Detection of QTLs for genotype × environment interactions in tomato seeds and seedlings

Seed quality and seedling establishment are the most important factors affecting successful crop development. They depend on the genetic background and are acquired during seed maturation and therefor, affected by the maternal environment under which the seeds develop. There is little knowledge about the genetic and environmental factors that affect seed quality and seedling establishment. The aim of this study is to identify the loci and possible molecular mechanisms involved in acquisition of seed quality and how these are controlled by adverse maternal conditions. For this, we used a tomato recombinant inbred line (RIL) population consisting of 100 lines which were grown under two different nutritional environmental conditions, high phosphate and low nitrate. Most of the seed germination traits such as maximum germination percentage (G_max), germination rate (t₅₀) and uniformity (U₈₄₁₆) showed ample variation between genotypes and under different germination conditions. This phenotypic variation leads to identification of quantitative trait loci (QTLs) which were dependent on genetic factors, but also on the interaction with the maternal environment (QTL × E). Further studies of these QTLs may ultimately help to predict the effect of different maternal environmental conditions on seed quality and seedling establishment which will be very useful to improve the production of high-performance seeds.     

Mapping QTLs for physiological and biochemical traits related to grain yield under control and terminal heat stress conditions in bread wheat (<Emphasis Type="Italic">Triticum aestivum</Emphasis> L.)

In order to detect genomic regions with different effects for some of the physiological and biochemical traits of wheat, four experiments were conducted at Research Farm of Agricultural and Natural Resources Research Center of Zabol in 2015–2016 and 2016–2017 growing seasons. The experiments were carried out using four alpha lattice designs with two replications under non-stress and terminal heat stress conditions. Plant materials used in this study included 167 recombinant inbred lines and their parents (‘SeriM82’ and ‘Babax’). Six traits including grain yield (GY), proline content (PRO), water soluble carbohydrates (WSC), maximum efficiency of photosystem II (Fv/Fm), cytoplasmic membrane stability (CMS) and chlorophyll content (CHL) were evaluated. Genetic linkage map consisted of 211 AFLP marker, 120 SSR marker and 144 DArT markers with 1864 cm length and 4.4 cm mean distance. QTL analysis was carried out using a mixed-model-based composite interval mapping (MCIM) method. By the combined analysis of normal phenotypic values, 27 additive QTLs and five pairs of epistatic effects were identified for studied traits, among which two additive and one epistatic QTL showed significant QTL?×?environment interactions. By the combined analysis of stress phenotypic values, a total of 26 QTLs with additive effects and 5 epistatic QTLs were detected, among which one additive and one epistatic QTL showed QTL?×?environment interactions. Six QTLs with major effects (QGY-2B, QGY-2D, QPro-5B, QWSC-4A, QFv/Fm-6A and QCMS-4B), which were common between two conditions could be useful for marker-assisted selection (MAS) in order to develop heat tolerant and high-performance wheat varieties.     

Molecular phylogeny of the mainly Mediterranean genera Chaenorhinum,Kickxia and Nanorrhinum (Plantaginaceae,tribe Antirrhineae), with focus on taxa in the Flora Iranica region

Plantaginaceae tribe Antirrhineae as revised by Sutton (1988) comprises about 30 genera that have undergone significant taxonomic changes in recent years, many of which have yet to be assessed by detailed phylogenetic analyses, including Kickxia, Nanorrhinum and Chaenorhinum. To examine the monophyly, relationships and rank of Kickxia, Nanorrhinum and Chaenorhinum, we conducted a phylogenetic analyses of the nuclear ribosomal DNA internal transcribed spacer region (ITS) and chloroplast DNA (rpl32‐trnL) sequence data, with special focus on the Flora Iranica region. We sampled 22 species of Kickxia s.l. (16 of Kickxia s.s. and 6 of Nanorrhinum), 2 species of Anarrhinum, 12 species of Chaenorhinum, 19 representatives of nine additional genera of Antirrhineae, and several outgroup taxa representing other genera of Plantaginaceae. Parsimony and Bayesian analyses of the two datasets produced almost congruent trees, although taxon sampling differed. Our results indicate that Chaenorhinum can be subdivided into two highly supported groups of species, partially matching two of the currently recognized sections of the genus. Albraunia and Holzneria are nested within the Chaenorhinum clade and should not be recognized as distinct genera. Two clades corresponding to Kickxia sect. Kickxia and Kickxia sect. Valvatae were also highly supported. Our data, whn combined with all other available evidence, support recognition of the clade comprising Kickxia sect. Valvatae at the genus level, as Nanorrhinum. Based on this result, six names are here transferred to Nanorrhinum. A diagnostic key to the seven genera of tribe Antirrhineae known from the Flora Iranica region is also provided.     

Towards the conservation of a critically endangered species, <Emphasis Type="Italic">Aphanius farsicus</Emphasis>: embryogenesis and development

Human-induced disturbance or anthropogenic activities, natural disturbance and also limited distribution, have forced Aphanius farsicus populations to the edge of extinction, during the past few years. As knowledge of fish ontogeny is fundamental for accurate stock assessment, and reproductive potential determination, thus for future conservation and management of the critically endangered species, we describe the first detailed normal embryonic development of this cyprinodontid fish from fertilization to post-hatching. Aphanius farsicus spontaneously spawned at 24°C. The newly-laid eggs were hyaline and spherical in shape (1.40 ± 0.02 mm, n = 11), sticky and full of egg yolk (telolecithal/macrolecithal) with oil droplets. We documented the main developmental stages at 24°C to zygote (0 h), cleavage (2 h), blastula (2 h), gastrula (17 h), segmentation, (34 h), pharyngula (100 h) and hatching (162 h).     

Early otolith development in the critically endangered tooth-carp, <Emphasis Type="Italic">Aphanius farsicus</Emphasis> (Teleostei: Cyprinodontidae)

Otolith morphology in the tooth-carp/killifish genus Aphanius is a source of informative taxonomic characters at both the species and population level. Most work on otoliths has focused on adult specimens, while evidence of ontogenetic variation is rarely provided. In this study we describe the development of otolith morphology during the early life stages of an endangered and endemic species, the Fars tooth-carp Aphanius farsicus from southern Iran. The study material comprises 34 larvae and early juveniles representing nine different developmental stages (0–120 days post hatching), all reared under the same laboratory conditions. The results reveal (i) a significant correlation between standard length and otolith size (length) in larval and early juvenile stages, (ii) clear differences in otolith morphology between larvae/early juveniles and adults, and (iii) a temporal link between the appearance of the sulcus on the otolith’s inner face and the emergence of the dorsal and anal fins. Our results indicate that otoliths of Aphanius can be recognized as originating from larval or early juvenile fish based on their short rostrum and antirostrum lengths and wide excisura, in addition to their small size. These immature otoliths are, however, not diagnostic at the species level in A. farsicus, nor most probably in other species of tooth-carp. The outcome of our study is also of interest to palaeontologists working with fossil killifish otoliths, as it can help avoid misinterpretation of ancient species diversity.     

Phytogeography of Genu and Homag,two mountains with an Irano–Turanian flora in the Saharo–Sindian regional zone,south Iran

The Saharo–Sindian regional zone encompasses the flat and arid areas of North Africa, the Arabian Peninsula, southern Iran and the deserts of Pakistan and west India. There are some scattered mountains situated within this area, like Hoggar in Sahara, Saint Catherine in Sinai and Genu and Homag in southern Iran. These highlands serve as interglacial refugia for cold adapted plant species. In the present study, phytogeographical patterns and relationships of the flora of Genu and Homag mountains are described and discussed in relation to the phytogeography of the flora of low‐lying Hormoz Island. According to a chorological assesment of the flora, Genu and Homag mountains belong to the Irano–Turanian region with 59% of the species restricted to this area. In contrast, the surrounding lowland plains are part of the Saharo–Sindian area with a rather high proportion of widespread species (17%) and Somalia–Masai‐linking elements (20%). It is noteworthy that several Turanian enclaves also occur in the lowland zone. Furthermore, the distributional patterns imply that the mountainous Irano–Turkestanian region is an integrated area which is supposedly distinct from the Turanian lowland areas in the north and from the Saharo–Sindian lowland areas in the south. On the other hand, the expansive floras of Turanian and Saharo–Sindian regions are linked to each other. Endemic species in lowland areas in south Iran are mostly either frost sensitive vicariants of cold adapted Turanian species or of Saharo–Sindian origin, while the highland endemics in the area trace their origins to the Irano–Turkestanian region.