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a Texas Agric. Exp. Stn., 3507 Hwy. 59 E, Beeville, TX 78102
b Texas Agric. Exp. Stn., 18619 C.R. 480, Merkel, TX 79536
c Texas Agric. Exp. Stn., 1229 N. U.S. Hwy. 281, Stephenville, TX 76401
d previously Texas Coop. Ext., Stephenville, TX, currently The Noble Foundation, 2510 Sam Noble Parkway, Ardmore, OK 73401
e Dep. of Agriculture, Angelo State Univ., ASU Station #10888, San Angelo, TX 76909-0888
* Corresponding author (w-ocumpaugh{at}tamu.edu).
‘Devine’ (Reg. No. CV-273, PI 642778) little burr medic [Medicago minima var. minima (L.) Bart.] was developed by the Texas Agricultural Experiment Station and released in 2005. Devine originated from a naturalized stand in a pasture on the Anderlitch Ranch south of Farm to Market Road 2200 and west of Devine, TX, 56 km southwest of San Antonio. Evaluation of spaced plants of the original collection revealed very little variation among plants, therefore the original accession was increased without selection. Devine was tested under the designation of BEDEV and Devine.
Little burr medic is a winter annual legume native to the Mediterranean region. Little burr medic was introduced into Texas more than 75 yr ago and became widely naturalized (Diggs et al., 1999). An exhaustive review of the literature by Fresnillo Fedorenko (2000) indicates little burr medic is widespread in Mediterranean-type climates of southern Australia, Mexico, California, Argentina, Chile, and the Cape region of South Africa. We have collected it from many semiarid locations in Texas. This is the first cultivar of M. minima to be released anywhere. Many commercial annual medics from Australia are well adapted to the calcareous soils of south and central Texas, but they lack adequate freeze tolerance and hard seededness (Ocumpaugh et al., 1997). In 1998, ‘Armadillo’ burr medic (M. polymorpha L.) was released by the TAES-Beeville Forage Program (Ocumpaugh et al., 2004). Armadillo exhibited superior winterhardiness to all the Australian annual medic cultivars we have tested, but it is subject to freeze damage in some years north of 31° N lat in Texas. Devine little burr medic was released to provide a winter annual legume that will persist and spread in pastures in the central region of Texas from near Dallas (32° N lat) southward to about 100 km south of San Antonio (29° N lat). Devine produces more forage and reseeds better in the more arid regions of Texas than Armadillo. It has a high level of hard seededness, which allows the seed to persist for years in the soil.
Dry matter yields of Armadillo and Devine are comparable to those of Australian commercially available medics. Yields of Armadillo of about 4500 kg ha–1 yr–1 are comparable to those observed over several years of evaluation of ‘Jemalong’ barrel medic (M. truncatula Gaertn.) (Ocumpaugh et al., 1997). Plantings of Devine little burr medic made in the area around San Antonio area and northward consistently produce as much or more than other available medics (Muir et al., 2005). Devine typically produces forage later in the season than Armadillo.
At Luling, TX, Armadillo produced 110 and 121% of Devine in 2001 and 2002, but in 2004, Armadillo only produced 79% of Devine yields. Devine out-produced several legumes in May harvests in 2004, to contribute to this superiority over other medics in the test. In north Texas, Devine will produce more forage than Armadillo, except in wet and mild winters, as Armadillo will winter kill in the cold winters in north Texas (Muir et al., 2005).
The primary advantage of Devine compared to most of the commercial medics except Armadillo is reseeding ability even under severe grazing (Ueckert et al., 2003; Butler and Muir, 2004). All the medics show superior reseeding ability compared to most other cool-season annual legumes (Trifolium and Vicia species). Research in the San Angelo, TX, area indicated that Devine and experimental black medic (M. lupulina L.) were among the most promising for the San Angelo area of Texas (Ueckert et al., 2003; Rod Reed, personal communication, 2004).
Devine little burr medic flowers and sets seed two or more weeks later than Armadillo burr medic. Seed size of Devine is less than half that of Armadillo, and seed production is about half that of Armadillo (Muir et al., 2005). Devine has about 1100 seeds g–1 and most pods contain four to five mature seeds. Pods are set in clusters with three to five pods per cluster. The hard seed content of freshly harvested, hand-thrashed pods is near 100%. Seed harvested with a commercial vacuum harvester consistently had about 50% hard seed. Spine length on the burs of Devine is 2 to 3 mm.
As the species name minima implies, Devine plant are smaller than most medic species. The plants are smaller in part because they grow very prostrate, however, they can produce a large amount of forage, because the canopy is dense. This winter annual legume germinates in the autumn and grows through the winter with flowering starting in February or early March.
The flowering habit is indeterminate with flowering continuing until just before the plant matures and dies in May. The leaf is green (7.5 GY 4/4, Munsell Color Chart) and pubescent, with the underside being lighter in color. Leaves (three) are pinnate with the center leaflet having a longer petiolule than the two lateral leaflets. Margins of the leaflets are moderately serrated.
Devine has no leaf markings. The stem is pubescent and branched at most nodes. Devine seldom exceeds 20 to 25 cm in height unless it is growing in association with a taller plant that will help support its stems.
A seed yield from harvests with commercial machinery is 200 to 250 kg ha–1. Seed production under grazing has not been documented but it will produce an abundance of seed even when herbage is removed (Muir et al., 2005). This high level of seed production combined with the hardseededness permits this plant to persist under grazing and erratic rainfall patterns of central Texas.
Disease and insect problems have not been observed under normal production practices, but we have observed powdery mildew [caused by Erysiphe polygoni DC], late in the season when total season growth is allowed to accumulate. Larval alfalfa weevil (Hypera postica Gyllenhal) will attack Devine, but this species is less affected than other annual medics (Muir et al., 2005).
Foundation seed of Devine is available to licensees and for research purposes from Texas Foundation Seed Services (a division of Texas Agric. Exp. Stn.), Vernon, TX. Devine will not be protected by Plant Variety Protection, and only Certified seed can be sold. Stand life on both Foundation and Certified fields are limited to 5 years. There is no Registered class of seed. An exclusive release of Devine marketing rights has been licensed to Pogue Agri Partners, Inc. Kenedy, TX. Twenty years after the date of release by the Texas Agricultural Experiment Station (2005), seed will also be available from the NPGS.
Footnotes
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. Permission for printing and for reprinting the material contained herein has been obtained by the publisher.
Received for publication May 24, 2006.
References
txjanr/. Texas J. Agric. Nat. Resourc. 16:86–92.
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