دوشنبه دوازدهم اسفند 1387

مطلب (1)

Cover

Current Issue:
January-February 2009
 
 
Selected Abstracts 
Returned: 32 citations and abstracts. Click on down arrow or scroll to see abstracts.

down H. Arnold Bruns
A Survey of Factors Involved in Crop Maturity
Agron. J. 101: 60-66.

down Nirit Bernstein, David Chaimovitch, and Nativ Dudai
Effect of Irrigation with Secondary Treated Effluent on Essential Oil, Antioxidant Activity, and Phenolic Compounds in Oregano and Rosemary
Agron. J. 101: 1-10.

down Claudia Arrieta, Philip Busey, and Samira H. Daroub
Goosegrass and Bermudagrass Competition under Compaction
Agron. J. 101: 11-16.

down L. Barton, G. G. Y. Wan, R. P. Buck, and T. D. Colmer
Nitrogen Increases Evapotranspiration and Growth of a Warm-Season Turfgrass
Agron. J. 101: 17-24.

down L. Barton, G. G. Y. Wan, R. P. Buck, and T. D. Colmer
Effectiveness of Cultural Thatch-Mat Controls for Young and Mature Kikuyu Turfgrass
Agron. J. 101: 67-74.

down Christian M. Baldwin, Haibo Liu, Lambert B. McCarty, Hong Luo, and Joe E. Toler
Nitrogen and Plant Growth Regulator Influence on ‘Champion’ Bermudagrass Putting Green under Reduced Sunlight
Agron. J. 101: 75-81.

down Nathan B. O'Berry, Joel C. Faircloth, Michael A. Jones, David A. Herbert, Jr., Azenegashe O. Abaye, Thomas E. McKemie, and Cavell Brownie
Differential Responses of Cotton Cultivars when Applying Mepiquat Pentaborate
Agron. J. 101: 25-31.

down Shawn P. Conley, Palle Pedersen, and Ellsworth P. Christmas
Main-Stem Node Removal Effect on Soybean Seed Yield and Composition
Agron. J. 101: 120-123.

down Jason L. De Bruin, and Palle Pedersen
Growth, Yield, and Yield Component Changes among Old and New Soybean Cultivars
Agron. J. 101: 124-130.

down Andrew P. Robinson, Shawn P. Conley, Jeffrey J. Volenec, and Judith B. Santini
Analysis of High Yielding, Early-Planted Soybean in Indiana
Agron. J. 101: 131-139.

down Michael E. Copas, Alvin J. Bussan, Michael J. Drilias, and Richard P. Wolkowski
Potato Yield and Quality Response to Subsoil Tillage and Compaction
Agron. J. 101: 82-90.

down Alpha Y. Kamara, Friday Ekeleme, David Chikoye, and Lucky O. Omoigui
Planting Date and Cultivar Effects on Grain Yield in Dryland Corn Production
Agron. J. 101: 91-98.

down P. J. Hodgen, R. B. Ferguson, J. F. Shanahan, and J. S. Schepers
Uptake of Point Source Depleted 15N Fertilizer by Neighboring Corn Plants
Agron. J. 101: 99-105.

down X. M. Fan, Y. M. Zhang, W. H. Yao, H. M. Chen, J. Tan, C. X. Xu, X. L. Han, L. M. Luo, and M. S. Kang
Classifying Maize Inbred Lines into Heterotic Groups using a Factorial Mating Design
Agron. J. 101: 106-112.

down P. A. Counce, K. B. Watkins, K. R. Brye, and T. J. Siebenmorgen
A Model to Predict Safe Stages of Development for Rice Field Draining and Field Tests of the Model Predictions in the Arkansas Grand Prairie
Agron. J. 101: 113-119.

down Carlos A. C. Crusciol, and Rogério P. Soratto
Nitrogen Supply for Cover Crops and Effects on Peanut Grown in Succession under a No-Till System
Agron. J. 101: 41-46.

down Nathan S. Boyd, Eric B. Brennan, Richard F. Smith, and Ron Yokota
Effect of Seeding Rate and Planting Arrangement on Rye Cover Crop and Weed Growth
Agron. J. 101: 47-51.

down J. C. Burns, M. G. Wagger, and D. S. Fisher
Animal and Pasture Productivity of ‘Coastal’ and ‘Tifton 44’ Bermudagrass at Three Nitrogen Rates and Associated Soil Nitrogen Status
Agron. J. 101: 32-40.

down R. L. Baumhardt, R. C. Schwartz, L. W. Greene, and J. C. MacDonald
Cattle Gain and Crop Yield for a Dryland Wheat-Sorghum-Fallow Rotation
Agron. J. 101: 150-158.

down Zhenling Cui, Fusuo Zhang, Zhengxia Dou, Miao Yuxin, Qinping Sun, Xinping Chen, Junliang Li, Youliang Ye, Zhiping Yang, Qiang Zhang, Chunsheng Liu, and Shaomin Huang
Regional Evaluation of Critical Nitrogen Concentrations in Winter Wheat Production of the North China Plain
Agron. J. 101: 159-166.

down Gregg R. Sanford, Amy R. Cook, Josh L. Posner, Janet L. Hedtcke, John A. Hall, and Jon O. Baldock
Linking Wisconsin Dairy and Grain Farms via Manure Transfer for Corn Production
Agron. J. 101: 167-174.

down Edgar A. Po, Sieglinde S. Snapp, and Alexandra Kravchenko
Rotational and Cover Crop Determinants of Soil Structural Stability and Carbon in a Potato System
Agron. J. 101: 175-183.

down D. M. Burner, D. H. Pote, and D. P. Belesky
Effect of Loblolly Pine Root Pruning on Alley Cropped Herbage Production and Tree Growth
Agron. J. 101: 184-192.

down Jeffrey T. Baker, Scott Van Pelt, Dennis C. Gitz, Paxton Payton, Robert Joseph Lascano, and Bobbie McMichael
Canopy Gas Exchange Measurements of Cotton in an Open System
Agron. J. 101: 52-59.

down Axel Garcia y Garcia, Larry C. Guerra, and Gerrit Hoogenboom
Impact of Planting Date and Hybrid on Early Growth of Sweet Corn
Agron. J. 101: 193-200.

down Graig Reicks, Howard J. Woodard, and Anthony Bly
Improving the Fermentation Characteristics of Corn through Agronomic and Processing Practices
Agron. J. 101: 201-206.

down Judith Nyiraneza, Martin H. Chantigny, Adrien N'Dayegamiye, and Marc R. Laverdière
Dairy Cattle Manure Improves Soil Productivity in Low Residue Rotation Systems
Agron. J. 101: 207-214.

down B. R. Ball Coelho, R. C. Roy, A. J. Bruin, A. More, and P. White
Zonejection: Conservation Tillage Manure Nutrient Delivery System
Agron. J. 101: 215-225.

down Rachid Drissi, Jean-Pascal Goutouly, Dominique Forget, and Jean-Pierre Gaudillere
Nondestructive Measurement of Grapevine Leaf Area by Ground Normalized Difference Vegetation Index
Agron. J. 101: 226-231.

down Darrin F. Roberts, Viacheslav I. Adamchuk, John F. Shanahan, Richard B. Ferguson, and James S. Schepers
Optimization of Crop Canopy Sensor Placement for Measuring Nitrogen Status in Corn
Agron. J. 101: 140-149.

down Dennis C. Gitz, and Jeffrey T. Baker
Methods for Creating Stomatal Impressions Directly onto Archivable Slides
Agron. J. 101: 232-236.

down Fred E. Below, Kateri A. Duncan, Martin Uribelarrea, and Thomas B. Ruyle
Occurrence and Proposed Cause of Hollow Husk in Maize
Agron. J. 101: 237-242.


Abstract 1 of 32 back

REVIEW & INTERPRETATION

A Survey of Factors Involved in Crop Maturity

H. Arnold Bruns*

USDA-ARS, Crop Genetics and Production Research Unit, Box 345, Stoneville, MS 38776. Trade names are used in this publication solely for the purpose of providing specific information. Mention of a trade name, proprietary product, or specific equipment does not constitute a guarantee or warranty by the USDA-ARS and does not imply approval of the named product to the exclusion of other similar products

* Corresponding author (arnold.bruns@ars.usda.gov ).

The time necessary for crops to successfully complete reproduction is species and environment dependent. Lifecycles can be completed in a few weeks or take several years depending on the plant species. Crop development is divided into phenophases that are affected primarily by light and temperature changes, interacting with phytohormones. Some species are influenced more by light and others by temperature. This review focuses on factors that influence maturation in several important agronomic crops.

Abbreviations: DNP, day-neutral plant • GDD, growing degree day • GDU, growing degree unit • LDP, long-day plant • MG, maturity group • Pfr, phytochrome far-red • Pr, phytochrome red • SDP, short-day plant

All rights reserved. No part of this periodical may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying, recording, or any information storage and retrieval system, without permission in writing from the publisher.

Received for publication August 13, 2007.

[Full Text of Bruns] [Reprint (PDF) Version of Bruns]


Abstract 2 of 32 back

AROMATIC PLANTS

Effect of Irrigation with Secondary Treated Effluent on Essential Oil, Antioxidant Activity, and Phenolic Compounds in Oregano and Rosemary

Nirit Bernsteina, David Chaimovitchb and Nativ Dudaib,*

a Institute of Soil Water and Environmental Science, Volcani Center, POB 6, Bet-Dagan, 50-250, Israel
b Aromatic, Medicinal and Spice Crops, ARO, Newe Ya'ar Research Center, P.O. Box 1021, Ramat Yishay 30095, Israel

* Corresponding author (nativdud@agri.gov.il ).

Shortage of water throughout the world dictates utilization of marginal water for irrigation. Treated urban wastewater is a common alternative water source for irrigation in arid and semiarid regions. In this study we aimed to evaluate the effect of irrigation with secondary-treated effluent on plant development, essential oil yield, antioxidant activity and selected antioxidant phenolic compounds in two commercial cultivars of the aromatic species, oregano (Origanum vulgare L.) and rosemary (Rosmarinus officinalis L.). The applied treated effluent contained higher levels of Na, Cl, HCO3,–1 P, K, NH4+1, NO3–1, Ca+Mg, B, Mn, and Fe than the local potable water used as control, and were characterized by higher values of electrical conductivity (EC), pH, and sodium absorption ratio (SAR). Since effluent effects on plants can become apparent only following several years of exposure, the plants were exposed to the water treatments for 3 yr. Despite the differences in water quality, the effluent did not affect yield quantity and quality in either crop. Plant morphological development, biomass production, percent dry leaves of the total biomass, quantity and composition of the essential oil produced, antioxidant activity, and contents of selected antioxidant-phenolic compounds were not affected by irrigation with treated effluent compared with potable water. Our results demonstrate that both oregano and rosemary are suitable as industrial crops for essential oil and antioxidant production under irrigation with secondary-treated municipal effluent because their yield quantity and quality were not affected.

Abbreviations: DM, dry mass • EC, electrical conductivity • ROS, reactive oxygen species • SAR, sodium absorption ratio

All rights reserved. No part of this periodical may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying, recording, or any information storage and retrieval system, without permission in writing from the publisher.

Received for publication April 17, 2007.

[Full Text of Bernstein et al.] [Reprint (PDF) Version of Bernstein et al.]


Abstract 3 of 32 back

TURFGRASS

Goosegrass and Bermudagrass Competition under Compaction

Claudia Arrietaa, Philip Buseyb,* and Samira H. Daroubc

a 12148 Rist Canyon Rd., Bellvue, CO 80512
b Fort Lauderdale Res. Educ. Ctr., Univ. Florida, 3205 College Ave., Davie, FL 33314
c Everglades Res. Educ. Ctr. and Soil and Water Sci. Dep., Univ. Florida, 3200 E. Palm Beach Rd., Belle Glade, FL 33430

* Corresponding author (pbusey@turfgrass.com ).

Goosegrass (Eleusine indica L.) is a serious weed in trafficked areas of bermudagrass (Cynodon spp.) golf and sports turf. The objective of this study was to evaluate soil compaction and canopy cover as determinants of goosegrass competition in bermudagrass turf in sand soil. Goosegrass cover, plant density, and soil penetration resistance (SPR) were measured in traffic and no-traffic plots in bermudagrass golf course tees and sports field foul areas. Goosegrass plant density and cover were larger in traffic plots compared with no-traffic plots. Soil penetration resistance increased only at 5.0 cm depth due to traffic, while other soil properties including bulk density measured in golf course tees showed no effect from traffic. Two experiments measured the effect of controlled soil compaction on root and shoot dry weight of goosegrass and bermudagrass in containers. The first experiment evaluated effects of three soil compaction levels (1.14, 1.24, 1.33 g cm–3 bulk density) on goosegrass and bermudagrass grown separately. The second experiment evaluated effects on the two species grown together in competition, from two soil compaction levels (1.07 and 1.26 g cm–3 bulk density), two N application rates (48 and 96 kg ha–1 mo–1), and two mowing heights (1.3 and 2.5 cm). The second experiment also evaluated goosegrass seedling emergence and tiller numbers. When species were grown separately, bermudagrass root and shoot dry weight showed no effect from soil compaction, but goosegrass root weight was reduced. When species were grown together, bermudagrass root weight was reduced by compaction, but goosegrass was not affected. Goosegrass seedling emergence was reduced 58% by high mowing height, which paralleled an increase in bermudagrass canopy cover based on shoot dry weight. Canopy cover, not compaction, more readily explained the competition and infestation of goosegrass in trafficked areas in sand soil.

Abbreviations: SPR, soil penetration resistance

All rights reserved. No part of this periodical may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying, recording, or any information storage and retrieval system, without permission in writing from the publisher.

Received for publication August 20, 2007.

[Full Text of Arrieta et al.] [Reprint (PDF) Version of Arrieta et al.]


Abstract 4 of 32 back

TURFGRASS

Nitrogen Increases Evapotranspiration and Growth of a Warm-Season Turfgrass

L. Barton*, G. G. Y. Wan, R. P. Buck and T. D. Colmer

School of Plant Biology, Faculty of Natural and Agricultural Sciences, The University of Western Australia, 35 Stirling Highway, Crawley 6009, Western Australia, Australia

* Corresponding author (lbarton@cyllene.uwa.edu.au ).

The effect of N fertilizer rate on Kikuyu turfgrass [Pennisetum clandestinum (Hochst. ex Chiov)] evapotranspiration was evaluated during two summers. Evapotranspiration was measured using weighing lysimeters (205 mm in diameter by 625 mm in length) inserted in turfgrass field plots (10 m2). The experiment was a randomized plot design with three replicates. Treatments included two turfgrass ages (established from 20 wk or 20-yr-old turfgrass) and three N application rates (0, 50, or 150 kg N ha–1 yr–1). Evapotranspiration ranged from 2.8 to 7.5 mm d–1 (or 56–81% of evaporative demand), and varied with daily evaporative demand, turfgrass age, and N fertilizer rate. The older turfgrass used more water than the younger turfgrass during both summers; while increasing the N application rate also increased evapotranspiration for both turfgrass types (younger turfgrass only in the second summer). Evapotranspiration was positively correlated with turfgrass growth (r2 = 0.74–0.80) and transpiring leaf area (r2 = 0.78). Older turfgrass at all N treatments, and the younger turfgrass receiving 150 kg N ha–1 yr–1, had adequate growth, color, and leaf N concentrations. Optimizing fertilizer applications such that the minimum N required to maintain turfgrass quality is applied, is an approach for decreasing water consumption by turfgrass.

Abbreviations: ET, evapotranspiration

All rights reserved. No part of this periodical may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying, recording, or any information storage and retrieval system, without permission in writing from the publisher.

Received for publication March 13, 2008.

[Full Text of Barton et al.] [Reprint (PDF) Version of Barton et al.]


Abstract 5 of 32 back

TURFGRASS

Effectiveness of Cultural Thatch-Mat Controls for Young and Mature Kikuyu Turfgrass

L. Barton*, G. G. Y. Wan, R. P. Buck and T. D. Colmer

School of Plant Biology, Faculty of Natural and Agricultural Sciences, The Univ. of Western Australia, 35 Stirling Hwy., Crawley 6009, Western Australia, Australia

* Corresponding author (lbarton@cyllene.uwa.edu.au ).

Excessive thatch and mat can be detrimental to turfgrass health and management. Mechanical and topdressing techniques to reduce accumulation of thatch and mat were evaluated in a 24-mo field study of kikuyu [Pennisetum clandestinum (Hochst. ex Chiov.)] turfgrass of two contrasting organic matter (OM) contents in the surface 50 mm of soil. Treatments included two kikuyugrass ages (established from 20 wk or 20-yr-old kikuyugrass) and five renovation techniques (none, verticutting, coring, topdressing with sand, coring + topdressing). The renovation techniques varied in effectiveness depending on the initial OM content of the soil immediately underlying the kikuyugrass. Annual verticutting, or twice annual topdressing with or without annual coring a young kikuyugrass were most successful at restricting the accumulation of soil OM (P < 0.05), with OM content <3.5% by 24 mo. Twice annual topdressing with or without annual coring, most rapidly decreased soil OM in the mature kikuyugrass (P < 0.05), with OM content averaging 6.2% by 24 mo. Combining coring with topdressing did not necessarily further decrease OM contents. Topdressing was up to three times more effective at reducing soil OM content than coring alone (P < 0.05). The color and N concentration of both kikuyugrass ages was maintained to local standards by all mechanical and topdressing techniques, although verticutting decreased the incidence of mower scalping in the second year. Verticutting was the most effective approach for restricting the progressive softening of young kikuyugrass with time (P < 0.05), whereas the mature kikuyugrass softened by the same amount irrespective of the renovation treatment.

Abbreviations: LSD, least significant difference • OM, organic matter • +, plus

All rights reserved. No part of this periodical may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying, recording, or any information storage and retrieval system, without permission in writing from the publisher.

Received for publication May 21, 2008.

[Full Text of Barton et al.] [Reprint (PDF) Version of Barton et al.]


Abstract 6 of 32 back

TURFGRASS

Nitrogen and Plant Growth Regulator Influence on ‘Champion’ Bermudagrass Putting Green under Reduced Sunlight

Christian M. Baldwina, Haibo Liub,*, Lambert B. McCartyb, Hong Luoc and Joe E. Tolerd

a Jacklin Seed Company, 5300 W. Riverbend Ave., Post Falls, ID 83854
b Dep. of Horticulture, D-136 Poole Ag. Center, Clemson University, Clemson, SC 29634-0319
c Dep. of Genetics and Biochemistry, Clemson University, Clemson, SC 29634-0318
d Dep. of Applied Economics and Statistics, Clemson University, Clemson, SC 29634-0318

* Corresponding author (haibol@clemson.edu ).

Managing warm-season turfgrasses with reduced sunlight is challenging due to C4 plant morphological limitations, such as reduced lateral stem growth. Adjusting cultural management practices, such as N and trinexapac-ethyl (TE) [4-(cyclopropyl-a-hydroxy-methylene)-3,5-dioxocyclohexanecarboxylic acid ethyl ester], application may benefit turfgrass performance when sunlight is reduced. Therefore, a 2-yr field study from 15 June to 15 September in 2006 and 2007 at Clemson University investigated the best management practices for sustaining a high quality ‘Champion’ bermudagrass (Cynodon dactylon (L.) Pers. X C. transvaalensis Burtt-Davy) putting green maintained at a 3.2-mm mowing height under reduced sunlight. Treatments included full-sunlight, 55% full-day shade, TE (0.02 kg a.i. ha–1 2 wk–1), Fe (2.7 kg ha–1 2 wk–1), and N as liquid urea at 147, 293, and 440 kg ha–1 yr–1. Data collection included visual turfgrass quality (TQ), total clipping yield, clipping chlorophyll concentration, root total nonstructural carbohydrates (TNC), thatch accumulation, and thatch depth. Overall, Fe applications minimally impacted parameters measured. Increasing N rates linearly increased TQ when grown under full sunlight. Applying N at ~40% lower (147 kg ha–1 yr–1) than the typical recommended rates for ultradwarf bermudagrass putting greens improved Champion TQ under reduced light compared to higher N rates. Applying TE resulted in a linear TQ increase for full sunlight and shade-grown Champion bermudagrass. Under reduced sunlight, a 15% chlorophyll concentration increase was noted for TE-treated plots compared to nonTE-treated plots. Shade reduced thatch accumulation 40% compared to sun-grown Champion, which suggests less aggressive cultivation practices are required for thatch control under reduced light. Champion bermudagrass did not provide an acceptable putting green quality when grown under 55% full-day shade, however, adjusting management practices enhanced Champion bermudagrass quality under reduced light.

Abbreviations: TE, trinexapac-ethyl • PGR, plant growth regulator • TNC, total nonstructural carbohydrates • TQ, turfgrass quality

All rights reserved. No part of this periodical may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying, recording, or any information storage and retrieval system, without permission in writing from the publisher.

Received for publication July 3, 2008.

[Full Text of Baldwin et al.] [Reprint (PDF) Version of Baldwin et al.]


Abstract 7 of 32 back

COTTON

Differential Responses of Cotton Cultivars when Applying Mepiquat Pentaborate

Nathan B. O'Berrya,*, Joel C. Fairclothb, Michael A. Jonesc, David A. Herbert, Jr.d, Azenegashe O. Abayee, Thomas E. McKemief and Cavell Brownieg

a Isle of Wight County Extension Office, 17100 Monument Circle, Suite B, Isle of Wight, VA 23397
b Dow AgroSciences, 1799 Percy Place, Collierville, TN 38017
c Clemson University, Pee Dee Research and Education Center, 2200 Pocket Road, Florence, SC 29506
d Virginia Polytechnic Institute and State University, Tidewater Agricultural Research and Extension Center, 6321 Holland Road, Suffolk, VA 23437
e Crop and Soil Environmental Science Dep., Campus Box 0404, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061
f BASF Corporation, 5104 Indigo Moon Way, Raleigh, NC 27613
g Professor Emerita, North Carolina State University, 3309 Horton Street, Raleigh, NC 27607

* Corresponding author (noberry@vt.edu ).

Plant growth regulators are routinely used in cotton (Gossypium hirsutum L.) production to reduce plant height and hasten maturity. The objective of this research was to determine the response of several cotton cultivars to mepiquat pentaborate (MPB) application in environments accumulating different levels of heat units. Four MPB application regimes were imposed on three cultivars in Virginia and South Carolina in 2005 and 2006. Total MPB season rates of 0.0, 54.9, 85.3, or 121.9 g ai ha–1 applied at the five-leaf stage, pin-head square, match-head square, and early bloom were used. The cultivars were: Deltapine (DP) 444 BG/RR, an "early-maturing" cultivar; Fibermax (FM) 960 BR, a "medium-maturing" cultivar; and DP 555 BG/RR, a "late-maturing" cultivar. In South Carolina in 2006, FM 960 BR July plant height was reduced by 25% with MPB application compared to only 12 and 13% for DP 444 BG/RR and DP 555 BG/RR, respectively, although actual plant height reductions were not different among cultivars. Mepiquat pentaborate applications decreased plant height at harvest by 8 to 34%, height-to-node ratio by 10 to 32%, enhanced maturity as measured by nodes above white flower for all cultivars, and decreased lint yield by 3.7 to 8.5% compared to untreated cotton. Higher seasonal totals and earlier initiation of MPB application resulted in the greatest decrease in lint yield.

Abbreviations: AMS, apical main-stem • DP, Deltapine • FM, Fibermax • HNR, height-to-node ratio • MC, mepiquat chloride • MPB, mepiquat pentaborate • NAWF, nodes above white flower • PGR, plant growth regulator

All rights reserved. No part of this periodical may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying, recording, or any information storage and retrieval system, without permission in writing from the publisher.

Received for publication August 15, 2008.

[Full Text of O'Berry et al.] [Reprint (PDF) Version of O'Berry et al.]


Abstract 8 of 32 back

SOYBEAN

Main-Stem Node Removal Effect on Soybean Seed Yield and Composition

Shawn P. Conleya,*, Palle Pedersenb and Ellsworth P. Christmasc

a Dep. of Agronomy, Univ. of Wisconsin, 1575 Linden Dr., Madison, WI 53706
b Dep. of Agronomy, Iowa State Univ., 2104 Agronomy Hall, Ames, IA 50011-1010
c Dep. of Agronomy, Purdue Univ., 815 W. State St., West Lafayette, IN 47907

* Corresponding author (spconley@wisc.edu ).

Hail injury to soybean [Glycine max L. (Merr.)] is common across the United States. Currently, U.S. hail adjusters use procedures that assume that yield reductions caused by stem cutoff and defoliation or defoliation without stem loss is similar during the vegetative development period. Our hypothesis was that seed yield will be affected by timing of node removal in vegetative soybean and that main-stem node removal will influence seed composition. Research was conducted in Indiana and Iowa from 2003 to 2005 to test if removing 0, 20, 40, 60, 80, or 100% of nodes at V2, V6, or R3 development stages affects seed yield and grain composition. In Indiana, imposing node removal at the V2 stage resulted in 15.9% greater yield than imposing at the V6 stage. In Iowa, imposing node removal at the V2 stage on the average resulted in 24.9 and 46.1% greater seed yield than imposing node removal at the V6 or R3 stages, respectfully. Seed mass was 7.7% greater when comparing the V2 to the V6 node removal timing in Indiana. In Iowa, seed mass decreased 7.0% when 60% of the nodes were removed at V6 and 5.6% when 20% of the nodes were removed at R3. Soybean oil content was only affected by extreme node removal treatments while protein content was unaffected. Our results indicate that the soybean development stage that node removal occurs must be considered when estimating soybean seed yield loss and that an oil content adjustment is not needed to properly compensate growers for economic losses caused by node removal.

All rights reserved. No part of this periodical may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying, recording, or any information storage and retrieval system, without permission in writing from the publisher.

Received for publication April 18, 2008.

[Full Text of Conley et al.] [Reprint (PDF) Version of Conley et al.]


Abstract 9 of 32 back

SOYBEAN

Growth, Yield, and Yield Component Changes among Old and New Soybean Cultivars

Jason L. De Bruin* and Palle Pedersen

Dep. of Agronomy, Iowa State Univ., 2104 Agronomy Hall, Ames, IA 50011-1010

* Corresponding author (jsndbrn@iastate.edu ).

Soybean [Glycine max (L.) Merr.] yield has increased at a rate of 25 to 30 kg ha–1 yr–1 due in part to improved genetic gain, and has been further advanced by the addition of resistance to soybean cyst nematode (Heterodera glycines Ichinohe; SCN) in new cultivars. The objective was to determine specific growth changes that explain the yield improvement from old to new cultivars and the further yield improvement gained from the addition of SCN resistance. Studies were conducted at three Iowa locations during 2005 and 2006. Two old and two new SCN-susceptible, and two new SCN-resistant cultivars were evaluated for total dry matter (TDM) accumulation and leaf area index (LAI) through the season along with yield and yield components at harvest. New cultivars produced yields superior to older cultivars due to increased crop growth rate (CGR) culminating in greater TDM 105 days after emergence (DAE). Yield was strongly associated with the number of seeds produced m–2 and this yield component accounted for almost all of the yield differences among cultivars. Seeds m–2 was positively related to CGR between 42 and 105 (growth stage R1–R5.5) DAE and to LAI 105 DAE. New SCN-resistant cultivars produced yields 17 to 19% greater than new susceptible cultivars across three locations. Increased TDM and CGR explained the yield response at the low-yield location, but not at the high-yield locations. Apparent harvest index (HI) was similar among all cultivars at each location. Selection for increased yield has indirectly selected for increased TDM and CGR with a similar amount partitioned to seed dry weight. Future yield gains will be made by (i) increasing the amount and the rate of dry matter (DM) and (ii) through the increased production and duration of leaf area.

Abbreviations: CGR, crop growth rate • DAE, days after emergence • DM, dry matter • HG, Heterodera glycines • HI, harvest index • LAI, leaf area index • MG, maturity group • Pi, initial SCN population density • SCN, soybean cyst nematode • TDM, total dry matter

All rights reserved. No part of this periodical may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying, recording, or any information storage and retrieval system, without permission in writing from the publisher.

Received for publication May 31, 2008.

[Full Text of De Bruin and Pedersen] [Reprint (PDF) Version of De Bruin and Pedersen]

نوشته شده توسط رامین زیلا ب پور در 21:43 |  لینک ثابت   •