Evidence for differences between three wheat cultivars in yield response to plant population

1991 ◽  
Vol 42 (5) ◽  
pp. 701 ◽  
Author(s):  
WK Anderson ◽  
J Barclay

Three wheat cultivars were grown at five seed levels in 15 experiments under rain-fed conditions in the central wheatbelt of Western Australia in the 1986, 1987 and 1988 seasons. Guthea (released in 1982, 87 cm tall) required less seed and fewer plants on average to achieve its maximum grain yield than either Gamenya (released in 1960, 82 cm) or Aroona (released in 1981, 73 cm). At sites where Gutha was best adapted its optimum population was 65 plants m-2, about half of the population required by the other two cultivars. At sites where Aroona was best adapted its optimum population was 110 plants m-2. Gutha produced larger ears, especially at small populations, but did not increase kernel numbers per m2 in response to increased populations as much as Aroona. It is suggested that when a new cultivar is released its optimum plant population should be assessed in the area for which it is recommended.

1986 ◽  
Vol 22 (3) ◽  
pp. 243-251 ◽  
Author(s):  
B. R. Taylor ◽  
J. Y. Chambi

SUMMARYField trials are described in which the seed yield response of row-sown sesame to increasing plant population was examined, and in which row-sowing was compared with broadcasting at different seed rates. Maximum yields were obtained at an intended 200 to 250 × 103 plants ha−1 but yields were not greatly affected by a wider range of populations. Broadcasting, the normal local practice, gave yields slightly higher than those from rows 50 cm apart, the un-thinned rate of 800 × 103 viable seeds sown ha−1 yielded as well as treatments thinned to the optimum population, and double this seed rate, unthinned, gave the lowest yields, especially in rows.


Plant Disease ◽  
2016 ◽  
Vol 100 (8) ◽  
pp. 1735-1743 ◽  
Author(s):  
Yuba R. Kandel ◽  
Kiersten A. Wise ◽  
Carl A. Bradley ◽  
Albert U. Tenuta ◽  
Daren S. Mueller

A 2-year study was conducted in Illinois, Indiana, Iowa, and Ontario in 2013 and 2014 to determine the effects of planting date, seed treatment, and cultivar on plant population, sudden death syndrome (SDS) caused by Fusarium virguliforme, and grain yield of soybean (Glycine max). Soybean crops were planted from late April to mid-June at approximately 15-day intervals, for a total of three to four plantings per experiment. For each planting date, two cultivars differing in SDS susceptibility were planted with and without fluopyram seed treatment. Mid-May plantings resulted in higher disease index compared with other planting dates in two experiments, early June plantings in three, and the remaining six experiments were not affected by planting date. Soil temperature at planting was not linked to SDS development. Root rot was greater in May plantings for most experiments. Resistant cultivars had significantly lower disease index than the susceptible cultivar in 54.5% of the experiments. Fluopyram reduced disease severity and protected against yield reductions caused by SDS in nearly all plantings and cultivars, with a maximum yield response of 1,142 kg/ha. Plant population was reduced by fluopyram seed treatment and early plantings in some experiments; however, grain yield was not affected by these reductions. Yields of plots planted in mid-June were up to 29.8% less than yields of plots planted in early May. The lack of correlation between early planting date and SDS severity observed in this study indicates that farmers do not have to delay planting in the Midwest to prevent yield loss due to SDS; cultivar selection combined with fluopyram seed treatment can reduce SDS in early-planted soybean (late April to mid May).


1986 ◽  
Vol 37 (3) ◽  
pp. 219 ◽  
Author(s):  
WK Anderson

Eight spring bread wheat cultivars (Triticum aestivum L.), differing widely in their nominal yield component characteristics, were tested under rain-fed conditions for three years at sowing densities ranging from 50 to 800 seeds m-2. The objectives of the experiments were to estimate the relationship between grain yield and particular yield components, the expression of plant type (yield components) in relation to plant density, and the plant population x cultivar interaction for grain yield over a range of seasons in a given environment. The 'optimum' plant population (at maximum grain yield) varied over 30-220 plants m-2, depending on season and cultivar. In general, variation in the 'optimum' population was greater between seasons for a given cultivar than between cultivars within seasons. The relationship between grain yield and yield components was examined at the 'optimum' population rather than at an arbitrary population at which grain yield may have been suboptimal for some cultivars or seasons. Grain yields at the optimum populations for the various cultivar x season combinations were positively related to culms m-2, spikes m-2 and seeds m-2. They were not clearly related to culm mortality (%). When averaged across seasons, cultivar grain yields were positively related to harvest index, but the general relationship was not so clear when seasons and cultivars were examined individually. Spike size (seeds spike-I or spike weight) and seed size were also not clearly related to grain yield at the 'optimum' population, and it was thus postulated that the production and survival of large numbers of culms, which in turn led to large numbers of seeds per unit area, were the source of large grain yields. Some interactions were found between yield components and plant population for some cultivars that could have implications for plant breeders selecting at low plant densities. The implications for crop ideotypes of the individual plant characters at the 'optimum' population are also discussed. Interactions between cultivars and plant populations implied that some cultivars required different populations to achieve maximum yields in some seasons. There was a tendency for larger yields to be achieved from cultivar x season combinations where the optimum population was larger, which suggested that commercial seed rates should be re-examined when changes to plant types or yield levels are made.


2018 ◽  
Vol 10 (4) ◽  
pp. 308-314
Author(s):  
M. Nankova ◽  
A. Atanasov

Abstract. During 2014–2017, the influence of some main agronomy factors on the size of the resultant agronomic effect from their application to contemporary common winter wheat cultivars was investigated. The study was carried out in the experimental field (Haplic Chernozems soil type) of Dobrudzha Agricultural Institute – General Toshevo. The trial was designed by the split plot method, in four replications, on harvest area of 12m2. Cultivars Sadovo 1, Pryaspa, Kami, Kalina, Kiara, Kossara and Katarjina were grown after winter oilseed rape, spring pea, sunflower and grain maize at four levels of nutrition regime. The nutrition regime was differentiated depending on the previous crop. After spring pea, 30, 60 and 90 kg N/ha were used, and after the rest of the previous crops – 60, 120 and 180 kg N/ha. With the exception of the check variant all fertilizer variants were against background fertilization with 60 kg P2O5/ha and 60 kg K2O/ha. The positive reaction from the complex interaction of the tested agronomy factors was best expressed in 2015 – 2409.2 kg/ha, while during the extremely unfavorable year 2016, the effect was only 628.2 kg/ha. The independent and combined action of the mineral fertilization and the year conditions had determining influence on the size of the agronomic effect (AE). The positive effect from the mineral fertilization on the values of AE was accompanied by slight differentiation between the tested fertilization norms. Within this study, the highest mean value of AE was determined after fertilization with N180P60K60 – 2274.2 kg/ha. The variation in the mean size of AE depending on the type of previous crop was high – from 900.6 kg/ha (pea) to 2031.2 kg/ha (oilseed rape). The applied agronomy practices caused differentiation in the mean values of AE according to the type of cultivar. The cultivars Kiara (1796.1 kg/ha) and Kalina (1704.5 kg/ha) were with the highest size of AE. They exceeded the AE values of the two standard cultivars Sadovo 1 and Pryaspa by 30.26% and 23.62%, respectively. Averaged for the research, it was found that AE was in positive statistically significant correlation with grain yield and its physical properties.


2010 ◽  
Vol 61 (10) ◽  
pp. 852 ◽  
Author(s):  
Heping Zhang ◽  
Neil C. Turner ◽  
Michael L. Poole

Grain yield depends on the number of grains per unit area (sink) and the availability of assimilates (source) to fill these grains. The aim of the current work was to determine whether wheat yield in the high-rainfall zone of south-western Australia is limited in current cultivars by the size of the sink or by the assimilates available for grain filling. Three wheat cultivars (Calingiri, Chara and Wyalkatchem) and two breeding lines (HRZ216 and HRZ203) were grown in four replicates in the field from 2005 to 2007. Dry matter and water soluble carbohydrates (WSC) at anthesis and maturity were measured and used to determine the source and sink balance of the crop. In 2007, three further treatments were applied to manipulate the sink–source relationships: (i) spikelets were removed on main stems to increase the source : sink ratio; (ii) incoming solar radiation was reduced by 40% by shading after anthesis to reduce the availability of assimilates to grains; and (iii) supplemental irrigation was used to maintain the capacity for photosynthesis by an improved water supply during grain filling. The source–sink balance of the crops showed that the potential source was 25% greater than the actual grain yield in average and above-average seasons (2005 and 2007), suggesting that sink size, represented by the number of grain per unit area, was a limiting factor to yield potential. However, the source may have become a limiting factor in a drought season (2006). The grain yield increased with increased number of grains/m2 and kernel weight remained relatively stable even when grain number increased from 7000 to 16 000 per m2. The removal of half of the spikelets on the main stem did not increase kernel mass of the remaining grains and an additional 33 mm of irrigation water did not increase grain yield, but significantly (P < 0.05) increased WSC left in stems and leaf sheaths at maturity. Shading after anthesis did not significantly reduce grain yield of the current cultivars Calingiri and Wyalkatchem, but it reduced grain yield by 23–25% (P < 0.05) in Chara and HRZ203. The source–sink balance over three seasons and three independent experiments in 2007 suggested that the yield of the current wheat cultivars is more sink- than source-limited and that breeding wheat with a larger sink size than in the current cultivars may lift the yield potential of wheat in the high-rainfall zone of south-western Australia.


Author(s):  
Haitham A. Ali ◽  
Salih Hadi Farhood AL-Salim ◽  
Ragheb Hadi A. AL-burky

A field experiment is conducted at Thi-Qar Province in AL-Shatra District located about 30 Km North AL-Nassiria City to study the response of three wheat Cultivars Triticum  aestivum L. to Growth regulators during 2014-2015 growing Season. The Cultivars are Latifia , AL-Rasheed and Iba 99. The growth regulators are Alga600, Atonik and Azomin32%. Factorial experiment in R.C.B.D.  with three replicates is used . The results showed that Iba 99  Cultivar gives the highest plant height , Spikes/m2 and grain yield , with a means 80.83 cm , 272.25 spike/m2 and 3.06 Ton/h) Respectively . Azomin32%  growth regulator gives the highest grain /spike , 1000 grain weight and grain yield , with a means 66.00 seed/spike ,43.55 gm , 272.33 spike/m2  respectively. In addition the interaction between Iba 99 Cultivar  and Azomin32% growth regulator gives the highest Leaf Area , number of grain/spike and grain yield with means 45.10 cm2 , 70.00 grain/spike and 3.16 ton/ha respectively.The combination treatment Iba 99 with Atonik growth regulator gives the highest number of spike/m2  with a mean 279.66 spike/m2  . In the other hand, the same cultivar with Atonik and Azomin32% gives the highest mean of grain yield with a amount 3.16 ton/ha.


1984 ◽  
Vol 64 (1) ◽  
pp. 25-30 ◽  
Author(s):  
J. A. IVANY ◽  
H. G. NASS

In field experiments at Charlottetown, P.E.I., five herbicides evaluated at two rates of application on eight spring wheat (Triticum aestivum L.) cultivars showed no effect on dry plant weight 20 days after treatment. Herbicide treatment with dicamba resulted in a greater number of deformed heads per plot compared with the untreated in 1980 and with all herbicides except diclofop-methyl in 1981. More deformed heads occurred with dicamba and the 2,4-D/mecoprop/dicamba mixture at the higher rate of application in 1981 than with the other herbicides and the lower rate of application. All cultivars had more deformed heads than the untreated control when treated with 2,4-D, dicamba and the 2,4-D/mecoprop/dicamba mixture in 1981. Neepawa and Dundas had more deformed heads than the other cultivars when treated with MCPA. Head deformation by herbicide treatment had no adverse effect on grain yield in this study.Key words: Spring wheat cultivars, herbicides, head deformation, 2,4-D, MCPA, dicamba, diclofop-methyl


2013 ◽  
Vol 58 (2) ◽  
pp. 147-152 ◽  
Author(s):  
Nemat A. Noureldin ◽  
H.S. Saudy ◽  
F. Ashmawy ◽  
H.M. Saed

2021 ◽  
Vol 923 (1) ◽  
pp. 012089
Author(s):  
Al-Burki Fouad Razzaq A. ◽  
Mohsin Haider Abdulhussein ◽  
Sarheed Abdullah F.

Abstract A field experiment was carried out in Samawa desert (70 km west of Samawa city, Al-Muthanna governorate), during the 2018-2019 and 2019-2020 agricultural seasons, to study the response of three Iraqi cultivars of wheat (Tamooz2, Ibaa99, Abu Ghraib3) to three planting dates (November 15, 1st December and December 15) under Samawa desert conditions. The results showed the superiority of Tamooz2 cultivar in all traits of the yield components, it gave the highest averages of grain yield, which amounted 5.75 and 5.89 tons/ha−1, weight of 1000 grains, which amounted 29.79 and 31.06 gm, and the number of grains per spike, which amounted 73.02 and 73.76 for the 2019 and 2019-2020 seasons, respectively. The date of December 15th also surpassed in the traits of grain yield, weight of 1000 grains, number of spike grains, and the highest grain yield reached 5.62 and 5.58 tons/ha−1 for the two seasons 2018-2019 and 2019-2020, respectively, and the combination (Tamooz 2 x December 15) gave superiority over the other combinations in terms of grain yield which amounted 6.05 tons ha−1 (2018-2019 season) and Ibaa99 × December 1 gave the highest grian yield about 6.10 tons ha-1 (2019-2020 season).


1991 ◽  
Vol 71 (2) ◽  
pp. 361-371 ◽  
Author(s):  
C. A. Grant ◽  
L. E. Gauer ◽  
L. D. Bailey ◽  
D. T. Gehl

A 3-yr field experiment was conducted to evaluate the response of semi-dwarf and conventional height barley cultivars to N fertility. Six spring barley cultivars (one conventional height malting type, and two semidwarf, two conventional height, and one short feed type) were grown at three sites with nitrogen applications ranging from 0 to 200 kg ha−1. The 9 site-years of data were divided into three classes, low, moderate, and high, based on estimated moisture supply. Under low moisture conditions, grain yield response to applied N was low, but yield increased with applications to 200 kg ha−. Under moderate conditions, grain yield response to applied N was greater, but yield did not increase above 80 kg ha−1 of fertilizer N. No interaction was observed between barley cultivar and grain yield response to nitrogen under low or moderate moisture supply, although yields of Virden were higher than those of the other cultivars at most nitrogen levels. Under high moisture conditions, the feed barley cultivars showed a higher grain yield response to applied N than did the malting barley cultivar, Bonanza. The short-strawed cultivar, Heartland had a greater increase in yield with N application than the other cultivars. With a high moisture supply, yield of Bonanza did not increase with fertilizer N applications above 120 kg ha−1, while yield of the other cultivars was still increasing with application of 200 kg N ha−1. Differences among cultivars in grain response to N applications were largely due to differences in the harvest index. Key words: Nitrogen, barley (Hordeum vulgare), cultivar × N interaction, moisture


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