A novel genome of C and the first autotetraploid species in the <Emphasis Type="Italic">Setaria</Emphasis> genus identified by genomic <Emphasis Type="Italic">in situ</Emphasis> hybridization

Genomic in situ hybridization (GISH) was used to investigate the genomic relationships among some newly collected species of genus Setaria. Previous work identified that S. viridis and S. adhaerens carry genomes A and B, respectively. GISH patterns obtained in this report clearly distinguished the genome of S. grisebachii from the known genomes A and B, and indicated its new genomic constitution which we suggest to name genome C of the Setaria genus. The two sets of chromosomes of tetraploid S. queenslandica hybridized well with the A genome of S. viridis indicating its autotetraploid nature. This is the first autotetraploid identified in the Setaria genus, which should be classified into the primary A genome gene pool rather than the tertiary gene pool as previously classified. GISH patterns did not distinguish the genome of S. leucopila from the A genome of S. viridis and S. italica, suggesting its close relation with foxtail millet. Strong hybridization signals were observed when S. adhaerens genomic DNA was used as probe to hybridize the chromosomes of diploid S. verticillata, inferring its B genome nature. Combined with morphological observation and previous work, we deduce that diploid S. verticillata and S. adhaerens are probably taxonomically the same species with different names. Y. Wang and H. Zhi contributed equally to this article.     

On the occurrence,distribution and taxonomy of <Emphasis Type="Italic">Momordica subangulata</Emphasis> Blume subsp. <Emphasis Type="Italic">renigera</Emphasis> (G. Don) de Wilde in India

Different authors in India and South East Asia treat dioecious species in the genus Momordica differently. The cultivated ‘bhat karela’ of East and North East India is referred to as Momordica dioica Roxb. by botanists and herbarium curators whereas agricultural scientists, in general, designate it as Momordica cochinchinensis Spreng. A critical study of 266 herbarium sheets housed at CAL and BSISH and in situ field studies at specific pockets in the North East India followed by preliminary characterization revealed its correct identity as Momordica subangulata Blume subsp. renigera (G. Don) de Wilde. First hand information on its occurrence, taxonomy and distribution in India is given. The species was found in wild as well as in homestead cultivation in North Eastern India and exemplify direct utilization of biodiversity by indigenous people.

Phylogenetic relationships within <Emphasis Type="Italic">Citrus</Emphasis> and its related genera as inferred from AFLP markers

We investigated the phylogenetic relationships among Citrus and its relatives, including 29 genotypes belonging to Citrus, Poncirus, Fortunella, Microcitrus, Eremocitrus, Atalantia and Severinia using AFLP analysis. Cluster analysis was conducted using neighbour joining (NJ) method. The results demonstrated that Poncirus, Microcitrus and Eremocitrus are distant from Citrus. A strong affiliation exists between C. halimii and Fortunella and the results did not support C. halimii as the fourth basic species. Further evidence was provided that P. polyandra should not be the hybrid between trifoliate orange and Citrus genotypes and it deserves species status. Neither the separation of subgenus Papeda and Citrus nor the separation of subgenus Archicitrus and Metacitrus were clearly resolved in the dendrogram. C. ichangesis is a distinct species very different from other Citrus genotypes, and the results showed it is improper to classify it into subgenus Metacitrus. C. reticulata, C. maxima and C. medica were separated into three distinct clusters. Therefore if only cultivated Citrus species are considered, the three basic species concept is acceptable. However, it is not applicable for whole genus Citrus.     

Evaluation of perennial wild <Emphasis Type="Italic">Cicer</Emphasis> species for drought resistance

About 90% of chickpea (Cicer arietinum L.) in the world is grown under rainfed conditions where drought is one of the major constraints limiting its productivity. Unlike the cultivated chickpea, wild Cicer species possesses sources of resistance to multiple stresses; we therefore evaluated perennial wild Cicer species for resistance to drought. C. anatolicum, C. microphyllum, C. montbretii, C. oxydon and C. songaricum were compared with special checks; C. echinospermum, C. pinnatifidum and C. reticulatum and five cultivated chickpeas. After the cultivated chickpeas were killed, accessions were evaluated using a 1–5 scale, where 1 = highly drought resistant (no visible drought effect and full recovery after three successive wiltings) and 5 = highly drought susceptible (leaves and branches dried out, no recovery at all). All accessions of perennial wild Cicer species were significantly superior to those annual wild species and the cultivated chickpeas including the best drought tolerant chickpea, ICC 4958 under drought conditions. Perennial wild Cicer species did not only recover after wilting and drying out above ground level, they also tolerated high temperatures up to 41.8°C. But, they do not cross with the cultivated chickpeas. C. anatolicum should be taken account in long term breeding programs because it has closer affinities to the first crossability group than the others.     

<Emphasis Type="Italic">Rhizobium</Emphasis>,<Emphasis Type="Italic"> Bradyrhizobium</Emphasis> and<Emphasis Type="Italic"> Agrobacterium</Emphasis> strains isolated from cultivated legumes

The present study was conducted to isolate and characterize rhizobial strains from root nodules of cultivated legumes, i.e. chickpea, mungbean, pea and siratro. Preliminary characterization of these isolates was done on the basis of plant infectivity test, acetylene reduction assay, C-source utilization, phosphate solubilization, phytohormones and polysaccharide production. The plant infectivity test and acetylene reduction assay showed effective root nodule formation by all the isolates on their respective hosts, except for chickpea isolate Ca-18 that failed to infect its original host. All strains showed homology to a typical Rhizobium strain on the basis of growth pattern, C-source utilization and polysaccharide production. The strain Ca-18 was characterized by its phosphate solubilization and indole acetic acid (IAA) production. The genetic relationship of the six rhizobial strains was carried out by random amplified polymorphic DNA (RAPD) including a reference strain of Bradyrhizobium japonicum TAL-102. Analysis conducted with 60 primers discriminated between the strains of Rhizobium and Bradyrhizobium in two different clusters. One of the primers, OPB-5, yielded a unique RAPD pattern for the six strains and well discriminated the non-nodulating chickpea isolate Ca-18 from all the other nodulating rhizobial strains. Isolate Ca-18 showed the least homology of 15% and 18% with Rhizobium and Bradyrhizobium, respectively, and was probably not a (Brady)rhizobium strain. Partial 16S rRNA gene sequence analysis for MN-S, TAL-102 and Ca-18 strains showed 97% homology between MN-S and TAL-102 strains, supporting the view that they were strains of B. japonicum species. The non-infective isolate Ca-18 was 67% different from the other two strains and probably was an Agrobacterium strain.     

Characterization of intergeneric hybrids of <Emphasis Type="Italic">Erianthus rockii</Emphasis> and <Emphasis Type="Italic">Saccharum</Emphasis> using molecular markers

Erianthus rockii, a wild relative of sugarcane, is drought and cold tolerant, and both are potentially important agronomic traits to the sugarcane industry worldwide. As such it is of interest as a source of parental germplasm to sugarcane breeders and is currently being used in sugarcane introgression programs in both China and Australia. To date morphological characters have been used to verify the putative hybrids produced. Two crosses were generated between two different Saccharum species and two E. rockii accessions. Over 400 AFLP markers were used to identify the intergeneric hybrid progeny as well as determine hybrid diversity. Both crosses generated hybrids but efficiency levels were very different and are probably related to the different Saccharum parent used in each cross. Cross 1 was between a Saccharum officinarum and E. rockii and generated 100% hybrid progeny. Cross 2, however, was between a sugarcane hybrid (S. officinarum × Saccharum spontaneum) and E. rockii and only 10% of the progeny were intergeneric hybrids. Inheritance of markers in the progeny was analysed and for both crosses there were equal numbers of markers from both parents indicating n + n transmission of chromosomes. This is the first verification of E. rockii hybrids with molecular markers. It may now be possible to exploit genes of value from E. rockii in sugarcane breeding programs.     

Molecular phylogeny of Chinese vegetable mustard (<Emphasis Type="Italic">Brassica juncea</Emphasis>) based on the internal transcribed spacers (ITS) of nuclear ribosomal DNA

Sequence variation of nuclear internal transcribed spacer regions of ribosomal DNA (ITS1, 5.8S rRNA and ITS2) from Chinese vegetable mustards (AB-genome) and its putative parents Brassica rapa (the A-genome) and Brassica nigra (the B-genome) were used to investigate the molecular phylogeny and the probable evolutional pattern of this amphidiploid species that uniquely formed in China. Totally, 16 accessions of Chinese vegetable mustard those covering nearly all the diverse variations were included in this study, and together with three accessions of B. rapa and one accession of B. nigra. The results disclosed two strongly supported clades, one containing four accessions of vegetable mustard which have closer relationship with B-genome species “B.nigra” lineage and the other containing 12 accessions of B. juncea and three A-genome accessions. This classification was in disagreement with the evidence from chloroplast DNA, mitochondrial DNA, nuclear DNA restriction fragment length polymorphism (RFLP), which suggested that B. juncea was closely related to the A-genome type. For the incongruence, we speculated that the B. juncea crops derived from Chinese have evolved through different recombined events of the diploid morphutypes and evolved unidirectional concerted evolution. The traditional phenotypic classification of B. juncea was not wholly supported by ITS results, and hence the phylogenetic relationships among these subspecies need to be reconsidered on molecular level.     

Diversity distribution and collection of genetic resources of cultivated and weedy type in <Emphasis Type="Italic">Perilla frutescens</Emphasis> (L.) Britton var. <Emphasis Type="Italic">frutescens</Emphasis> and their uses in Indian Himalaya

Perilla frutescens (L.) Britton is a traditional crop of East Asia and sporadically cultivated in different parts of the Himalayas. The Western and the Eastern Himalayan regions of India exhibit rich variability in oilseed Perilla, Perilla frutescens (L.) Britton var. frutescens. The present communication deals with the distribution pattern of diversity and survey, exploration and germplasm collection and its uses in India. Brief information on botanical characterization on the basis of systematic study of cultivated and weedy types and thrust on areas for germplasm collection from diverse habitats have been discussed.     

Resistance reaction to powdery mildew (<Emphasis Type="Italic">Erysiphe pisi</Emphasis>) in a germplasm collection of <Emphasis Type="Italic">Lathyrus cicera</Emphasis> from Iberian origin

Several Lathyrus species have a considerable potential as alternative pulses in sustainable dryland farming systems mainly due to their high tolerance to drought and disease resistance. Powdery mildew is a serious disease affecting several Lathyrus species. Little is known on the availability of resistance and the underlying resistance mechanisms against powdery mildew in the Lathyrus genus. The present study assessed and characterized the resistance reaction to powdery mildew, Erysiphe pisi, in a collection of Iberian Lathyrus cicera accessions. In general, a compatible reaction with no macroscopically visible necrosis was observed but accessions with reduced disease severity despite of a high infection type have also been identified. This Partial Resistance was in some accessions only expressed in the adult plant stage. The controlling genes of the Lathyrus resistance mechanisms can be of great interest not only for the Lathyrus improvement per se but also for related legume species, like field pea.     

Classification and phylogenetic relationships in <Emphasis Type="Italic">Solanum</Emphasis> section <Emphasis Type="Italic">Lycopersicon</Emphasis> based on AFLP and two nuclear gene sequences

The classification and phylogeny of the species belonging to Solanum section Lycopersicon is a complex issue that has not yet reached a widely accepted consensus. These species diverged recently, are still closely related and, in some cases, are still even capable of interspecific hybridization, thereby blurring the difference between intra- and interspecific variation. To help resolve these issues, in the present study, several accessions covering the natural range for each species were used. In addition, to avoid biases due to the molecular method employed, both AFLP markers and two nuclear-gene sequences, CT179 and CT66, were used to characterize the plant materials. The data obtained suggest a classification similar to those previously proposed by other authors, although with some significant changes. Twelve species were recognized as distinct based on this dataset. According to the data presented, the recently proposed species, S. corneliomulleri, is indistinguishable from S. peruvianum s.str. In addition, both the sequence and the AFLP trees suggest that S. arcanum could represent a complex of populations composed of two cryptic species. With regard to phylogenetic relationships among these species, some clear groups were found: the Lycopersicon group formed by S. pimpinellifolium, S. lycopersicum, S. cheesmaniae and S. galapagense; the Arcanum group constituted by S. chmielewskii, S. neorickii, S. arcanum and S. huaylasense; and the Eriopersicon group made up of S. peruvianum and S. chilense. Solanum pennellii and S. habrochaites are not included in any group, but are the closest to the S. lycopersicoides outgroup. Jose Blanca and Fernando Nuez have contributed equally to this work and should be regarded as co-second authors.     

Genetic diversity and conservation of two endangered eggplant relatives (<Emphasis Type="Italic">Solanum vespertilio</Emphasis> Aiton and <Emphasis Type="Italic">Solanum lidii</Emphasis> Sunding) endemic to the Canary Islands

Solanum vespertilio Aiton and Solanum lidii Sunding are endemic, endangered wild species from the Canary Islands. These species are of potential value for eggplant (S. melongena) breeding, given that they are part of the secondary genepool of this crop. We study genetic diversity with amplified fragment length polymorphisms (AFLPs) markers from 5 populations of S. vespertilio (47 samples) and 3 of S. lidii (26 samples). Five related African species (S. dasyphyllum Schumach. et Thonn., S. delagoense Dunal, S. campylacanthum Hochst., S. panduriforme E. Mey, S. aff. violaceum Ortega) were also included in the analysis. A total of 235 AFLP markers included 178 and 156 that were polymorphic in S. vespertilio and S. lidii, respectively. Analysis of genetic distance, phenograms, and principal component plots showed that these rare Canarian species are differentiated (G _ST = 0.412) from the continental materials and that Solanum vespertilio is more distinct to its African congeners than is S. lidii. There is a relatively high level of differentiation between the two species (G _ST = 0.373), that presumably reflects geographic restrictions (S. lidii to Gran Canaria; S. vespertilio essentially to Tenerife). However, both species have similar levels of total diversity. We speculate that the combination of the many unusual reproductive features (andromonoecy, zygomorphy, heteranthery and weak enantiostyly in S. vespertilio) help explain genetic diversity that is high for self compatible species. The high genetic diversity may also indicate populations were larger in the past. A decrease in population size could contribute to the relatively low genetic differentiation among the populations. The data presented herein provide the foundation for initiation of ex situ and in situ conservation programs for these wild relatives of eggplant. This paper is dedicated to the memory of Dr. Richard N. Lester, who made significant contributions to the taxonomy, biosystematics and conservation of genetic resources of African species of Solanum.     

A bradyrhizobial-<Emphasis Type="Italic">Penicillium</Emphasis> spp. biofilm with nitrogenase activity improves N<Subscript>2</Subscript> fixing symbiosis of soybean

A bradyrhizobial-fungal biofilm (i.e. Bradyrhizobium elkanii SEMIA 5019-Penicillium spp.) developed in vitro was assayed for its nitrogenase activity and was evaluated for N₂-fixing symbiosis with soybean under greenhouse conditions. The biofilm showed nitrogenase activity, but the bradyrhizobial strain alone did not. Shoot and root growth, nodulation and N accumulation of soybean increased significantly with an inoculum developed from the biofilm. This study concludes that such biofilmed inoculants can improve N₂-fixing symbiosis in legumes, and can also directly contribute to soil N fertility in the long term. Further studies should be conducted to investigate the performance of these inoculants under field conditions.     

Genetic diversity of the D-genome in <Emphasis Type="Italic">T. aestivum</Emphasis> and <Emphasis Type="Italic">Aegilops</Emphasis> species using SSR markers

Simple sequence repeats (SSRs), highly dispersed nucleotide sequences in genomes, were used for germplasm analysis and estimation of the genetic relationship of the D-genome among 52 accessions of T. aestivum (AABBDD), Ae. tauschii (D^tD^t), Ae. cylindrica (CCD^cD^c) and Ae. crassa (MMD^cr1D^cr1), collected from 13 different sites in Iran. A set of 21 microsatellite primers, from various locations on the seven D-genome chromosomes, revealed a high level of polymorphism. A total of 273 alleles were detected across all four species and the number of alleles per each microsatellite marker varied from 3 to 27. The highest genetic diversity occurred in Ae. tauschii followed by Ae. crassa, and the genetic distance was the smallest between Ae. tauschii and Ae. cylindrica. Data obtained in this study supports the view that genetic variability in the D-genome of hexaploid wheat is less than in Ae. tauschii. The highest number of unique alleles was observed within Ae. crassa accessions, indicating this species as a great potential source of novel genes for bread wheat improvement. Knowledge of genetic diversity in Aegilops species provides different levels of information which is important in the management of germplasm resources.     

Nematofauna associated with exotic and native leguminous plant species in West Africa: effect of<Emphasis Type="Italic"> Glomus intraradices</Emphasis> arbuscular mycorrhizal symbiosis

Ten leguminous trees, four exotic species (Australian Acacia) and six indigenous species (three Sahelian Acacia spp. and three Sesbania spp.), were grown for 4 months in a natural Sahelian soil inoculated with or without the endomycorrhizal fungus, Glomus intraradices. In control trials, the determinant factor structuring the soil nematode fauna was the plant species, related plants having a similar influence on the nematode community in the soil. Soil nematode abundance increased from exotic acacias (3.3 g^-1 dry soil) to native acacias (11.5 g^-1 dry soil) and Sesbania species (17.6 g^-1 dry soil). Plant feeding nematodes (mainly Scutellonema and Tylenchorhynchus) were significantly less abundant under exotic acacias (1.4 g^-1 dry soil) than under native acacias (7.2 g^-1 dry soil) or Sesbania species (7.3 g^-1 dry soil). Bacterial feeding nematode density increased from exotic acacias (1.2 g^-1 dry soil) to native acacias (3.0 g^-1 dry soil) and Sesbania species (7.7 g^-1 dry soil) as total densities. However, the differences in the structure of the nematode communities between plant groups were suppressed in the presence of the mycorrhizal fungus. In fact, no difference in nematode densities remained between plant groups when G. intraradices developed in several dominant taxa belonging to different trophic groups, particularly: Tylenchorhynchus, Apelenchina, Cephalobus and Dorylaimoidea. This study clearly indicated that inoculation with the arbuscular mycorrhizal fungus G. intraradices diminished the plant-specific effect on the structure of the soil nematode community.     

Analysis of Genetic Variation Among Accessions of <Emphasis Type="Italic">Pueraria montana</Emphasis> (Lour.) Merr. var. <Emphasis Type="Italic">lobata</Emphasis> and <Emphasis Type="Italic">Pueraria phaseoloides</Emphasis> (Roxb.) Benth. based on RAPD Markers

Pueraria montana var. lobata and P. phaseoloides originating from tropical Asia and parts of Oceania are ecologically and economically important legumes that are used as green manure, cover crop or forage plants. Conservation and use of plant genetic resources require an understanding of the extent and distribution of genetic diversity in any given region. In this study, genetic variation of five P. montana var. lobata and 16 P. phaseoloides accessions was analysed developing a random amplified polymorphic DNA (RAPD) marker methodology for Pueraria species and thereby creating basic data for follow-up research and the development of conservation strategies. Seeds were collected from native populations in Bac Kan Province, a mountainous region in Northeast Vietnam. P. montana var. lobata presented a high level of variation with 54.3% of the detected markers being polymorphic, whereas P. phaseoloides exhibited an intermediate to high level of variation (45.5%). The P. montana var. lobata accessions clustered in congruence with their eco-geographical origin. For P. phaseoloides no correspondence between sampling sites and genetic differentiation was found. Inter-population differentiation was measured as Jaccard's similarity coefficient (JSC). Mean JSC amounted to 0.35 in P. montana var. lobata and 0.52 in P. phaseoloides. Results are compared to other genetic studies of herbaceous legumes and conservation strategies are suggested.     

<Emphasis Type="Italic">Persea</Emphasis> (avocados) Phylogenetic Analysis Based on Morphological Characters: Hypothesis of Species Relationships

The genus Persea consists of two subgenera, Persea (known as avocados) and Eriodaphne (known as aguacatillos, avocado-like species). The present study aimed to determine whether the genus Persea is a monophyletic group and whether the division into two subgenera is an artificial one. In conjunction with these goals, a hypothesis of the phylogenetic relationships among Persea species is proposed. Our results suggest that Persea is not a monophyletic group. Two clades of Persea can be recognized. The results suggest that Eriodaphne and Persea should be considered to be independent genera. Various leaf and floral characters contributed for separation into groups. The definition of Eriodaphne is based on fruit color, sessile glands at the base of the stamens, vein prominence and leaf shape. Persea is more closely related to genera Nectandra and Ocotea than Eriodaphne. The 11 species included in Persea are recognized as species. The group is defined by fruit flavor, mature leaf color, number of tertiary divergent veins, and pubescent bracts in the inflorescence. Within this group, a clade of six species in which P. guatemalensis is included is recovered by seed shape, venation pattern relief, and number of fruits per cluster. Moreover, the seed shape supports the separation of P. floccosa and P. zentmyerii. A molecular character analysis is necessary to support the Persea clades proposed herein. Nevertheless the phylogenetic relationships revealed by this study provide new bases for the selection and conservation of the species Persea.     

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.     

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     

A note on the evolution of kabuli chickpeas as shown by induced mutations in <Emphasis Type="Italic">Cicer reticulatum</Emphasis> Ladizinsky

Two distinct chickpeas of the domestic chickpea, C. arietinum L., exist and are referred to as ‘desi’ or microsperma and ‘kabuli’ or macrosperma. Cicer reticulatum Ladiz. is considered to be the wild progenitor of the domestic chickpea. However, the morphological variation in 18 original accessions of C. reticulatum is narrower than those of the domestic chickpeas. The aim of the study is to increase the variability in C. reticulatum. In M₂ generation, a mutant with white flower color was isolated despite of the fact that the parent has the pink flower. Although seed coat color of the parent was dark brown, the mutant was cream like ‘kabuli’ chickpea. It is commonly accepted that the large seeded domestic ‘kabuli’ chickpeas originated from the small seeded ‘desi’ chickpeas, but the induced mutants (white flower and cream seed coat color) of C. reticulatum may suggest an additional path for the evolution of ‘kabuli’ chickpea. ‘Kabuli’ chickpeas could have originated from spontaneous mutants of C. reticulatum. In M₃ generation, multipinnate leaf, erect growth habit, green seed and double-podded chickpeas were isolated. Among these progenies, morphologic variability increased and approached domesticated chickpea. Based on historical records and the induced mutants obtained from this study, the domestic ‘kabuli’ chickpea could have directly emerged from C. reticulatum in ancient Eastern Turkey.