Breeding for high water-use efficiency Condon, A.G; Richards, R.A; Rebetzke, G.J ...
Journal of experimental botany,
11/2004, Letnik:
55, Številka:
407
Journal Article, Conference Proceeding
Recenzirano
Odprti dostop
There is a pressing need to improve the water-use efficiency of rain-fed and irrigated crop production. Breeding crop varieties with higher water-use efficiency is seen as providing part of the ...solution. Three key processes can be exploited in breeding for high water-use efficiency: (i) moving more of the available water through the crop rather than it being wasted as evaporation from the soil surface or drainage beyond the root zone or being left behind in the root zone at harvest; (ii) acquiring more carbon (biomass) in exchange for the water transpired by the crop, i.e. improving crop transpiration efficiency; (iii) partitioning more of the achieved biomass into the harvested product. The relative importance of any one of these processes will vary depending on how water availability varies during the crop cycle. However, these three processes are not independent. Targeting specific traits to improve one process may have detrimental effects on the other two, but there may also be positive interactions. Progress in breeding for improved water-use efficiency of rain-fed wheat is reviewed to illustrate the nature of some of these interactions and to highlight opportunities that may be exploited in other crops as well as potential pitfalls. For C3 species, measuring carbon isotope discrimination provides a powerful means of improving water-use efficiency of leaf gas exchange, but experience has shown that improvements in leaf-level water-use efficiency may not always translate into higher crop water-use efficiency or yield. In fact, the reverse has frequently been observed. Reasons for this are explored in some detail. Crop simulation modelling can be used to assess the likely impact on water-use efficiency and yield of changing the expression of traits of interest. Results of such simulations indicate that greater progress may be achieved by pyramiding traits so that potential negative effects of individual traits are neutralized. DNA-based selection techniques may assist in such a strategy.
Church governance is not often debated within a philosophical or theological sphere. This is perhaps because church governance has been part of tradition since Constantine and the initial Greek ...philosophical world view of sovereignty and hierarchy. Such a stance has led towards a managerial mindset that follows and conforms to the world, which plays out within the Anglican polity in the setting of an adversarial parliamentary style synod. This style encourages bounded communities of power that often refute the burgeoning inspirations of the Spirit. In changing the underlying theological basis of such a stance, by invoking the understanding of an undeniable community in the singularity of the Triune God, governance becomes more open. Engaging with, primarily, Agamben but also others from philosophy, a new viewpoint is presented to challenge the manner through which tradition is wielded as the only possibility. In seeing through a differing lens, communities can be conceived as both porous and interconnected, thus allowing the body of Christ to respond with transformative action as opposed to a continuum of conformance with secular legality. In this manner, the bishop’s role may become more centralised towards a Eucharistic one, as opposed to the managerial mindset and role, to enhance the possibilities of God’s love. This then removes the need for a hierarchy driven by a sovereign mindset that tradition bolsters, whilst maintaining loving and authoritative oversight that tradition suggests.
Abstract
The questions of how the bulk of the Universe’s visible mass emerges and how it is manifest in the existence and properties of hadrons are profound, and probe the heart of strongly ...interacting matter. Paradoxically, the lightest pseudoscalar mesons appear to be key to a further understanding of the emergent mass and structure mechanisms. These mesons, namely, the pion and kaon, are the Nambu–Goldstone boson modes of quantum chromodynamics (QCD). Unravelling their partonic structure and the interplay between emergent and Higgs-boson mass mechanisms is a common goal of three interdependent approaches—continuum QCD phenomenology, lattice-regularised QCD, and the global analysis of parton distributions—linked to experimental measurements of hadron structure. Experimentally, the anticipated electron–ion collider will enable a revolution in our ability to study pion and kaon structures, accessed by scattering from the ‘meson cloud’ of the proton through the Sullivan process. With the goal of enabling a suite of measurements that can address these questions, we examine key reactions that identify the critical detector-system requirements needed to map tagged pion and kaon cross-sections over a wide range of kinematics. The excellent prospects for extracting pion structural, functional, and form-factor data are outlined, and similar prospects for kaon structures are discussed in the context of a worldwide programme. The successful completion of the programme outlined herein will deliver deep, far-reaching insights into the emergence of pions and kaons, their properties, and their role as QCD’s Goldstone boson modes.
Greater yield per unit rainfall is one of the most important challenges in dryland agriculture. Improving intrinsic water-use efficiency (W(T)), the ratio of CO(2) assimilation rate to transpiration ...rate at the stomata, may be one means of achieving this goal. Carbon isotope discrimination (Delta(13)C) is recognized as a reliable surrogate for W(T) and there have now been numerous studies which have examined the relationship between crop yield and W(T) (measured as Delta(13)C). These studies have shown the relationship between yield and W(T) to be highly variable. The impact on crop yield of genotypic variation in W(T) will depend on three factors: (i) the impact of variation in W(T) on crop growth rate, (ii) the impact of variation in W(T) on the rate of crop water use, and (iii) how growth and water use interact over the crop's duration to produce grain yield. The relative importance of these three factors will differ depending on the crop species being grown and the nature of the cropping environment. Here we consider these interactions using (i) the results of field trials with bread wheat (Triticum aestivum L.), durum wheat (T. turgidum L.), and barley (Hordeum vulgare L.) that have examined the association between yield and Delta(13)C and (ii) computer simulations with the SIMTAG wheat crop growth model. We present details of progress in breeding to improve W(T) and yield of wheat for Australian environments where crop growth is strongly dependent on subsoil moisture stored from out-of-season rains and assess other opportunities to improve crop yield using W(T).
Wheat productivity is commonly limited by a lack of water essential for growth. Carbon isotope discrimination (Δ), through its negative relationship with transpiration efficiency, has been used in ...selection of higher wheat yields in breeding for rainfed environments. The potential also exists for selection of increased Δ for improved adaptation to irrigated and high rainfall environments. Selection efficiency of Δ would be enhanced with a better understanding of its genetic control. Three wheat mapping populations (Cranbrook/Halberd, Sunco/Tasman and CD87/Katepwa) containing between 161 and 190 F₁-derived, doubled-haploid progeny were phenotyped for Δ and agronomic traits in 3-5 well-watered environments. The range for Δ was large among progeny (c. 1.2-2.3per thousand), contributing to moderate-to-high single environment (h ² = 0.37-0.91) and line-mean (0.63-0.86) heritabilities. Transgressive segregation was large and genetic control complex with between 9 and 13 Δ quantitative trait loci (QTL) identified in each cross. The Δ QTL effects were commonly small, accounting for a modest 1-10% of the total additive genetic variance, while a number of chromosomal regions appeared in two or more populations (e.g. 1BL, 2BS, 3BS, 4AS, 4BS, 5AS, 7AS and 7BS). Some of the Δ genomic regions were associated with variation in heading date (e.g. 2DS, 4AS and 7AL) and/or plant height (e.g. 1BL, 4BS and 4DS) to confound genotypic associations between Δ and grain yield. As a group, high Δ progeny were significantly (P < 0.10-0.01) taller and flowered earlier but produced more biomass and grain yield in favorable environments. After removing the effect of height and heading date, strong genotypic correlations were observed for Δ and both yield and biomass across populations (r g = 0.29-0.57, P < 0.05) as might be expected for the favorable experimental conditions. Thus selection for Δ appears beneficial in increasing grain yield and biomass in favorable environments. However, care must be taken to avoid confounding genotypic differences in Δ with stature and development time when selecting for improved biomass and yield especially in environments experiencing terminal droughts. Polygenic control and small size of individual QTL for Δ may reduce the potential for QTL in marker-assisted selection for improved yield of wheat.
To examine the emotional communication that takes place between patients and health care providers during surveillance cystoscopy for non-muscle invasive bladder cancer (NMIBC).
Participants were 57 ...patients with a diagnosis of NMIBC attending for surveillance cystoscopy and 10 health care professionals (HCPs). Cystoscopy procedures were audio-recorded and transcribed verbatim. Two approaches to analysis of transcriptions were undertaken: (1) a template analysis and (2) Verona Coding Definitions of Emotional Sequences.
Communication during cystoscopy generally comprised of “social/small talk,” “results of the cystoscopy,” and “providing instructions to the patient.” Emotional talk was present in 41/57 consultations, with 129 emotional cues and concerns expressed by patients. Typically patients used hints to their emotions rather than stating explicit concerns. The majority (86%) of HCPs responses to the patient did not explicitly mention the patient’s emotional concern or cue. Urology trainees were less likely than other HCPs to provide space for patients to explore their emotional concerns (t = −1.78, P <.05).
Emotional communication was expressed by the majority of patients during cystoscopy. While all HCPs responded to patients’ emotional communication, there were a number of missed opportunities to “pick-up” on patients’ emotional cues and improve communication. Urologists need to be aware of the nuances of patients’ emotional communication. Learning to identify and respond appropriately to emotional cues may improve communication with patients.
Crop breeding, genetics and cytology are discussed. Genetic gain is characteristically slow when selecting directly for increased grain yield under water-limited conditions.
Change of direction speed (CODS) underpins performance in a wide range of sports but little is known about how stiffness and asymmetries affect CODS. Eighteen healthy males performed unilateral drop ...jumps to determine vertical, ankle, knee and hip stiffness, and a CODS test to evaluate left and right leg cutting performance during which ground reaction force data were sampled. A step-wise regression analysis was performed to ascertain the determinants of CODS time. A two-variable regression model explained 63% (R
2
= 0.63; P = 0.001) of CODS performance. The model included the mean vertical stiffness and jump height asymmetry determined during the drop jump. Faster athletes (n = 9) exhibited greater vertical stiffness (F = 12.40; P = 0.001) and less asymmetry in drop jump height (F = 6.02; P = 0.026) than slower athletes (n = 9); effect sizes were both "large" in magnitude. Results suggest that overall vertical stiffness and drop jump height asymmetry are the strongest predictors of CODS in a healthy, non-athletic population.
The origin of anatomically modern Homo sapiens and the fate of Neanderthals have been fundamental questions in human evolutionary studies for over a century. A key barrier to the resolution of these ...questions has been the lack of substantial and accurately dated African hominid fossils from between 100,000 and 300,000 years ago. Here we describe fossilized hominid crania from Herto, Middle Awash, Ethiopia, that fill this gap and provide crucial evidence on the location, timing and contextual circumstances of the emergence of Homo sapiens. Radioisotopically dated to between 160,000 and 154,000 years ago, these new fossils predate classic Neanderthals and lack their derived features. The Herto hominids are morphologically and chronologically intermediate between archaic African fossils and later anatomically modern Late Pleistocene humans. They therefore represent the probable immediate ancestors of anatomically modern humans. Their anatomy and antiquity constitute strong evidence of modern-human emergence in Africa.
Celotno besedilo
Dostopno za:
DOBA, IJS, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
► Existing wheat dwarfing genes increase harvest index but reduce seedling vigour. ► Developed and assessed multiple populations containing gibberellin-responsive dwarfing genes. ► New genes reduce ...plant height to reduce plant lodging and increase harvest index to increase grain yield. ► Influence on plant height differs between genes while all genes enable development of reduced height, high vigour wheats.
Improved ability to establish well when sowing at depth, into crop residues or hard soils should lead to increased yields in these situations. The semi-dwarfing
Rht-B1b and
Rht-D1b genes reduce plant height and increase grain number and yield in favourable environments. However, these genes are associated with reduced coleoptile length and leaf length extension to slow leaf area and biomass accumulation especially when seed are sown deep. Preliminary evidence indicates the potential of
Rht4,
Rht5,
Rht8,
Rht12 and
Rht13 gibberellin-responsive (GAR) dwarfing genes to reduce plant height without affecting seedling vigour. Four large, inbred populations were generated varying for presence of one or more GAR-dwarfing genes. Lines were genotyped with molecular markers linked to each dwarfing gene and grown in multiple environments to evaluate seedling growth and agronomic performance. Genotypic variation was large for plant height, aerial biomass, grain yield and its components, grain number and size. Height reduction was greatest for
Rht5 (−55%),
Rht12 (−45%),
Rht13 (−34%),
Rht4 (−17%), and to a lesser extent
Rht8 (−7%). In comparison, height reductions associated with
Rht-B1b averaged 23%. Reduced height was genetically correlated with reduced lodging score (
r
g
=
0.84–0.93), increased dry-matter partitioning to grain (i.e. harvest index;
r
g
=
−0.46** to −0.86**) and increased grain number (
r
g
=
−0.22* to −0.73**). Most dwarfing genes were associated with increased grain number:
Rht13 (+27%),
Rht4 (+19%),
Rht12 (+19%), and
Rht-B1b (+9%).
Rht8 had little effect on grain number (−1%) whereas later maturity associated with
Rht5 contributed to reduced grain number (−66%). The influence of dwarfing genes on aerial biomass was negligible, with some
Rht4,
Rht12 and
Rht13 semi-dwarf lines identified combining greater partitioning and aerial biomass to increase grain yield. Compared to tall siblings, coleoptile lengths and seedling leaf breadths were largely unaffected by GAR-dwarfing genes but leaf length was on average smaller in lines containing
Rht5 or
Rht12. These studies demonstrate the potential of GAR-dwarfing genes for increasing grain number and yield without compromising aerial biomass or coleoptile length in bread wheat.
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