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Yield Components (yield + component)
Selected AbstractsEffect of Straw on Yield Components of Rice (Oryza sativa L.) Under Rice-Rice Cropping SystemJOURNAL OF AGRONOMY AND CROP SCIENCE, Issue 2 2006K. Surekha Abstract Field experiments were conducted at the Directorate of Rice Research experimental farm, ICRISAT campus, Patancheru, Hyderabad, during 1998,2000 for five consecutive seasons (three wet and two dry seasons) with five treatments [T1 , 100 % straw incorporation; T2 , 50 % straw incorporation; T3 , 100 % straw + green manure (GM) incorporation; T4 , 100 % straw burning and T5 , 100 % straw removal (control)] along with the recommended dose of fertilizers to evaluate the effect of different crop residue management (CRM) practices on yield components and yield of rice in rice,rice cropping sequence. The ammonium N measured at active tillering was higher in 100 % straw-added plots over 50 % straw addition and straw removal with maximum values in the straw + GM-incorporated plots. Among the yield components, tillers, panicles and spikelets were influenced from the second season of residue incorporation with significant increase in 100 % straw-added treatments. The increase in tiller and panicle number could be attributed to the increased NH4 -N in these treatments, which is evident from the significant correlation between tiller number and NH4 -N (r = 0.82**) and panicle number and NH4 -N (r = 0.87**). The influence of residue treatments on rice grain yield was observed from the third season onwards where incorporation of straw alone or in combination with GM and burning of straw significantly increased grain and straw yields. Grain yield showed significant positive correlation with the number of tillers (r = 0.74*,0.81**) and panicles (r = 0.74*,0.84**) in three treatments (T1, T3 andT4) where grain yields were significantly higher. The regression analysis showed that 57,66 % and 64,75 % of the variation in yield could be explained by tillers and panicles together in these three treatments during wet and dry seasons respectively. Thus, CRM practices such as addition of 100 % straw either alone or with GM and straw burning influenced the yield components (tillers, panicles and spikelets) positively and thereby increased rice grain yields. [source] Grapevine productivity and yield components: A case study using field vines of Zante currantAUSTRALIAN JOURNAL OF GRAPE AND WINE RESEARCH, Issue 2 2004JOHN A. CONSIDINE Abstract Yield components of the parthenocarpic cultivar Zante were analysed for five vineyards of diverse age and management. The data was obtained as part of an experiment to improve fruit set and yield by applying combinations of gibberellin and 2-chloroethyltrimethyl ammonium chloride or 4-chlorophenoxyacetic acid. Four of the vineyards were located in the Brockman valley north of Perth, Western Australia, two of these were irrigated, one was rain fed and one received supplementary flood irrigation. The fifth lay in an adjacent area of coastal sand plain, at the foot of the Darling scarp, and was irrigated. The vines were aged from 6 to 50 years. Principal component analysis showed that vine age was negatively correlated with vigour (pruning weight) and with berry number per bunch. Vine age however was not strongly related to either yield or yield components (bunch number and berry volume). Sugar concentration was negatively correlated with all yield components but imprecisely modelled based on any combination of the measured variables. Berry number per vine appeared to be the underlying factor determining ,sink' strength though this was inextricably confounded with bunch number per vine. Interpretation of the data leads to the conclusion that increased berry volume is an inefficient means of increasing dried yield. This conclusion argues for caution in the application of plant growth regulators that act primarily to increase berry volume. Yield of sugar per vine was accurately modelled based on second order relationships with bunch number per vine, berry number per bunch, berry volume and pruning weight. Vine age also showed a second order relationship to yield although the range was relatively small. The observations are considered in terms of developing strategies for maximising dried yield and devising mathematical models to account for photoassimilate (dry matter) partitioning in Vitis. [source] Effects of Water Shortage and Air Temperature on Seed Yield and Seed Performance of Lucerne (Medicago sativa L.) in a Mediterranean EnvironmentJOURNAL OF AGRONOMY AND CROP SCIENCE, Issue 6 2009A. J. Karamanos Abstract Seed production and performance of lucerne is characterized by fluctuating yields with often poor seed quality, and is dependent on environmental conditions, genetic characteristics and agronomic techniques applied during seed set, development, maturation and storage. A field experiment was carried out in two successive growing seasons at Kopais (southern Greece) to evaluate the effects of drought stress imposed by three irrigation treatments, and temperature during flowering and seed filling on lucerne seed yield and quality. Plant water status, expressed in terms of the water potential index (WPI), growth in leaf area and dry weight, seed yield and yield components, flowering and seed quality parameters were measured throughout the growing seasons. The adopted irrigation schemes produced a clear differentiation among treatments concerning their plant water status. Seed yield and leaf growth showed close positive correlations with WPI. An irrigation effect was also detected for the number of pods/plant, but not for the average weight of seeds/pod. Less negative values of WPI, and, especially, higher temperatures during flowering were also positively associated with a longer duration of flowering, as well as with higher total numbers of inflorescences. A very good description of the time course of seed germination was performed by fitting the Richards' function to the real data. By examining the germination parameters derived from this function it was found that final germination and germination rate were improved, while germination duration was shortened with more negative values of WPI. The effects of growing season and seeding period were occasionally equally or more important than irrigation effects. These results are also discussed in terms of their practical implications for seed producing lucerne crops. [source] Effects of Deficit Drip Irrigation Ratios on Cotton (Gossypium hirsutum L.) Yield and Fibre QualityJOURNAL OF AGRONOMY AND CROP SCIENCE, Issue 1 2009H. Basal Abstract Increasing irrigation costs and declining water availability compel producers to adapt irrigation strategies for maximum crop yield and water use efficiency. A field trial was conducted to observe the effects of various drip irrigation ratios (IR-0, IR-25, IR-50, IR-75 and IR-100) on water use efficiency (WUE), the irrigation water use efficiency (IWUE), lint yield, yield components and fibre quality at two upland cotton varieties during 2004 and 2005. WUE was found to increase from 0.62 to 0.71 kg m,3 as the irrigation water applied was reduced from 100 % to 75 % of soil water depletion. Deficit irrigation of cotton with drip irrigation at 75 % treatment level (IR-75) did not decrease seed cotton yield and yield components during 2 years, with the exception of the number of bolls in 2005. Among fibre quality parameters, no significant differences in fibre length, fineness, uniformity index and elongation were detected between the 100 % and 75 % irrigation levels in 2005. The results revealed that irrigation of cotton with a drip irrigation method at 75 % level had significant benefits in terms of saved irrigation water without reducing yield, and high WUE indicated a definitive advantage of employing deficit irrigation under limited water supply conditions. [source] Drip Irrigation Frequency: The Effects and Their Interaction with Nitrogen Fertilization on Sandy Soil Water Distribution, Maize Yield and Water Use Efficiency Under Egyptian ConditionsJOURNAL OF AGRONOMY AND CROP SCIENCE, Issue 3 2008S. E. El-Hendawy Abstract Irrigation frequency is one of the most important factors in drip irrigation scheduling that affects the soil water regime, the water and fertilization use efficiency and the crop yield, although the same quantity of water is applied. Therefore, field experiments were conducted for 2 years in the summer season of 2005 and 2006 on sandy soils to investigate the effects of irrigation frequency and their interaction with nitrogen fertilization on water distribution, grain yield, yield components and water use efficiency (WUE) of two white grain maize hybrids (Zea mays L.). The experiment was conducted by using a randomized complete block split-split plot design, with four irrigation frequencies (once every 2, 3, 4 and 5 days), two nitrogen levels (190 and 380 kg N ha,1), and two maize hybrids (three-way cross 310 and single cross 10) as the main-plot, split-plot, and split-split plot treatments respectively. The results indicate that drip irrigation frequency did affect soil water content and retained soil water, depending on soil depth. Grain yield with the application of 190 kg N ha,1 was not statistically different from that at 380 kg N ha,1 at the irrigation frequency once every 5 days. However, the application of 190 kg N ha,1 resulted in a significant yield reduction of 25 %, 18 % and 9 % in 2005 and 20 %, 13 % and 6 % in 2006 compared with 380 kg N ha,1 at the irrigation frequencies once every 2, 3 and 4 days respectively. The response function between yield components and irrigation frequency treatments was quadratic in both growing seasons except for 100-grain weight, where the function was linear. WUE increased with increasing irrigation frequency and nitrogen levels, and reached the maximum values at once every 2 and 3 days and at 380 kg N ha,1. In order to improve the WUE and grain yield for drip-irrigated maize in sandy soils, it is recommended that irrigation frequency should be once every 2 or 3 days at the investigated nitrogen levels of 380 kg N ha,1 regardless of maize varieties. However, further optimization with a reduced nitrogen application rate should be aimed at and will have to be investigated. [source] Irrigation Level Affects Isoflavone Concentrations of Early Maturing Soya Bean CultivarsJOURNAL OF AGRONOMY AND CROP SCIENCE, Issue 4 2007A. M. Al-Tawaha Abstract Field experiments were conducted in 2003/2004 in Québec to determine the effects of irrigation levels (none, low and high) and cultivars (AC Orford, AC Proteina and Golden) on soya bean [Glycine max (L.) Merr.] isoflavone concentrations and yields. Seed yield, yield components, and oil and crude protein (CP) concentrations were concurrently determined. Response to irrigation was greater in 2003, which was substantially warmer and drier than in 2004. In both years, most responses were observed with the lower of the two irrigation levels evaluated, which increased total isoflavones concentration by an average of 45 % compared with a non-irrigated control. Cultivars, however, responded differently to irrigation. In 2003, response of AC Proteina was greater than that of AC Orford, while Golden did not respond. In 2004, some responses were observed with AC Proteina and Golden but none with AC Orford. Overall, in both years, AC Proteina had the greatest isoflavone concentrations and AC Orford the lowest. Responses of seed yield and yield components depended on the year and were also greater in 2003. Both irrigation treatments generally increased seed yield and yield components compared with a non-irrigated control; the response was greater with the higher irrigation level. Irrigation had no effect on oil and CP concentrations. Finally, isoflavone yield response to irrigation was again greater in 2003, and depended on the cultivar. Results thus demonstrate that specific soil moisture levels will maximize soya bean isoflavone concentrations, excess irrigation sometimes negating any potential benefits. [source] Impact of Water Stress on Maize Grown Off-Season in a Subtropical EnvironmentJOURNAL OF AGRONOMY AND CROP SCIENCE, Issue 4 2007C. M. T. Soler Abstract During the last decade, the production of off-season maize has increased in several regions of Brazil. Growing maize during this season, with sowing from January through April, imposes several climatic risks that can impact crop yield. This is mainly caused by the high variability of precipitation and the probability of frost during the reproduction phases. High production risks are also partially due to the use of cultivars that are not adapted to the local environmental conditions. The goal of this study was to evaluate crop growth and development and associated yield, yield components and water use efficiency (WUE) for maize hybrids with different maturity ratings grown off-season in a subtropical environment under both rainfed and irrigated conditions. Three experiments were conducted in 2001 and 2002 in Piracicaba, state of São Paulo, Brazil with four hybrids of different maturity duration, AG9010 (very short season), DAS CO32 and Exceler (short season) and DKB 333B (normal season). Leaf area index (LAI), plant height and dry matter were measured approximately every 18 days. Under rainfed conditions, the soil water content in the deeper layers was reduced, suggesting that the extension of the roots into these layers was a response to soil water limitations. On average, WUE varied from 1.45 kg m,3 under rainfed conditions to 1.69 kg m,3 under irrigated conditions during 2001. The average yield varied from 4209 kg ha,1 for the hybrids grown under rainfed conditions to 5594 kg ha,1 under irrigated conditions during 2001. Yield reductions under rainfed conditions were affected by the genotype. For the hybrid DKB 333B with a normal maturity, yield was reduced by 25.6 % while the short maturity hybrid Exceler was the least impacted by soil water limitations with a yield reduction of only 8.4 %. To decrease the risk of yield loss, the application of supplemental irrigation should be considered by local farmers, provided that this practice is not restricted by either economic considerations or the availability of sufficient water resources. [source] Morphological Traits above the Flag Leaf Node as Indicators of Drought Susceptibility Index in Durum WheatJOURNAL OF AGRONOMY AND CROP SCIENCE, Issue 2 2007D. Villegas Abstract Selection criteria for drought tolerance would be helpful tools for wheat breeding programmes. To assess the usefulness of some morphological traits above the flag leaf node as indicators of yield and the susceptibility index (SI) of Fischer and Maurer, 10 durum wheat genotypes were used in experiments conducted under two water regimes at two latitudes in Spain during 3 years. Morphological traits were measured at anthesis, and yield, yield components and quality traits were evaluated at ripening. Principal components analysis showed associations between morphological traits and yield, yield components and quality, most of them caused by differences between environments. Peduncle weight, spike weight and length and awn length were significantly related to SI within environments. Spike and peduncle weight were the traits more related to yield and SI in all the experiments together and in the rainfed sites, while in the irrigated sites spike length was better. The spike weight and length were negatively associated with SI, while peduncle weight was positively associated to SI. Genotype means across all experiments were associated with SI values. These morphological traits could be selection criteria in breeding programmes to obtain varieties with good yield stability. The genetic variability found suggests opportunity for selection. [source] Effect of Straw on Yield Components of Rice (Oryza sativa L.) Under Rice-Rice Cropping SystemJOURNAL OF AGRONOMY AND CROP SCIENCE, Issue 2 2006K. Surekha Abstract Field experiments were conducted at the Directorate of Rice Research experimental farm, ICRISAT campus, Patancheru, Hyderabad, during 1998,2000 for five consecutive seasons (three wet and two dry seasons) with five treatments [T1 , 100 % straw incorporation; T2 , 50 % straw incorporation; T3 , 100 % straw + green manure (GM) incorporation; T4 , 100 % straw burning and T5 , 100 % straw removal (control)] along with the recommended dose of fertilizers to evaluate the effect of different crop residue management (CRM) practices on yield components and yield of rice in rice,rice cropping sequence. The ammonium N measured at active tillering was higher in 100 % straw-added plots over 50 % straw addition and straw removal with maximum values in the straw + GM-incorporated plots. Among the yield components, tillers, panicles and spikelets were influenced from the second season of residue incorporation with significant increase in 100 % straw-added treatments. The increase in tiller and panicle number could be attributed to the increased NH4 -N in these treatments, which is evident from the significant correlation between tiller number and NH4 -N (r = 0.82**) and panicle number and NH4 -N (r = 0.87**). The influence of residue treatments on rice grain yield was observed from the third season onwards where incorporation of straw alone or in combination with GM and burning of straw significantly increased grain and straw yields. Grain yield showed significant positive correlation with the number of tillers (r = 0.74*,0.81**) and panicles (r = 0.74*,0.84**) in three treatments (T1, T3 andT4) where grain yields were significantly higher. The regression analysis showed that 57,66 % and 64,75 % of the variation in yield could be explained by tillers and panicles together in these three treatments during wet and dry seasons respectively. Thus, CRM practices such as addition of 100 % straw either alone or with GM and straw burning influenced the yield components (tillers, panicles and spikelets) positively and thereby increased rice grain yields. [source] Field Pea Seeding Management for Semi-arid Mediterranean ConditionsJOURNAL OF AGRONOMY AND CROP SCIENCE, Issue 2 2004A. M. Tawaha Abstract The effects of seeding rate (30, 60 and 90 seeds m,2), seeding date (14 January, 28 January and 12 February), seed weight (0.18 and 0.25 g seed,1), seeding depth (3 and 6 cm), and phosphorus fertilization rate (17.5, 35.0 and 52.5 kg P ha,1) and placement method (banded or broadcasted) on field pea (Pisum sativum L.) development and seed yields were investigated in irrigated field experiments conducted in northern Jordan in 2000 and 2001. Results and treatment responses were consistent in both years. Seeding rate, seeding date, seed weight and rate and method of phosphorus fertilization had significant effects on most traits measured; planting depth however did not affect any of the traits. Generally a positive correlation was observed between each factor and seed yield and yield components, with the exception of a negative correlation between seeding rate and yield components, and seeding date and yield and yield components. Increase in seeding rate from 30 to 90 seeds m,2, and increase in P fertilization from 17.5 to 52.5 kg ha,1 alone increased seed yields by 50 and 41 %, respectively. Each delay of 2 weeks for seeding from mid-January resulted in reductions of 12 % in seed yields. Overall, the results revealed that a combination of early seeding (14 January), of large seeds at an high seeding rate (90 seeds m,2), with P fertilizer banding (52.5 kg P ha,1) maximize field pea yields in irrigated fields in semi-arid Mediterranean environments. With such management pea seed yields can be as high as 2800 kg ha,1. [source] Allocation 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] Uniformity, Performance and Seed Quality of Soybean (Glycine max (L.) Merrill) Seed Crops Grown from Sub-samples of One Seed Lot Obtained after Selection for Physical Seed AttributesJOURNAL OF AGRONOMY AND CROP SCIENCE, Issue 2 2000R. A. Illipronti Jr In a glasshouse experiment it was examined whether narrow grading and selection from a commercial soybean seed lot cultivar ,IAS-5', could improve the uniformity of the seed crop grown from it and thereby enhance yield, quality and uniformity of seeds produced. The classes created were: Control (original seed lot); Size-graded seeds (projected area measured by image analysis 37,46 mm2); Non-cracked seeds; Yellow seeds; Size-graded sound seeds (size-graded, non-cracked, yellow, non-wrinkled, non-etched). Compared to the control, percentage of emergence, survival and number of yielding plants were enhanced in crops from non-cracked, yellow or size-graded sound seeds. Differences in plant numbers did not result in differences in crop yield. The different seed lots also did not differ in crop uniformity: time interval between stages of plant development, plant height 20 days after sowing, yield components, physical or physiological quality attributes of seeds produced, and respective coefficients of variation were similar. Fewer plants survived in crops showing a larger variation in plant height 20 days after sowing, thus reducing differences in initial plant-to-plant variation. Creating more uniform crops by additional grading or selection of commercial seed lots may therefore not be promising. Zusammenfassung In einem Gewächshausexperiment wurde untersucht, ob Sortierung in engen Werten und Selektion aus einer kommerziellen Sojabohnen-Samenprobe (Kultivar IAS-5) die Einheitlichkeit des Bestandes verbessern und damit Ertrag, Qualität und Einheitlichkeit der Samenproduktion verbessern kann. Die berücksichtigten Klassen waren: Kontrolle (originale Samenprobe); nach Gröie eingeteilte Samen (mit Grenzwerten zwischen 37,46 mm2); nicht geplatzte Samen; gelbe Samen, nach Gröie eingeteilte gesunde Samen (nach Gröie eingeteilt, nicht beschädigt, gelb, nicht runzelige, nicht verätzt). Im Vergleich zur Kontrolle waren Auflaufprozentsatz, Überlebensfähigkeit und Anzahl der Ertrag bringenden Pflanzen bei Beständen aus nicht beschädigten, gelben oder nach Gröie eingeteilten nicht beschädigten Samen erhöht. Unterschiede in der Pflanzenzahl führten nicht zu Unterschieden im Bestandesertrag. Die Unterschiedlichen Samengruppen unterschieden sich auch nicht in der Bestandes-Einheitlichkeit: Zeitintervalle zwischen den Stadien der Pflanzenentwicklung, Pflanzenhöhe zwanzig Tage nach der Aussaat, Ertragskomponenten, äuiere oder physiologische Qualitätseigenschaften der produzierten Samen und Variationskoeffizienten waren vergleichbar. Weniger Pflanzen überlebten in Beständen, die eine gröiere Variation in der Pflanzenhöhe zwanzig Tage nach der Aussaat aufwiesen, wodurch eine Reduzierung der Unterschiede in der Ausgangsvariation von Pflanze zu Pflanze eintrat wurde. Die Erzeugung von mehr einheitlichen Beständen durch zusätzliche Gröieneinordnung oder Selektion von kommerziellen Samenproben könnte daher nicht als zweckmäiig betrachtet werden. [source] Differences in growth and yield in response to cadmium toxicity in cotton genotypesJOURNAL OF PLANT NUTRITION AND SOIL SCIENCE, Issue 1 2004Feibo Wu Abstract A greenhouse hydroponic experiment was conducted to study the effects of cadmium (Cd; 0, 0.1, 1.0, 10 ,M in nutrient solution) on yield and yield components as well as Cd concentration and accumulation in three cotton genotypes (Simian 3, Zhongmian 16, Zhongmian 16,2). The results showed that Cd concentration in different organs increased with increasing Cd levels in the nutrient solution in the following order: root > petiole > xylem > fruiting branch, leaf > phloem in vegetative organs and seed coat, seed nut > boll shell > fiber in reproductive organs. There were significant genotypic differences in functional leaf and petiole Cd concentrations at 1 and 10 ,M Cd treatments, with the cultivar Simian 3 showing higher Cd concentrations and greater reductions in lint yield than the other two genotypes. [source] Improving the precision of cotton performance trials conducted on highly variable soils of the southeastern USA coastal plainPLANT BREEDING, Issue 6 2007B. T. Campbell Abstract Reliable agronomic and fibre quality data generated in Upland cotton (Gossypium hirsutum L.) cultivar performance trials are highly valuable. The most common strategy used to generate reliable performance trial data uses experimental design to minimize experimental error resulting from spatial variability. However, an alternative strategy uses a posteriori statistical procedures to account for spatial variability. In this study, the efficiency of the randomized complete block (RCB) design and nearest neighbour adjustment (NNA) were compared in a series of cotton performance trials conducted in the southeastern USA to identify the efficiency of each in minimizing experimental error for yield, yield components and fibre quality. In comparison to the RCB, relative efficiency of the NNA procedure varied amongst traits and trials. Results show that experimental analyses, depending on the trait and selection intensity employed, can affect cultivar or experimental line selections. Based on this study, we recommend researchers conducting cotton performance trials on variable soils consider using NNA or other spatial methods to improve trial precision. [source] Resource distribution and the trade-off between seed number and seed weight: a comparison across crop speciesANNALS OF APPLIED BIOLOGY, Issue 1 2010B.L. Gambín In grain crops, total sink capacity is usually analysed in terms of two components, seed number and individual seed weight. Seed number and potential individual seed weight are established at a similar timing, around the flowering period, and seed weight at maturity is highly correlated with the potential established earlier. It is known that, within a species, available resources during the seed set period are distributed between both yield components, resulting in a trade-off between seed number and seed weight. Here we tested if this concept could apply for interspecific comparisons, where combinations of numbers and size across species could be related to the total available resources being either allocated to more seed or larger potential individual seed weight during the seed set period. Based on this, species differences in seed weight should be related to resource availability per seed around the period when seed number is determined. Resource availability per seed was estimated as the rate of increase in aboveground biomass per seed around the period of seed set. Data from 15 crop species differing in plant growth, seed number, seed weight and seed composition were analysed from available literature. Because species differed in seed composition, seed weight was analysed following an energy requirement approach. There was an interspecific trade-off relationship between seed number per unit of land area and seed weight (r = 0.92; F(1, 13) = 32.9; n = 15; P < 0.001). Seed weight of different species was positively correlated (r = 0.90; F(1, 13) = 52.9; n = 15; P < 0.001) with resource availability per seed around the seed set period. This correlation included contrasting species like quinoa (Chenopodium quinoa; ,100000 seeds m,2, ,4 mg equivalent-glucose seed,1) or peanut (Arachis hypogaea; ,800 seeds m,2, ,1000 mg equivalent-glucose seed,1). Seed number and individual seed weight combinations across species were related and could be explained considering resource availability when plants are adjusting their seed number to the growth environment and seeds are establishing their storage capacity. Available resources around the seed set period are proportionally allocated to produce either many small seeds or few larger seeds depending on the particular species. [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] Remote monitoring of leaf turgor pressure of grapevines subjected to different irrigation treatments using the leaf patch clamp pressure probeAUSTRALIAN JOURNAL OF GRAPE AND WINE RESEARCH, Issue 3 2010S. RÜGER Abstract Background and Aims:, Effects of four irrigation treatments on leaf turgor pressure of grapevines were studied using the novel leaf patch clamp pressure (LPCP) probe. Data were correlated with yield and yield components. Methods and Results:, The LPCP probe measures leaf water status by monitoring the attenuation of an external pressure applied magnetically to a leaf patch. The output pressure signals, Pp, are inversely correlated with cell turgor pressure. Measurements showed that changes in transpiration and stomatal conductance induced by environmental parameters were reflected nearly immediately in Pp. Ongoing non-irrigation resulted in a continuous increase of Pp, in the occurrence of stomatal oscillations and in an increased turgor pressure recovery phase during afternoon. Interestingly, analysis of the numerous diurnal Pp data sets showed that east-directed leaves responded more sensitively to water stress than west-directed leaves. Conclusions:, For the cultivar and conditions used in this study, the probe data as well as the yield data support irrigation on a 3-day basis with relatively small amounts of water. Significance of the Study:, The results show that the LPCP probe is a user-friendly, high precision instrument for online-monitoring of leaf turgor pressure in dependency on changes in microclimate and irrigation, thus helping growers to increase yield while simultaneously saving water. [source] Grapevine productivity and yield components: A case study using field vines of Zante currantAUSTRALIAN JOURNAL OF GRAPE AND WINE RESEARCH, Issue 2 2004JOHN A. CONSIDINE Abstract Yield components of the parthenocarpic cultivar Zante were analysed for five vineyards of diverse age and management. The data was obtained as part of an experiment to improve fruit set and yield by applying combinations of gibberellin and 2-chloroethyltrimethyl ammonium chloride or 4-chlorophenoxyacetic acid. Four of the vineyards were located in the Brockman valley north of Perth, Western Australia, two of these were irrigated, one was rain fed and one received supplementary flood irrigation. The fifth lay in an adjacent area of coastal sand plain, at the foot of the Darling scarp, and was irrigated. The vines were aged from 6 to 50 years. Principal component analysis showed that vine age was negatively correlated with vigour (pruning weight) and with berry number per bunch. Vine age however was not strongly related to either yield or yield components (bunch number and berry volume). Sugar concentration was negatively correlated with all yield components but imprecisely modelled based on any combination of the measured variables. Berry number per vine appeared to be the underlying factor determining ,sink' strength though this was inextricably confounded with bunch number per vine. Interpretation of the data leads to the conclusion that increased berry volume is an inefficient means of increasing dried yield. This conclusion argues for caution in the application of plant growth regulators that act primarily to increase berry volume. Yield of sugar per vine was accurately modelled based on second order relationships with bunch number per vine, berry number per bunch, berry volume and pruning weight. Vine age also showed a second order relationship to yield although the range was relatively small. The observations are considered in terms of developing strategies for maximising dried yield and devising mathematical models to account for photoassimilate (dry matter) partitioning in Vitis. [source] | |||||||||||||