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The South Australian Research and Development Institute is a state government funded institute with locations throughout South Australia. SARDI is part of Primary Industries and Resources South Australia Wikipedia.

Sadras V.O.,South Australian Research And Development Institute | Petrie P.R.,Treasury Wine Estates Ltd
Australian Journal of Grape and Wine Research

Background and Aim: Early maturity of grape crops associated with recent warming is well documented but poorly understood. Here, we ask the question: is early maturity associated with early onset of ripening or with increased rate of sugar accumulation? Methods and Results: We used records of grape juice total soluble solids (TSS) for Chardonnay, Shiraz and Cabernet Sauvignon collected in commercial vineyards between 1995 and 2009. The combination of 15 vintages and three climatic regions yielded a range of average seasonal temperature between 15.5 and 20.5°C. Using boundary functions of TTS versus time, we derived the onset and rate of increase in TSS, and the time of maturity set at 12 °Bé for comparative purposes. Pooled across varieties, the rate of change in maturity was -9.8±0.94°C/d. Shifts in onset accounted for 86% of the variation in time of maturity and the rate of ripening for the remaining variation. Conclusion: Early maturity associated with higher temperature (and related factors including higher radiation and higher vapour pressure deficit) is primarily driven by early onset of ripening under a wide range of production systems in south-eastern Australia. Significance of the Study: Viticultural practices aiming at delaying maturity to counteract the effect of high temperature, high radiation and high vapour pressure deficit are more likely to be successful if they target the onset of ripening. © 2011 Australian Society of Viticulture and Oenology Inc. Source

Howie J.H.,South Australian Research And Development Institute
Crop and Pasture Science

Boron (B) is present at toxic levels in the subsoils of much of the semiarid south-eastern Australian cereal-livestock zone. Boron toxicity is typically associated with alkaline soils, where annual medics (Medicago spp.) are generally the best-adapted pasture legume. New medic cultivars have been developed for which there is no published B tolerance information. Five species of annual medic represented by 13 cultivars were grown in soil amended with B and evaluated for B tolerance. A rating system based on expression of symptoms was modified from earlier research. There was a wide range of response to B, both between and within species. Cultivars varied widely in their expression of symptoms; from showing no or few leaf symptoms (tolerant) to significant leaf necrosis (very sensitive). An integrated summary of both published and previously, unpubl. data for these and other medics is presented to provide a comprehensive and up-to-date comparison between different species and most commercial cultivars. This information will be useful for plant breeders, agronomists and farmers who manage soils with high B levels. Journal compilation © CSIRO 2012. Source

Sadras V.O.,South Australian Research And Development Institute | Richards R.A.,CSIRO
Journal of Experimental Botany

Crop yield in dry environments can be improved with complementary approaches including selecting for yield in the target environments, selecting for yield potential, and using indirect, trait- or genomic-based methods. This paper (i) outlines the achievements of direct selection for yield in improving drought adaptation, (ii) discusses the limitations of indirect approaches in the context of levels of organization, and (iii) emphasizes trade-offs and synergies between nitrogen nutrition and drought adaptation. Selection for yield in the water- and nitrogen-scarce environments of Australia improved wheat yield per unit transpiration at a rate of 0.12kg ha-1 mm-1 yr-1; for indirect methods to be justified, they must return superior rates of improvement, achieve the same rate at lower cost or provide other cost-effective benefits, such as expanding the genetic basis for selection. Slow improvement of crop adaptation to water stress using indirect methods is partially related to issues of scale. Traits are thus classified into three broad groups: those that generally scale up from low levels of organization to the crop level (e.g. herbicide resistance), those that do not (e.g. grain yield), and traits that might scale up provided they are considered in a integrated manner with scientifically sound scaling assumptions, appropriate growing conditions, and screening techniques (e.g. stay green). Predicting the scalability of traits may help to set priorities in the investment of research efforts. Primary productivity in arid and semi-arid environments is simultaneously limited by water and nitrogen, but few attempts are made to target adaptation to water and nitrogen stress simultaneously. Case studies in wheat and soybean highlight biological links between improved nitrogen nutrition and drought adaptation. © The Author 2014. Published by Oxford University Press on behalf of the Society for Experimental Biology. Source

Latta R.A.,South Australian Research And Development Institute
Crop and Pasture Science

In mixed cropping and livestock dryland farming systems in southern Australia, grazing of cereals during their vegetative growth stages (typically during winter) can provide a valuable contribution of high-quality feed during a period of low pasture growth. This paper reports results from a series of experiments investigating the impact of defoliation on the grain production of cereals in the Eyre Peninsula region of South Australia. The comparative dry matter production and grain yield of wheat, barley and oats cultivars, with and without defoliation, at a range of growth stages were measured in four experiments over three growing seasons, two of which were water-deficient. The barley varieties evaluated produced up to twice the dry matter of the wheat or oats cultivars to the time of defoliation. Mowing following stem elongation more than halved grain yield (1.9 to 0.9tha-1) relative to no defoliation in an early-maturing variety, but with less reduction in later maturing varieties. Defoliation before stem elongation in two seasons of very low growing-season rainfall (<100mm) caused no or very little loss in grain yields, which were generally <1tha-1. A long-season winter wheat produced similar grain yields irrespective of defoliation and timing, but with no yield advantage over the defoliated spring cereals. The results suggest opportunities to incorporate the grazing of cereals to fill a winter feed-gap in the low-rainfall zone of southern Australia. © 2015 CSIRO. Source

Sadras V.O.,South Australian Research And Development Institute | Lemaire G.,French National Institute for Agricultural Research
Field Crops Research

The nitrogen economy of the crop is a critical driver of biomass and grain production, and its importance is reflected in a large, worldwide research effort to link nitrogen, growth and yield. Particular research questions require measurement of specific traits, hence the need to quantify multiple, often complementary traits including crop nitrogen uptake, nitrogen use efficiency and its components, nitrogen concentration in the crop and its parts, down to relevant enzymes (e.g. nitrate reductase) and other products of gene expression. Nitrogen uptake, however, is co-regulated by both soil nitrogen availability and crop biomass accumulation; hence, crop nitrogen uptake or shoot nitrogen concentration reflect univocally crop nitrogen status only if comparisons are made at similar biomass. Although the allometric relationships between biomass and nitrogen uptake have been established for over two decades, many studies still report results in terms of nominal treatments, e.g. high vs low nitrogen, which are uninformative; curves relating yield and fertiliser rate, which are of local interest but provide little insight on the underlying processes and have low generic value; and nitrogen-related traits that are incomplete or inadequate to quantify crop nutrition status. Often, the allometric relationships between nitrogen and biomass are overlooked. In this opinion paper, we summarise the already well established concepts of dilution curves and nitrogen nutrition index, outline the standard partitioning of nitrogen use efficiency, and highlight the confounded effects in nitrogen use efficiency when the allometric relationship between nitrogen uptake and biomass is ignored. A sample of recent papers is used to survey the most common approaches to characterise nitrogen related traits. We illustrate the application of dilution curves and nitrogen nutrition index in the assessment and interpretation of crop responses to agronomic practices and comparisons of wheat cultivars and maize hybrids. © 2014 Elsevier B.V. Source

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