HARVEST INDEX AS A SELECTION CRITERION FOR GRAIN YIELD IN TWO SPRING WHEAT CROSSES GROWN AT TWO POPULATION DENSITIES

1980 ◽  
Vol 60 (4) ◽  
pp. 1141-1146 ◽  
Author(s):  
H. G. NASS
Keyword(s):  
Population Density ◽  
Grain Yield ◽  
Spring Wheat ◽  
Harvest Index ◽  
Plant Density ◽  
Selection Criterion ◽  
Triticum Aestivum L ◽  
Wheat Breeding ◽  
Seeding Rate ◽  
Population Densities

The use of harvest index as a selection criterion for grain yield in F2 populations of spring wheat (Triticum aestivum L.) grown at two population densities was investigated. Harvest index was useful in delineating yield differences between lines for both crosses. The F4 lines selected in F2 for a high harvest index yielded about 9% more per plot in 1978 than F4 lines having a low harvest index in F2. Generally, lines selected at the higher commercial seeding rate yielded more than lines selected at the lower plant density. In 1979, a heavy Fusarium infection reduced the mean grain yield of the F6 lines and suppressed any significant response to selection resulting from population density and harvest index in F2. While selection based on high harvest index at low population density can be used to select higher yielding plants it was not as effective as selection at high population density which more closely approximates commercial crop densities. Additional research is needed before the use of harvest index as a selection tool in wheat breeding programs can be recommended for use in Atlantic Canada.

EFFECT OF SEEDING RATE ON GRAIN YIELD, STRAW YIELD AND HARVEST INDEX OF EIGHT SPRING WHEAT CULTIVARS

1982 ◽  
Vol 62 (2) ◽  
pp. 285-291 ◽  
Author(s):  
R. J. BAKER
Keyword(s):  
Triticum Aestivum ◽  
Grain Yield ◽  
Spring Wheat ◽  
Linear Response ◽  
Harvest Index ◽  
Triticum Aestivum L ◽  
Wheat Cultivars ◽  
Seeding Rate ◽  
Straw Yield ◽  
Rate Interaction

Eight cultivars of spring wheat, Triticum aestivum L., were evaluated at seeding rates of 110, 270 and 430 seeds/m2 in a total of nine experiments spanning three locations, two dates of seeding and 2 yr. Grain yield exhibited a significant cultivar × experiment × linear response to seeding rate interaction. Grain yield of Pitic 62 showed a significant decrease with increased seeding rate in one experiment while giving the greatest increase in another. Over all experiments, the highest seeding rate gave the highest grain yield. For straw yield, Chester showed the greatest response to seed rate, Canuck the least. With the exception of Canuck, which showed a significant increase in harvest index with increased seeding rate, harvest index tended to be greater at the intermediate seeding rate.

Grain Yield Gains and Associated Traits in Tropical X Temperate Maize Germplasm Under High and Low Plant Density

2021 ◽  
Author(s):  
Vince Ndou ◽  
Edmore Gasura ◽  
Pauline Chivenge ◽  
John Derera
Keyword(s):  
Population Density ◽  
Grain Yield ◽  
Plant Density ◽  
Plant Population ◽  
Population Densities ◽  
Genetic Gains ◽  
Maize Germplasm ◽  
High Plant Density ◽  
Number Of Leaves ◽  
Plant Population Density

Abstract Development of ideal breeding and crop management strategies that can improve maize grain yield under tropical environments is crucial. In the temperate regions, such yield improvements were achieved through use of genotypes that adapt high plant population density stress. However, tropical germplasm has poor tolerance to high plant population density stress, and thus it should be improved by temperate maize. The aim of this study was to estimate the genetic gains and identify traits associated with such gains in stable and high yielding temperate x tropical hybrids under low and high plant population densities. A total of 200 hybrids derived from a line x tester mating design of tropical x temperate germplasm were developed. These hybrids were evaluated for grain yield and allied traits under varied plant population densities. High yielding and stable hybrids, such as 15XH214, 15XH215 and 15XH121 were resistant to lodging and had higher number of leaves above the cob. The high genetic gains of 26% and desirable stress tolerance indices of these hybrids made them better performers over check hybrids under high plant population density. At high plant population density yield was correlated to stem lodging and number of leaves above the cob. Future gains in grain yield of these hybrids derived from temperate x tropical maize germplasm can be achieved by exploiting indirect selection for resistance to stem lodging and increased number of leaves above the cob under high plant density conditions.

Effect of wheat seeding rate on wild oat competition

1980 ◽  
Vol 20 (102) ◽  
pp. 77 ◽  
Author(s):  
BJ Radford ◽  
BJ Wilson ◽  
O Cartledge ◽  
FB Watkins
Keyword(s):  
Population Density ◽  
Grain Yield ◽  
Dry Weight ◽  
Field Trials ◽  
Wild Oat ◽  
Seeding Rate ◽  
Population Densities ◽  
Wild Oats ◽  
Wheat Population ◽  
A Site

A series of field trials was sown on black earth soils on the Darling Downs, Queensland, with five wheat seeding rates x five levels of wild oat infestation. The lowest seeding rate required to produce optimum grain yield at a site was higher in wild oat infested plots than in weed-free plots. Increase in seeding rate reduced the dry weight of wild oats at maturity and increased the dry weight of wheat at maturity until wheat population density exceeded 150 plants m-2. Increase in seeding rate also reduced wild oat seed production, especially at low wild oat population densities.

Wheat seeding rate for spread and distinct row seed placement with air seeders

2001 ◽  
Vol 81 (4) ◽  
pp. 885-890 ◽  
Author(s):  
Adrian M. Johnston ◽  
F. Craig Stevenson
Keyword(s):  
Triticum Aestivum ◽  
Grain Yield ◽  
Spring Wheat ◽  
Triticum Aestivum L ◽  
Yield Potential ◽  
Row Spacing ◽  
N Availability ◽  
Seeding Rate ◽  
Hard Red Spring Wheat ◽  
Seed Placement

Air (pneumatic) seeding systems that have seed row opener options that spread seed rather than place it in distinct rows may allow producers to uniformly distribute plants and increase seeding rates to improve cereal crop yield. A study was conducted to determine if seed placement configuration influenced hard red spring wheat (Triticum aestivum L.) response to seeding rate. The study was carried out at Melfort, SK, from 1997 to 1999, using three seed configurations (23 cm and 30 cm distinct row with a hoe opener; and a 20 cm spread using a 28 cm sweep on 23 cm row spacing) and four seeding rates (67, 100, 134, and 167 kg ha–1). Grain yield increased 6% when seeding rate was increased from 100 (recommended rate) to 168 kg ha–1 in 1997. Improved grain yield with increased seeding rates was related to greater kernels head–1. In the 2 following years, yield decreased by 9% when seeding rate was increased from 100 to 168 kg ha–1. Yield reductions in these years were associated with high yield potential (high soil N availability) and lodging, that in turn resulted in decreased kernels head–1 and kernel weight with increased seeding rates. Grain yield did not differ between the sweep and distinct rows, regardless of the seeding rate. Furthermore, the similar yields among the three seed configurations occurred despite lodging being less with sweeps compared with 23 or 30 cm row spacing at the highest seeding rate in 1998. The increased distance between wheat plants with sweeps did not improve grain yields as a result of reduced inter-plant competition, regardless of seeding rate. This absence of grain yield differences between the sweep and distinct row placement illustrates the yield stability associated with Canadian hard red spring wheat cultivars through yield component compensation. Key words: Wheat (Triticum aestivum L.), row spacing, seeding rate, lodging, seed placement

scholarly journals Optimal Agronomics Increase Grain Yield and Grain Yield Stability of Ultra-Early Wheat Seeding Systems

Agronomy ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 240
Author(s):  
Graham R. S. Collier ◽  
Dean M. Spaner ◽  
Robert J. Graf ◽  
Brian L. Beres
Keyword(s):  
Grain Yield ◽  
Great Plains ◽  
Spring Wheat ◽  
Ambient Air ◽  
Triticum Aestivum L ◽  
Yield Stability ◽  
Northern Great Plains ◽  
Seeding Rate ◽  
Soil Temperatures ◽  
The Impact

Ultra-early seeding of spring wheat (Triticum aestivum L.) on the northern Great Plains can increase grain yield and grain yield stability compared to current spring wheat planting systems. Field trials were conducted in western Canada from 2015 to 2018 to evaluate the impact of optimal agronomic management on grain yield, quality, and stability in ultra-early wheat seeding systems. Four planting times initiated by soil temperature triggers were evaluated. The earliest planting was triggered when soils reached 0–2.5 °C at a 5 cm depth, with the subsequent three plantings completed at 2.5 °C intervals up to soil temperatures of 10 °C. Two spring wheat lines were seeded at each planting date at two seeding depths (2.5 and 5 cm), and two seeding rates (200 and 400 seeds m−2). The greatest grain yield and stability occurred from combinations of the earliest seeding dates, high seeding rate, and shallow seeding depth; wheat line did not influence grain yield. Grain protein content was greater at later seeding dates; however, the greater grain yield at earlier seeding dates resulted in more protein production per unit area. Despite extreme ambient air temperatures below 0 °C after planting, plant survival was not reduced at the earliest seeding dates. Planting wheat as soon as feasible after soil temperatures reach 0 °C, and prior to soils reaching 7.5–10 °C, at an optimal seeding rate and shallow seeding depth increased grain yield and stability compared to current seeding practices. Adopting ultra-early wheat seeding systems on the northern Great Plains will lead to additional grain yield benefits as climate change continues to increase annual average growing season temperatures.

scholarly journals A STUDY OF ANCESTRAL AND MODERN CANADIAN SPRING WHEATS

1987 ◽  
Vol 67 (1) ◽  
pp. 87-97 ◽  
Author(s):  
P. HUCL ◽  
R. J. BAKER
Keyword(s):  
Grain Yield ◽  
Spring Wheat ◽  
Harvest Index ◽  
Negative Impact ◽  
Wheat Yield ◽  
Triticum Aestivum L ◽  
Kernel Weight ◽  
Environment Interaction ◽  
Canadian Prairie ◽  
Spike Number

Spring wheat cultivars (Triticum aestivum L.) representing a century of crop breeding effort were evaluated in three rain-fed environments to determine which yield-related traits have been altered over time. Plant height and the length of the vegetative growth phase were shortened during the pre-Thatcher era. Spikelet number has been reduced but kernel weight increased during the period of cultivar development discussed herein. Tiller production has changed little since the turn of the century while spike number has been reduced slightly in the post-Thatcher period. Harvest indices increased with the introduction of Thatcher, but neither that trait nor crop grain yield have undergone consistent improvements since the 1930s. A significant cultivar × environment interaction resulted from adverse environment having a greater negative impact on grain yield of the older cultivars Red Fife and Marquis relative to their descendents. HY320, representing a potential new market class (Canadian Prairie Spring), yielded 25% more than standard height cultivars due to a higher biological yield and harvest index. Crop and spike grain yields were associated with kernel number/spike (r = 0.78,0.75) and days to spike emergence (r = 0.50,0.55), suggesting that high grain yield in this material is a function of maturity-dependent kernel production. Future improvements in grain yield might result from selection for higher harvest index since the latter trait is positively correlated with yield (r = 0.63) but not associated with maturity (−0.17).Key words: Old cultivars, spring wheat, yield components, harvest index, cultivar × environment interaction

Comparison of a branched spike wheat with the cultivars Neepawa and HY320 for grain yield and yield components

1992 ◽  
Vol 72 (3) ◽  
pp. 671-677 ◽  
Author(s):  
P. Hucl ◽  
B. J. Fowler
Keyword(s):  
Grain Yield ◽  
Spring Wheat ◽  
Yield Components ◽  
Triticum Turgidum ◽  
Triticum Aestivum L ◽  
Kernel Weight ◽  
High Yield ◽  
Seeding Rate ◽  
Higher Plant ◽  
Branched Spike

Branched-spike spring wheat (Triticum turgidum L.) genotypes are periodically promoted in western Canada as having very high grain yield capacity. These "Miracle" wheats tend to have a low tillering capacity and may require higher plant populations in order to achieve maximum grain yield. This study was conducted to critically evaluate the high-yield claims of a branched-spike wheat (BSW) and to determine whether this cultivar has a higher optimum seeding rate requirement than the spring wheat (Triticum aestivum L.) cultivars Neepawa and HY320. The three cultivars were seeded at rates of 150, 250, 350, 450, and 550 seeds m−2 in each of three experiments: two dryland and one irrigated. Averaged over experiments and seeding rates the BSW yielded 45% less than the conventional cultivars. Significant (P < 0.05) cultivar × experiment cross-overs were detected for spikes m−2, spikelets spike−1, and kernels spike−1. BSW and HY320 switched ranks for spikes m−2, spikelets spike−1 and kernels spike−1 in 1988 and 1989. In 1988, on average, BSW produced 230% as many fertile spikelets as the other cultivars, but 40% fewer spikelets in 1989. Similarly, BSW produced more kernels spike−1 than Neepawa and HY320 in 1988 while the reverse was observed in 1989. The three cultivars responded differently to seeding rate, as indicated by significant (P < 0.01) cultivar × seeding rate interaction for spikelets spike−1 and kernel weight. Neither of these interactions involved significant changes in cultivar rank from one seeding rate to the next. BSW yielded less grain than either Neepawa or HY320, regardless of seeding rate. Attempts to increase the grain yield of a BSW cultivar by manipulating yield components via increased seeding rates were not successful.Key words: Branched-spike, spring wheat, seeding rate, Triticum turgidum L.

Spring wheat seed size and seeding rate effects on yield loss due to wild oat (Avena fatua) interference

Weed Science ◽  
2004 ◽  
Vol 52 (1) ◽  
pp. 133-141 ◽  
Author(s):  
Robert N. Stougaard ◽  
Qingwu Xue
Keyword(s):  
Grain Yield ◽  
Seed Size ◽  
Spring Wheat ◽  
Plant Density ◽  
Cropping System ◽  
Wild Oat ◽  
Wheat Seed ◽  
Seeding Rate ◽  
Cereal Grain ◽  
Rate Effects

The development of competitive cropping systems could minimize the negative effects of wild oat competition on cereal grain yield, and in the process, help augment herbicide use. A 3-yr field experiment was conducted at Kalispell, MT, to investigate the effects of spring wheat seed size and seeding rate on wheat spike production, biomass, and grain yield under a range of wild oat densities. Wheat plant density, spikes, biomass, and yield all increased as seed size and seeding rates increased. Averaged across all other factors, the use of higher seeding rates and larger seed sizes improved yields by 12 and 18%, respectively. Accordingly, grain yield was more highly correlated with seed size than with seeding rate effects. However, the combined use of both tactics resulted in a more competitive cropping system, improving grain yields by 30%. Seeding rate effects were related to spike production, whereas seed size effects were related to biomass production. As such, plants derived from large seed appear to have greater vigor and are able to acquire a larger share of plant growth factors relative to plants derived from small seed.

EFFECTIVENESS OF SEVERAL SELECTION METHODS FOR GRAIN YIELD IN TWO F2 POPULATIONS OF SPRING WHEAT

1983 ◽  
Vol 63 (1) ◽  
pp. 61-66 ◽  
Author(s):  
H. G. NASS
Keyword(s):  
Grain Yield ◽  
Spring Wheat ◽  
Harvest Index ◽  
Triticum Aestivum L ◽  
Selection Method ◽  
Random Selection ◽  
Selection Methods ◽  
Yield Performance ◽  
Head Weight ◽  
Selection Of

Visual head selection by three selectors, head weight, harvest index, and random selection were evaluated for selecting high-yielding plants in two F2 populations of spring wheat (Triticum aestivum L.). Forty F2 lines of two crosses for each selection method were evaluated for yield performance in F4 during 2 yr. There was no advantage of any of the selection methods over random selection in the lower-yielding cross 1 and no advantage of the harvest index and head weight methods over visual selection in both crosses. Visual head selection produced more late-heading, tall plants, and was the most effective method in selecting for yield in cross 2. Harvest index tended towards the selection of lines with short height in cross 2. A larger number of the top 15% of F4 lines were from the high yielding cross 2, and selectors 1 and 2 chose the greatest number of superior lines.Key words: Selection methods, head weight, harvest index, grain yield, spring wheat, visual head selection.

Canopy apparent photosynthesis, respiration and yield in wheat

1994 ◽  
Vol 122 (1) ◽  
pp. 7-12 ◽  
Author(s):  
Dong Shuting
Keyword(s):  
Population Density ◽  
Grain Yield ◽  
Field Experiments ◽  
Plant Density ◽  
Growth Period ◽  
Grain Filling ◽  
Plant Population ◽  
Population Densities ◽  
Area Index ◽  
Chamber Volume

SUMMARYField experiments explored the relationship between canopy apparent photosynthesis (CAP) and grain yield and examined the effect of plant population density on CAP. Two cultivars of wheat were grown at five plant population densities in 1986 and 1987 in Taian, China. Measurements of CAP were made at intervals during the growth period by placing a large plastic-covered chamber over a 0·7 m2 segment of the canopy and measuring CO2 depletion with infra-red gas analysers for 1–2 min at c. 25 °C around noon when solar radiation was > 1100 umol/m2/s. Canopy respiration (CR) rates were measured by covering the whole chamber with a black screen in the daytime. Calculations of CAP and CR were made using the chamber volume, air temperature and changes in CO2 concentration over time and expressed on a land area basis.Maximum values of CAP and CR were 4–6 g and 2–3 g CO2/m2/h, respectively, at the anthesis stage, decreasing with age during grain filling. The decrease was more rapid at the high than at the low population density. The difference in CAP between plant densities before booting and after anthesis could be attributed to reductions in leaf area index (LAI) and photosynthetic rate.Grain yield also differed between plant population densities, the range being from 5250 to 7500 kg/ha in both years. Grain yield and 1000-grain weight were positively correlated with CAP during grain filling (r = 0·78 and 0·99, P < 0·01, 8 D.F.). Effects of plant density on CR were highly significant, but CR was not related to yield (r = 0·50).

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