Grain number determination in an old and a modern Mediterranean wheat as affected by pre-anthesis shading

2009 ◽  
Vol 60 (3) ◽  
pp. 271 ◽  
Author(s):  
Martín M. Acreche ◽  
Guillermo Briceño-Félix ◽  
Juan A. Martín Sánchez ◽  
Gustavo A. Slafer
Keyword(s):  
Solar Radiation ◽  
Field Experiments ◽  
Unit Area ◽  
Dry Weight ◽  
Good Method ◽  
Structural Components ◽  
Grain Number ◽  
Growing Period ◽  
Incoming Solar Radiation ◽  
Advanced Line

As the number of grains per unit area has been the main bread wheat (Triticum aestivum) yield determinant affected by breeding, and this variable is highly responsive to pre-anthesis shading, the analysis of the effects of shading on old and modern wheats appears to be a good method to explore how breeding has improved yield. Two field experiments were carried out in a region of Mediterranean Spain with an old cultivar (Aragon 03) and a modern line (advanced line ID-2151) and with 4 shading treatments that reduced by c. 75% the daily incoming solar radiation: unshaded control, shading from jointing to anthesis, shading from jointing to the beginning of booting, and shading from the beginning of booting to anthesis. Grain number per m2 differed between cultivars and was affected by shading. The old cultivar had much fewer grains per spikelet (c. 45%) and slightly fewer spikelets per spike (c. 15%) than the modern line and shading decreased only the number of grains per spikelet in direct proportion to the reduction of the incoming solar radiation, leaving the number of spikes per m2 unaffected by either of the 2 factors. Shading the crop during the entire spike growing period also decreased harvest index (c. 17%), although the reduction in partitioning was not evident at anthesis. As the biomass and spike dry weight at anthesis were similarly and consistently reduced by shading, it seemed that pre-anthesis shading reduced the number of developing florets, with its effects on the number of grains per m2, without major changes in resource allocation among structural components of the spike (rachis, glumes, and awns).

Cultivar effects on relationship between grain number and photothermal quotient or spike dry weight in wheat

2011 ◽  
Vol 150 (4) ◽  
pp. 442-459 ◽  
Author(s):  
L. LÁZARO ◽  
P. E. ABBATE
Keyword(s):  
Solar Radiation ◽  
Field Experiments ◽  
Dry Weight ◽  
Grain Filling ◽  
Wheat Cultivars ◽  
Grain Number ◽  
Incident Solar Radiation ◽  
Fertility Index ◽  
Sowing Dates ◽  
Intercepted Solar Radiation

SUMMARYIn wheat, the photothermal quotient (Q, the ratio between mean incident solar radiation and mean temperature is greater than 4·5°C in the 30 days preceding anthesis), is a good estimator of grain number/m2 (GN) and of yield. Previous investigations have not analysed in depth whether the responses of GN to Q differ between wheat cultivars, or what is the cause of the eventual variation. In the present work, the results of field experiments carried out between 1994 and 2001 in various locations were used to test the following hypotheses: (i) the responses of GN to Q differ between wheat cultivars; (ii) these differences are caused by differences in the spike fertility index (GN/g spike dry weight/m2 at the beginning of grain filling (SDW)). The responses of GN to Q were compared for five wheat cultivars (four bread wheats and one durum wheat) and it was found that with Q values above 0·3 MJ/m2/d°C, all responses of GN to Q were linear, positive and parallel. A method was then proposed to obtain cultivar-specific GN from a common relationship between GN and Q. This method would facilitate GN estimation in crops with changes in sowing dates, sites or years, starting from data of potential GN and yield that is relatively easy to obtain. Differences among cultivars in response to Q were due to differences in GN response at SDW. Similar SDW values produced different GN, depending on the spike fertility index of each cultivar. The cultivars did not differ in their responses of SDW to Q. The association between spike fertility index and SDW was strongly negative in bread wheat. At lower levels of Q or SDW, the spike fertility index increased in all cultivars, at least when changes in SDW or Q were caused mainly by intercepted solar radiation, but the present results demonstrate that differences between cultivars also exist in this relationship.

Selective Weed Control in Syrian Marjoram (Origanum syriacum) with Oxadiazon and Oxyfluorfen Herbicides

2006 ◽  
Vol 20 (3) ◽  
pp. 670-676 ◽  
Author(s):  
Jamal R. Qasem ◽  
Chester L. Foy
Keyword(s):  
Weed Control ◽  
Field Experiments ◽  
Dry Weight ◽  
Weed Competition ◽  
Jordan Valley ◽  
Crop Failure ◽  
Growing Period ◽  
Shoot Dry Weight ◽  
Central Jordan ◽  
Low Rate

Field experiments were conducted to study the effects of oxadiazon and oxyfluorfen on weeds and Syrian marjoram (Origanum syriacumL.) in the central Jordan Valley during the period from 1998 to 2001. Results showed that weed competition with marjoram for the whole growing period resulted in almost complete crop failure. Oxyfluorfen and oxadiazon applied preplanting or postplanting to marjoram controlled weeds effectively, resulted in significant increase in marjoram shoot fresh and dry weight yields and in more branches per plant compared with the weed-infested control. High marjoram yield was obtained with oxyfluorfen applied at 0.72 kg ai/ha in preplanting treatment and with oxadiazon at 1.25 and 0.75 kg ai/ha in pre- and postplanting treatments, respectively. In preplanting treatment, 0.36 kg ai/ha of oxyfluorfen was highly selective, but 1.44 kg ai/ha reduced marjoram yield. Conflicting results were obtained with oxadiazon under the same treatments. In postplanting, oxyfluorfen at 0.24 and 0.96 kg ai/ha significantly increased marjoram yield over the weed-infested control. However, the highest shoot dry weight of marjoram was obtained at 0.96 kg ai/ha of this herbicide. In contrast, the low rate (0.38 kg ai/ha) of oxadiazon was highly selective and increased marjoram yield, but the herbicide failed to increase yield beyond the weed-infested control when the higher rate (1.5 kg ai/ha) was used. Results showed that both oxyfluorfen and oxadiazon herbicides were highly selective and effective for weed control in Syrian marjoram, providing normal rates of both are used, although high rates of the two herbicides were also selective and increased marjoram yield over the weed-infested control.

scholarly journals Flower and pod development, grain-setting characteristics and grain yield in Chinese milk vetch (Astragalus sinicus L.) in response to pre-anthesis foliar application of paclobutrazol

PLoS ONE ◽  
2021 ◽  
Vol 16 (2) ◽  
pp. e0245554
Author(s):  
Chunfeng Zheng ◽  
Chunzeng Liu ◽  
Wei Ren ◽  
Benyin Li ◽  
Yuhu Lü ◽  
...  
Keyword(s):  
Grain Yield ◽  
Field Experiments ◽  
Foliar Application ◽  
Unit Area ◽  
Foliar Spray ◽  
Yield Component ◽  
Grain Number ◽  
Astragalus Sinicus ◽  
Pod Development ◽  
Chinese Milk Vetch

The number of grains per unit land area is the most important grain yield component in Chinese milk vetch. Flower and pod survival seem to be critical determinants of grain number, which is related to the number of fertile flowers and pods during the anthesis period. Flower and pod growth are frequently considered the key determinants to establish grain number. The objective of this study was to explore the influences of paclobutrazol on flower and pod development, grain-setting characteristics and grain yield in Chinese milk vetch under different concentrations of foliar spray and try to explore the physiological regulatory mechanisms. Field experiments were carried out during the 2017–2018 and 2018–2019 growing seasons at the Dayuzhuang experimental field. The experiment involved the Chinese milk vetch cultivar “Xinzi No. 1” and six levels of foliar application of paclobutrazol, 0, 200, 300, 400, 500, and 600 mg L-1, in treatments CK, T1, T2, T3, T4, and T5, respectively. Foliar spray was applied once, at the squaring stage. In comparison with the CK treatment, all of the paclobutrazol treatments yielded, to various degrees, increased values of the number of inflorescences per unit area, number of pods per unit area, grain-setting rate of pods, and number of grains per pod in all six inflorescence layers, with the largest increases observed in the T3 treatment. In the T3 treatment compared with the CK treatment, from the first to sixth inflorescence layers, the number of inflorescences per unit area was increased by 34.07–58.97%, the number of pods per unit area was increased by 39.69–68.35%, the grain number per pod was increased by 44.31–53.69%, and the grain-setting rate of pods was increased by 1.84–4.89%. An analysis of yield composition revealed that the paclobutrazol spray treatment had little impact on the grain weight of Chinese milk vetch. The correlations between the concentration of paclobutrazol spray and the grain yield of Chinese milk vetch reached a significant level. Grain yield was highest at the paclobutrazol concentration of 373.10 mg/L. The inflorescence contents of gibberellic acid 3 (GA3), indole-3-acetic acid (IAA), and abscisic acid (ABA) were reduced, whereas that of cytokinin (CTK) was increased, by foliar application of paclobutrazol (400 mg L-1, T3 treatment) relative to CK treatment during the stages of flowers and pods developing into grains.

Comparative growth analysis of Brassica napus and Brassica juncea under Swedish conditions

1993 ◽  
Vol 73 (3) ◽  
pp. 795-801 ◽  
Author(s):  
C. Kjellström
Keyword(s):  
Brassica Napus ◽  
Brassica Juncea ◽  
Growth Analysis ◽  
Field Experiments ◽  
Dry Weight ◽  
Climatic Conditions ◽  
Plant Component ◽  
Area Index ◽  
Growing Period ◽  
Yield Level

Indian cultivars of Brassica juncea were tested in field experiments at the research farm of the Swedish University of Agricultural Sciences, Uppsala, to determine their agronomic performance under Swedish climatic conditions. In this study, production and development of a B. juncea cultivar of Indian origin and a Swedish B. napus cultivar were compared in a growth analysis during 1987–1990. Plants were harvested at approximately weekly intervals from emergence to maturity, and separated into leaves, stems, pods and seeds. Area indices of leaves, stems and pods were calculated, and dry weight of each plant component was determined. On an average of 4 yr, the total growing period was similar for both cultivars, 107 d or ca. 1030 growing degree days (GDD), with an earlier onset and a shorter duration of flowering for B. juncea. Dry weights of all vegetative plant components, especially stems, reached higher maximum levels in the highly branched B. juncea cultivar than in the B. napus cultivar. By the end of the flowering stage, B. napus had accumulated a significantly higher percentage of final total dry matter than B. juncea. After flowering, the crop growth rate was significantly higher in B. juncea, 0.54 g m−2 GDD−1, than in B. napus. Seed yield level was similar in both species, and in year 1990 ca. 2.2 t ha−1 was harvested. Key words: Brassica juncea, Brassica napus, growth analysis, area index

A study of grain number in two contrasting wheat cultivars

1978 ◽  
Vol 29 (3) ◽  
pp. 431 ◽  
Author(s):  
PJ Bremner ◽  
JL Davidson
Keyword(s):  
Harvest Index ◽  
Dry Matter ◽  
Unit Area ◽  
Dry Weight ◽  
Wheat Cultivars ◽  
Grain Number ◽  
Detectable Difference ◽  
Production And Distribution ◽  
The Difference ◽  
Total Dry Weight

The origin of the grain number difference between two contrasting wheat cultivars (WW 15, Mexican semidwarf; Timgalen, Australian) was studied in terms of (i) the production and distribution of dry matter during the pre-anthesis development of the ear; (ii) the number of florets initiated; and (iii) interaction between grains during grain set. Grain yield was much more closely related to harvest index than to total dry weight, and harvest index appeared to be largely a function of the number of grains produced per unit area. The difference in grain number between the cultivars bore no relation to the number of florets initiated by them. Nor was the inhibition of grain set in the distal florets of spikelets by rapid growth of grains in basal florets involved. Large differences in grain number occurred between the cultivars where there was no detectable difference between them in the production and distribution of dry matter during pre-anthesis ear development, i.e. the semidwarf cultivar was superior in setting grains for some reason other than the pattern of distribution of dry matter between grain and straw.

Purification of Pisciculture Waters through Cultivation and Harvesting of Aquatic Biomass

1987 ◽  
Vol 19 (10) ◽  
pp. 113-121 ◽  
Author(s):  
C. Simeon ◽  
M. Silhol
Keyword(s):  
Aquatic Macrophyte ◽  
Dry Weight ◽  
Final Decision ◽  
Effluent Water ◽  
Aquatic Biomass ◽  
Growing Period ◽  
European Climate ◽  
Nuclear Plants ◽  
Economical Optimization ◽  
Water Hyacinths

The study of thermal wastes from the nuclear plants around Pierrelatte for agricultural, piscicultural, energy and environmental protection purposes resulted in the establishment of a pilot facility as early as 1976. An aquatic macrophyte pilot facility has been operational since 1983 to study the use of water hyacinths from the aspects of energy and ecology. The results obtained suggest that production yields for the 7 month growing period should exceed 60 metric tons (MT) (dry weight) per hectare in a European climate, and that such crops can feasibly be cultivated in temperate regions. The pilot facility is supplied with pisciculture effluent water, making it possible to quantify the stabilization power of the plants. Without primary decantation, with a retention time of 4 days and stabilization with water hyacinths only, the organic matter waste pond surface area required is 3.5 m2/m2 of pisciculture pond. Any primary or secondary facilities will lead to a reduction of these areas. The final decision will depend on the economical optimization of all the wastewater.

scholarly journals Functional ecology of the biological soil crust in semiarid SE Spain: sun and shade populations of Diploschistes diacapsis (Ach.) Lumbsch.

2005 ◽  
Vol 37 (5) ◽  
pp. 425-432 ◽  
Author(s):  
Ana PINTADO ◽  
Leopoldo G. SANCHO ◽  
T. G. Allan GREEN ◽  
José Manuel BLANQUER ◽  
Roberto LÁZARO
Keyword(s):  
Water Content ◽  
Chlorophyll Content ◽  
Unit Area ◽  
Biological Soil Crust ◽  
Dry Weight ◽  
Mean Annual Precipitation ◽  
Plant Colonization ◽  
Soil Crust ◽  
Active Time ◽  
Exposed Population

The Tabernas badlands in semiarid south-east Spain is one of the driest regions in Europe with a mean annual precipitation of c. 240 mm. The landscape is deeply dissected, with canyons, ramblas and sparsely vegetated eroded badland slopes. The vegetation is predominantly a biological soil crust consisting of different types of lichen-rich communities, one of the more conspicuous being dominated by Diploschistes diacapsis (Ach.) Lumbsch. This lichen is mainly restricted to the north- facing slopes, where it forms extensive whitish carpets and probably plays an important role in preventing erosion of the slopes and allowing plant colonization. South-facing slopes are much more eroded and generally lack vegetation. %The photosynthetic performance of north (shade) and south-facing (sun) populations of D. diacapsis was studied to determine if these different populations showed any adaptations to the microclimatic conditions of their individual habitats. The response of CO2 exchange to light intensity, temperature and water content was measured under controlled conditions in the laboratory. Dry weight-based net photosynthetic rates were higher in the southern-exposed population but quantum efficiency, and light compensation points were similar. Thallus weight per unit area (LMA) was considerably higher for shade specimens but maximum water content and optimal water content were very similar and chlorophyll content on a dry weight basis was also similar. Chlorophyll content on an area basis was higher in the northern-exposed population and always much larger than those reported in other studies on the same species (up to 8 times larger) with the result that NP values on a chlorophyll basis were relatively low. The larger LMA meant that shade thalli stored more water per unit area which should ensure longer active periods than sun thalli. The results support a strategy pair of high NP and short active time versus low NP and long active time, both having been reported for other soil crust species. However, the visibly larger biomass of the shade D. diacapsis suggests that the lichen is at the limit of its adaptability in these habitats.

Contrasting yield formation characteristics in two super-rice hybrids that differ in growth duration

2021 ◽  
pp. 1-10
Author(s):  
Min Huang ◽  
Zui Tao ◽  
Tao Lei ◽  
Fangbo Cao ◽  
Jiana Chen ◽  
...  
Keyword(s):  
Solar Radiation ◽  
Biomass Production ◽  
Field Experiments ◽  
Crop Improvement ◽  
Total Biomass ◽  
Growth Duration ◽  
Area Index ◽  
Rice Hybrid ◽  
Use Efficiency ◽  
Yield Formation

Summary The development of high-yielding, short-duration super-rice hybrids is important for ensuring food security in China where multiple cropping is widely practiced and large-scale farming has gradually emerged. In this study, field experiments were conducted over 3 years to identify the yield formation characteristics in the shorter-duration (∼120 days) super-rice hybrid ‘Guiliangyou 2’ (G2) by comparing it with the longer-duration (∼130 days) super-rice hybrid ‘Y-liangyou 1’ (Y1). The results showed that G2 had a shorter pre-heading growth duration and consequently a shorter total growth duration compared to Y1. Compared to Y1, G2 had lower total biomass production that resulted from lower daily solar radiation, apparent radiation use efficiency (RUE), crop growth rate (CGR), and biomass production during the pre-heading period, but the grain yield was not significantly lower than that of Y1 because it was compensated for by the higher harvest index that resulted from slower leaf senescence (i.e., slower decline in leaf area index during the post-heading period) and higher RUE, CGR, and biomass production during the post-heading period. Our findings suggest that it is feasible to reduce the dependence of yield formation on growth duration to a certain extent in rice by increasing the use efficiency of solar radiation through crop improvement and also highlight the need for a greater fundamental understanding of the physiological processes involved in the higher use efficiency of solar radiation in super-rice hybrids.

scholarly journals Vegetative and Reproductive Response to Fruit Load in Two Jojoba (Simmondsia chinensis) Cultivars

Agronomy ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 889
Author(s):  
Aviad Perry ◽  
Noemi Tel-Zur ◽  
Arnon Dag
Keyword(s):  
Vegetative Growth ◽  
Accumulation Rate ◽  
Dry Weight ◽  
High Yield ◽  
Lower Amount ◽  
Simmondsia Chinensis ◽  
Alternate Bearing ◽  
Fruit Removal ◽  
Growing Period ◽  
Fruit Load

Jojoba (Simmondsia chinensis) is a wax crop cultivated mainly in arid and semi-arid regions. This crop has been described as an alternate-bearing plant, meaning that it has a high-yield year (“on-year”) followed by a low-yield year (“off-year”). We investigated the effect of fruit load on jojoba’s vegetative and reproductive development. For two consecutive years, we experimented with two high-yielding cultivars—Benzioni and Hazerim—which had opposite fruit loads, i.e., one was under an on-year load, while the other was under an off-year load simultaneously. We found that removing the developing fruit from the shoot during an off-year promotes further vegetative growth in the same year, whereas in an on-year, this action has no effect. Moreover, after fruit removal in an on-year, there was a delay in vegetative growth renewal in the consecutive year, suggesting that the beginning of the growing period is dependent on the previous year’s yield load. We found that seed development in the 2018 season started a month earlier than in the 2017 season in both cultivars, regardless of fruit load. This early development was associated with higher wax content in the seeds. Hence, the wax accumulation rate, as a percentage of dry weight, was affected by year and not by fruit load. However, on-year seeds stopped growing earlier than off-year seeds, resulting in smaller seeds and an overall lower amount of wax per seed.

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