Phytonematodes Associating Wheat in North Eastern Egypt and Pathogenicity of Heterodera avenae on Certain Cereal Cultivars

A survey of plant-parasitic nematodes (PPNs) associating wheat in Ismailia governorate, northeastern Egypt was carried-out during 2016/2017 and 2017/2018 growing seasons. Results showed that seven PPNs genera and/or species were found associating wheat roots. These genera and/or species, in descending order of frequency, were: Tylenchorhynchus spp. (14%), Helicotylenchus spp. (10%), Heterodera avenae (8%), Ditylenchus spp. (5%), Meloidogyne javanica (4%), Pratylenchus spp. and Xiphinema spp. (3%, each). Two screening pot experiments, in two consecutive growing seasons (2017/17 and 2017/18) were carried out to determine the host suitability of 15 Egyptian cereal cultivars including bread wheat (Triticum aestivum), barley (Hordeum vulgare) and oat (Avena sativa) to the cereal cyst nematode, Heterodera avenae, under greenhouse conditions. Results of both experiments were very similar and showed that oat cv. Baladi and wheat cv. Giza 171 were highly susceptible, while wheat cvs. Masr 1, Masr 2, Masr 3, Sakha 95, Seds 1, Seds 12, and Shandawel 1 were susceptible. However, barley cvs. Giza 135, Giza 123, Giza 124, and Giza 125 were found to be moderately resistant to the tested nematode. H. avenae suppressed (P ≤ 0.05) the dry weights of roots, shoots and spikes of the inoculated plants, compared to the non-inoculated checks. Another greenhouse pot experiment was carried out during the wheat-growing season 2018/2019 to determine the effect of different initial population densities (Pi) of H. avenae on the growth parameters of wheat cv. Giza 171 and on nematode reproduction. Results showed that as the nematode Pi increased, both the wheat growth parameters and the nematode reproduction factor (Rf) were decreased (P ≤ 0.05).

Adaptation of Winter Barley Cultivars to Inversion and Non-Inversion Tillage for Yield and Rhynchosporium Symptoms

Modern cereal cultivars are highly adapted to, and normally bred and trialled under, high input, high soil disturbance conditions. On-farm conditions are often suboptimal for high yield and frequently use minimal soil tillage, sometimes no-tillage, and therefore, cultivars may be differentially adapted to such conditions. We report a series of trials across 10 years comparing multiple cultivars within years and smaller numbers across years to identify stable cultivars showing preferential adaptation to different levels of soil tillage. Cultivars responded differentially to inversion and non-inversion tillage but were not affected by the level of cultivation within each of these tillage types. Yield declined over time but much more so in the non-inversion tillage treatment. Rhynchosporium symptoms were also increasingly suppressed in the non-inversion tillage type. Several cultivars were identified that showed strong adaptation to tillage type, and some of these were consistent across several trial years. These cultivars can be used to identify traits and genotypes associated with tillage adaptation to target breeding for on-farm conditions.

Grassflies of genus Meromyza (Diptera, Chloropidae) and grasses: the evolution of host plant preference

The present and literature data showed that Meromyza flies developed on grasses from 5 tribes: Poeae, Triticeae, Bromeae, Nardeae, Arundinarieae. The preference of host plants for 25, mainly Western Palaearctic species of Meromyza flies was analyzed: 11 species developed on grasses of the tribe Poeae, 4 on Triticeae, 9 on grasses from different tribes, 1 species developed on bamboo. A phylogenetic tree based on the mtDNA CO1 gene locus was constructed in the BEAST for 28 species of Meromyza flies, for 8 species of Drosophila and Campiglossa pygmaea. The host plants were known for 19 species Meromyza flies out of 28 studied species. An overview of the evolution of grasses is given. By the possible time of the genus Meromyza origin (not earlier than the middle of the Miocene), based on the known evolutionary scale of Drosophila, the Pooideae grasses had already been isolated and division into tribes occured. The features of non-specialized phytophage-oligophage (except M. acuminata) confirmed by the wide spectrum of host plants have been supposed for species close to ancestral haplotypes (M. nigriseta, M. pratorum, M. saltatrix, M. variegata) or representing independent branches in their clusters (M. acuminata, M. mosquensis, M. nigriventris). The differentiation of Meromyza genus with formation of new species with narrow oligophagy or monophagy was associated with adaptation to other wild grasses following the formation and increase in the abundance of core pooids (Triticodae + Poodae) grasses and the spread of herbal biomes in the Miocene. Oligophages M. nigriventris, M. nigriseta, M. variegata and monophages M. acuminata, M. grandifemoris damage cereal cultivars.

Pratylenchus thornei: The Relationship Between Presowing Nematode Density and Yield Loss in Wheat and Barley

The root lesion nematode Pratylenchus thornei causes economic losses in wheat and barley internationally through both reduced grain yield and grain quality. This study investigated the relationships between the presowing P. thornei density and grain yield and the postharvest nematode densities. Four field experiments were conducted at the same site between 2010 and 2014. A range of presowing P. thornei densities was established in the first year by growing three cereal cultivars that ranged from resistant to susceptible. In the following year, plots were sown with the five same cereal cultivars. A linear relationship was observed between the natural log of the presowing P. thornei density and grain yield across all seasons. The results showed that grain yield losses varied between cultivars and seasons. The importance of season was significant, with this study conducted over several seasons, and it highlighted the variability in yield losses between seasons, which will need further investigation. The greatest yield losses observed were 25 to 28% when the maximum presowing P. thornei densities ranged between 150 and 250 P. thornei g of soil−1. An analysis of the relationship between the presowing and postharvest nematode densities revealed that increased presowing nematode densities resulted in decreased multiplication rates in all seasons and in all cultivars. Nematode multiplication rates also varied between seasons. These results explain why it is difficult to predict nematode levels based on cropping history, and additionally, they highlight the importance of growing resistant cultivars to maintain low levels of P. thornei to minimize risk of yield losses.

Milk, Game or Grain for a Manchurian Outpost

The long record of imperial China’s Inner Asian borderland relations is not simply multi-ethnic, but ‘multi-environmental’. Human dependencies on livestock, wild animals and cereal cultivars were the prerequisite environmental relations for borderland incorporation. This paper examines such dependencies during the Qing Dynasty’s (1644–1912) establishment of the Manchurian garrison of Hulun Buir near the Qing border with Russia. Garrison logistics proved challenging because provisioning involved several indigenous groups—Solon-Ewenki, Bargut and Dagur (Daur)—who did not uniformly subsist on livestock, game or grain, but instead exhibited several, sometimes overlapping, practices not always confined within a single ethnicity. Ensuing deliberations reveal official convictions, some of which can be traced back to the preceding Ming Dynasty (1368–1644), regarding the variable effects of these practices on the formation of Inner Asian military identities. Such issues were distinctive of Qing borderland dynamics that constructed ‘Chinese’ empire not only in more diverse human society, but also in more diverse ecological spheres.