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Grain Weight (grain + weight)
Selected AbstractsAllocation of Photosynthates and Grain Growth of Two Wheat Cultivars with Different Potential Grain Growth in Response to Pre- and Post-anthesis ShadingJOURNAL OF AGRONOMY AND CROP SCIENCE, Issue 5 2003Z. Wang Abstract Grain yield in wheat is dependent on photosynthate production and allocation. Light intensity is one of the main factors affecting photosynthate production and allocation, and grain yield. This study was conducted to determine whether cultivars varying in grain number per spike and grain weight respond differently to pre-anthesis shading (PRE) and post-anthesis shading (POST), and to characterize the responses in production and allocation of photosynthate, yield and yield components, and spike traits. Both PRE and POST caused a decrease in both dry matter (DM) accumulation and allocation to grain. Cultivar Lumai 22, which has a large spike and large grains, was more sensitive to either PRE or POST. PRE reduced photosynthate production and partitioning to the spike in Lumai 22 at anthesis. In contrast, PRE had little influence on these parameters in the small-spike, small-grain cultivar Yannong 15. POST reduced the partitioning to the grain, especially in Lumai 22, for which marked reductions in biomass and grain yield were found for both the PRE and POST treatments. Changes in yield components attributable to shading varied with cultivars. The number of spikes m,2 was not affected by either PRE or POST. Lumai 22 was more seriously affected by shading than Yannong 15 in terms of grain number per spike and weight per grain. The decreases in grain number or weight per spikelet in both the PRE and POST treatments took place mainly in the upper and basal spikelets, especially in Lumai 22. We concluded that the adaptability of the small-spike, small-grain cultivar Yannong 15 to either PRE or POST was much greater than that of the large-spike, large-grain cultivar Lumai 22 in terms of many characteristics closely related to grain yield. Hence, we suggest that, in areas where low light intensity often occurs, the small-spike, small-grain cultivar would be more likely to produce high, stable grain yields. [source] Lack of Interaction between Extreme High-Temperature Events at Vegetative and Reproductive Growth Stages in WheatJOURNAL OF AGRONOMY AND CROP SCIENCE, Issue 3 2003B. Wollenweber Abstract Increased climatic variability and more frequent episodes of extreme conditions may result in crops being exposed to more than one extreme temperature event in a single growing season and could decrease crop yields to the same extent as changes in mean temperature. The developmental stage of the crop exposed to increased temperatures will determine the severity of possible damage experienced by the plant. It is not known whether or not the damaging effects of heat episodes occurring at different phenological stages are additive. In the present study, the interaction of high-temperature events applied at the stages of double ridges and anthesis in Triticum aestivum (L.) cv. Chablis was investigated. Biomass accumulation of control plants and that of plants experiencing high temperatures during the double-ridge stage were similar and were reduced by 40 % when plants were subjected to a heat event at anthesis. Grain number on the main and side tillers declined by 41 %, and individual grain weight declined by 45 % with heat stress applied at the double-ridge stage and anthesis or at anthesis alone. The harvest index was reduced from 0.53 to 0.33. Nitrogen contents in leaves were reduced by 10 % at the double-ridge stage and by 25 % at anthesis. The maximum rates of CO2 assimilation increased with heat stress at the double-ridge stage and higher rates were maintained throughout the growing season. The results clearly indicate that an extreme heat event at the double-ridge stage does not affect subsequent growth or the response of wheat to heat stress at anthesis. [source] Analysing the contribution of component cultivars and cultivar combinations to malting quality, yield and disease in complex mixturesJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 12 2008Adrian C Newton Abstract BACKGROUND: Mixtures of cereal cultivars grown together generally enhance yield and reduce disease but end-users will not accept them for quality uses. Some combinations with very different quality may be problematic, others complementary. The common origin of Maris Otter for quality in winter barley may enable the benefits of complex mixtures to be exploited without quality compromises. RESULTS: Seven winter barley cultivar monocultures and all their equal proportion mixtures were trialled and data analysed by ANOVA, REML and principal component analyses to determine the contribution of particular varieties or combinations to crop performance. Agronomic yield was positively correlated with component number. Pipkin contributed negatively to thousand grain weight (TGW), but positively to several quality traits; Gleam negatively to the same quality traits but strongly positively to yield; and Melanie combined strong yield and TGW characteristics with neutral quality traits. Interactions in mixtures with Maris Otter, from which most of the cultivars are likely to derive some of their quality traits, were less apparent for quality than for yield. CONCLUSIONS: Complex mixtures gave yield benefits generally without compromising quality, and analysis methods were developed to identify the beneficial or negative effects of component cultivars on malting quality traits, thereby providing data for optimising mixtures design. Copyright © 2008 Society of Chemical Industry [source] The effects of irrigation, nitrogen fertilizer and grain size on Hagberg falling number, specific weight and blackpoint of winter wheatJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 3 2004Matthew P Clarke Abstract The effects of irrigation and nitrogen (N) fertilizer on Hagberg falling number (HFN), specific weight (SW) and blackpoint (BP) of winter wheat (Triticum aestivum L) were investigated. Mains water (+50 and +100 mm month,1, containing 44 mg NO3, litre,1 and 28 mg SO42, litre,1) was applied with trickle irrigation during winter (17 January,17 March), spring (21 March,20 May) or summer (24 May,23 July). In 1999/2000 these treatments were factorially combined with three N levels (0, 200, 400 kg N ha,1), applied to cv Hereward. In 2000/01 the 400 kg N ha,1 treatment was replaced with cv Malacca given 200 kg N ha,1. Irrigation increased grain yield, mostly by increasing grain numbers when applied in winter and spring, and by increasing mean grain weight when applied in summer. Nitrogen increased grain numbers and SW, and reduced BP in both years. Nitrogen increased HFN in 1999/2000 and reduced HFN in 2000/01. Effects of irrigation on HFN, SW and BP were smaller and inconsistent over year and nitrogen level. Irrigation interacted with N on mean grain weight: negatively for winter and spring irrigation, and positively for summer irrigation. Ten variables derived from digital image analysis of harvested grain were included with mean grain weight in a principal components analysis. The first principal component (,size') was negatively related to HFN (in two years) and BP (one year), and positively related to SW (two years). Treatment effects on dimensions of harvested grain could not explain all of the effects on HFN, BP and SW but the results were consistent with the hypothesis that water and nutrient availability, even when they were affected early in the season, could influence final grain quality if they influenced grain numbers and size. Copyright © 2004 Society of Chemical Industry [source] Genotypic and temperature effects on wheat grain yield and quality in a hot irrigated environmentPLANT BREEDING, Issue 4 2006I. S. A. Tahir Abstract High temperature influences both grain yield and end-use quality of wheat. The objectives of this study were to evaluate the performance of selected wheat genotypes under heat stress and to examine the effects of high temperatures during grain filling on grain yield and end-use quality parameters. Fifteen bread wheat genotypes in 2000/2001 and 18 genotypes in 2002/2003 were evaluated under the optimum and late-sowing conditions of the irrigated hot environment of the Gezira Research Farm, Wad Medani, Sudan. The genotypes comprised released varieties and elite lines from the Sudanese wheat improvement programme. Data collected included grain yield, grain weight and grain end-use quality including protein content, protein composition, SDS sedimentation values (SDSS) and gluten strength as determined by mixograph analyses. High temperatures significantly decreased grain yield by decreasing grain weight. Although genotypes exhibited variation in magnitude of response, results indicated that high temperature during grain filling increased both soluble and insoluble protein contents, SDSS, mixograph peak height (MPH) and the descending slope at 2 min past peak (MDS). In contrast, mixograph peak time (MPT) and the curve width at 2 min past peak (MCW) were significantly decreased. Flour protein correlated positively with SDSS, MPH and MDS and negatively with MCW. MPT correlated negatively with MDS and positively with MCW. Results indicate that high temperature increased both soluble and insoluble protein contents, SDSS and MPH, and hence the gluten strength, but decreased flour mixing time and tolerance and hence the dough elasticity. Variation observed among genotypes suggests that grain end-use quality could be improved under high temperature conditions utilizing the available variability; however, it might require evaluation under various growing conditions. [source] An investigation of the relationship between hullability and morphological features in grains of four oat varietiesANNALS OF APPLIED BIOLOGY, Issue 2 2010E. White Milling of oats involves separation of the kernel from its enclosing husk. The ease with which this happens is termed ,hullability'. The association between morphological characteristics measured using image analysis and hullability was examined in oat varieties sampled from Recommended List variety trials conducted at AFBI Crossnacreevy, Belfast, UK in 2000 and 2006. Grain features of the varieties were distinctive and showed differing relationships with weight, Barra changing only slightly, whilst Mascani showed the maximal changes with increasing grain weight. Hullability was poorer in larger grain, and better in Barra and Mascani than in Gerald and Tardis. Fitting of exponential models for the percentage of hulled grain with dehulling duration identified features associated with different aspects of dehulling behaviour. Greater width of grains of Mascani and Tardis was associated with a more rapid increase in hullability at shorter durations of dehulling. Greater roundness in Barra and Gerald in 2000 was associated with better hullability at very short durations of dehulling relative to other varieties. It is concluded that these features of the grain could be of use in selecting high hullability in breeding programmes. [source] Effects of diseases on the growth and yield of spring linseed (Linum usitatissimum), 1988,1998ANNALS OF APPLIED BIOLOGY, Issue 3 2000S A M PERRYMAN Summary In spring linseed field experiments with fungicides at Rothamsted from 1988 to 1998, substantial yield losses assoeiated with diseases occurred in three years and slight losses could be associated with diseases in other years. These yield losses were related to decreases in yield components (thousand grain weights and number of capsules). Leaf browning was observed each year and percentage leaf area with browning was the disease factor most consistently related to yield losses (in five years). Yield loss relationships for these five years suggested that for each 10% increase in percentage leaf area with browning there was a yield loss of 0.10 to 0.18 t ha,1. Stem browning, lesions on capsules and powdery mildew were associated with yield losses in two years, three years and one year, respectively. Yield losses were greatest in years when the period of flowering and early capsule development in June and July was wetter than average; the predominant disease was grey mould (Botrytis cinerea) in wet years up to 1996, whereas pasmo (Mycosphaerella linicola) was most important in 1997 and 1998. Observed yield losses were small in hot, dry years when powdery mildew (Sphaerotheca lini) and verticillium (Verticillium dahliae) were the predominant diseases. [source] | ||||||||||