The Enigma of <Emphasis Type="Italic">Solanum maglia</Emphasis> in the Origin of the Chilean Cultivated Potato, <Emphasis Type="Italic">Solanum tuberosum</Emphasis> Chilotanum Group<Superscript>1</Superscript>

The Enigma of Solanum maglia in the Origin of the Chilean Cultivated Potato, Solanum tuberosum Chilotanum Group. Landrace potato cultivars occur in two broad geographic regions: the high Andes from western Venezuela south to northern Argentina (Solanum tuberosum Andigenum Group, “Andigenum”), and lowland south-central Chile (S. tuberosum Chilotanum Group, “Chilotanum”), with a coastal desert and 560 km between southernmost populations of Andigenum and Chilotanum. Unlike Andigenum landraces, Chilotanum landraces are adapted to long days and carry a 241 base pair plastid DNA deletion. However, Andigenum and Chilotanum landraces are morphologically similar. We investigated a hypothesis that Chilotanum landraces arose from Solanum maglia, a rare tuber-bearing species found in Chile and Argentina. This hypothesis was formulated first based on morphological analyses of starch grains of extant and preserved (12,500 years before present) S. maglia, and on putative sympatry of extant S. maglia and Chilotanum landraces. Our new starch grain analyses fail to support this hypothesis; we could find no evidence of current sympatric distributions, and S. maglia lacks the 241-bp plastid deletion. However, microsatellite data group all accessions of S. maglia exclusively with Chilotanum, which is supported by our previous observation at the single locus of the waxy gene. These results could be interpreted in various ways, but all explanations have problems. One explanation is that S. maglia is a progenitor of Chilotanum. However, the plastid deletion in Chilotanum but not S. maglia cannot be easily explained. Another explanation is that Chilotanum was formed by hybridization between S. maglia and pre-Chilotanum, but this conflicts with prior cladistic analyses. These new data shed light on aspects of this question and highlight various evolutionary scenarios, but the origin of Chilotanum and the involvement of S. maglia in its origin remain an enigma.     

The single Andigenum origin of Neo-Tuberosum potato materials is not supported by microsatellite and plastid marker analyses

Neo-Tuberosum refers to cultivated potato adapted to long-day tuberization and a syndrome of related morphological and physiological traits, developed by intercrossing and selection of short-day adapted potatoes of the Solanum tuberosum Andigenum Group, native from the Andes of western Venezuela to northern Argentina. This re-creation of the modern potato helped support the theory of an Andigenum Group origin of potato in temperate regions and the possibility to access the largely untapped diversity of the Andigenum Group germplasm by base broadening breeding. This Neo-Tuberosum derived theory, the re-creation of the modern potato from Andigenum germplasm, has been universally accepted for almost 40 years, and has had tremendous impact in planning some breeding programs and supporting phylogenetic conclusions in cultivated potato. We show, with microsatellite (simple sequence repeat, SSR) and plastid DNA marker data, that Neo-Tuberosum germplasm is closely related to Chilotanum Group landraces from lowland south-central Chile rather than to Andigenum Group germplasm. We interpret this quite unexpected result to be caused by strong rapid selection against the original Andigenum clones after unintended hybridization with Chilotanum Group germplasm. In addition, we show that Neo-Tuberosum and Andigenum Group germplasm did not serve to broaden the overall genetic diversity of advanced potato varieties, but rather that Neo-Tuberosum lines and lines not using this germplasm are statistically identical with regard to genetic diversity as assessed by SSRs. These results question the long-standing Neo-Tuberosum derived theory and have implications in breeding programs and phylogenetic reconstructions of potato. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Successive domestication and evolution of the Andean potatoes as revealed by chloroplast DNA restriction endonuclease analysis

Five chloroplast DNA (ctDNA) types (W, T, C, S, and A) have previously been identified in the Andean tetraploid cultivated potatoes (Solanum tuberosum ssp. andigena) and three types (C, S, and A) in diploid cultivated potatoes (S. stenotomum). In this study, ctDNA types were determined for an additional 35 accessions of S. stenotomum and 97 accessions of putative ancestral wild species (15 of S. brevicaule, 26 of S. bukasovii, 4 of S. candolleanum, 25 of S. canasense, 17 of S. leptophyes, and 10 of S. multidissectum). The first five ctDNA types were also identified in S. stenotomum. The wild species were also polymorphic for ctDNA types except for S. brevicaule, which had only W-type ctDNA. T-type ctDNA was not found in any of the wild species and could have originated from W-type ctDNA after S. stenotomum arose. The other types of ctDNA evolved in wild species. The geographical distribution of each ctDNA type indicated that A-type ctDNA arose in central Peru and T-type ctDNA in the Bolivia-Argentine boundary. It is implied that potatoes were successively domesticated and that, in parallel, several wild species were differentiated from time to time and place to place from the ancestral species complex. Subsequent sexual polyploidization formed a wide ctDNA diversity among the Andean tetraploid potatoes, and selection from them formed the limited ctDNA diversity found in Chilean tetraploid potatoes (ssp. tuberosum).Hawkes' (1990) classification system is tentatively adopted throughout this text. Synonyms indicated by Hawkes (1990) for the species names described by various authors are presented in parentheses.     

Reclassification of landrace populations of cultivated potatoes (Solanum sect. Petota)

Cultivated potatoes have been classified as species under the International Code of Botanical Nomenclature (ICBN) and as cultivar-groups under the International Code of Nomenclature of Cultivated Plants (ICNCP); both classifications are still widely used. This study examines morphological support for the classification of landrace populations of cultivated potatoes, using representatives of all seven species and most subspecies as outlined in the latest taxonomic treatment. These taxa are S. ajanhuiri, S. chaucha, S. curtilobum, S. juzepczukii, S. phureja subsp. phureja, S. stenotomum subsp. stenotomum, S. stenotomum subsp. goniocalyx, S. tuberosum subsp. andigenum, and S. tuberosum subsp. tuberosum. The results show some phenetic support for S. ajanhuiri, S. chaucha, S. curtilobum, S. juzepczukii, and S. tuberosum subsp. tuberosum, but little support for the other taxa. Most morphological support is by using a suite of characters, all of which are shared with other taxa (polythetic support). These results, combined with their likely hybrid origins, multiple origins, evolutionary dynamics of continuing hybridization, and our classification philosophy, leads us to recognize all landrace populations of cultivated potatoes as a single species, S. tuberosum, with the eight cultivar-groups: Ajanhuiri Group, Andigenum Group, Chaucha Group, Chilotanum Group, Curtilobum Group, Juzepczukii Group, Phureja Group, and Stenotomum Group. We defer classification of modern cultivars, traditionally classified in Tuberosum Group, to a later study.     

Ecogeography of ploidy variation in cultivated potato (Solanum sect. Petota)

? Premise of the study: The taxonomy of cultivated potatoes has been highly controversial, with estimates of species numbers ranging from 3 to 17. Ploidy level has been one of the most important taxonomic characters to recognize cultivated potato species, containing diploid (2n = 2x = 24), triploid (2n = 3x = 36), tetraploid (2n = 4x = 48), and pentaploid (2n = 5x = 60) cultivars. We tested the environmental associations of different ploidy levels in cultivated potato species that traditionally have been recognized as Linnaean taxa to see whether, in combination with prior morphological, molecular, and crossing data, some of the ploidy variants can be recognized as distinct taxa. ? Methods: We summarize 2780 chromosome counts of landrace cultivated potatoes, provide georeferences to 2048 of them, and analyze these data for 20 environmental variables at 10-min resolution using the randomForest algorithm to explore associations with taxa and ploidy variants. ? Key results: Except for the S. tuberosum Chilotanum Group and extreme northern and southern range extensions of the Andigenum Group, it is impossible to find distinct habitats for the ploidy variants of the S. tuberosum Andigenum Group. ? Conclusions: Our distributional and ecological data, in combination with prior results from morphology, microsatellites, and crossing data, provide yet additional data to support a major reclassification of cultivated potato species. A rational, stable, and universally accepted taxonomy of this major crop plant will greatly aid all users of wild and cultivated potatoes from breeders to gene bank managers to ecologists and evolutionary biologists.     

The Photosynthetic Response to Elevated CO2 in High Altitude Potato Species (Solanum curtilobum)

Plants of Solanum curtilobum (from high altitude) and Solanum tuberosum (from low altitude) were grown in open-top chambers in a greenhouse at either ambient (AC, 360 µmol mol^–1) or ca. twice ambient (EC, 720 µmol mol^–1) CO₂ concentrations for 30 d. CO₂ treatments started at the reproductive stage of the plants. There were similar patterns in the physiological response to CO₂ enrichment in the two species. Stomatal conductance was reduced by 59 % in S. tuberosum and by 55 % in S. curtilobum, but such a reduction did not limit the net photosynthetic rate (P _N), which was increased by approximately 56 % in S. curtilobum and 53 % in S. tuberosum. The transpiration rate was reduced by 16 % in both potato species while instantaneous transpiration efficiency increased by 80 % in S. tuberosum and 90 % in S. curtilobum. Plants grown under EC showed 36 and 66 % increment in total dry biomass, whereas yields (dry mass of tubers) were increased by 40 and 85 % in S. tuberosum and S. curtilobum, respectively. EC promoted productivity by increasing P _N. Thus S. tuberosum, cultivated around the world at low altitudes, and S. curtilobum, endemic of the highland Andes, respond positively to EC during the tuberisation stage.     

The use and limits of AFLP data in the taxonomy of polyploid wild potato species in Solanum series Conicibaccata

Solanum sect. Petota (tuber-bearing wild and cultivated potatoes) are a group of approximately 190 wild species distributed throughout the Americas from the southwestern United States south to Argentina, Chile, and Uruguay. Solanum series Conicibaccata are a group of approximately 40 species within sect. Petota, distributed from central Mexico to central Bolivia, composed of diploids (2n = 2x = 24), tetraploids (2n = 4x = 48) and hexaploids (2n = 6x = 64); the polyploids are thought to be polysomic polyploids. This study initially was designed to address species boundaries of the four Mexican and Central American species of series Conicibaccata with AFLP data with the addition of first germplasm collections of one of these four species, Solanum woodsonii, as a follow-up to prior morphological, chloroplast DNA, and RAPD studies; and additional species of series Conicibaccata from South America. AFLP data from 12 primer combinations (1722 polymorphic bands) are unable to distinguish polyploid species long thought to be distinct. The data suggest a complex reticulate history of the tetraploids or the need for a broad downward reevaluation of the number of species in series Conicibaccata, a trend seen in other series of sect. Petota. Separately, through flow cytometry, we report the first ploidy level of S. woodsonii, as tetraploid (2n = 48). The U.S. Government’s right to retain a non-exclusive, royalty-free license in and to any copyright is acknowledged.     

Who is the mother of the potato? — restriction endonuclease analysis of chloroplast DNA of cultivated potatoes

Summary Chloroplast DNA from 44 lines of 16 wild and 7 cultivatedSolanum species were compared by restriction endonuclease analysis. Seven chloroplast genome types were identified among them by 5 restriction enzymes: Type A (S. tuberosum ssp.andigena andS. maglia); Type S (S. goniocalyx, S. phureja, S. stenotomum, S. ×chaucha and a line of ssp.andigena); Type C (S. acaule, S. bukasovii, S. canasense, S. multidissectum andS. ×juzepczukii); Type T (S. tuberosum ssp.tuberosum); Type W (other wild species); Type W (S. chacoense f.gibberulosum) and Type W (S. tarijense). From this cytoplasmic identification, it was concluded thatS. goniocalyx, S. phureja, S. ×chaucha and ssp.andigena were derived fromS. stenotomum or its primitive type, which may have originally evolved itself fromS. canasense. The chloroplast genome of the European potato, however, was introduced from the Chilean potato, which might have been primarily constructed with the nuclear genome from ssp.andigena and with cytoplasm from other species. The cytoplasmic donor of the Chilean potato could not be determined.Contribution from the Laboratory of Genetics, Faculty of Agriculture, Kyoto University, Japan, No. 479. This work was done at Kyoto University when the author was a graduate student at Kobe University     

Salt marsh colonization by a rocky shore invader: Balanus glandula Darwin (1854) spreads along the Patagonian coast

Balanus glandula, an east Pacific acorn barnacle from rocky shores, was introduced to Mar del Plata, Argentina more than 40 years ago and has spread over 17 latitudinal degrees southward. Here we report the first record of this species living in a soft-bottom environment colonizing the salt marsh plant species Limonium brasiliense, Spartina densiflora, S. alterniflora and Sarcocornia perennis. In addition, we describe the size frequency distribution, density and spatial distribution of the barnacles colonizing the different plant species. The size frequency distribution of Balanus showed a bimodal pattern in all plants. Barnacles were mostly large in S. densiflora, but small in S. alterniflora, with more balanced distributions of small and large barnacles on S. perennis and L. brasiliense. The highest density of barnacles was observed on S. perennis (x = 35.8 ind/cm², SD = 40.5) and S. alterniflora (x = 33.8 ind/cm², SD = 23), while the lowest on L. brasiliense (x = 1.5 ind/cm², SD = 1.18) and S. densiflora (x = 0.17 ind/cm², SD = 0.09). More than 90% of the barnacles on any given plant were found living. While barnacles colonized only the first few centimeters above the soil surface level in S. alterniflora and L. brasiliense, they reached their highest point on S. perennis. The finding of a rocky shore species successfully colonizing soft-bottom marshes within an invaded region brings new perspectives to discussions in biological invasion ecology, and raises additional considerations for coastal environmental management.     

Evidence for gametoclonal variation in potato (<Emphasis Type="Italic">Solanum tuberosum</Emphasis> L.)

Gametoclonal variation that occurs in gametic cells in culture and is recovered in their regenerated derivatives has not been reported in potato (Solanum tuberosum L.). Based on a set of 24 differentiating phenotypic traits, canonical variates analysis genetically distinguished the androgenic (di)haploid (2n = 2x = 24) D4 from its tetraploid (2n = 4x = 48) anther-derived sibs and anther donor JTH/C-107. Nuclear microsatellite analysis over six polymorphic loci indicated that meiotic rearrangements and mutant alleles were primarily associated with the release of gametoclonal variation. The incidence of null alleles in D4 at the loci STACCAS3 and STM0031 was also indicative of mutations occurring within the priming sequence. Microsatellite results were supported by random amplified polymorphic DNA (RAPD) assays that characterized a total of 567 loci (bins) representing 4,258 amplified fragments. Sixty-five new RAPDs that were absent in the anther donor and in either of its parents, viz., S. phureja Juz. & Buk. IVP-35 and S. tuberosum cv. Kufri Jyoti were present in D4, indicating the occurrence of extensive recombinational events. The results have been discussed in the context of microsatellite null alleles providing the most conclusive evidence for gametoclonal variation.     

Managing Potato Biodiversity to Cope with Frost Risk in the High Andes: A Modeling Perspective

Austral summer frosts in the Andean highlands are ubiquitous throughout the crop cycle, causing yield losses. In spite of the existing warming trend, climate change models forecast high variability, including freezing temperatures. As the potato center of origin, the region has a rich biodiversity which includes a set of frost resistant genotypes. Four contrasting potato genotypes –representing genetic variability- were considered in the present study: two species of frost resistant native potatoes (the bitter Solanum juzepczukii, var. Luki, and the non-bitter Solanum ajanhuiri, var. Ajanhuiri) and two commercial frost susceptible genotypes (Solanum tuberosum ssp. tuberosum var. Alpha and Solanum tuberosum ssp. andigenum var. Gendarme). The objective of the study was to conduct a comparative growth analysis of four genotypes and modeling their agronomic response under frost events. It included assessing their performance under Andean contrasting agroecological conditions. Independent subsets of data from four field experiments were used to parameterize, calibrate and validate a potato growth model. The validated model was used to ascertain the importance of biodiversity, represented by the four genotypes tested, as constituents of germplasm mixtures in single plots used by local farmers, a coping strategy in the face of climate variability. Also scenarios with a frost routine incorporated in the model were constructed. Luki and Ajanhuiri were the most frost resistant varieties whereas Alpha was the most susceptible. Luki and Ajanhuiri, as monoculture, outperformed the yield obtained with the mixtures under severe frosts. These results highlight the role played by local frost tolerant varieties, and featured the management importance –e.g. clean seed, strategic watering- to attain the yields reported in our experiments. The mixtures of local and introduced potatoes can thus not only provide the products demanded by the markets but also reduce the impact of frosts and thus the vulnerability of the system to abiotic stressors.     

Sugarcane genome architecture decrypted with chromosome‐specific oligo probes

Sugarcane (Saccharum spp.) is probably the crop with the most complex genome. Modern cultivars (2n = 100–120) are highly polyploids and aneuploids derived from interspecific hybridization between Saccharum officinarum (2n = 80) and Saccharum spontaneum (2n = 40–128). Chromosome‐specific oligonucleotide probes were used in combination with genomic in situ hybridization to analyze the genome architecture of modern cultivars and representatives of their parental species. The results validated a basic chromosome number of x = 10 for S. officinarum. In S. spontaneum, rearrangements occurred from a basic chromosome of x = 10, probably in the Northern part of India, in two steps leading to x = 9 and then x = 8. Each step involved three chromosomes that were rearranged into two. Further polyploidization led to the wide geographical extension of clones with x = 8. We showed that the S. spontaneum contribution to modern cultivars originated from cytotypes with x = 8 and varied in proportion between cultivars (13–20%). Modern cultivars had mainly 12 copies for each of the first four basic chromosomes, and a more variable number for those basic chromosomes whose structure differs between the two parental species. One?four of these copies corresponded to entire S. spontaneum chromosomes or interspecific recombinant chromosomes. In addition, a few inter‐chromosome translocations were revealed. The new information and cytogenetic tools described in this study substantially improve our understanding of the extreme level of complexity of modern sugarcane cultivar genomes.     

AFLP analysis to assess genomic stability in Solanum regenerants derived from wild and cultivated species

The cultivated potato as well as its tuber-bearing relatives are considered model plants for cell and tissue culture, and therefore for exploiting the genetic variation induced by in vitro culture. The association between molecular stability and tissue culture in different genetic backgrounds and ploidy levels has already been explored. However, it still remains to be ascertained whether somaclonal variation differs between callus-derived chromosome-doubled and undoubled regenerants. Our research aimed at investigating, through amplified fragment length polymorphism (AFLP) markers, the genetic changes in marker-banding patterns of diploid and tetraploid regenerants obtained from one clone each of Solanum bulbocastanum Dunal and S. cardiophyllum Lindl (both 2n = 2x = 24) and tetraploids from cultivated S. tuberosum L. (2n = 4x = 48). Pairwise comparisons between the banding patterns of regenerants and parents allowed detecting considerable changes associated to in vitro culture both at diploid and tetraploid level. The percentages of polymorphic bands between diploid and tetraploid regenerants were, respectively, 57 and 69% in S. bulbocastanum and 58 and 63% in S. cardiophyllum. On average, the frequencies of lost parental fragments in regenerants were significantly higher than novel bands both in S. bulbocastanum (48 vs. 22%) and S. tuberosum (36 vs. 18%) regenerants. By contrast, in S. cardiophyllum, a similar incidence of the two events was detected (32 vs. 29%). Our results revealed that structural changes after tissue culture process strongly affected the genome of the species studied, but diploid and tetraploids regenerated plants responded equally.     

The ploidy composition of offspring from Solanum tuberosum (4×) ×S. phureja (2×) crosses with special reference to triploid frequencies

Data on the production of offspring of 4×× 2× crosses in potato are presented. The ploidy composition of seedlings varied from year to year and parent to parent. Products of dihaploid induction crosses were chiefly 2× or 3× whereas crosses between S. tuberosum cultivars and unreduced gamete-producing S. phureja clones were mainly 3× or 4×. Substantial percentages of 3× seedlings were produced by some crosses in some years. It was concluded that the so-called ‘triploid block’ in potatoes is a variable phenomenon and that factors which increase seed production may suppress the proportion of triploids produced.     

Electrofusion of protoplasts from <Emphasis Type="Italic">Solanum tuberosum</Emphasis>, <Emphasis Type="Italic">S. bulbocastanum</Emphasis> and <Emphasis Type="Italic">S. pinnatisectum</Emphasis>

This paper discusses a number of experiments performed, involving the fusion by an electric field of mesophyll protoplasts from Solanum tuberosum cv. Bintje, S. tuberosum dihaploid clones 243, 299 and the wild tuberous disease-resistant species S. bulbocastanum and S. pinnatisectum. Three fusion experiments (S. bulbocastanum + S. tuberosum dihaploid 243, S. pinnatisectum + S. tuberosum cv. Bintje and S. pinnatisectum + S. tuberosum dihaploid 299) yielded 542 calli, the 52 ones of which produced shoots. Obtained regenerants were estimated by the flow-cytometry (FC) and RAPD analysis to determine hybrid plants.The utilisation of the FC as a useful method for detecting somatic hybrids is also discussed in this paper. The combination S. bulbocastanum + S. tuberosum dihaploid 243 led to the creation of eight somatic hybrids, the combination S. pinnatisectum + S. tuberosum cv. Bintje yielded four somatic hybrids and the combination S. pinnatisectum + S. tuberosum dihaploid 299 resulted in no hybrid regenerants. Morphology in vitro, growth vigour and production of tuber-like structures were evaluated in hybrid plants. Plants were transferred in vivo for further estimation (acclimatization, habitus evaluation and tuberization ability).     

Identification of Diploid <Emphasis Type="Italic">Stylosanthes seabrana</Emphasis> Accessions from Existing Germplasm of <Emphasis Type="Italic">S. scabra</Emphasis> Utilizing Genome-Specific STS Markers and Flow Cytometry,and Their Molecular Characterization

Stylosanthes seabrana (Maass and ‘t Mannetje) (2n = 2x = 20), commonly known as Caatinga stylo, is an important tropical perennial forage legume. In nature, it largely co-exist with S. scabra, an allotetraploid (2n = 4x = 40) species, sharing a very high similarity for morphological traits like growth habit, perenniality, fruit shape and presence of small appendage at the base of the pod or loment. This makes the two species difficult to distinguish morphologically, leading to chances of contamination in respective germplasm collections. In present study, 10 S. seabrana accessions were discovered from the existing global germplasm stock of S. scabra represented by 48 diverse collections, utilizing sequence-tagged-sites (STS) genome-specific markers. All the newly identified S. seabrana accessions displayed STS phenotypes of typical diploid species. Earlier reports have conclusively indicated S. seabrana and S. viscosa as two diploid progenitors of allotetraploid S. scabra. With primer pairs SHST3F3/R3, all putative S. seabrana yielded single band of ~550 bp and S. viscosa of ~870 bp whereas both of these bands were observed in allotetraploid S. scabra. Since SHST3F3/R3 primer pairs are known to amplify single or no band with diploid and two bands with tetraploid species, the amplification patterns corroborated that all newly identified S. seabrana lines were diploid in nature. Flow cytometric measurement of DNA content of the species, along with distinguishing morphological traits such as flowering time and seedling vigour, which significantly differ from S. scabra, confirmed all identified lines as S. seabrana. These newly identified lines exhibited high level of similarity among themselves as revealed by RAPD and STS markers (>92% and 80% respectively). Along with the enrichment in genetic resources of Stylosanthes, these newly identified and characterized accessions of S. seabrana can be better exploited in breeding programs targeted to quality.     

Origin of chloroplast DNA diversity in the Andean potatoes

Summary Wide chloroplast DNA (ctDNA) diversity has been reported in the Andean cultivated tetraploid potato, Solanum tuberosum ssp. andigena. Andean diploid potatoes were analyzed in this study to elucidate the origin of the diverse ctDNA variation of the cultivated tetraploids. The ctDNA types of 58 cultivated diploid potatoes (S. stenotomum, S. goniocalyx and S. phureja), 35 accessions of S. sparsipilum, a diploid weed species, and 40 accessions of the wild or weed species, S. chacoense, were determined based on ctDNA restriction fragment patterns of BamHI, HindIII and PvuII. Several different ctDNA types were found in the cultivated potatoes as well as in weed and wild potato species; thus, intraspecific ctDNA variation may be common in both wild and cultivated potato species and perhaps in the higher plant kingdom as a whole. The ctDNA variation range of cultivated diploid potatoes was similar to that of the tetraploid potatoes, suggesting that the ctDNA diversity of the tetraploid potato could have been introduced from cultivated diploid potatoes. This provided further evidence that the Andean cultivated tetraploid potato, ssp. andigena, could have arisen many times from the cultivated diploid populations. The diverse but conserved ctDNA variation noted in the Andean potatoes may have occurred in the early stage of species differentiation of South American tuber-bearing Solanums.     

Epigenetic patterns newly established after interspecific hybridization in natural populations of Solanum

Interspecific hybridization is known for triggering genetic and epigenetic changes, such as modifications on DNA methylation patterns and impact on phenotypic plasticity and ecological adaptation. Wild potatoes (Solanum, section Petota) are adapted to multiple habitats along the Andes, and natural hybridizations have proven to be a common feature among species of this group. Solanum × rechei, a recently formed hybrid that grows sympatrically with the parental species S. kurtzianum and S. microdontum, represents an ideal model for studying the ecologically and evolutionary importance of hybridization in generating of epigenetic variability. Genetic and epigenetic variability and their correlation with morphological variation were investigated in wild and ex situ conserved populations of these three wild potato species using amplified fragment length polymorphism (AFLP) and methylation‐sensitive amplified polymorphism (MSAP) techniques. We observed that novel methylation patterns doubled the number of novel genetic patterns in the hybrid and that the morphological variability measured on 30 characters had a higher correlation with the epigenetic than with the genetic variability. Statistical comparison of methylation levels suggested that the interspecific hybridization induces genome demethylation in the hybrids. A Bayesian analysis of the genetic data reveled the hybrid nature of S. × rechei, with genotypes displaying high levels of admixture with the parental species, while the epigenetic information assigned S. × rechei to its own cluster with low admixture. These findings suggested that after the hybridization event, a novel epigenetic pattern was rapidly established, which might influence the phenotypic plasticity and adaptation of the hybrid to new environments.     

Mycelial cultivation of <Emphasis Type="Italic">Phellinus linteus</Emphasis> using cheese-processing waste and optimization of bioconversion conditions

A medicinal mushroom, Phellinus linteus, was successfully cultivated using a cheese-processing waste, whey, and the optimal bioconversion conditions for the maximum mycelial growth rate was also estimated through solid-state cultivation experiments. Response surface analysis with a face-centered design (center point replication = 5) was applied to statistically approximate the simultaneous effects of the three variables, i.e., substrate concentration (10–30 g lactose l⁻¹), temperature (20–30°C), and pH (4–6), on the mycelial growth rate of P. linteus. The following is a partial cubic model where η is the mycelial growth rate (K _r ) and x _k is the corresponding variable term (k = substrate concentration, temperature, and pH in order): η = −23.8 + 8.67 × 10⁻² x ₁ + 1.48x ₂ + 1.77x ₃ + 8.00 × 10⁻⁴ x ₁ x ₂ + 7.25 × 10⁻² x ₁ x ₃ + 5.13 × 10⁻² x ₂ x ₃ −1.28 × 10⁻² x ₁² –3.18 × 10⁻² x ₂². −2.64 × 10⁻¹ x ₃² −3.28 × 10⁻³ x ₁ x ₂ x ₃ + 4.68 × 10⁻⁴ x ₁² x ₂. The produced response surface model proved to be significant (r ² > 0.99, P-value <0.0001, coefficient of variation <5%) to describe the explored space. Temperature was found to be the most significant factor of dominant effects on the mycelial growth rate, and other variables such as temperature², pH, pH², and (substrate concentration² × temperature) also showed significant effects on the model output. The maximum mycelial growth rate was predicted to be 2.80 mm d⁻¹ at 29.7 g lactose l⁻¹, 26.2°C, and pH 5. Our results proved a good potential of whey to serve as an alternative growth medium for cultivating P. linteus mycelia. This may provide another potential for managing this nutrient-rich waste in a cost-effective way.     

A new species of Stegodon (Mammalia,Proboscidea) from the Kazusa Group (lower Pleistocene), Hachioji City,Tokyo, Japan and its evolutionary morphodynamics

Abstract: Stegodon protoaurorae sp. nov. (Proboscidea) from the lower Pleistocene Terada Formation of the Kazusa Group in Japan is proposed as a new species based on characteristic features of plate formula, molar size, tooth enamel and plate frequency, and is described herein. The specimen of the new species was transported by autumn storms and buried. The new species fills an evolutionary gap between S. miensis and S. aurorae. Speciation in the lineage from S. miensis through S. protoaurorae to S. aurorae is inferred to have been caused by reduction of terrestrial space during marine transgression. The biostratigraphic distribution of S. protoaurorae suggests intercalation of a new S. protoaurorae Zone between the S. miensis Zone and the S. aurorae Zone. The S. protoaurorae Zone can be defined in the Nakatsu Group and the Terada Formation of the Kazusa Group, and can be assigned an age of 2.9–2.1 Ma.