SummaryWe present genome‐wide gene expression patterns as a time series through the infection cycle of the fungal pine needle blight pathogen, Dothistroma septosporum, as it invades its gymnosperm host, Pinus radiata. We determined the molecular changes at three stages of the disease cycle: epiphytic/biotrophic (early), initial necrosis (mid) and mature sporulating lesion (late). Over 1.7 billion combined plant and fungal reads were sequenced to obtain 3.2 million fungal‐specific reads, which comprised as little as 0.1% of the sample reads early in infection. This enriched dataset shows that the initial biotrophic stage is characterized by the up‐regulation of genes encoding fungal cell wall‐modifying enzymes and signalling proteins. Later necrotrophic stages show the up‐regulation of genes for secondary metabolism, putative effectors, oxidoreductases, transporters and starch degradation. This in‐depth through‐time transcriptomic study provides our first snapshot of the gene expression dynamics that characterize infection by this fungal pathogen in its gymnosperm host.

Development of winter wheat (Triticum aestivum) synthetics started at CIMMYT-Mexico in 2004, when winter durum wheat (Triticum turgidum) germplasm from Ukraine and Romania was crossed with Aegilops tauschii accessions from the Caspian Sea region. Chromosomes were doubled after pollination and embryo rescue, but chromosome number and cytological validation was not performed. F2 populations were grown in Mexico and were shipped to Turkey in 2008. During 2009–2015, these populations were subjected to rigorous pedigree selection under dry, cold, disease-affected environments of the Central Anatolian Plateau. The wide segregation and partial sterility observed in 2009 gradually decreased and, by 2016, most of the F8 single spike progenies demonstrated good fertility and agronomic performance. Since 2013, lines have been selected from synthetic populations and evaluated at multiple sites. Superior lines were characterized for resistance to leaf, stripe and stem rust, plant height, and reaction to common bunt and soil-borne pathogens. Thousand kernel weight of many lines exceeded 50 g, compared with the check varieties that barely reached 40 g. Threshability of synthetic lines varied from 0 to 95%, demonstrating genetic variation for this important domestication trait. Screening against Hessian fly, sunny pest and Russian wheat aphid identified several resistant genotypes. Both durum and Aegilops parents affected synthetic wheat traits. Several studies are underway to reveal the genetic diversity of synthetic lines and the basis of resistance to diseases and insects. This synthetic germplasm represents a new winter bread wheat parental pool. It is available upon request to interested breeding/research programmes.

The normalized difference vegetation index (NDVI) continues to provide easy and fast methodologies to characterize wheat genetic resources in response to abiotic stresses. This study identifies ways to maximize green leaf area duration during grain filling and develops NDVI models to predict physiological maturity and different stay-green parameters to increase grain yield of rainfed winter wheat under terminal drought. Three wheat populations were evaluated: one containing 240 landraces from Afghanistan, the second with 250 modern lines and varieties, tested for two years under low rainfall conditions in Turkey, and the third with 291 landraces from Central and Western Asia (grown for one year in the same location). The onset of senescence, maximum "greenness", rate of senescence and residual "greenness" at physiological maturity were estimated using sequential measurements of NDVI and have shown significant correlations with grain yield under low rainfall rainfed conditions. Trade-offs were identified among the different stay-green attributes, e.g. delayed onset of senescence and high maximum "greenness" resulted in accelerated rates of senescence and highest yields and were most evident in the landrace populations. It is concluded, that the use of rate of senescence to select for staygreen must be coupled with other stay-green components, e.g. onset of senescence or maximum "greenness" to avoid the effects of the trade-offs on final grain yield. The NDVI decay curves (using the last three NDVI measurements up to maturity) were used to estimate days to maturity using the NDVI decay during the senescence period and days to heading. A training and testing set (20 and 80% of each population, respectively) were used for calibrations allowing for correlations between predicted and observed maturity of up to r=+0.85 (P<0.0001). This procedure will facilitate large-scale wheat phenotyping in the future.

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Development of new wheat cultivars combining good local adaptation, disease resistance and grain quality represents an important strategy component for national food security. Uzbekistan was identified by N. Vavilov as important center of wheat diversity. An inventory of landraces was conducted in 2010-2013 in western Tien-Shan Mountains to survey, collect, and characterize old wheats still grown by farmers. Thirty landraces were collected from 17 villages in Jizzakh, Kashkadarya and Surkhandarya Regions. The material went through spike selection, head-rows, un-replicated trials in Tashkent, Uzbekistan (2012)(2013)(2014)(2015), and replicated trials in Konya, Turkey (2018. Landrace diversity was described using spike morphological traits and DNA profiles as reflected by single nucleotide polymorphism. A socioeconomic survey demonstrated that wheat landraces are grown in remote mountain communities by subsistence farmers despite having access to modern cultivars, and both are frequently grown together. The main reasons for the maintenance of landraces are: (1) large grain with excellent breadmaking quality and suitability for home-baking; (2) specific adaptations allowing stable and reliable yield; and (3) straw yield and quality. Similar genomic profiles shared by some landraces from remote regions of Uzbekistan and neighboring Tajikistan demonstrated their common origin and are indicative of seed exchange between farmers. Agronomic characterization demonstrated the resilient nature of their adaptation based on spring and facultative growth habit and superiority of some landraces for grain yield and its components compared to local checks. Viable options for maintaining and expanding on-farm wheat diversity include their improvement through selection and breeding, market development, variable incentives, and capacity building. For the first time, this paper presents results of a unique 10-year study in Uzbekistan on social conditions in the areas where wheat landraces are grown, analyses the diversity of these landraces, evaluates agronomic characteristics, and discusses the sustainability options for on-farm wheat landraces use and conservation.