheritance of some morphological characteristics, are reported. Annual habit, anthocyanin pigmentation in leaf and stem, enlarged stem, glossy foliage, dark green foliage, white flower and leaf pubescence were all expressed as dominant characteristics and in most cases were determined by one or two genes. 172 intra- and interspecific hybrids of the species belonging to the Brassica oleracea cytodeme were analyzed for fertility and meiotic chromosome behavior. B. alboglabra, B. bourgeaui, B. cretica spp. cretica, B. montana and B. oleracea produced fertile interspecific hybrids, indicating that geographical isolation is the only barrier to gene exchange. Interspecific hybrids generated from crosses of B. incana, B. insularis and B. rupestris to other n = 9 species were semi-sterile. This was shown to be associated with abnormal meiotic behavior. The former two species, when crossed, produced fully fertile hybrids. Therefore, three different karyotypes are identified among the n = 9 Brassica species. Frequent changes in the genome of the species belonging to the Brassica oleracea cytodeme could have led to the formation of accessory chromosomes present in certain accessions.     

Identification and overcoming barriers between Brassica rapa L. em. Metzg. and B. nigra (L.) Koch crosses for the resynthesis of B. juncea (L.) Czern.

Brassica juncea (2n = 36, AABB) is an amphidiploid derived from its diploid progenitor species B. rapa (2n = 20, AA) and B. nigra (2n = 16, BB). Resynthesis of B. juncea by exploiting the wider gene pool of the present day diploids offers a powerful tool for obtaining novel genetic variation. Hybridization between the two species is difficult because of the presence of crossability barriers. Barriers to hybridization were identified using Aniline Blue Fluorescence (ABF) method. Crosses were classified as having pre- or post-fertilization barriers based on whether less than or more than one per cent ovules showed pollen tube entry. Of the 23 crosses studied, seven crosses all with B. rapa as the female parent showed pre-fertilization barriers. Only 0 to 0.3 per cent ovules were fertilized in these crosses. The remaining 16 crosses, four with B. rapa as the female parent and 12 with B. nigra as the female parent, showed post-fertilization barriers. In crosses with pre-fertilization barriers use of bud pollination and stump pollination ensured or increased fertilization. These two simple techniques were used in combination with ovary-ovule culture to ensure recovery of hybrids. In crosses with post-fertilization barriers, ovary-ovule culture alone helped to obtain hybrids. Hybrids were obtained at higher frequency with the use of direct ovule culture compared to ovary-ovule culture. The F₁ plants obtained in vitro were multiplied on MS medium + 2 mg/l Kn + 0.2 mg/l IAA. These F₁ plants were confirmed as true hybrids through morphology, leaf isozymes and cytology. In all 17 hybrids were obtained of which three were amphidiploids.     

Characterization of fertile amphidiploid between <Emphasis Type="Italic">Raphanus sativus</Emphasis> and <Emphasis Type="Italic">Brassica alboglabra</Emphasis> and the crossability with <Emphasis Type="Italic">Brassica</Emphasis> species

A fertile amphidiploid × Brassicoraphanus (RRCC, 2n = 36) between Raphanus sativus cv. HQ-04 (2n = 18, RR) and Brassica alboglabra Bailey (2n = 18, CC) was synthesized and successive selections for seed fertility were made from F₄ to F₁₀. F₁₀ plants exhibited good fertility with 14.9 seeds per siliqua and 32.3 g seeds per plant. Cytological observation revealed that frequent secondary pairing occurred among 3 chromosome pairs in pollen mother cells of plants (F₄) with lower fertility, but not of plants with high fertility (F₁₀). GISH analysis indicated that these F₁₀ plants included the expected 18 chromosomes from R. sativus and B. alboglabra, respectively, but they lost approximately 27.6% R. sativus and 35.6% B. alboglabra AFLP (amplified fragment length polymorphism) bands. The crossability of the Raphanobrassica with R. sativus and 5 Brassica species (13 cultivars) were investigated. Seeds or F₁ seedlings were easy to be produced from crosses × Brassicoraphanus × R. sativus, and B. napus, B. juncea and B. carinata × Brassicoraphanus. Fewer seeds or seedlings were obtained from crosses × Brassicoraphanus × B. napus, B. juncea and B. carinata. However, few seeds were harvested in the reciprocals of × Brassicoraphanus with B. rapa and B. oleracea. The possible cause of fertility improvements and the potential of the present × Brassicoraphanus for breeding were discussed.     

Interspecific relationship and genetic diversity in wild beets in section Corollinae genus Beta: Isozyme and RAPD analyses

Interspecific relationship among wild beets in section Corollinae was analyzed. Isozyme allele composition supports the concept of three basic species consisting of two diploid species, Beta lomatogona and Beta macrorhiza and the tetraploid species, Beta corolliflora. The polyploid and apomictic species referred to as Beta trigyna and Beta intermedia were found as hybrids. Based on isozyme and RAPD results, B. corolliflora was also found more related to B. macrorhiza than to B. lomatogona. From the phylogenetic trees constructed from isozyme data, B. corolliflora and B. macrorhiza seem to be the end members of the evolutionary line. Analysis of genetic diversity showed that B. corolliflora was more polymorphic and heterozygous than B. lomatogona and B. macrorhiza. Differences between B. macrorhiza accessions from Turkey and Dagestan were found.     

Production and analysis of reciprocal hybrids between <Emphasis Type="Italic">Asparagus officinalis</Emphasis> L. and <Emphasis Type="Italic">A. schoberioides</Emphasis> Kunth

The genus Asparagus (Asparagaceae) encompasses 100–300 species, including the important vegetable crop, A. officinalis (garden asparagus). Previous attempts to hybridize garden asparagus with A. densiflorus (Kunth) Jessop, with the aim of introducing disease resistance, were unsuccessful because of the failure of endosperm development. In the present study, reciprocal interspecific hybrids between garden asparagus and A. schoberioides Kunth were generated by hand pollination. The F1 hybrids were analyzed by using both morphological and molecular techniques. This is the first report describing the production of an interspecific hybrid between garden asparagus at the diploid level (2n = 2x = 20) and its diploid (2n = 2x = 20) wild relative, A. schoberioides. Morphological characteristics of candidate hybrids were a mixture of those found in the parents, and cytological and RFLP analyses confirmed that morphologically intermediate plants were indeed diploid hybrids of those two species. In other words, post-zygotic isolation is not complete between phylogenetically distinct these two species. Our results suggest that other Asparagus species may be capable of hybridizing with A. officinalis and that introducing wild characters through interspecific hybridization may offer advantages for breeding for novel traits. Takuro Ito and Toshinori Ochiai authors are contributed equally to this work     

Glucosinolates and other seed quality traits of resynthesized Brassica napus L. derived from domesticated and wild Brassica taxa

Resynthesized Brassica napus L. genotypes can be used to increase the variation in the rapeseed genepool. We evaluated seed quality parameters of resynthesized lines that originated from crosses of oilseed B. rapa L. with domesticated (vegetable) B. oleracea L., and resynthesized lines that were obtained from crosses of B. rapa oilseed cultivars with wild B. oleracea ssp. oleracea and with seven Brassica species from the B. oleracea group (B. bourgeaui Kuntze, B. cretica Lam., B. incana Ten., B. hilarionis Post, B. montana Pourret, B. rupestris Raf., B. villosa Bivona-Bernardi). Twenty-three resynthesized lines and ten cultivars were grown in 1 year and six locations in Germany and the United Kingdom. The mean seed oil, phytosterole, and sinapine contents of the resynthesized lines were lower than in the cultivars, while protein, glucosinolate, and erucic acid contents were higher, respectively. Nearly all resynthesized lines derived from wild Brassica taxa showed a glucosinolate pattern very different from all cultivars and from nearly all resynthesized lines obtained from crosses with domesticated B. oleracea. The newly developed wild Brassica based resynthesized lines represent an immense source of genetic variation that has not been used to full capacity up to now.     

Taxonomic status of Oryza glumaepatula Steud. II. Hybridization between New World diploids and AA genome species from Asia and Australia

Intraspecific and interspecific crosses were made using O. glumaepatula Steud., O. rufipogon Griff., O. nivara Sharma et Shastry, O. meridionalis Ng, and other diploid accessions from the New World to determine biosystematic relationships among the New World, Asian, and Australian AA genome species. All intraspecific and interspecific combinations produced seeds and hybrids, but at different levels of success. The O. glumaepatula, O. rufipogon, and O. nivara intraspecific hybrids were generally fertile with mean pollen stainability ranging from 75.2% to 80.1% and mean spikelet fertility varying from 32.1% to 87.7%. The O. meridionalis intraspecific crosses showed 3.8% pollen stainability and 0.1% spikelet fertility. Interspecific hybrids showed varying fertilities. Crosses of O. glumaepatula with the New World diploid accessions IRGC 103812 and 105561 produced highly fertile hybrids with 68.0% to 89.7% pollen stainability and 70.8% to 86.6% spikelet fertility. In crosses between O. glumaepatula and the Asian species and other diploid New World accessions IRGC 100961, 103810, and 104386, sterile hybrids were produced with pollen fertility ranging from 0 to 35.1% and spikelet fertility from 0 to 8.2%. IRGC 103810 and 104386 formed fertile hybrids when crossed to O. nivara and O. rufipogon, which were also interfertile. Interspecific crosses of O. meridionalis with the other species produced highly sterile hybrids.     

The extent of embryo and endosperm growth following interspecific hybridization between Cicer arietinum L. and related annual wild species

In vivo interspecific pollinations were performed and immature seed development investigated by histological methods in order to study crossability barrier(s) in Cicer L. species wide hybridization. Seven of the eight wild annual Cicer species, belonging to the secondary and tertiary gene pools, were used in reciprocal crosses with the cultivated chickpea. It was confirmed that the zygote was formed in all interspecific crosses. The embryos showed continued and retarded growth at different rate in various crosses, but eventually aborted at an early pro-embryo stage in all crosses except C. arietinum L. ×C. echinospermum Dav. Reciprocal cross differences were observed in early embryo growth rate and could have implications in obtaining hybrids. This study further emphasizes the necessity for developing appropriate and efficient in vitro procedures for rescuing immature globular hybrid pro-embryos, which will make the wild Cicer gene resources amenable to chickpea improvement.     

Cytoplasmic diversity of Brassica napus L., Brassica oleracea L. and Brassica rapa L. as determined by chloroplast microsatellite markers

Cytoplasmic genomes in most angiosperms are known to be maternally inherited. Oilseed rape (Brassica napus L.) as a natural amphidiploid species hence may carry the B. oleracea L. or the B. rapa L. cytoplasm, depending on the cross direction. The presence of either the B. oleracea or the B. rapa cytoplasm in oilseed rape has been reported to affect agronomically important traits. However, to date little is known about the cytoplasmic composition and genetic diversity of current winter oilseed rape cultivars and breeding material. The aim of this study was to assess the usefulness of 40 previously published chloroplast cpSSR markers from Brassica species and Arabidopsis thaliana (L.) Heynh. for distinguishing the cytoplasms of 49 different genotypes of B. napus and its diploid ancestor species. Results showed that only 14 out of the 40 tested primer combinations were suitable to distinguish the cytoplasms of a test set of 8 Brassica genotypes. With the 14 primer pairs 64 different cpSSR alleles were identified in the set of 49 genotypes. Cluster analysis indicated distinct groups for the cytoplasms of B. napus, B. rapa, and B. oleracea. However, an unambiguous identification and classification of the cytoplasm types was not possible in all cases with the available polymorphic set of cpSSR primer pairs.     

Fatty Acid Inheritance in Wide Reciprocal Oilseed Crosses (Brassica rapa and B. napus)

Abstract

Erucic acid content and inheritance were studied in Brassica alboglabra, B. rapa and resynthesized B. napus from these parental species. Although significant variation in erucic acid content was found between the 20 B. alboglabra lines, all of them had to be classified as high erucic types. No major erucic acid gene polymorphism was identified.

In B. rapa the erucic acid content was regulated by one major gene, which showed partial dominance in three of the four crosses analysed. The high erucic gene seemed to function more efficiently in the Yellow Sarson cytoplasm, resulting in maternal differences when reciprocal crosses were compared. In crosses where modern low erucic acid lines were used as female parents the zero erucic acid F₂-individuals occurred more frequently than expected.

Segregation of the erucic acid content in crosses involving resynthesized B. napus showed a good fit to a two locus model. No maternal effects were found, but deviations from mid-parent values in the high erucic acid direction occurred in most of the F₁-hybrids, indicating partial dominance. Crosses between resynthesized oilseed rape and natural oilseed rape resulted in oleic acid transgressive F₅-lines.     

SEED YIELD AND YIELD COMPONENTS RESPONSE OF RAPE (B. NAPUS) VERSUS MUSTARD (B. JUNCEA) TO SULFUR AND POTASSIUM FERTILIZER APPLICATION IN NORTHWEST PAKISTAN

Improper sulfur (S) and potassium (K) fertilizer management, particularly with continued soil nutrient mining, is one of the major factors contributing to low seed yield of canola in northwestern Pakistan. A field experiment was conducted in 2007?2008 on a S and K deficient clay loam soil at the Research Farm of NWFP (Northwest Frontier Province) Agricultural University, Peshawar, Pakistan, with an objective to determine seed yield and yield components response of Brassica oilseed rape versus mustard to S and K application. Twenty treatments in a randomized complete block design were consisted of two oilseed rape (B. napus canola) and mustard (B. juncea canola) genotypes at three rates each of S (15, 30, and 45 kg S ha^?1) and K (30, 60, and 90 kg K ha^?1) fertilizers plus one control (no S and K applied). Seed yield and yield components increased significantly with K and S fertilization as compared to the zero-S/zero-K control. Both genotypes responded positively for seed yield and yield components to K and S fertilization, but the magnitude of response varied with levels of S and K, as well as combined K + S applications. It is concluded that a combination of 60 kg K + 30 kg S ha^?1 would improve seed yield and yield components of rape and mustard in the study area and contribute significantly to increased production. Growing B. napus was better than B. juncea in the study area, because B. napus produced significantly higher seed yield and yield components than B. juncea, indicating that yield components are the most important criteria for selection of Brassica genotypes for higher seed yield.     

Advantages of Wild Diploid Solanum Species Over Cultivated Diploid Relatives in Potato Breeding Programs

For breeding programs of the tetraploid potato (Solanum tuberosum), both wild and cultivated diploid relatives are valuable sources of genetic diversity. While both types of germplasm are used in breeding programs, there are several advantages to using wild relatives. Diploid relatives are typically crossed with haploids (2n = 2x = 24) from tetraploid S. tuberosum to improve daylength adaptation. Most haploids are male sterile, so they are typically used as female parents. Cultivated diploids, such as members of the Phureja Group, produce male sterile hybrids when crossed as females to haploids; wild relatives, such as S. tarijense, often produce male fertile hybrids. Tuber yield following crosses of haploids to cultivated or wild relatives is often high. However, cultivated relatives generally produce hybrids with a high set of small tubers; hybrids from wild relatives are variable, but many are similar to cultivars in tuber size and set. While tubers of hybrids from cultivated relatives are typically rough, with deep eyes and raised internodes, those from wild relatives are often smooth. Tuber dormancy in hybrids with cultivated relatives is generally short, while that in hybrids with wild species is longer, allowing for storage over winter. Finally, resistance to several major diseases and stresses has been found in wild species and their hybrids with S. tuberosum haploids. The desirable traits in hybrids are transmitted to tetraploids via unilateral sexual polyploidization (4x × 2x or 2x × 4x crosses in which the diploid parent produces 2n gametes). Wild Solanum species are recommended for use in potato breeding programs as sources of genetic diversity that can be adapted easily following hybridization with S. tuberosum haploids.     

Reclamation of Polluted Soil: Phytoremediation Potential of Crop-Related BRASSICA Species

Soils polluted by heavy metals can be reclaimed using a number of expensive tactics that either remove the contaminants or stabilize them within the soil. The value of metal accumulating plants for environmental remediation has recently been appreciated and promising results have been obtained. This paper reports a study on the behavior of Brassica napus, Brassica juncea, Raphanus sativus and Brassica carinata grown on a substrate contaminated by several heavy metals caused by the use of contaminated irrigation water. Data on carbon dioxide assimilation, biomass growth and the bioconcentration and translocation factor of each metal in each species were measured. The polluted substrate caused only a small variation in photosynthesis, however transpiration was more affected by the experimental substrate and in all three species of the genus Brassica the presence of metals in the substrate resulted in higher transpiration levels.Two bioconcentration factors were calculated respectively for the roots (BCF) and the shoots (BCF); the BCF was >1 for all the species for Cd, Cu, Ni and Zn without significant differences among species. All the values of BCF were lower than 0.5; among the metals, all Brassica species demonstrated a similar performance for Cd and Zn, whereas for other elements the bioconcentration factor was very low.     

Genetic Variation of Ethiopian Mustard (Brassica carinata A. Braun) Germplasm in Western Canada

Information on genetic diversity and genetic relationships among genotypes of Brassica carinata is currently limited. The objectives of this study were to evaluate patterns and levels of genetic diversity in B. carinata based on amplified fragment length polymorphisms (AFLP) as compared with Brassica juncea and Brassica nigra, and to evaluate agronomic and seed quality data for plants grown in the field in western Canada. A total of 296 AFLP bands were generated from four primer pair combinations and scored for presence/absence in 66, 20 and 7 accessions of B. carinata, B. juncea and B. nigra, respectively. B. carinata was less genetically diverse than the other two species. Differences in diversity were evident in the proportion of polymorphic loci within each species: 23, 35 and 50% for B. carinata, B. nigra and B. juncea, respectively. Pair-wise similarity measures based on the Jaccard coefficient were highest among accessions of B. carinata and showed the narrowest range: 0.911 (0.810–0.981) compared to B. nigra: 0.569 (0.438–0.660) and B. juncea: 0.715 (0.345–0.951). AFLP-based genetic distance information can be used by plant breeders to select diverse genotypes. AFLPs are also useful for fingerprinting cultivars and two primer pair combinations were sufficient to uniquely identify all the accessions of B. carinata. More variation among accessions was identified in the agronomic trial than had previously been described in studies of B. carinata in western Canada, but the data were too limited to draw conclusions regarding specific accessions. Overall, the findings were in agreement with other published work describing the favourable agronomic potential of this species.     

Cassava (<Emphasis Type="Italic">Manihot esculenta</Emphasis> Crantz) genetic resources: a case of high iron and zinc

Cassava hybrids from interspecific crosses with Manihot caerulescens Pohl, M. pseudoglaziovii Pax and Hoffmann and M. dichotoma Ule showed a very high iron and zinc content in both roots and leaves, e.g. 98.15 mg kg⁻¹ in roots of the interspecific hybrid cassava-M. caerulescens versus 12.17 mg kg⁻¹ in a cassava cultivar. This promising results show the potential of wild Manihot species for micronutrient enhancement of cassava.     

Crossability relationships between the common potato, Solanum tuberosum spp. tuberosum, and its wild diploid relatives S. kurtzianum and S. ruiz-lealii

The common potato, Solanum tuberosum spp. tuberosum (tbr), is a tetraploid species with a narrow genetic base, but with a large number of related species that harbor great genetic diversity for numerous characters of agronomic interest. S. kurtzianum (ktz) and S. ruiz-lealii (rzl) are wild diploid relatives with potential resistance to adverse biotic and abiotic factors. To evaluate if this wild germplasm can be incorporated by conventional crosses into the tbr gene pool, pollen-pistil compatibility relations and seed set in interspecific crosses with tbr were investigated. In 4x tbr × 2x ktz crosses and the reciprocals, 89% and 52.2% of genotypic combinations (respectively) were compatible at the pollen-pistil level. Seeds were obtained from some genotypic combinations in both directions of the cross, suggesting that functional 2n gametes might be produced by particular ktz genotypes. In 2x rzl × 4x tbr crosses and their reciprocals, 35% and 11.7% (respectively) of the genotypic combinations were compatible at the pollen-pistil level, but no seeds were obtained. These results indicate that the reproductive isolation between 4x tbr and 2x ktz is incomplete, and that gene exchange between them is feasible. Moreover, further studies will have to be carried out with rzl to ascertain its crossability with 4x tbr.     

Phosphorus Response of Oryza sativa,O. glaberrima,and Hybrid Rice Cultivars on an Ultisol

Phosphorus (P) deficiency is a major constraint to upland rice production on Ultisols in the humid zone of West Africa. Integrated use of P-efficient cultivars and P nutrition is needed for enhanced sustainable productivity on these soils. This article reports on the P responsiveness of interspecific rice hybrids (crosses from Oryza sativa and O. glaberrima) along with O. sativa and O. glaberrima cultivars grown on an acidic Ultisol, low in available P. The cultivars differed in yield and P-uptake response to fresh and residual P. Two interspecific cultivars gave a linear response to P and produced the greatest grain yield under direct and residual P. The O. glaberrima cultivar CG 14 did not respond to the applied P, whereas the O. sativa cultivar was moderate in its performance. Our results show that the interspecific rice cultivars have the potential to adapt and perform well on acidic upland soils.     

Physiological and genetic responses to boron deficiency in Brassica napus: A review

Abstract

Boron (B) is an essential microelement for the growth and development of plants, and B deficiency affects many biochemical and physiological processes. Brassica napus L. has a high demand for B and is extremely sensitive to B deficiency. Seed yields and oil quality of B. napus are often limited by the low availability of B in soils. Developing new cultivars of B. napus with high B efficiency is therefore required, which requires a greater understanding of responses to B deficiency. Significant genotypic differences in response to low soil B have been observed among varieties of B. napus. B-efficient genotypes can grow and yield normally and usually have a larger root system than B-inefficient genotypes at low B conditions. The mechanisms for B efficiency in B. napus are attributed to B absorption, transportation and utilization. In addition, the cell wall component plays an important role in the tolerance of B. napus to B deficiency, and the B-efficient line presents fewer B-binding sites in the cell walls compared with the B-inefficient line. Genetic and proteomic analyses in B. napus revealed the modulation of a complex network in response to B deficiency. This review gives a comparative overview of the physiological and genetic responses to B deficiency in B. napus and discusses the possible underlying mechanisms of B efficiency.     

Analysis of Genetic Diversity in the Brassica napus L. Gene Pool Using SSR Markers

Genetic diversity throughout the rapeseed (Brassica napus ssp. napus) primary gene pool was examined by obtaining detailed molecular genetic information at simple sequence repeat (SSR) loci for a broad range of winter and spring oilseed, fodder and leaf rape gene bank accessions. The plant material investigated was selected from a preliminary B. napus core collection developed from European gene bank material, and was intended to cover as broadly as possible the diversity present in the species, excluding swedes (B. napus ssp. napobrassica (L.) Hanelt). A set of 96 genotypes was characterised using publicly available mapped SSR markers spread over the B. napus genome. Allelic information from 30 SSR primer combinations amplifying 220 alleles at 51 polymorphic loci provided unique genetic fingerprints for all genotypes. UPGMA clustering enabled identification of four general groups with increasing genetic diversity as follows (1) spring oilseed and fodder; (2) winter oilseed; (3) winter fodder; (4) vegetable genotypes. The most extreme allelic variation was observed in a spring kale from the United Kingdom and a Japanese spring vegetable genotype, and two winter rape accessions from Korea and Japan, respectively. Unexpectedly the next most distinct genotypes were two old winter oilseed varieties from Germany and Ukraine, respectively. A number of other accessions were also found to be genetically distinct from the other material of the same type. The molecular genetic information gained enables the identification of untapped genetic variability for rapeseed breeding and is potentially interesting with respect to increasing heterosis in oilseed rape hybrids.