Genetic gain in yield and associated changes in phenotype, trait plasticity and competitive ability of South Australian wheat varieties released between 1958 and 2007

2011 ◽  
Vol 62 (7) ◽  
pp. 533 ◽  
Author(s):  
Victor O. Sadras ◽  
Chris Lawson
Keyword(s):  
Growth Rate ◽  
Grain Size ◽  
Stem Elongation ◽  
Crop Growth ◽  
Grain Number ◽  
Wheat Varieties ◽  
Crop Growth Rate ◽  
Australian Wheat ◽  
Use Efficiency ◽  
Radiation Use

To quantify the genetic gain in yield and associated changes in phenotype, we compared 13 South Australian wheat varieties released between 1958 and 2007. Crops were grown in three environments with a range of yield between 4.1 and 6.1 t/ha. Yield increased linearly with year of cultivar release at a rate of 25 ± 3.4 kg/ha per year. Yield improvement was associated with a linear increase in harvest index over the whole period 1958–2007 and increased shoot biomass for varieties released after the early 1980s. A non-linear model with an inflection point at 1982 ± 1.6 emphasised two phases in the time trend of grain size: it decreased between 1957 and 1982 and increased afterwards. The plasticity of grain size increased 2-fold after 1982. Grain number increased until the early 1980s and stabilised afterwards. Grain number was associated with crop growth rate between stem elongation and anthesis, and grain size was associated with crop growth rate per grain. Crop growth rate between stem elongation and anthesis increased after the early 1980s in parallel with increased radiation-use efficiency and independently of changes in capture of radiation. Candidate traits to explain the improvement in radiation-use efficiency include increased stomatal conductance and greener leaves. The concentration of water-soluble carbohydrates in shoots at anthesis increased with year of cultivar release at 0.12 ± 0.018% per year. In two out of three environments, yield response to competition declined with year of cultivar release, which was consistent with the communal plant ideotype.

scholarly journals Phosphorus fertilization in the implantation of a silvopastoral system: morphogenic and structural characteristics of Mombaça grass

2021 ◽  
Vol 22 ◽  
Author(s):  
Thais Valéria Souza Silva PACHECO ◽  
Luciano Fernandes SOUSA ◽  
Antônio Clementino dos SANTOS ◽  
José Geraldo Donizetti dos SANTOS ◽  
Valdinéia Patrícia DIM ◽  
...  
Keyword(s):  
Growth Rate ◽  
Structural Characteristics ◽  
Stem Elongation ◽  
Rest Period ◽  
Crop Growth ◽  
Phosphorus Fertilization ◽  
Silvopastoral System ◽  
Area Index ◽  
Crop Growth Rate ◽  
Cultivation Systems

ABSTRACT The objective of this study was to evaluate the effect of phosphate fertilization on morphogenic and structural characteristics of Mombasa grass under conditions of implantation of silvopastoral system with eucalyptus and monoculture in the Amazon/Cerrado ecotone. The experiment was conducted at UFT-EMVZ during the rainy seasons of the 2016/2017 and 2017/2018 agricultural years. The experimental area was subdivided into two cultivation systems, Mombaça grass monoculture, with 0.25 hectare and silvopastoral system, intercropping eucalyptus with Mombaça grass, with 0.75 hectare area. The design used was a 4 x 2 factorial IHD with four doses of phosphorus (0; 50; 100; 200 kg.ha -1 P2O5 year-1) and two cultivation systems (monoculture and silvopastoral) with three repetitions. Three cycles were evaluated for an average rest period of 21 days. Weekly measurements were taken to evaluate structural and morphogenic characteristics of plants. In general, factors tested such as phosphorus fertilization, cultivation system and year (implantation and following year) showed influence, altering the development of Mombaça grass, reflecting on the morphogenic and structural characteristics. Tiller population density, crop growth rate, leaf area index showed interactions between phosphorus fertilization and the cultivation systems analyzed (P <0.05). Phosphorus fertilization used in the implantation, moment of greatest requirement of the plant, influenced forage development by increasing the crop growth rate, leaf appearance, as well as leaf and stem elongation in the two evaluated systems.

The effects of radiation and nitrogen on number of grains in wheat

1995 ◽  
Vol 124 (3) ◽  
pp. 351-360 ◽  
Author(s):  
P. E. Abbate ◽  
F. H. Andrade ◽  
J. P. Culot
Keyword(s):  
Growth Rate ◽  
Dry Weight ◽  
N Fertilization ◽  
Crop Growth ◽  
Grain Number ◽  
Crop Growth Rate ◽  
Growing Seasons ◽  
N Supply ◽  
Intercepted Radiation ◽  
N Rates

SUMMARYThe possible interacting effects of shading and N supply on number of grains of Triticum aestivum L. (cv. Buck Ñandú) were investigated at Balcarce, Argentina, during the 1988/89 and 1989/90 growing seasons. Shading was imposed from c. 13 days before anthesis to 6 days after, and four rates of N fertilization were supplied within each shading treatment around the date of terminal spikelet formation. Water and other nutrients were not limiting.Total grain yield was strongly correlated with grain number/m2, regardless of shading or N supply. At the highest N rates, grain number and dry weight of spikes at anthesis were linearly related to a photothermal quotient, i.e. the ratio of intercepted photosynthetically active radiation (PAR) to mean temperature minus 4·5 °C, during the period from 20 days before anthesis to 10 days after. The response of grain number to the photothermal quotient was interpreted in terms of the supply of assimilates to the spike at anthesis, which determined flower survival. The response of dry weight of spikes to photothermal quotient was interpreted in terms of crop growth rate since there was a linear relationship between crop growth rate and intercepted radiation. The lowest N rates reduced the number of grains/m2, at any given photothermal quotient. Since the reduction in grain number also occurred at any given dry weight of spikes, it cannot be explained by a reduced supply of assimilates to the spikes. Grain number responded directly to the supply of N to the spike, probably through the survival of differentiated flowers. The relationship between spike growth rate and crop growth rate was not affected by N supply. Crop growth rate was reduced by reduced N supply, because less radiation was intercepted and because radiation-use efficiency was lowered. These results indicate that current models for determining yield and number of grains/m2, based on crop growth, are not adequate when N is deficient.

Relationship between yield, growth and spike weight in wheat under phosphorus deficiency and shading

2009 ◽  
Vol 148 (1) ◽  
pp. 83-93 ◽  
Author(s):  
L. LÁZARO ◽  
P. E. ABBATE ◽  
D. H. COGLIATTI ◽  
F. H. ANDRADE
Keyword(s):  
Growth Rate ◽  
Dry Matter ◽  
Phosphorus Deficiency ◽  
Dry Weight ◽  
Crop Growth ◽  
Grain Number ◽  
Dry Matter Partitioning ◽  
P Deficiency ◽  
Crop Growth Rate ◽  
Intercepted Radiation

SUMMARYThe effect of phosphorus deficiency on yield formation in spring wheat (Triticum aestivum cv. Prointa Oasis) was investigated, focusing on crop growth and dry matter partitioning during the spike growth period (SGP), which is critical for grain number determination. Two experiments combining shading and P deficiency were performed at Balcarce, Argentina (37°45′S). The main treatments were two levels of soil P-availability: low P, a naturally low P fertility soil (7·0 and 5·5 mg Bray extractable P/kg soil, in the first and second experiments respectively) and high P, a P dose that does not limit growth. The sub-treatments were two levels of radiation (shaded and control). Phosphorus deficiency affected yield mainly through the number of grains/unit surface (m2). Differences in grain number/m2 were related to differences in dry weight of spikes/m2, measured 7 days after anthesis, excluding grain weight. The duration of the SGP did not change much as result of P deficiency: 27 days with high P and only 3 days more with low P. Therefore, changes in spike dry weight were mainly due to differences in spike growth rate. In turn, the spike growth rate of all treatments was linearly related to crop growth rate, with little effect of dry matter partitioning to spikes. Finally, differences in crop growth rate between P treatments were mainly determined by the amount of intercepted radiation. It was concluded that P deficiency resulted in a reduction in intercepted radiation during the SGP, thus causing a reduction in grain number and crop yield.

scholarly journals Growth and yield of wheat at different dates of sowing under chrland ecosystem of Bangladesh

2017 ◽  
Vol 14 (2) ◽  
pp. 147-154 ◽  
Author(s):  
MM Kamrozzaman ◽  
MAH Khan ◽  
S Ahmed ◽  
N Sultana
Keyword(s):  
Growth Rate ◽  
Leaf Area Index ◽  
Leaf Area ◽  
Dry Matter ◽  
Block Design ◽  
Grain Filling ◽  
Crop Growth ◽  
Growth And Yield ◽  
Area Index ◽  
Crop Growth Rate

An experiment was conducted at Sadipur charland under Farming System Research and Development Site, Hatgobindapur, Faridpur, during rabi season of 2012-13 and 2013-14 to study the growth and yield performance of cv. BARI Gom-24 as affected by different dates of sowing under Agro-ecological Zone-12 (AEZ-12) of Bangladesh. The experiment was laid out in randomized complete block design with six replications, comprising five different dates of sowing viz. November 5, November 15, November 25, December 5 and December 15. Results reveal that the tallest plant, leaf area index, total dry matter, and crop growth rate were observed in November 25 sown crop and leaf area index, total dry matter and crop growth rate were higher at booting, grain filling, and tillering stages of the crop. Maximum effective tillers hill-1 (3.49), spikes m-2, (311), number of grains spike-1 (42.20) and 1000-grain weight (52.10 g) were produced by November 25 sown crop exhibited the highest grain (4.30 t ha-1) and straw yield (4.94 t ha-1) as well as harvest index (46.88%) of the crop. Lowest performance was observed both in early (November 5) and late sown crop (December 15). The overall results indicated that November 25 sown crop showed better performance in respect of growth and yield of wheat under charland ecosystem of Bangladesh.J. Bangladesh Agril. Univ. 14(2): 147-154, December 2016

scholarly journals Formowanie powierzchni asymilacyjnej i biomasy przez rośliny buraków cukrowych [Formation of the assimilation area and biomass by sugar beet plants]

2015 ◽  
Vol 31 (1–2) ◽  
pp. 21-32
Author(s):  
K. Olech ◽  
Z. K. Blamowski
Keyword(s):  
Growth Rate ◽  
Sugar Beet ◽  
Crop Growth ◽  
Crop Growth Rate ◽  
Fast Growing ◽  
Final Yield ◽  
Whole Plants

Measurements were carried out of the assimilation area, NAR value, the crop growth rate (C) and of the yield of roots and leaves of sugar beet plants in a production field during two successive vegetation years. An interdependence was found between the formation of the assimilation area in the canopy and the final yield of biomass. The assimilation area depended mainly on the date of sowing. In 1975, the sowing was earlier by 15 days, amid this resulted in a much more favourable LAI and in a higher yield of biomass. During both vegetation years, a violent decrease of the crop growth rate was observed at the end of August and at the beginning of September. This may be due to an unfavourable change in the ratio of the area of younger, photosynthetically active leaves to older, less active leaves and also to the increased participation of the loss of the assimilates resulting from stronger respiration of the fast growing roots while the photosynthesis of the whole plants decreases.

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