Abstract: The improvements in crop production needed to meet the increasing food demand in the 21st Century will rely on improved crop management and better crop varieties. In the last decade our ability to use genetics and genomics in crop science has been revolutionised, but these advances have not been matched by our ability to phenotype crops. As rapid and effective phenotyping is the basis of any large genetic study, there is an urgent need to utilise the recent advances in crop scale imaging to develop robust high-throughput phenotyping. This review discusses the use and adaptation of infra-red thermography (IRT) on crops as a phenotyping resource for both biotic and abiotic stresses. In particular, it addresses the complications caused by external factors such as environmental fluctuations and the difficulties caused by mixed pixels in the interpretation of IRT data and their effects on sensitivity and reproducibility for the detection of different stresses. Further, it highlights the improvements needed in using this technique for quantification of genetic variation and its integration with multiple sensor technology for development as a high-throughput and precise phenotyping approach for future crop breeding.

Abstract: The research trial was carried out in the Mediterranean region where high summer temperatures have been proved to have a detrimental effect on the delicate tomato fruitset process. The flower to fruit set process was simultaneously monitored in fogged and unfogged shelters during the three-month Mediterranean summer season. Comparisons of pollen quality, fruit set rates and fruit yield revealed that mean daily temperatures of 25–26 °C are the upper limit for proper fruit set and fruit yield for tomatoes grown in protected cultivation during the hot Mediterranean summer period. A moderate reduction of 1–1.5 °C in mean daily temperatures together with the increased RH (relative humidity) from 50% to 70% during day time improved the pollen grain’s viability. Suggestions concerning more efficient controls on the fogging system considering those findings are discussed.

Abstract: It is claimed that the addition of biochar to soil improves C sequestration, soil fertility and plant growth, especially when combined with organic fertilizers such as compost. However, little is known about agricultural effects of small amounts of composted biochar. This greenhouse study was carried out to examine effects of co-composted biochar on oat ( Avena sativa L.) yield in both sandy and loamy soil. The aim of this study was to test whether biochar effects can be observed at very low biochar concentrations. To test a variety of application amounts below 3 Mg biochar ha −1 , we co-composted five different biochar concentrations (0, 3, 5, 10 kg Mg −1 compost). The biochar-containing compost was applied at five application rates (10, 50, 100, 150, 250 Mg ha −1 20 cm −1 ). Effects of compost addition on plant growth, Total Organic Carbon, N tot , pH and soluble nutrients outweighed the effects of the minimal biochar amounts in the composted substrates so that a no effect level of biochar of at least 3 Mg ha

Abstract: Developing cultivars with improved adaptation to drought and heat stressed environments is a priority for plant breeders. Canopy temperature (CT) is a useful tool for phenotypic selection of tolerant genotypes, as it integrates many physiological responses into a single low-cost measurement. The objective of this study was to determine the ability of CT to predict grain yield within the flow of a wheat breeding program and assess its utility as a tool for indirect selection. CT was measured in both heat and drought stressed field experiments in northwest Mexico on 18 breeding trials totaling 504 spring wheat lines from the International Maize and Wheat Improvement Center (CIMMYT) Irrigated Bread Wheat program. In the heat treatment, CT was significantly correlated with yield (r = −0.26) across all trials, with a maximum coefficient of determination within the individual trials of R2 = 0.36. In the drought treatment, a significant correlation across all trials was only observed when days to heading or plant height was used as a covariate. However, the coefficient of determination within individual trials had a maximum of R2 = 0.54, indicating that genetic background may impact the ability of CT to predict yield. Overall a negative slope in the heat treatment indicated that a cooler canopy provided a yield benefit under stress, and implementing selection strategies for CT may have potential for breeding tolerant genotypes.

Abstract: Phenotyping in field experiments is challenging due to interactions between plants and effects from biotic and abiotic factors which increase complexity in plant development. In such environments, visual or destructive measurements are considered the limiting factor and novel approaches are necessary. Remote multispectral imaging is a powerful method that has shown significant potential to estimate crop physiology. However, precise measurements of phenotypic differences between crop varieties in field experiments require exclusion of the disturbances caused by wind and varying sunlight. A mobile and closed multispectral imaging system was developed to study canopies in field experiments. This system shuts out wind and sunlight to ensure the highest possible precision and accuracy. Multispectral images were acquired in an experiment with four different wheat varieties, two different nitrogen levels, replicated on two different soil types at four different dates from 15 May (BBCH 13) to 18 June (BBCH 41 to 57). The images were analyzed and derived vegetation coverage and Normalized Difference Vegetation index (NDVI) were used to assess varietal differences. The results showed potentials for differentiating between the varieties using both vegetation coverage and NDVI, especially at the early growth stages. The perspectives of high-precision and high-throughput imaging for field phenotyping are discussed including the potentials of measuring varietal differences via spectral imaging in comparison to other simpler technologies such as spectral reflectance and RGB imaging.

Abstract: Traditional rice varieties maintained and cultivated by farmers are likely sources of germplasm for breeding new rice varieties. They possess traits potentially adaptable to a wide range of abiotic and biotic stresses. Characterization of these germplasms is essential in rice breeding and provides valued information on developing new rice cultivars. In this study, 307 traditional rice varieties newly conserved at the PhilRice genebank were characterized to assess their phenotypic diversity using 57 morphological traits. Using the standardized Shannon-Weaver diversity index, phenotypic diversity indices averaged at 0.73 and 0.45 for quantitative and qualitative traits, respectively. Correlation analyses among agro-morphological traits showed a high positive correlation in some traits such as culm number and panicle number, flag leaf width and leaf blade width, grain width and caryopsis width. Cluster analysis separated the different varieties into various groups. Principal component analysis (PCA) showed that seven independent principal components accounted for 74.95% of the total variation. Component loadings for each principal component showed morphological characters, such as culm number, panicle number and caryopsis ratio that were among the phenotypic traits contributing positive projections in three principal components that explained 48% of variation. Analyses of results showed high diversity in major traits assessed in farmers’ rice varieties. Based on plant height and maturity, 11 accessions could be potential donor parents in a rice breeding program. Future collection trips and characterization studies would further enrich diversity, in particular traits low in diversity, such as anthocyanin coloration, awn presence, awn color, culm habit, panicle type and panicle branching.

Abstract: This study examines the agronomic response, efficiency and profitability of fertilizer microdosing in maize. An experiment with the following treatments was conducted: control without fertilizer, microdosing treatments, with the rate of 27 + 27, 53 + 53 and 80 + 80 kg ha−1, and banding of fertilizer with 100 + 100 kg ha−1 of di ammonium phosphate (DAP) + urea, applied at planting and jointing, respectively. The treatments were arranged in a randomized complete block design with four replications. The experiment was conducted during the 2011/2012 and 2012/2013 cropping seasons at Ziway, Melkassa and Hawassa in the semiarid central rift valley region of Ethiopia. Compared to the control, the fertilizer treatments had higher yield and fertilizer use efficiency (FUE) profitably. The 27 + 27 kg ha−1 fertilizer rate increased the grain yield by 19, 45 and 46% at Hawassa, Ziway and Melkassa, respectively, and it was equivalent to the higher rates. The value cost ratio (VCR) was highest with the lowest fertilizer rate, varying between seven and 11 in the treatment with 27 + 27 kg ha−1, but two and three in the banding treatment. Similarly, FUE was highest with the lowest fertilizer rate, varying between 23 and 34 kg kg−1 but 7 and 8 kg kg−1 in the banding treatment. The improved yield, FUE, VCR and gross margin in maize with microdosing at the 27 + 27 kg ha−1 of DAP + urea rate makes it low cost, low risk, high yielding and profitable. Therefore, application of this particular rate in maize may be an option for the marginal farmers in the region with similar socioeconomic and agroecological conditions.

Abstract: Great care is needed to obtain spectral data appropriate for phenotyping in a scientifically rigorous manner. This paper discusses the procedures and considerations necessary and also suggests important pre-processing and analytical steps leading to real-time, non-destructive assessment of crop biophysical characteristics. The system has three major components: (1) data-collection platforms (with a focus on backpack and tractor-mounted units) including specific instruments and their configurations; (2) data-collection and display software; and (3) standard products depicting crop-biophysical characteristics derived using a suite of models to transform the spectral data into accurate, reliable biophysical characteristics of crops, such as fraction of green vegetation, absorbed photosynthetically active radiation, leaf area index, biomass, chlorophyll content and gross primary production. This system streamlines systematic data acquisition, facilitates research, and provides useful products for agriculture.

Abstract: Tomato (Solanum lycopersicum L.) is an important vegetable for supplying vitamins, minerals and fiber in human diets worldwide. Successful open field production of tomato in the tropics is limited by insect pests among other constraints. Two trials were conducted at the Horticulture Research and Teaching Field, Egerton University, Kenya with the objective of evaluating the effects of agricultural nets (agronets) herein called eco-friendly nets (EFNs) and floating row covers (FRCs) on pest population and yield of tomatoes. A randomized complete block design with five replications was used. Tomato plants were protected with either fine mesh EFN (0.4-mm pore diameter), large mesh EFN (0.9-mm pore diameter) or FRC. The EFN and FRC were maintained permanently closed or opened thrice a week from 9 am to 3 pm. Two control treatments were used: open unsprayed (untreated control) or open and sprayed with alpha-cypermethrin based insecticide (treated control). The use of EFN and FRC helped to manage pests with the lowest pest population obtained under FRC maintained permanently covered and the highest population recorded in the untreated control. Covering tomato plants with EFN or FRC also resulted in more marketable fruit and lower yield losses compared with the unprotected systems. The EFN and FRC offer great potential as part of integrated systems for pest management and yield improvement in tomato production in regions with a tropical climate.

Abstract: In greenhouse and field experiments, a mycelial formulation of the fungus Myrothecium verrucaria (IMI 361690) containing 0.20% Silwet L-77 surfactant exhibited high bioherbicidal efficacy against the problematic weed hemp sesbania. Infection and mortality levels of 100% of hemp sesbania seedlings occurred within 48 h after fungal application in the greenhouse. In rice field tests conducted over a three year period, M. verrucaria at an inoculum concentration of 50 g L−1 (dry mycelium equivalent) controlled 95% of ≤20 cm tall hemp sesbania plants. M. verrucaria also controlled larger plants (≥60 cm tall) using this high inoculum concentration. This level of weed control, as well as rice yields from plots where weeds were effectively controlled, were similar to those which occurred with the herbicide acifluorfen. These results suggest that a mycelial formulation of M. verrucaria has potential as a bioherbicide for controlling hemp sesbania in rice.

Abstract: Boron (B) is an essential micronutrient needed for normal plant growth and development. To evaluate the response of corn to foliar B applications at V4-V6 (4-6 leaves with visible collars) and VT (tasseling) growth stages on fine textured soils, a field experiment was conducted at four sites from 2008 to 2010 in Northeast Missouri. The treatments included a non-treated control; V4-V6 applied B at 0.56, 1.12 and 2.24 kg·ha −1 ; and VT applied B at 0.28, 0.56 and 1.12 kg·ha −1 . Foliar B, applied at V4-V6 at 2.24 kg·ha −1 , resulted in higher yields than VT applications. No significant differences in yield were found for B applications at different timings for concentrations of 0.56 and 1.12 kg·ha −1 . Boron applied at V4-V6 and 2.24 kg·ha −1 increased yield 0.29 Mg·ha −1 compared to the non-treated control. The B applications at VT increased ear leaf tissue B concentration compared to V4-V6 applications and non-treated control, but it had no significant effect on corn yields. No significant difference between B treatments was observed for grain oil, protein, starch or extractable starch concentration; severity of anthracnose stalk rot or common rust; and ear tip fill. The B application of 2.24 kg·ha −1 at V4-V6 decreased the severity of gray leaf spot, but increased the severity of northern leaf blight compared to the non-treated control. Boron applied at V4-V6 at 2.24 kg·ha −1 was the most beneficial timing and concentration evaluated in these fine textured soils.

Abstract: Unsustainable agronomic practices and environmental change necessitate a revolution in agricultural production to ensure food security. A new generation of crops that yield more with fewer inputs and are adapted to more variable environments is needed. However, major changes in breeding programmes may be required to achieve this goal. By using the genetic variation in crop yield in specific target environments that vary in soil type, soil management, nutrient inputs and environmental stresses, robust traits suited to specific conditions can be identified. It is here that long-term experimental platforms and field phenotyping have an important role to play. In this review, we will provide information about some of the field-based platforms available and the cutting edge phenotyping systems at our disposal. We will also identify gaps in our field phenotyping resources that should be filled. We will go on to review the challenges in producing crop ideotypes for the dominant management systems for which we need sustainable solutions, and we discuss the potential impact of three-way interactions between genetics, environment and management. Finally, we will discuss the role that modelling can play in allowing us to fast-track some of these processes to allow us to make rapid gains in agricultural sustainability.

Abstract: A common strategy for ameliorating soil acidity is the application of agricultural lime. However, this measure is hampered by the lack of high resolution soil maps that can enable lime application according to the spatial variability of soil pH in an area. Therefore, this study was carried out to map soil acidity in South Eastern Zambia. The objective of the study was to apply geostatistical procedures to mapping soil acidity in the country. Ordinary kriging was performed on a set of 119 soil samples collected from the 0–20 cm soil layer whose pH was determined by the electrometric method. The kriging model that was developed was found to be satisfactory with low prediction errors (root mean square error 0.36). Thus, the map produced could be used to draw up strategies for management of soil acidity in the area.

Abstract: Wheat (Triticum aestivum L.) breeding programs strive to increase grain yield; however, the progress is hampered due to its quantitative inheritance, low heritability, and confounding environmental effects. In the present study, a winter wheat population of 159 recombinant inbred lines (RILs) was evaluated in six trials under rainfed, terminal drought, and fully-irrigated conditions, over four years. Quantitative trait locus/loci (QTL) mapping was conducted for grain yield main effect (GY) and the genotype × environment interaction (GEI) effect. A total of 17 QTL were associated with GY and 13 QTL associated with GEI, and nine QTL were mapped in the flanking chromosomal regions for both GY and GEI. One major QTL Q.Gy.ui-1B.2, explaining up to 22% of grain yield, was identified in all six trials. Besides the additive effect of QTL associated with GY, interactions among QTL (QTL × QTL interaction), QTL × environment, and QTL × QTL × environment were also observed. When combining the interaction effects, QTL Q.Gy.ui-1B.2 along with other QTL explained up to 52% of the variation in grain yield over the six trials. This study suggests that QTL mapping of complex traits such as grain yield should include interaction effects of QTL and environments in marker-assisted selection.

Abstract: In order to evaluate the environmental effect on plant development and mini-tuber production of a diverse group of potato genotypes grown under an aeroponic system, a G × E interaction experiment was carried out in greenhouses located at CIP’s experimental stations in La Molina (Lima) and Huancayo (Junin). Five contrasting environments were set-up and evaluated. A combined Analysis of Variance was performed for the variables “days to tuber set”, “days to senescence” and “plant height”. An Additive Main Effects and Multiplicative Interaction (AMMI) Analysis was performed for yield variables: mini-tuber “weight” and “number of mini-tubers” per plant. There was a high variation in all the responses to the treatments. “Days to tuber set” was influenced by genetic responses, temperature and greenhouse Photosynthetically Active Radiation intensity. Considerable increases in the length of the vegetative cycle and plant height were recorded for all genotypes, and these were particularly notable in the warmer coastal environments. AMMI analysis showed that yield variables were primarily influenced by the genotypic effect followed by the genotype by environment interaction effect. The Venturana variety (T2) was the best performing genotype with a total average mini-tuber “weight” of 644 g per plant while the Chucmarina variety (T1) performed best for the variable “number of mini-tubers” with an overall average of 60.2 mini-tubers per plant. Both showed stability across different environments for these variables. The advanced clones T3 (395434.1), T5 (397077.16) and T6 (397073.16) showed stability for yield variables, but their performance was below the overall average of the trial. It is recommended that the environment and management should ideally be tailored to the genotype as this will result in significant yield gains.

Abstract: Controlled-release N fertilizer, such as polymer-coated urea (PCU), may be a fall N management option for wheat (Triticum aestivum L) grown in poorly-drained claypan soils Field research evaluated (1) urea release from fall-applied PCU in 2006 and 2007; (2) broadcast fall-spring split (25%:75%) of N sources; and (3) a single fall (100%) application of PCU, urea, urea plus NBPT (N-(n-butyl) thiophosphoric triamide] (U + NBPT), ammonium nitrate (AN), or urea ammonium nitrate (UAN) at 0, 56, 84, and 112 kg·N·ha−1 on wheat yield, wheat biomass, N uptake by wheat, and frost-seeded red clover (FSC) (Trifolium pratense L) forage yield (2004–2007) PCU applied in fall released less than 30% urea by February Urea released from PCU by harvest was 60% and 85% in 2006 and 2007, respectively In poorly-drained soils, wheat yields ranked PCU > AN > U + NBPT > urea ≥ UAN over the rates evaluated for fall-only application PCU was a viable fall-applied N source, with yields similar to or greater than urea or U + NBPT split-applied Split-N applications of AN, urea, UAN, and U + NBPT generally resulted in greater wheat yields than a fall application Enhanced efficiency fertilizers provide farmers with flexible options for maintaining high yielding production systems

Abstract: GPS guidance of farm machinery has been increasingly adopted by farmers because of the perceived gains in efficiency that it provides. In the southeastern USA one of the reasons farmers adopt GPS guidance, and specifically automated steering (auto-steer), is that it can theoretically result in large yield gains when used to plant and invert peanuts—one of the region’s most important crops. The goal of our study was to quantify the yield benefit of using real time kinematic (RTK)-based auto-steer to plant and invert peanuts under a variety of terrain conditions. Yield benefits result from reduced digging losses. The study was conducted for two consecutive years (2010 and 2011) on a private farm in Georgia, USA. When all data are grouped together, auto-steer outperformed conventional by 579 kg/ha in 2010 and 451 kg/ha in 2011. We also evaluated the performance of auto-steer under different curvature conditions using low, medium, and high curvature rows. The results showed that auto-steer outperformed conventional under all curvature by a minimum of 338 kg/ha. Finally, we evaluated passive implement guidance in combination with auto-steer and found that it holds tremendous potential for further reducing digging losses. In many cases, auto-steer will pay for itself within a year.

Abstract: Chlorophyll-deficient mutants have been studied persistently to understand genetic mechanisms controlling metabolic pathways. A spontaneous chlorophyll-deficient lethal mutant was observed in self-pollinated progeny of a soybean cultivar “BSR 101”. Observed segregation patterns indicated single-gene recessive inheritance for this lethal-yellow mutant. The objectives of this investigation were to develop a genetic linkage map of the region containing the lethal-yellow (YL_PR350) gene and identify putative candidate genes for this locus. The YL_PR350 gene was mapped to chromosome 15 and is flanked by BARCSOYSSR_15_1591 and BARCSOYSSR_15_1597. This region physically spans ~153 kb and there are 14 predicted genes that lie in this region. The predicted gene Glyma.15g275900 is an excellent candidate for the YL_PR350 gene as it is homologous to an Arabidopsis gene, At3g08010, which codes for a chloroplast-localized protein (ATAB2) involved in the biogenesis of Photosystem I and II. This thylakoid membrane protein is crucial for photosynthesis in Arabidopsis. Future characterization of the candidate gene may enhance our knowledge about photosynthesis, a complex metabolic process critical for sustainability of plants.

Abstract: Varying degrees of soil nitrous oxide (N2O) mitigation have been observed following biochar applications. Laboratory incubation experiments were conducted using soils from agriculture, forest, prairie, and a sterilized sand to examine the relative contributions of bacteria and fungi to this N2O alteration. Selective chemical inhibitors were used to distinguish the relative contributions of fungal and bacterial groups to N2O production/suppression in each soil type following a fast-pyrolysis macadamia nut shell biochar (10% w/w) addition. Overall, suppressed production of N2O was initially observed between the agricultural and prairie soils following biochar addition and stimulation of N2O production was observed in the biochar amended forest soil. However, if the N2O production that was observed in the biochar control (sterile sand and biochar = 4.2 ± 0.7 ng-N g−1 day−1) was subtracted from all treatments, N2O production following biochar addition was consistently lower in all soils following biochar additions. In terms of the microbial contributions, there were no significant differences in N2O production between the microbial inhibitor treatments, despite CO2 production rate differences. Therefore, the response in the N2O production to biochar could not be directly attributed to a particular microbial group (fungi or bacteria). These results suggest the presence of abiotic production or consumption routes for nitrogen species in biochar amended soils.

Abstract: Tolerance to frequent defoliations is critical for native warm-season grasses managed for forage and wildlife habitat. Yield response of big bluestem (Andropogon gerardii), indiangrass (Sorghastrum nutans), and little bluestem (Schizachyrium scoparium) to treatments (30-, 40-, 60-, 90- or 120-d harvest intervals) and durations were assessed on early-succession mixed stands. Over three years, phased harvestings were initiated in May, on sets of randomized plots, in five replications to produce one-, two-, and three-year old stands, by the third year. Each plot had marked indiangrass and big bluestem plants which were hand-clipped on harvest-days before whole-plot harvesting. Species yields were greater in first- than second-year plots but not affected by treatments. June–September yields in 2008 were greatest for the 30-d, and more in the first- (8472 kg ha−1) than second-year (7627 kg ha−1) plots. In 2009, yields were also greater in first- than second-year plots but without treatment effects. Recovery yields showed no treatment effect, but were about 67% less for second- compared to first-year plots and much less than plots never harvested before. Data suggest that harvesting similar mixed native warm-season grass stands at 30- to 40-d intervals may provide good hay yields without compromising post-season stand recovery for multiple uses.

Abstract: Microbial infections of crop plants present an ongoing threat to agricultural production. However, in recent years, we have developed a more nuanced understanding of the ecological role of microbes and how they interact with plants. This includes an appreciation of the influence of crop physiology and environmental conditions on the expression of disease symptoms, the importance of non-pathogenic microbes on host plants and pathogens, and the capacity for plants to act as hosts for human pathogens. Alongside this we now have a variety of tools available for the identification and quantification of microbial infections on crops grown under field conditions. This review summarises some of the consequences of microbial infections in crop plants, and discusses how new and established assessment tools can be used to understand these processes. It challenges our current assumptions in yield loss relationships and offers understanding of the potential for more resilient crops.

Abstract: Phenotyping trials may not take into account sufficient spatial context to infer quantitative disease resistance of recommended varieties in commercial production settings. Recent ecological theory—the dispersal scaling hypothesis—provides evidence that host heterogeneity and scale of host heterogeneity interact in a predictable and straightforward manner to produce a unimodal (“humpbacked”) distribution of epidemic outcomes. This suggests that the intrinsic artificiality (scale and design) of experimental set-ups may lead to spurious conclusions regarding the resistance of selected elite cultivars, due to the failure of experimental efforts to accurately represent disease pressure in real agricultural situations. In this model-based study we investigate the interaction of host heterogeneity and scale as a confounding factor in the inference from ex-situ assessment of quantitative disease resistance to commercial production settings. We use standard modelling approaches in plant disease epidemiology and a number of different agronomic scenarios. Model results revealed that the interaction of heterogeneity and scale is a determinant of relative varietal performance under epidemic conditions. This is a previously unreported phenomenon that could provide a new basis for informing the design of future phenotyping platforms, and optimising the scale at which quantitative disease resistance is assessed.

Abstract: Turfgrass growth, performance and quality are affected by abiotic stress factors and are of primary concern for persons managing turfgrass areas under seasonal tropical climates. Under these conditions, common Savannahgrass (SG) may have a performance advantage over imported hybrid turfgrasses. A greenhouse study was conducted to comparatively evaluate the performance of tropical turfgrasses exposed to water and compaction related stresses across a range of soils, with or without the addition of a surface sand layer. Turfgrass productivity and quality was monitored over a four-month growth period. Clipping yield (CY) was lower at the higher compaction effort for all turfgrasses, but across all stresses, drought (D) and waterlogging (WL) resulted in lower CY. Values were significantly lower under D. SG had the highest clipping yield across all soils. The chlorophyll index (CI) was lower for all turfgrasses under water-induced stress compared to compaction stresses. SG had a significantly higher CI across all stress treatments. Correlation analysis showed a positive (r² = 0.420) and significant (p < 0.05) relationship between CY and CI. Similar to CI, stress type influenced turfgrass visual quality (VQ), with D stress, resulting in the lowest VQ rating among turfgrasses. Bermudagrass (BG) had the lowest VQ across all stress treatments, whilst, comparatively, Zoysiagrass (ZG) had significantly higher VQ under high compaction (HC), low compaction (LC) and WL stress. Overall, SG showed a higher level of tolerance to applied stresses and warrants greater attention as a potential turfgrass under tropical conditions.

Abstract: The root zone physical condition influences root development and function, which affects turfgrass growth, quality and performance. The temporal variability of root zone properties was investigated in a factorial experiment combining sand layering compaction and moisture stress on the performance of Savannahgrass (SG) (Axonopus compressus), Bermudagrass (BG) (Cynodon dactylon (L.) Pers.) (cv. Tifway 419) and Zoysiagrass (ZG) (Zoysia spp.) grown in four contrasting soils. Four stresses—drought (D), waterlogging (WL), high compaction (HC) and low compaction (LC)—were applied either with or without a surface sand layer. Root zone properties, including root weight (RW), bulk density (BD), surface hardness (SH), redox potential (Eh) and non-capillary pore space (NCPS), were monitored over a four-month growth period. Surface hardness values were greater for the high compaction effort in treatments without sand, but were highest under drought. Sand addition resulted in lower SH for all grass × soil combinations. The soil texture influenced root zone BD for all turfgrasses, with the clay soils recording significantly lower bulk densities (<1.00 g/cm3) than those with coarser fractions. Compaction had a minimal influence on BD, the effect being further modified by grass type. Low BD was associated with high RW. RW was also significantly higher in the sand-amended treatments. Waterlogging reduced Eh for all soils, with higher values recorded in the sand treatments. The redox potential was lowest in River Estate soil and in pots planted with ZG. Across turfgrasses, Princes Town and Talparo soils had significantly lower NCPS for the sand treatment. NCPS was highest for ZG across stress treatments, but values were similar to SG under compaction treatments. Sand layering improved the root zone aeration status, particularly with SG, resulting in a better physical condition.

Abstract: Field trials conducted in 2008 and 2009 investigated whether plot size affects incidence of white flower anther injury by tarnished plant bug (Lygus lineolaris (Palisot de Beauvois)) in host plant resistance (HPR) evaluations. The three cotton lines evaluated in the trial included a susceptible frego bract line (RBCDHGPIQH-197) and 2 standards, SureGrow (SG) 105 and Deltapine (DP) 393. Samplers monitored white flower anther injury between single row mini-plots embedded within multiple row max-plots. A sub-section of the max-plots was sprayed with insecticides to evaluate these tactics on altering the incidence of white flower anther injury. Plant bug numbers were very low in 2008, while infestation levels were higher in 2009. Significantly higher numbers of flowers with anther injury were observed in both years in the susceptible frego bract line compared to SG 105 and DP 393 lines. In both years, anther injury levels were similar in the max- and mini-plots, with lower levels observed in max-sprayed plots. The white flower monitoring procedure is a consistent indicator of adult plant bug preferences and is not influenced by plot size or interspersions of cultivar lines among plots.

Abstract: Plant breeding trials are extensive (100s to 1000s of plots) and are difficult and expensive to monitor by conventional means, especially where measurements are time-sensitive. For example, in a land-based measure of canopy temperature (hand-held infrared thermometer at two to 10 plots per minute), the atmospheric conditions may change greatly during the time of measurement. Such sensors measure small spot samples (2 to 50 cm 2 ), whereas image-based methods allow the sampling of entire plots (2 to 30 m 2 ). Capturing images from an aircraft which is flown precisely at low altitude (10 to 40 m) to obtain high ground resolution data for every plot allows the rapid measurement of large numbers of plots. This

Abstract: The consequences of changes in spatial resolution for application of thermal imagery in plant phenotyping in the field are discussed. Where image pixels are significantly smaller than the objects of interest (e.g., leaves), accurate estimates of leaf temperature are possible, but when pixels reach the same scale or larger than the objects of interest, the observed temperatures become significantly biased by the background temperature as a result of the presence of mixed pixels. Approaches to the estimation of the true leaf temperature that apply both at the whole-pixel level and at the sub-pixel level are reviewed and discussed.

Abstract: We present a draft genome sequence for enset (Ensete ventricosum) available via the Sequence Read Archive (accession number SRX202265) and GenBank (accession number AMZH01. Enset feeds 15 million people in Ethiopia, but is arguably the least studied African crop. Our sequence data suggest a genome size of approximately 547 megabases, similar to the 523-megabase genome of the closely related banana (Musa acuminata). At least 1.8% of the annotated M. acuminata genes are not conserved in E. ventricosum. Furthermore, enset contains genes not present in banana, including reverse transcriptases and virus-like sequences as well as a homolog of the RPP8-like resistance gene. We hope that availability of genome-wide sequence data will stimulate and accelerate research on this important but neglected crop.

Abstract: The achievements made in genomic technology in recent decades are yet to be matched by fast and accurate crop phenotyping methods. Such crop phenotyping methods are required for crop improvement efforts to meet expected demand for food and fibre in the future. This review evaluates the role of proximal remote sensing buggies for field-based phenotyping with a particular focus on the application of currently available sensor technology for large-scale field phenotyping. To illustrate the potential for the development of high throughput phenotyping techniques, a case study is presented with sample data sets obtained from a ground-based proximal remote sensing buggy mounted with the following sensors: LiDAR, RGB camera, thermal infra-red camera and imaging spectroradiometer. The development of such techniques for routine deployment in commercial-scale breeding and pre-breeding operations will require a multidisciplinary approach to leverage the recent technological advances realised in computer science, image analysis, proximal remote sensing and robotics.