Development of ergosterol, microbial biomass C, N, and P after steaming as a result of sucrose addition, and Sinapis alba cultivation

A pot experiment was carried out to monitor the recovery of a steaming-reduced microbial biomass (C, N, and P) and fungal ergosterol by sucrose addition. The second objective was to investigate the recovery of a steaming-reduced microbial biomass by white mustard (Sinapis alba) cultivation and its interactions with microbial residues, freshly formed from sucrose addition. Thirty days after steaming, the soil microbial biomass C and N was still significantly reduced by 80%, leading to a rather constant microbial biomass C/N ratio around 7 throughout the experiment. The steaming-induced decreases of microbial biomass P and ergosterol were only roughly 50%, leading to a decrease in the microbial biomass C/P ratio and an increase in the ergosterol-to-microbial biomass C ratio. Sucrose addition led to a 25% reduction in the ergosterol-to-microbial biomass C ratio. Mustard cultivation had significant positive effects on microbial biomass C, N, P, and ergosterol, but the effects were smaller than those of sucrose addition. Cultivating mustard had no significant effects on the C loss or on the incorporation of sucrose C into the microbial biomass. In contrast, the application of sucrose led to a significant decrease in the mustard shoot biomass and especially in the mustard root biomass.     

Genetic diversity and relationships between wild and cultivated olives (<Emphasis Type="Italic">Olea europaea</Emphasis> L.) in Sardinia as assessed by SSR markers

The genetic relationships within and between wild and cultivated olives were examined and clarified in an isolated and restricted area, such as the Mediterranean island of Sardinia. Wild (21 individuals) and cultivated olive trees (22 local cultivars from a germplasm collection and 35 ancient trees) were genotyped by means of 13 SSR loci. Five cases of synonymy were observed and nine distinct genotypes were identified in the collection. Five novel genotypes were also detected among the ancient trees. Differences on the allelic composition and heterozygosity levels were found between wild and cultivated trees. Model-based clustering method classified the olive trees into two major gene pools: (a) wild genotypes and (b) local cultivars from the collection and from heritage olives. Regarding the cultivated plant material, we observed that: (a) most of the Sardinian cultivars shared the same allelic profiles with the ancient cultivated trees and (b) the majority of these cultivars and all the novel genotypes were not related to any other cultivars included in this study. These findings as well as the detection of unique alleles and a certain wild genetic background at some cultivars revealed by the Bayesian analysis may indicate their autochthonous origin. The synonymy cases found between local cultivars and Italian mainland cultivars indicate interchange of genetic material among these growing areas, suggesting thus a possible allochthonous origin. The information obtained can assist in the management of an olive collection and sheds some light on the survival of true oleasters and the origin of Sardinian cultivars.     

Genetic variation in the endangered Rutaceae species <Emphasis Type="Italic">Citrus hongheensis</Emphasis> based on ISSR fingerprinting

Citrus hongheensis is a critically endangered species endemic to the Honghe river region in southeastern Yunnan, China. Its genetic diversity and differentiation were investigated using Inter-Simple Sequence Repeat (ISSR) markers. One hundred primers were screened, and a total of 245 loci were amplified from seven natural populations by 13 informative and reliable primers. Of these 245 ISSR loci, 233 were polymorphic and the detected variations revealed a relatively high level of intraspecific genetic diversity. At the population level, the mean percentage of polymorphic loci (PPB) was 36.50%, while the average expected heterozygosity (He) and Shannon diversity index (Ho) were 0.1327 and 0.1972, respectively. At the species level (across all populations), PPB was 95.10%, while He and Ho were 0.3520 and 0.5195, respectively. A high Gst value (0.6247) indicated that there is significant differentiation among populations, which was confirmed by AMOVA analysis (Φst = 0.6420). Pairwise genetic identity (I) values among populations ranged from 0.6341 to 0.7675, with a mean of 0.7008. We propose that the high level of genetic differentiation may be the result of habitat fragmentation and limited gene flow (Nm = 0.1502). For effective in situ conservation and population restoration of C. hongheensis it will be important to maintain historical processes, including high outbreeding rates, sufficient gene flow, and large effective population sizes.     

Study of clonally propagated cassumunar ginger (<Emphasis Type="Italic">Zingiber montanum</Emphasis> (Koenig) Link ex Dietr.) and its relation of wild <Emphasis Type="Italic">Zingiber</Emphasis> species from Thailand revealed by RAPD markers

The genetic relatedness among 51 accessions, 14 species of the genus Zingiber and genetic variability of a clonally propagated species, Zingiber montanum (Koenig) Link ex Dietr., from Thailand were studied using random amplified polymorphic DNA (RAPD) profiles. Twenty-nine random primers gave reproducible amplification banding patterns of 607 polymorphic bands out of 611 scored bands accounting for 99.40% polymorphism across the genotypes. Jaccard’s coefficient of similarity varied from 0.119 to 0.970, indicative of distant genetic relatedness among the genotype studied. UPGMA clustering indicated eight distinct clusters of Zingiber, with a high cophenetic correlation (r = 1.00) value. Genetic variability in Z. montanum was exhibited by the collections from six regions of Thailand. High molecular variance (87%) within collection regions of Z. montanum accessions was displayed by AMOVA and also explained the significant divergence among the sample from six collection regions. Our results indicate that RAPD technique is useful for detecting the genetic relatedness within and among species of Zingiber and that high diversity exists in the clonally propagated species, Z. montanum.     

Six new botanical varieties of <Emphasis Type="Italic">Triticum</Emphasis> from Oman

Due to its geographic position on the northeastern tip of the Arabian Peninsula and its sea trade relationships with Asia, East Africa and the Middle East, Oman has for millennia been at the cross-roads of inter-regional exchange of cultivated plants. This is reflected in recent findings of new cultivars of banana (Musa spp.) and wheat (Triticum spp.) in remote oases of the Hajar Mountains in northern Oman. Material collected in 2003 and 2004 contained six new botanical varieties of wheat which are described here. One of them belongs to the tetraploid T. aethiopicum, the others are hexaploid.     

Microsatellite analyses for evaluation of genetic diversity among Sicilian grapevine cultivars

A total of 82 grapevine genotypes were sampled from several areas of the Italian region of Sicily where vineyards are widely spread. The grapevines were characterized using six microsatellite markers (VVS2, VVMD5, VVMD7, VVMD27, VrZAG62 and VrZAG79) to evaluate genetic diversity. Thirty-seven of the 82 cultivars sampled had their names quoted in historical and literary sources, while 45 cultivars from old vineyards did not have their names reported in ancient literature. According to their genetic profiles at SSR loci, 70 different cultivars were found, while interesting cases of synonymies (Regina and Moscato bianco, Alicante and Dolcetta or among different clones of Zibibbo and Catarratto) and cases of homonymy (Frappato and Nerello Mascalese) were discovered. Several genetic parameters were calculated to assess the efficacy of the loci chosen in this work. Pairwise genetic distances between all cultivars were calculated. A dendrogram representing the genetic similarities among cultivars was depicted using the UPGMA method to investigate their relationships, explaining them from a historical point of view. The cluster distribution of cultivars clearly does not reflect their current geographical distribution, suggesting successive introductions of cultivars in Sicily from different areas of origin.     

Collection and ethnobotanical investigation of <Emphasis Type="Italic">Corchorus</Emphasis> species in Ethiopia: potential leafy vegetables for dry regions

Little information is available regarding the biodiversity and potential use of jute (Corchorus species) in Ethiopian agriculture. The present study summarizes species’ occurrence, use, geographical distribution, ecology, and ethnobotany of Corchorus species in Ethiopia. An ecogeographical study, conducted in the Amhara, Oromia and Gambella Regional States in 2005 and 2008 resulted in the collection of seven different species with more than 100 accessions. The study revealed low similarity in species composition between the Regional States, indicating that each region has its own unique set of species. Species numbers are higher in the north-eastern and south-western than the central part of the country. C. aestuans L. and C. tridens L. are restricted to humid lowlands of south-western part of Ethiopia, growing at elevations up to 490 m, whereas, C. urticifolius Wight et Arn., C. trilocularis L. and C. schimperi Cufod. were collected only in the north-eastern part of the country with elevation ranges of 1,380–2,130 m. The only species collected at a higher elevation (>2,100 m) was C. schimperi Cufod. Farmers’ perception, indigenous knowledge and folk taxonomy of jute species are better in Gambella than the other studied regions. Although several Corchorus species are reported from Ethiopia, these species are neither cultivated nor popularly used as leafy vegetables. This is mainly due to lack of awareness or knowledge about the species use, and abundant distribution of the species that allows gathering of edible leaves with little expenditure of time, labour and other resources. Our results revealed that some species are threatened, which necessitates highest priority for jute germplasm conservation in the country. In addition, creating public awareness about the use of jute species as a cheap source of leafy vegetable will play an important role to diversify food sources, reduce malnutrition, and contribute to household income generation of the farming community.     

Germination of 151-year old <Emphasis Type="Italic">Acacia</Emphasis> spp. seeds

A collection of seeds from five Acacia species was made in Egypt in 1856. Since then, the seeds have been stored at room temperature in different Swedish museums. Due to the extreme longevity within the seeds of Acacia and related species, germination tests were performed on the now 151-year old seed. Seeds of two of the five species tested germinated. The first, Acacia farnesiana (L.) Willd., had two seeds germinate, and Acacia melanoxylon R. Br. ex Ait. f. had one seed germinate. In addition, DNA was extracted from the aged seed and DNA preservation was analyzed. Four of the tested species displayed well preserved DNA, whereas DNA from Albizia lebbeck (L.) Benth. showed signs of degradation. The 151-year longevity of the Acacia seeds is among the longest of dry-stored seeds reported. Several independent studies now report on extreme survival capacity for Acacia and related genera suggesting that these genera are suitable for studies on the characteristics of seeds with long storage performance. The results also demonstrate that herbaria and seed collections stored in museums and institutional depositories can be alternate sources of plants genetic material and should be given conservation attention.