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Key message GWAS on a bread wheat panel with high D genome diversity identified novel alleles and QTLs associated with resilience to combined heat and drought stress under natural field conditions. Abstract As heat (H) and drought stresses occur concurrently under field conditions, studying them separately offers limited opportunities for wheat improvement. Here, a wheat diversity panel containing Aegilops tauschii introgressions was evaluated under H and combined heat–drought (HD) stresses to identify quantitative trait loci (QTLs) associated with resilience to the stresses, and to assess the practicability of harnessing Ae. tauschii diversity for breeding for combined stress resilience. Using genome-wide analysis, we identified alleles and QTLs on chromosomes 3D, 5D, and 7A controlling grain yield (GY), kernel number per spike, and thousand-kernel weight, and on 3D (521–549 Mbp) controlling GY alone. A strong marker–trait association (MTA) for GY stability on chromosome 3D (508.3 Mbp) explained 20.3% of the variation. Leaf traits—canopy temperature, vegetation index, and carbon isotope composition—were controlled by five QTLs on 2D (23–96, 511–554, and 606–614 Mbp), 3D (155–171 Mbp), and 5D (407–413 Mbp); some of them were pleiotropic for GY and yield-related traits. Further analysis revealed candidate genes, including GA20ox, regulating GY stability, and CaaX prenyl protease 2, regulating canopy temperature at the flowering stage, under H and HD stresses. As genome-wide association studies under HD in field conditions are scarce, our results provide genomic landmarks for wheat breeding to improve adaptation to H and HD conditions under climate change.

A negative effect of increasing temperature on wheat production in the coming decades has been projected for Sudan, which is a major wheat producer in Sub-Saharan Africa. Wheat is susceptible to high temperature, so trend analysis of historical yields together with observed temperature is critical for understanding the effect of climate change. The objective of this study was to determine the association between yield of irrigated wheat in hot drylands of Sudan and temperature during the growing season (November–February). Regional-scale yield data in three major wheat-producing areas (Northern State, Gezira State, and Kassala State) in 48 crop seasons (1970/71–2017/18) were used to determine the correlation of yield with maximum (TMAX) and minimum temperatures (TMIN) at representative meteorological stations (Dongola, Wad Medani, and New Halfa, respectively). Frequencies of days with maximum temperature above 35 °C (THD) and minimum temperature above 20 °C (THN) were also used for correlation analysis. In all three areas, regression analysis detected upward trends in the growing-season temperature. The increase in temperature was particularly evident at Dongola, although no such trend has been reported previously. The yields were negatively correlated with the growing-season temperature, particularly THN in Northern State, TMAX in Gezira State, and TMIN in Kassala State. These results confirm that the recent increase in the growing-season temperature might have reduced the yield to some extent in the breadbasket of Sudan.

Climate warming poses challenges for food production at low latitudes, particularly in arid regions. Sudan, where wheat demand could triple by 2050, has the world’s hottest wheat-growing environments, and observed yield declines in hot seasons are prompting the national government to prepare for a warming of 1.5–4.2 °C. Using advanced crop modelling under different climate and socioeconomic scenarios, we show that despite the use of adjusted sowing dates and existing heat-tolerant varieties, by 2050, Sudan’s domestic production share may decrease from 16.0% to 4.5–12.2%. In the relatively cool northern region, yields will need to increase by 3.1–4.7% per year, at non-compounding rates, to meet demand. In the hot central and eastern regions, improvements in heat tolerance are essential, and yields must increase by 0.2–2.7% per year to keep pace with climate warming. These results indicate the potential contribution of climate change adaptation measures and provide targets for addressing the wheat supply challenge. Sudan faces population growth to 80 million people, rising temperatures and trebling in demand for wheat by 2050. Crop modelling under climate and socioeconomic scenarios indicates the regional rates of yield growth that must be achieved by breeding heat-tolerant varieties to adapt wheat production to climate change and increased demand.

The innovation platforms (IP) concept was adopted in Sudan as an effective multi-stakeholders approach for sustainable agricultural R4D. The objectives of this study were to evaluate the IP approac...

Improved nitrogen use-efficient cultivars could be the most economically beneficial and environmentally friendly approach to reduce pollution associated with excessive N fertilization. The performance and genetic gain in grain yield and nitrogen use efficiency (NUE) of a historical set of 12 bread wheat cultivars released for a heat-stressed environment were investigated at four N levels (0 (N0), 43 (N43), 86 (N86), and 129 (N129) kg/ha) for two seasons. Averaged across seasons, increasing N level from N0 to N43, N86, and N129 resulted in yield increases ranging from 4−45%, 13–69%, and 34–87% at N43, N86, and N129, respectively. These yield increases were associated with increases in biomass (r = 0.86, P<0.01). Regressing grain yield of cultivars released during 1960 to 2006 against the year of release showed no trend at N0 and positive nonsignificant trends at N43;. however, significant positive trends were found at N86 and N129 with genetic gain rates of 12.65 and 15.76 kg ha−1 year−1, respectively. This gain was associated with progresses in harvest index (HI) at N43, N86, and N129 but not at N0. On the other hand, during the period from 1960 to 1990, the genetic gain in grain yield at N86 was 24.5 kg ha−1 year−1. Regressing NUE against the year of release showed significant linear trends at N86 and N129 (R2 = 0.511 and R2 = 0.477, respectively), but not at N43. The results indicate that breeders improved grain yield and NUE over 46 years under the heat-stressed environment of Sudan although the rate of increase in yield has been slowed down in recent years. Further improvement in NUE might require broadening the genetic diversity and simultaneous evaluation at low and high N levels.

PurposeThe purpose of this paper was to study the genetic variability, heritability, heat tolerance indices and phenotypic and genotypic correlation studies for traits of 250 elite International Center for Agricultural Research in the Dry Areas (ICARDA) bread wheat genotypes under high temperature in Wad Medani, Center in Sudan.Design/methodology/approachBread wheat is an important food on a global level and is used in the form of different products. High temperature associated with climate change is considered to be a detrimental stress in the future on world wheat production. A total of 10,250 bread wheat genotypes selected from different advanced yield trials introduction from ICARDA and three checks including were grown in two sowing dates (SODs) (1st and 2nd) 1st SOD heat stress and 2nd SOD non-stress at the Gezira Research Farm, of the Agricultural Research Corporation, Wad Medani, Sudan.FindingsAn alpha lattice design with two replications was used to assess the presence of phenotypic and genotypic variations of different traits, indices for heat stress and heat tolerance for 20 top genotypes and phenotypic and genotypic correlations. Analysis of variance revealed significant differences among genotypes for all the characters. A wide range, 944-4,016 kg/ha in the first SOD and 1,192-5,120 kg/ha in the second SOD, was found in grain yield. The average yield on the first SOD is less than that of the secondnd SOD by 717.7 kg/ha, as the maximum and minimum temperatures were reduced by 3ºC each in the second SOD when compared to the first SOD of the critical stage of crop growth shown.Research limitations/implicationsSimilar wide ranges were found in all morpho-physiological traits studied. High heritability in a broad sense was estimated for days to heading and maturity. Moderate heritability estimates found for grain yield ranged from 44 to 63.6 per cent, biomass ranged from 37.8 to 49.1 per cent and canopy temperature (CT) after heading ranged from 44.2 to 48 per cent for the first and secondnd SODs. The top 20 genotypes are better than the better check in the two sowing dates and seven genotypes (248, 139, 143, 27, 67, 192 and 152) were produced high grain yield under both 1st SOD and 2nd SOD.Practical implicationsThe same genotypes in addition to Imam (check) showed smaller tolerance (TOL) values, indicating that these genotypes had a smaller yield reduction under heat-stressed conditions and that they showed a higher heat stress susceptibility index (SSI). A smaller TOL and a higher SSI are favored. Both phenotypic and genotypic correlations of grain yield were positively and significantly correlated with biomass, harvest index, number of spikes/m2, number of seeds/spike and days to heading and maturity in both SODs and negatively and significantly correlated with canopy temperature before and after heading in both SODs.Originality/valueGenetic variations, heritability, heat tolerance indices and correlation studies for traits of bread wheat genotypes under high temperature

The Global Wheat Head Detection (GWHD) dataset was created in 2020 and has assembled 193,634 labelled wheat heads from 4,700 RGB images acquired from various acquisition platforms and 7 countries/institutions. With an associated competition hosted in Kaggle, GWHD has successfully attracted attention from both the computer vision and agricultural science communities. From this first experience in 2020, a few avenues for improvements have been identified, especially from the perspective of data size, head diversity and label reliability. To address these issues, the 2020 dataset has been reexamined, relabeled, and augmented by adding 1,722 images from 5 additional countries, allowing for 81,553 additional wheat heads to be added. We now release a new version of the Global Wheat Head Detection (GWHD) dataset in 2021, which is bigger, more diverse, and less noisy than the 2020 version. The GWHD 2021 is now publicly available at http://www.global-wheat.com/ and a new data challenge has been organized on AIcrowd to make use of this updated dataset., Comment: 8 pages, 2 figures, 1 table

Twenty-four wheat lines, developed by Aegilops tauschii Coss. introgressions and previously selected for heat or salinity stress tolerance, were evaluated under a drought-rewatering-drought cycle for two years. The objective was to select breeding lines that are resilient to more than one abiotic stress. The experiment was designed in alpha lattice with three replications. Drought was imposed by withholding water during flowering. The results revealed considerable genetic variability in physio-agronomic traits, reflecting the variation in the introgressed segments. High heritability estimates (above 47%) were recorded for most traits, including days to 50% heading, plant height, and thousand-grain weight, indicating the genetic control of these traits which may be useful for cultivar development. The trait-trait correlations within and between water regimes highlighted a strong association among the genetic factors controlling these traits. Some lines exhibited superior performance in terms of stress tolerance index and mean productivity compared with their backcross parent and elite cultivars commonly grown in hot and dry areas. Graphical genotyping revealed unique introgressed segments on chromosomes 4B, 6B, 2D, and 3D in some drought-resilient lines which may be linked to drought resilience. Therefore, we recommend these lines for further breeding to develop climate-resilient wheat varieties.

Heat stress is one of the major environmental constraints for wheat production; thus, a comprehensive understanding of the metabolomic responses of wheat is required for breeding heat-tolerant varieties. In this study, the metabolome responses of heat-tolerant genotypes Imam and Norin 61, and susceptible genotype Chinese Spring were comparatively analyzed using Fourier transform infrared (FTIR) spectroscopy in combination with chemometric data mining techniques. Principal component analysis of the FTIR data suggested a spectral feature partially overlapping between the three genotypes. FTIR spectral biomarker assay showed similar heat responses between the genotypes for markers Fm482 and Fm1502, whereas genotype-dependent variations were observed for other markers. The markers Fm1251 and Fm1729 showed contrasting behaviors between heat-tolerant and susceptible genotypes, suggesting that these markers may potentially serve as a tool for distinguishing heat-tolerant genotypes. Linear discriminant analysis (LDA) of the spectra demonstrated a clear separation between the three genotypes in terms of the heat stress effect. Analysis of LDA coefficients identified several spectral regions that were potentially responsible for the discrimination of FTIR spectra between different genotypes and environments. These results suggest that a combination of FTIR and chemometrics can be a useful technique for characterizing the metabolic behavior of diverse wheat genotypes under heat stress.

Drought and high temperature are the major abiotic stresses for wheat production. The present study investigated the effect of drought and chronic heat stress on physiological parameters of durum wheat lines derived from interspecific crosses and their association with yield. Seventy-seven durum wheat lines were evaluated during two seasons (2016–2017 and 2017–2018) for drought tolerance at Tessaout (Morocco) using irrigated and rainfed treatments and for heat tolerance at Wad Medani (Sudan). Five drought screening indices (alone or combined) and physiological parameters were used to assess drought and heat tolerance. Among the physiological parameters used, canopy temperature (CT) had moderate heritability and was significantly affected by both severe and moderate drought stresses. CT at early heading showed a stronger correlation with grain yield (GY) and total biomass (BY) under heat stress. The use of maximum quantum yield of PSII (Fv/Fm) for drought/heat screening was limited by the low genetic variation despite its significant correlation with yield under drought (r2 = 0.22) and heat (r2 = 0.4). The normalized difference vegetation index (NDVI) at vegetative stage was highly correlated with GY and BY and it showed high genotypic variation that can allow for efficient selection. The grain filling rate (GFR) was found to be highly correlated with GY and BY under heat stress. The modified stress tolerance index (MsSTI) had the highest association with GY under drought (R2 = 0.82) while the mean productivity (MP) was adapted to both optimal conditions (R2 = 0.77) and drought stress (R2 = 0.73). The computation of a mean score index (MSI) improved the selection efficiency under drought (R2 = 0.92). The results showed good potential for lines derived from wide crosses to increase variability for heat and drought adaptive physiological traits.

In wheat (Triticum aestivum L.) high temperature (≥30°C) during grain filling leads to considerable reduction in grain yield. We studied 400 multiple synthetic derivatives (MSD) lines to examine the genetic variability of heat stress–adaptive traits and to identify new sources of heat tolerance to be used in wheat breeding programs. The experiment was arranged in an augmented randomized complete block design in four environments in Sudan. A wide range of genetic variability was found in most of the traits in all environments. For all traits examined, we found MSD lines that showed better performance than their parent ‘Norin 61’ and two adapted Sudanese cultivars. Using the heat tolerance efficiency, we identified 13 highly heat-tolerant lines and several lines with intermediate heat tolerance and good yield potential. We also identified lines with alleles that can be used to increase wheat yield potential. Our study revealed that the use of the MSD population is an efficient way to explore the genetic variation in Ae. tauschii for wheat breeding and improvement.

Kernel weight and shape-related traits are inherited stably and increase wheat yield. Narrow genetic diversity limits the progress of wheat breeding. Here, we evaluated kernel weight and shape-related traits and applied genome-wide association analysis to a panel of wheat multiple synthetic derivative (MSD) lines. The MSD lines harbored genomic fragments from Aegilops tauschii. These materials were grown under optimum conditions in Japan, as well as under heat and combined heat–drought conditions in Sudan. We aimed to explore useful QTLs for kernel weight and shape-related traits under stress conditions. These can be useful for enhancing yield under stress conditions. MSD lines possessed remarkable genetic variation for all traits under all conditions, and some lines showed better performance than the background parent Norin 61. We identified 82 marker trait associations (MTAs) under the three conditions, most of them originated from the D genome. All of the favorable alleles originated from Ae. tauschii. For the first time, we identified markers on chromosome 5D associated with a candidate gene encoding a RING-type E3 ubiquitin–protein ligase and expected to have a role in regulating wheat seed size. Our study provides important knowledge for the improvement of wheat yield under optimum and stress conditions. The results emphasize the importance of Ae. tauschii as a gene reservoir for wheat breeding.

Eight chickpea cultivars (Shendi, Jabel Marra, Wad Hamid, Atmor, Hwata, Burgeig, Salwa and Matama) were evaluated for genetic variability, yield stability and contribution of yield attributes to seed yield. Field experiments were carried out for four seasons (2007/2008, 2009/2010, 2010/2011 and 2011/2012) at Hudeiba Research Farm in River Nile State, Sudan. Randomized complete block design with six replications was used. Most of the studied traits recorded highly significant difference (P≤ 0.01) due to cultivars, seasons and their interaction. High heritability and low level of differences among phenotypic coefficient of variation (PCV) and genotypic coefficient of variation (GCV) for studied traits indicated that cultivars influenced more in the expression of these traits. Based on the stability analysis for seed yield; the top yielding cultivars Burgeig and Hwata were adapted to favorable conditions. Both cultivars were late in flowering and maturity and had high number of seeds plant-1, biomass and harvest index. The cultivar Atmor with an intermediate seed yield was the most stable cultivar across seasons. The cultivar Salwa is optional due to its relatively high yield and large seed size. Combining farmer-preferred traits such as high and stable yield, large seed size, plant type and maturity into new cultivars will remain the main objective of the chickpea breeding program in Sudan. Key words: Chickpea cultivars, genetic variability, yield stability, Sudan.

Aims: This experiment aimed at identification of some forage-quality attributes of Sudan pearl millet (Pennisetum glaucum L.) collection for possible future utilization. Study Design: Randomized Complete Block Design (RCBD) with three replications. Place and Duration of Study: The analysis was carried out at the feed analysis laboratory, Elobeid Research Station of Agricultural Research Corporation (ARC), Elobeid, Sudan. Methodology: The selected accessions (42 rainy sown and 38 winter sown) for proximate chemical entities were from 100 pearl millet accessions evaluated for dry matter yield in two field trials. Prior to the proximate quality analysis, the dried samples were ground and oven dried once again. The dried samples were used in 3 replicates for the proximate analysis to determine crude protein (CP), crude fiber (CF) and Nitrogen Free Extract (NFE). Results: Among the studied accessions, nine (in both rainy and winter seasons) had Crude protein (CP%) more than 9%. Nineteen accessions (in rainy) and 36 (in winter) had Crude fiber (CF%) less than 40%, whereas 25 (in rainy) and 32 (in winter) had Nitrogen free extract (NFE%) more than

The original article was corrected. Author Muhammad Kundi should instead read: Muhammad Sohail.

Adaptation of wheat (Triticum aestivum L.) to high temperatures could be improved by introducing alien genes from wild relatives. We evaluated the responses of wheat-Leymus racemosus chromosome introgression lines to high temperature to determine their potentiality for developing improved wheat cultivars. Introgression lines and their parent Chinese Spring were evaluated in a growth chamber at the seedling stage and in the field at the reproductive stage in two heat-stressed environments in Sudan. Optimum and late planting were used to ensure exposure of the plants to heat stress at the reproductive stage. The results revealed the impact of several Leymus chromosomes in improving wheat adaptation and tolerance to heat. Three lines possessed enhanced adaptation, whereas two showed high heat tolerance. Two addition lines showed a large number of kernels per spike, while one possessed high yield potential. Grain yield was correlated negatively with the heat susceptibility index, days to heading and maturity and positively with kernel number per spike and triphenyl tetrazolium chloride assay under late planting. The findings suggest that these genetic stocks could be used as a bridge to introduce the valuable Leymus traits into a superior wheat genetic background, thus helping maximize wheat yield in heat-stressed environments.

Triggered by the need to develop inter-seasonal, multi-cut cereal forage crops, this study aimed at the exploitation of phenotypic variations among the rich pearl millet (Pennisetum glaucum L.) collections in Sudan for possible utilization in forage-type breeding programmes. A total of 100 pearl millet accessions were used in three field trials grown in rainy, winter and summer seasons (2008–2009) at the Gezira Research Station Farm and the Gezira University Experimental Farm. Wide diversity and highly significant differences in the total dry forage yield, days to harvest, plant height, number of tillers/plant and leaf/stem ratio were found among the accessions. At an 80% morphological similarity level, the 100 accessions of pearl millet were clustered into four main groups. In the rainy and winter seasons, 71 and 56% of the accessions produced forage yield of more than 5 t/ha, respectively. In contrast, 77% of the accessions produced less than 5 t/ha in the summer season. Among the top-ranking 25 accessions, two accessions (HSD 2190 and HSD 2236) were common in dry matter yield in the three seasons, whereas 11 accessions were identified in at least two seasons. The presence of such common accessions in more than one season is encouraging for growing pearl millet as a multi-cut crop for a longer period. These results indicated the possibility of the development of forage-suited varieties of pearl millet directly through further evaluation of those common accessions or indirectly through a crop breeding programme.

Heat and drought adaptive quantitative trait loci (QTL) in a spring bread wheat population resulting from the Seri/Babax cross designed to minimize confounding agronomic traits have been identified previously in trials conducted in Mexico. The same population was grown across a wide range of environments where heat and drought stress are naturally experienced including environments in Mexico, West Asia, North Africa (WANA), and South Asia regions. A molecular genetic linkage map including 475 marker loci associated to 29 linkage groups was used for QTL analysis of yield, days to heading (DH) and to maturity (DM), grain number (GM2), thousand kernel weight (TKW), plant height (PH), canopy temperature at the vegetative and grain filling stages (CTvg and CTgf), and early ground cover. A QTL for yield on chromosome 4A was confirmed across several environments, in subsets of lines with uniform allelic expression of a major phenology QTL, but not independently from PH. With terminal stress, TKW QTL was linked or pleiotropic to DH and DM. The link between phenology and TKW suggested that early maturity would favor the post-anthesis grain growth periods resulting in increased grain size and yields under terminal stress. GM2 and TKW were partially associated with markers at different positions suggesting different genetic regulation and room for improvement of both traits. Prediction accuracy of yield was improved by 5 % when using marker scores of component traits (GM2 and DH) together with yield in multiple regression. This procedure may provide accumulation of more favorable alleles during selection.

The new stem rust race Ug99 is an alarming threat to the wheat (Triticum aestivum L.) production of the world for the very fact that it overcomes many of the known Sr genes including the most commonly used genes such as Sr31, Sr24, and Sr36. The wheat breeding program at the International Center for Agricultural Research in the Dry Areas (ICARDA) has distributed the first stem rust resistant spring wheat yield trials composed of 24 wheat genotypes for the Central and West Asia and North Africa (CWANA) region to identify high yielding wheat genotypes, which can be recommended for direct release and/or parentage purposes by the National Agricultural Research Systems (NARSs). The additive main effects and multiplicative interaction (AMMI) analysis of variance for grain yield (kg ha-1) of 24 wheat genotypes tested in 15 environments showed that wheat grain yield was significantly (p < 0.01) affected by environments (E), genotypes (G), and genotype × environment interaction (GEI). From the total sum of squares due to treatments (G + E + GEI), E contributed 90.1% and GEI accounted for 8.3% while G effect represented only 1.6%. According to AMMI2 estimate, Baasha-14 and Amir-2 with mean grain yield levels of 5168 and 5127 kg ha-1, respectively, are identified as the best genotypes with high yield potential across a wide range of environments. Based on correlation and clustering analysis among environments, the Ghab site in Syria (E7) is identified as the highest yielding and best correlated site and therefore it is recommended as a key location for evaluation of wheat germplasm yield potential in ICARDA's wheat breeding program. We recommend the high yielding and Ug99 resistant genotypes identified in this study for direct release as replacement of the susceptible varieties by the respective NARS and/or to be used as parents at ICARDA and by NARS collaborators.

Genetic progress in yield will increase if more traits conferring better agronomic and physiological performance are brought together in the same variety through full exploitation of genotyping and phenotyping techniques in breeding. A set of 288 spring wheat advanced lines was tested in different countries in North Africa, Western and South Asia, as well as in Mexico (total of 12 environments) to: identify high yielding germplasm adapted to the former regions; identify sources of variation for physiological traits; and test the ability of physiological traits to predict yield. A group of high yielding advanced lines has been selected in these environments, but significant genotype by environment interactions were observed and were significantly explained (21% of yield variation) by soil pH and air temperature. Associations between traits were dependent on the environment, specifically TKW was positively associated with yield in almost all environments however in Sudan, negative associations were observed. In contrast cooler CT was consistently associated with yield and the trait showed moderate heritability. Agronomic and physiological variables were able to predict 27% of yield variation across advanced lines ( R 2 % by ridge regression) using means of all environments and this model became more significant under stress environments (explaining around 34% of yield variation). Results suggested that if drought and heat adaptive traits are brought together in one genotype, yields can be further increased particularly in low yielding environments.

SUMMARYIn non-traditional, heat-stressed environments, wheat breeding programmes were mainly concerned with the introduction and adaptation of high-yielding, heat-tolerant cultivars regardless of the end-use quality. For the recently developed quality-oriented markets, new cultivars should combine the above-mentioned traits with good grain quality to improve economic feasibility of wheat production in these environments. This study aimed to examine the suitability of the conventional sodium dodecyl sulfate sedimentation (SDSS) test for predicting bread-making quality and to evaluate the effectiveness of a prolonged-swelling SDSS test in improving the predictability of end-use quality under heat stress conditions. Conventional and prolonged-swelling SDSS volumes were measured from whole meal of 15 bread wheat genotypes grown for two seasons under two sowing conditions at Gezira Research Farm, Wad Medani, Sudan. Results of correlations of SDSS volumes with total and insoluble protein contents, mixograph peak height and mixograph descending slope indicated the suitability of the SDSS test in predicting bread-making quality under heat-stress irrigated conditions. However, the absence of significant correlations with some quality attributes, such as mixograph peak time and mixograph curve width, demonstrated the non-exclusiveness of the SDSS test for predicting all bread-making quality attributes. The prolonged-swelling SDSS tests did not improve identification of differences among genotypes over the conventional test despite similarly predicting some quality attributes and showing relatively small increases in the correlation coefficient magnitudes with others. SDSS after 10 min from settlement (SDSS10) showed strong correlations with all other SDSS volumes at various times and with most of quality attributes. This suggested that SDSS10 could be used for evaluation of bread-making quality in early generations of the breeding programme in the hot irrigated conditions of Sudan and similar environments.

Understanding wheat (Triticum aestivum L.) response to high shoot/root temperature during the early growth stages is important for successful production in tropical and subtropical environments. This study examined the physiological response of wheat cultivars to high shoot and/or root temperatures during early growth stages. Three cultivars; Imam, Fang and Siete Cerros were grown in soil and hydroponically at three shoot/root temperatures (23/23, 23/35 and 35/35ºC for the soil experiment; and 22/22, 22/38 and 38/38ºC for the hydroponic experiment). Leaf dry weight and leaf area plant-1 were significantly decreased by high shoot/ root temperature (HS/HR, 35/35 and 38/38ºC) but was not affected by a normal shoot/high root temperature (NS/HR, 23/35 and 22/38ºC). The NS/HR (22/38ºC) and HS/HR (38/38ºC) treatments in the hydroponic experiment significantly decreased photosystem II quantum yield ( Φpsii), photosynthetic rate (Pn) and specific leaf area (SLA) compared with the normal shoot/normal root (NS/NR, 22/22ºC) temperature treatment. Chlorophyll accumulation was significantly decreased by NS/HR, but increased significantly by HS/HR in most of the measuring dates. The heat-tolerant cultivar, Fang, always had the highest chlorophyll content, Φpsii and Pn under all temperature treatments, while the heat-sensitive cultivar, Siete Cerros, always had the greatest reduction in these traits especially towards the end of the experiment. Imam and Fang responded to HS/HR in the hydroponic experiment by immediate and greater reductions in leaf dry weight, total leaf area and SLA during the first wk of the treatments compared with Siete Cerros. The response changed with the treatments duration such that Imam showed the least reduction and Siete Cerros was the most affected cultivar towards the end of the experiment. Thus, wheat cultivars differentially responded to high shoot/root temperature by reducing the leaf weight and area and hence accumulating more chlorophyll in the diminished leaves. The failure to undergo such changes led to significantly lower chlorophyll accumulation, Φpsii and Pn under high root temperature.

High temperatures, whether of shoot or root, are reported to affect shoot and root growth of various plant species. The scanty information available on the differential response of wheat genotypes to high shoot and root-zone temperatures triggered this investigation to study the response and adaptation of shoot and root growth of three wheat genotypes to high shoot and root-zone temperatures during early growth stages. Three wheat genotypes; Fang (heat tolerant), Siete Cerros (heat sensitive) and Imam (recent cultivar adapted to a hot irrigated environment) were grown in soil and hydroponically. Three shoot/root-zone temperatures (23/23, 23/35 and 35/35 °C for the soil experiment and 22/22, 22/38 and 38/38 °C for the hydroponic experiment) were applied at three-leaf growth stage. High root-zone temperature alone or combined with high shoot temperature reduced xylem sap flow rate, root dry weight, root length and root/shoot ratio. Unexpectedly, shoot fresh and dry weights and relative growth rate (RGR) were not significantly affected by the high root-zone temperature except for the susceptible genotype, Siete Cerros, after prolonged exposure in the hydroponic experiment. In contrast, high shoot/root-zone temperature significantly reduced shoot fresh and dry weights from as early as the first week of the hydroponic experiment. The 38/38 °C treatment also caused significant reduction in RGR and net assimilation rate during the first 2 weeks, but no significant differences were found during the last 2 weeks compared with 22/22 °C. Interesting responses were observed among genotypes in terms of shoot and root dry weights and root/shoot ratio at 38/38 °C treatment. The heat-sensitive Siete Cerros showed the least reduction in these traits during the first 2 weeks while the heat-tolerant Fang and Imam responded by greatly reducing their shoot and root weights. The situation was almost reversed with the duration of treatments such that Siete Cerros became the most affected genotype while Fang and Imam were better adapted to high shoot/root-zone temperature. Specific root weight was the exceptional trait that increased under high temperature treatments. Results indicate that despite the reduction in root length and weight observed under high root-zone temperature, shoot growth was not much affected suggesting that the use of suitable cultivar coupled with proper management could alleviate most of high root-zone temperature effects during early growth stages.

Canopy cooling in dry heat-stressed areas is regarded as one of the most physiologically efficient way to attain high grain yields in wheat. Twelve wheat genotypes were grown with four N levels in a 2-year field trial to investigate their efficiency to utilize addition of nitrogen for canopy cooling and high chlorophyll accumulation under a dry but irrigated hot environment in Sudan. Both canopy temperature depression (CTD) and chlorophyll content (CC) increased significantly with addition of 43 (N43), 86 (N86) and 129 (N129) kg N/ha compared to zero N (N0) treatment. The two-season average increases in CTD were 33, 59 and 67% at N43, N86 and N129, respectively, relative to N0. The average increases in CC were 15, 22 and 23% at N43, N86 and N129, respectively. However, genotypes showed a wide range of responses to addition of N especially for CTD. The combined genotypic ranges in percent increase of CTD and CC were 19 to 63% and 4 to 22% at N43, 38 to 88% and 13 to 36% at N86, and 34 to 113% and 15 to 28% At N129, respectively. Strong association was found between CTD and CC, which in-turn, was highly and significantly associated with biomass and grain yield. On the other hand, CTD showed significant negative association with harvest index. The results indicate that application of N fertilizer was reflected in a cooler canopy under the dry heat stress conditions of this study. However, genotypic variation in utilizing N fertilizer in canopy cooling necessitate that this should be done in accordance with the response and efficiency of each cultivar. Key words: Nitrogen fertilizer, canopy temperature depression, chlorophyll content, heat stress, wheat.

Papillary squamous cell carcinoma (PSCC) of the uterine cervix is a rare variant of squamous cell carcinoma (SCC). It is characterized by a papillary architecture and markedly atypical epithelium. Invasion and metastasis have been reported. We report a case of PSCC in a 72-year-old woman who subsequently tested positive for HPV 16. To our knowledge, this is the first report of HPV typing in a case of PSCC. Our finding of a high-risk HPV type in PSCC may help explain why PSCC has been reported to have a clinical course similar to that of nonpapillary SCC.

The false-negative fraction (FNF) is emerging as a statistical parameter that may be used to evaluate the efficacy of Papanicolaou smear screening laboratories. Our objectives for this paper are to acquaint non-laboratorians with this important measurement and to measure the FNF of the Air Force Cyto-center (AFCC) at the Armed Forces Institute of Pathology in Washington, DC. The FNF is defined as estimated false negatives divided by (true positives plus estimated false negatives). Most often, the number generated is multiplied by 100 and expressed as a percent. We have determined the FNF of the AFCC to be 3.7%. This value compares favorably with most others reported in the medical literature.

Context.—The Food and Drug Administration has recently approved several devices that use computerized image analysis to rescreen Papanicolaou (Pap) smears that have already been examined by cytotechnologists. Physicians and laboratories must decide whether the utility of these devices justifies the cost.Objective.—To determine the effectiveness and cost of PAPNET-assisted rescreening in identifying cervical abnormalities not identified by manual rescreening.Design.—PAPNET-assisted rescreening of 5478 Pap smears obtained in 1994 and 1995 previously identified as "within normal limits" or "benign changes" on both initial and random screening.Patients.—Female service members and dependents aged 12 to 88 years.Setting.—Air Force clinics in the United States and Japan.Intervention.—Rescreening of Pap smears by PAPNET, followed by reevaluation of abnormal smears by the consensus panel, consisting of 3 cytotechnologists and 3 pathologists.Main Outcome Measures.—Proportion of Pap smears initially screened as normal identified as abnormal by both PAPNET and consensus panel; costs of rescreening.Results.—PAPNET screening identified 1614 (29%) slides requiring additional microscopic review. On further review, 448 (8% of total) had possibly abnormal cells. Ultimately, 11 of these cases were reviewed by the consensus panel for potentially atypical cells. Of these 11 cases, 5 were reclassified as atypical squamous cells of undetermined significance (ASCUS) and 1 as atypical glandular cells of undetermined significance (AGUS). No additional squamous intraepithelial neoplasia (SIL) was identified in these smears; the patient with a diagnosis of AGUS on rescreening was diagnosed as having a low-grade SIL (LSIL) on follow-up. Costs were $5825 to $33781 for each additional ASCUS or AGUS diagnosis. A cost of $17475 to $101343 is expected for each case of LSIL identified by PAPNET-assisted rescreening and not by traditional manual rescreening.Conclusions.—PAPNET-assisted rescreening identified a few more cases of ASCUS than did manual rescreening, but at a relatively high cost. The costs of rescreening should be carefully compared with the expected efficacy in reducing cervical cancer mortality.

The Global Wheat Head Detection (GWHD) dataset was created in 2020 and has assembled 193,634 labelled wheat heads from 4700 RGB images acquired from various acquisition platforms and 7 countries/institutions. With an associated competition hosted in Kaggle, GWHD_2020 has successfully attracted attention from both the computer vision and agricultural science communities. From this first experience, a few avenues for improvements have been identified regarding data size, head diversity, and label reliability. To address these issues, the 2020 dataset has been reexamined, relabeled, and complemented by adding 1722 images from 5 additional countries, allowing for 81,553 additional wheat heads. We now release in 2021 a new version of the Global Wheat Head Detection dataset, which is bigger, more diverse, and less noisy than the GWHD_2020 version., Plant Phenomics, 2021