Evers, Gerald Wayne

Parsons, Margaret J.

English

Texas A&M University

Seedling Development of Alfalfa, Sweetclover, and Annual Medic

Texas A&amp;M Repository

    PUBLICATIONS 2006 SEEDLING DEVELOPMENT OF ALFALFA,SWEETCLOVER, AND ANNUAL MEDICG. W. Evers and M. J. ParsonsBackground. Livestock producer interest in using forage legumes has increasedbecause of rising nitrogen fertilizer prices. In the southeastern US, cool-season foragelegumes are primarily grown with cool-season grasses and used for grazing. Goodseedling vigor and rapid leaf production enhance establishment and competitivenesswhen grown with grasses. Three relatively new forage legume species for Texas aregrazing-tolerant alfalfa, multi-stem annual sweetclover, and Armadillo annual medic.Since most alfalfa varieties have been developed for hay production they will not persistunder grazing. Although annual sweetclover is a well adapted forage legume for CentralTexas, very little is planted because of high coumarin levels that can cause animal healthproblems and a large central stem that reduces digestibility. New sweetclover varietiesare in the development stage that have low coumarin and a multi-stem morphology likealfalfa. Annual medics are close relatives to alfalfa and have good seedling vigor andexcellent reseeding ability.Twelve pots (6 in. high x 6 in. diameter) were planted to Alfagraze andAmerigraze 702 alfalfa, Hubam and Emerald sweetclover, and Armadillo medic onFebruary 12,2004. Two seed were planted in the center of the pot and 7 to 8 seed plantedaround the outer edge of the pot to simulate plant growth in the field. The center plantswere thinned to one plant on which measurements were taken. Each day seedlings werechecked for new fully expanded leaves, beginning with the unifoliate leaf, and secondarybranching.Research Findings. The rate of leaf appearance is important because leaf areainfluences the amount of photosynthesis which provides carbohydrates for growth. Leafappearance of the alfalfas and Armadillo medic was more rapid than sweetclover (Fig. 1).A new leaf appeared every 3.2 days on alfalfa and Armadillo medic and every 4.8 dayson sweetclover. Appearance of new branches on the main stem was slow for all entries upto 24 days after planting (DAP) (Fig. 2). Armadillo medic and Emerald sweetcloverseedlings produced the most secondary branching followed by Alfagraze alfalfa. Both99alfalfas were similar up to 24 DAP. From that point Alfagraze had slightly moresecondary branching indicating better grazing tolerance. The main stem morphology ofHubam sweetclover resulted in the poorest secondary branching.Application. Alfalfa and Armadillo medic had a faster rate of leaf appearanceindicating better seedling vigor than sweetclover. Secondary branching of multi-stemEmerald sweetclover was significantly greater than Hubam sweetclover and slightlybetter than alfalfa indicating better grazing tolerance.AmerigrazeArmadilloEmeraldAlfagrazeHubam...--,.,;~.,.,.,. __......... -.7.-:·-:·" .'",'" ,." .. ,.,,-_ ....., ...,","'---' .. "" .. ,# "' ........ •• , .•••••••-"" .',------:-, .....'" "" .. ",'" .. 'OL....loo.'~-"-~----'--_-L-_---J._--'--_---J~--"----'--------'E 8l!!IIIc:'co 6Ec:o~ 4>co~-oci 2z6 9 12 15 18 21 24 27 30Days after plantingFig. 1. Leaf development on the main stem of five forage legumes.,,,.,'.,',.'AlfagrazeAmerigrazeArmadilloEmeraldHubam-----',",'"........." "./ ..... "/' /• 1/ ,-_1. ,/-' ,------- .,. ,,y .... - - --'oI!.~' .. - -",-:7 , __ - _..,'/ "---- / .,- . ., .. ,' ....",'. - -,,' , ,' .21 24 27 30 33 36 39Days after plantingFig. 2. Branch production on the main stem of five forage legumes.E 6Ql(jjc:5'roEc:40IIIQl.I:: 3uc:co~.0 2-0ci 1z018100

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Seedling Development of Alfalfa, Sweetclover, and Annual Medic

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Texas A&M University

Texas A&M Repository

Seedling Development of Alfalfa, Sweetclover, and Annual Medic

Abstract

Similar works

Full text

Available Versions

Texas A&M University

Texas A&amp;M Repository

Texas A&M Repository