Plant Damage and Yield Response to the Russian Wheat Aphid (Homoptera: Aphididae) on Susceptible and Resistant Winter Wheats in Colorado

2003 ◽  
Vol 96 (2) ◽  
pp. 352-360 ◽  
Author(s):  
Terri L. Randolph ◽  
Frank B. Peairs ◽  
Mary K. Kroening ◽  
John S. Armstrong ◽  
Robert W. Hammon ◽  
...  
Keyword(s):  
Russian Wheat Aphid ◽  
Yield Response ◽  
Plant Damage

Damage and Yield Response of Wheat Lines with Dn4 and Dn7 Genes Resistant to Russian Wheat Aphid Biotype RWA21

2020 ◽  
Vol 45 (2) ◽  
pp. 369
Author(s):  
Darren M. Cockrell ◽  
Terri L. Randolph ◽  
Cynthia B. Walker ◽  
Rachael Sitz ◽  
Scott D. Haley ◽  
...  
Keyword(s):  
Russian Wheat Aphid ◽  
Yield Response ◽  
Wheat Lines

scholarly journals Influence of Three Resistance Sources in Winter Wheat Derived from TAM 107 on Yield Response to Russian Wheat Aphid

2005 ◽  
Vol 98 (2) ◽  
pp. 389-394 ◽  
Author(s):  
Terri L. Randolph ◽  
Frank B. Peairs ◽  
Michael Koch ◽  
Cynthia B. Walker ◽  
James S. Quick
Keyword(s):  
Winter Wheat ◽  
Russian Wheat Aphid ◽  
Yield Response ◽  
Resistance Sources

Yield Response and Categories of Resistance to Russian Wheat Aphid in Four Dn4 Hard Red Winter Wheat Cultivars

2005 ◽  
Vol 98 (2) ◽  
pp. 588-594 ◽  
Author(s):  
Terri L. Randolph ◽  
Frank B. Peairs ◽  
Michael Koch ◽  
Cynthia B. Walker ◽  
Jesse R. Stubbs ◽  
...  
Keyword(s):  
Winter Wheat ◽  
Russian Wheat Aphid ◽  
Yield Response ◽  
Wheat Cultivars ◽  
Hard Red Winter Wheat ◽  
Winter Wheat Cultivars ◽  
Red Winter Wheat

Yield Response to Russian Wheat Aphid (Homoptera: Aphididae) in Mixtures of Resistant and Susceptible Winter Wheats

2007 ◽  
Vol 32 (1) ◽  
pp. 7-15 ◽  
Author(s):  
Terri L. Randolph ◽  
Frank B. Peairs ◽  
Scott Merrill ◽  
Michael Koch ◽  
Cynthia B. Walker
Keyword(s):  
Russian Wheat Aphid ◽  
Yield Response

Wheat Genotype, Early Plant Growth Stage and Infestation Density Effects on Russian Wheat Aphid (Homoptera: Aphididae) Population Increase and Plant Damage

2000 ◽  
Vol 35 (1) ◽  
pp. 22-38 ◽  
Author(s):  
Nilsa A. Bosque-Pérez ◽  
Dennis J. Schotzko
Keyword(s):  
Plant Growth ◽  
Growth Stage ◽  
Initial Density ◽  
Russian Wheat Aphid ◽  
Reproductive Rate ◽  
Diuraphis Noxia ◽  
Population Increase ◽  
Growth Stages ◽  
Plant Damage ◽  
Aphid Density

Population increase of the Russian wheat aphid, Diuraphis noxia (Mordvilko) (Homoptera: Aphididae), and its effect on early plant growth and damage were studied under laboratory conditions on two winter wheat genotypes, susceptible ‘Stephens’ and resistant 10085-5. Three early plant growth stages (one-, two-, and three-leaf stage), and three insect densities (0, 5 and 20 aphids per plant) were compared. Insect counts, plant damage assessments, plant height, leaf number and dry weight measurements were made. Diuraphis noxia population increase was greater on ‘Stephens’ than on 10085-5, but this was highly influenced by plant growth stage at time of infestation and initial aphid density. Host quality of ‘Stephens’ decreased rapidly when plants were infested at the 1 -left stage, especially with the high initial density (20 aphids), resulting in low aphid population increase. For all plant developmental stages and genotypes, D. noxia per capita population increase was lower at initial densities of 20 compared to 5 aphids per plant, probably due to a density-dependent reduction in reproductive rate associated with a reduction in host-plant quality and/or crowding. Diuraphis noxia significantly affected plant growth, but the magnitude of the effect was influenced by genotype. In general, susceptible ‘Stephens’ had significantly more damage and a greater reduction in growth than resistant 10085-5.

Responses of soybean genotypes to intercropping with maize in the Southern Guinea Savanna, Nigeria

2004 ◽  
Vol 52 (2) ◽  
pp. 157-163
Author(s):  
C. U. Egbo ◽  
M. A. Adagba ◽  
D. K. Adedzwa
Keyword(s):  
Seed Yield ◽  
Block Design ◽  
Field Trials ◽  
Yield Response ◽  
Ecological Zone ◽  
Land Equivalent Ratio ◽  
Guinea Savanna ◽  
Days To Maturity ◽  
Soybean Genotypes ◽  
Location Interaction

Field trials were conducted in the wet seasons of 1997 and 1998 at Makurdi, Otukpo and Yandev in the Southern Guinea Savanna ecological zone of Nigeria to study the responses of ten soybean genotypes to intercropping. The experiment was laid out in a randomised complete block design. The genotypes TGX 1807-19F, NCRI-Soy2, Cameroon Late and TGX 1485-1D had the highest grain yield. All the Land Equivalent Ratio (LER) values were higher than unity, indicating that there is great advantage in intercropping maize with soybean. The yield of soybean was positively correlated with the days to 50% flowering, days to maturity, plant height, pods/plant and leaf area, indicating that an improvement in any of these traits will be reflected in an increase in seed yield. There was a significant genotype × yield × location interaction for all traits. This suggests that none of these factors acted independently. Similarly, the genotype × location interaction was more important than the genotype × year interaction for seed yield, indicating that the yield response of the ten soybean genotypes varied across locations rather than across years. Therefore, using more testing sites for evaluation may be more important than the number of years.

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