Studies of grain production in Sorghum vulgare. II. Sites responsible for grain dry matter production during the post-anthesis period

1971 ◽  
Vol 22 (1) ◽  
pp. 39 ◽  
Author(s):  
KS Fischer ◽  
GL Wilson

The relative contributions of different photosynthetic sites to the filling of the grain in grain sorghum (Sorghum vulgare cv. Brolga) were estimated by measuring the 14C in the grain after exposing various leaves and the head to radioactive carbon dioxide. Methods for preventing photosynthesis were also used. Of the grain yield, 93% was due to assimilation by the head and upper four leaves. The head contribution of 18 % was due equally to direct assimilation of atmospheric carbon dioxide and to reassimilation of carbon dioxide released within the grain by respiration of material translocated from the leaves. The remaining 75 % was equally assimilated by the upper four leaves, the flag leaf being the most efficient contributor per unit area and the third uppermost leaf the least efficient. The percentage contributions to the grain by the flag leaf and fourth leaf, estimated from the decrease in grain yield when they were shaded, agreed closely with the estimates obtained by using 14CO2.

1971 ◽  
Vol 22 (1) ◽  
pp. 33 ◽  
Author(s):  
KS Fischer ◽  
GL Wilson

Sorghum plants were allowed to assimilate known relative amounts of 14C in the two periods: (i) from full expansion of the third uppermost leaf to anthesis; and (ii) from anthesis to grain maturity. By comparing relative 14C activity in the mature grain, the relative partitioning of photosynthate between grain production and other uses in the two periods was calculated. Plant and grain dry weight data from another experiment showed the amounts of net photosynthesis in the two periods. It was then possible to calculate the maximum amount of the material assimilated in the pre-anthesis period that could have gone to grain production, and thus the percentage of grain material derived from this earlier period. The estimate was 12%.


1972 ◽  
Vol 12 (55) ◽  
pp. 165 ◽  
Author(s):  
JR Syme

Four wheats of similar maturity were compared at two seed rates and two nitrogen levels. The cultivars were two high-yielding Mexican semi-dwarf wheats, Pitic 62 and accession WW 15, one local semidwarf crossbred, HMR, and one Australian variety, Robin. At each of two sites WW 15 yielded most grain and Robin the least. Yield components, growth, development and leaf characters were studied at one site. The semi-dwarf wheats had a higher proportion of ear weight at anthesis and set more grains per ear and per unit area. The high yield of WW 15 was associated with many grains per ear and a dense ear population. There were relatively small differences in total dry matter yield and leaf area index. WW 15 formed the most leaves on the main stem, had the shortest period from flag leaf emergence to anthesis and showed delay in the senescence of its flag leaves. Its leaves were also particularly narrow and small. The early effects of a higher seed rate on crop growth diminished with time in the main experiment but resulted in a small increase in grain yield. Nitrogen stimulated growth throughout the season, but the increased vegetative potential was not fully reflected in grain yield. Both nitrogen and the higher seed rate hastened flag leaf senescence.


2012 ◽  
Vol 60 (4) ◽  
pp. 385-396 ◽  
Author(s):  
E. Sugár ◽  
Z. Berzsenyi

The effect of four rates of nitrogen (N) fertilisation (0, 80, 160, 240 kg ha−1) on the growth and yield components of three winter wheat varieties with different maturity dates (Mv Toborzó — extra early, Mv Palotás — early, Mv Verbunkos — mid-early) was analysed in a long-term experiment laid out in a two-factorial split-plot design with four replications in the years 2007–2009. The dry matter production of the whole plant and of individual plant organs, the maximum leaf area, the area of the flag-leaf and all the yield components except the thousand-kernel weight were significantly the greatest in the N160 or the N240 treatments. Averaged over the varieties and years the grain yield in the N treatments was N0: 5.5, N80: 7.1, N160: 7.3 and N240: 7.5 t ha−1. Averaged over N treatments and years the variety Mv Verbunkos had the highest dry matter production, stem mass, spike mass, number of grains per spike and grain yield. Mv Verbunkos had the greatest leaf area in the favourable years of 2008 and 2009 and the greatest flag-leaf area in 2008. Averaged over N treatments and varieties the dry matter production per plant, the leaf and stem mass, the number of spikes per square metre and the thousand-kernel weight were greatest in 2007. The spike mass was lowest in 2007 and had higher, very similar values in 2008 and 2009. The maximum leaf area per plant, the area of the flag-leaf, the number of grains per spike and the grain yield were highest in 2008. The values and dynamics of the growth parameters gave a good characterisation of the effect of the treatments (N fertilisation, variety, year) on plant production (yield, yield components) in various stages of growth.


2015 ◽  
Vol 66 (4) ◽  
pp. 308 ◽  
Author(s):  
Alison. J. Frischke ◽  
James R. Hunt ◽  
Dannielle K. McMillan ◽  
Claire J. Browne

In the Mallee region of north-western Victoria, Australia, there is very little grazing of crops that are intended for grain production. The success of dual-purpose crops in other regions in south-eastern Australia with higher and more evenly distributed rainfall has driven interest in assessing the performance of dual-purpose cereals in the region. Five experiments were established in five consecutive years (2009–13) in the southern Mallee to measure the forage production and grain yield and quality response in wheat and barley to grazing by sheep or mechanical defoliation. The first three experiments focused on spring cultivars sown from late April to June, and the last two on winter cultivars planted from late February to early March. Cereal crops provided early and nutritious feed for livestock, with earlier sowing increasing the amount of dry matter available for winter grazing, and barley consistently produced more dry matter at the time of grazing or defoliation than wheat. However, the grain-production response of cereals to grazing or defoliation was variable and unpredictable. Effects on yield varied from –0.7 to +0.6 t/ha, with most site × year × cultivar combinations neutral (23) or negative (14), and few positive (2). Changes in grain protein were generally consistent with yield dilution effects. Defoliation increased the percentage of screenings (grains passing a 2-mm sieve) in three of five experiments. Given the risk of reduced grain yield and quality found in this study, and the importance of grain income in determining farm profitability in the region, it is unlikely that dual-purpose use of current cereal cultivars will become widespread under existing grazing management guidelines for dual-purpose crops (i.e. that cereal crops can be safely grazed once anchored, until Zadoks growth stage Z30, without grain yield penalty). It was demonstrated that early-sown winter wheat cultivars could produce more dry matter for grazing (0.4–0.5 t/ha) than later sown spring wheat and barley cultivars popular in the region (0.03–0.21 t/ha), and development of regionally adapted winter cultivars may facilitate adoption of dual-purpose cereals on mixed farms.


2016 ◽  
Vol 51 (9) ◽  
pp. 1633-1642 ◽  
Author(s):  
Claudio Hideo Martins da Costa ◽  
Carlos Alexandre Costa Crusciol ◽  
Jayme Ferrari Neto ◽  
Gustavo Spadotti Amaral Castro

Abstract The objective of this work was to evaluate the long-term effects of the surface application of lime on soil fertility and on the mineral nutrition and grain yield of soybean, and of black oat and sorghum in crop succession. The experiment was carried out on a clayey Oxisol, in a randomized complete block design, with four replicates. Treatments consisted of lime the rates of 0, 1,000, 2,000, and 4,000 kg ha-1, applied in October 2002 and November 2004. Soil samples were collected at five soil layers, down to 0.60-m depth. Surface liming was effective in reducing soil acidity and increasing Ca2+ and Mg2+ contents in the subsurface. Moreover, it increased available phosphorus contents and soil organic matter in the long term (48 to 60 months after the last lime application). Surface liming improved plant nutrition, mainly for N, Ca, and Mg, and increased dry matter production and grain yield of the crops, even in years with regular distribution of rainfall. The greatest productivities of soybean, black oat, and sorghum were obtained with the respective estimated lime doses of 4,000, 2,333, and 3,281 kg ha-1, for shoot dry matter, and of 2,550, 3,555, and over 4,000 kg ha-1, for grain yield.


1982 ◽  
Vol 22 (115) ◽  
pp. 76 ◽  
Author(s):  
KA Boundy ◽  
TG Reeves ◽  
HD Brooke

The effect of serial planting on dry matter production, leaf area, grain yield and yield components cf Lupinus angustifoiius (cvv. Uniwhite, Uniharvest and Unicrop) and L. albus (cv. Ultra) was investigated in field plots at Rutherglen in 1973 and 1974. Delayed planting reduced dry matter production of all cultivars, and leaf area for Ultra. Differences in dry matter partitioning were observed between the late flowering Uniharvest, and the early flowering Unicrop and Ultra. In Uniharvest, delayed plantings resulted in a greater proportion of total dry matter being produced during the flowering phase, whereas the reverse was true for Unicrop and Ultra. The later flowering cultivars showed marked grain yield and yield component reduction with later sowing. Yields were reduced by 160.6 kg/ha and 222.5 kg/ha for each week's delay in sowing Uniharvest and Uniwhite, respectively. This effect was offset in the early flowering cultivars by greater development of lateral branches. In addition, when Unicrop and Ultra were planted in April, pod and flower abortion on the main stem resulted from low temperatures at flowering time. Optimum sowing time was early April for Uniwhite and Uniharvest, and early May for Unicrop and Ultra. Excellent vegetative growth under ideal moisture conditions highlighted the poor harvest indices of lupins and the scope for genetic improvement in the genus.


1986 ◽  
Vol 37 (5) ◽  
pp. 459 ◽  
Author(s):  
GD Batten ◽  
IF Wardlaw ◽  
MJ Aston

Experiments were designed to examine the effect of the level and duration of application of phosphorus (P) on yield in wheat and the effect of growth conditions prior to anthesis on the utilisation of P taken up during the early stages of development. In the first experiment, wheat (Triticum aestivum cv. Kite) was grown in sand and supplied with a complete nutrient solution containing either 1 mM phosphate or 0.25 mM phosphate. The supply of P was maintained until grain maturity, or stopped at different stages of development (floral initiation, flag leaf emergence, anthesis). The increase in total plant dry matter over this period ranged from 8.8 to 17.6 g/plant, with the 1.0 mM P supply and from 4.1 to 9.5 g/plant with the 0.25 mM P supply. Supply of P beyond anthesis resulted in more tiller dry matter and increased the P content of the grain, but did not increase grain yield at either level. With 1 mM P to maturity, up to 21% P of the grain P could be attributed to retranslocation of P within the plant after anthesis. With 0.25 mM P to floral initiation, 58% of the grain P could be attributed to such retranslocation. In a second experiment plants (cv. Kite) were grown initially at 18/13�C with 0.25 mM P until floral initiation and thereafter with a P-free solution until maturity. Between floral initiation and anthesis plants were placed in six dayhight temperatures, extending (in 3�C steps) from 15/10�C to 30/25OC, and then returned to the standard condition of 18/13�C. Higher pre-anthesis temperatures reduced the pre-anthesis growth period and the plant height, but increased the leaf phosphorus concentration and uptake of phosphorus per plant in both the pre- and post-anthesis periods. Net CO2 exchange indicated that leaf senescence in P-deficient plants was closely associated with the export of nitrogen as well as the export of P. Grain P increased from 0.15% to 0.3% when the preanthesis temperature was increased from 15/10 to 30/25�C, although grain yield per main culm did not vary greatly. These findings highlight the importance of environmental conditions in determining the level of P deficiency in wheat, and show that grain yield is not limited by the amount of P in the grain.


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