Progress 10/01/02 to 09/30/07
Outputs
OUTPUTS: During the period of this project research has been conducted primarily on cool season clovers and a fescue population improvement project. With the clovers, research has focused on white, red, and crimson clover. In white clover, research focused on enhancing root-knot nematode (RKN) resistance in a population derived from the cultivar 'Osceola'. This cultivar, released from previous research at Florida, is intermediate between "Ladino type" and "Intermediate type" white clovers with higher seed yields than typical Ladino types and higher dry matter yields than typical intermediate types. It has been a dominat cultivar in the US market for over 15 years. Five cycles of recurrent phenotypic selection resulted in the development of a population with high level of RKN tolerance without shifting the other superior attributes of Osceola. This RKN tolerant population was released as UF WC5 in 2005 and should enter the seed production channel in 2008. A similar project in red
clover was conducted using the cultivar 'Cherokee' as a base population. Cherokee was the first semi-nondormant cultivar of red clover developed in the US and has a moderate level of RKN resistance. Cherokee has excellent seed production and has found a market niche in the SE USA with moderate sales since its release in 1993. A combination of seven cycles of recurrent phenotypic and genotypic selection were used to develop a red clvoer population with very high levels of RKN tolerance. This population was released in 2004 as the cultivar 'Southern Belle'. Some initial seed increase difficulties were experienced in the Pacific NW, but a reasonable seed supply should be available in 2008. Three additional populations of red clover have undergone a preliminary breeder seed increase and are in regional evaluation for possible cultivar release. A population designated FL24D was selected for tolerance to 2,4-D and very early flowering. It has shown superior first harvest yields in an number
of experiments. The population FMD4 was selected as an intermediate dormancy population incorporating germplasm from Cherokee, Kenstar, and Marathon, and is intermediate in date of first spring flowering between Cherokee and Kenstar. The population FL4X is an induced tetraploid population out of the cultivar Cherokee that was shown in research to have superior seedling vigor compared to diploid Cherokee. In crimson clover, populations have been developed that incorporated a low or high frequency of a white flowered trait and a low frequency of germplasm collected in Bulgaria. Populations were also selected for early and for late flowering. These populations are currently in advanced regional tests for cultivar release. Two additional recurrent phenotypic cycles of selection for persistance were completed in the fescue population during the period of this project. In addition to this research, we have evalauted clover germplasm from Uruguay and from Calfironia for performance and
potential in the SE USA.
PARTICIPANTS: Dr. David Wofford, Agronomy Department, University of Florida. Dr. Ken Quesenberry, Agronomy Department, University of Florida. Dr. Marco Dalla Rizza, INIA, Uruguay. Dr. Daniel Real. INIA, Uruguay.
TARGET AUDIENCES: The primary traget audience for this project has been forage livestock producers in the lower Coastal Plains and peninsular Florida.
PROJECT MODIFICATIONS: This is the termination report for this project.
Impacts
Primary outcomes of this project were cultivar releases and development of populations of germplasm. These are listed below with current status. Southern Belle red clover - Released with seed available in 2008. UF WC5 white clover - Released with seed available in 2008. FL24D red clover - Experimental germplasm population in regional test. FLMD4 red clover - Experimental germplasm population in regional test. FL4X red clover - Experimental germplasm population in regional test. FLER crimson clover - Experimental germplasm population in regional test. FLW crimson clover - Experimental germplasm population in regional test.
Publications
- Blount, Ann, Ken Quesenberry, Ron Barnett, and Gordon Prine. 2007. Selection and use of cool season legumes. In Proc. 56th Beef Cattle Short Course, IFAS, Univ. of Florida, Gainesville, FL, 2-4 May, 2007.
- Dalla Rizza, Marco, Daniel Real, Rafael Renyo,Valentina Porro, Eugenia Errico, and Kenneth H. Quesenberry. 2007. Genetic diversity and DNA content of three South American and three Eurasiatic Trifolium species. Genetics and Molecular Biology 30:1118-1124.
- Real, Daniel, Marco Dalla Rizza, Rafael Renyo, and Kenneth H. Quesenberry. 2007. Breeding system of the areial flowers in an amphicarpic clover species: Trifolium polymorphum. Crop Sci. 47 1401-1406.
- Shoaf, Samantha, and Kenneth Quesenberry. 2007. Thiadiazuron effects on tissue culture of red clover. In ASA-CSSA-SSSA-CSSS Abstracts 2006 [CD-ROM]. ASA, CSSA, and SSSA, Madison, WI.
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Progress 10/01/05 to 09/30/06
Outputs
A white clover cultivar with improved tolerance to the southern root-knot nematode (Meloidogyne incognita) was approved for release in 2006 after five cycles of selection from the original source population (Osceola). Multiple year and location field performance trials under no nematode pressure reported no forage yield differences between the new cultivar and the original source population. Three years of flowering data revealed the new cultivar was as prolific in flowering as Osceola, and significantly higher than the other ladino types. In several greenhouse inoculation tests, the new cultivar uniformly had significantly better nematode tolerance than Osceola as measured by the number of galls, number of egg masses, and nematode reproduction as measured by egg counts. Both top and root growth yields of plants from of the new cultivar were also significantly better than plants from Osceola regardless of the specific isolate of the nematode used in the test. White
clover plants bearing a unique leaf mark had been selected and established for seed production during 2006. Clones of each individual were made and clones were randomly planted to enhance interpollination. A useable quantity of seed was harvested and cleaned and was plants in small pots for evaluation of the leaf mark trait. After losing the 400 half-sib families developed for a genetic study in crimson clover in fall 2005, over 450 plants of crimson clover from the same population were established in the field to produce another set of half-sib families. This material traces to a population created by field crossing among all entries comprising the US germplasm collection for the species. These plants are being managed to maximize individual plant seed production in order to produce sufficient seed for furhter evaluation. A field evaluation experiment of five native legume species and over 30 accessions of Desmodium incanum was evaluated for dry matter yields and nutritive value a
third year at Gainesville, FL. Leaf tissue tannin analyses conducted in 2006 showed repeatability with 2005, although lower levels. The eight superior D. incanum accessions previously identified were sampled for forage yield and quality in 2006, but showed less plant spread in the weed free monoculture of this experiment than when growing with bahiagrass in the previous experiment. A continuing field evaluation of elite rhizoma perennial peanut accessions was harvested for the fourth year at Marianna and Gainesville, FL in 2005. Two of the new selections will likely be proposed as potential cultivar releases in 2007. Continued evaluations of three new red clover populations (FLMD4, a mid-dormant 2x red clover; FL24D, an early 2,4-D tolerant population; and FL4X, a non-dormant 4x red clover) showed that the FL24D was among the highest yielding at first harvest, that the FLMD4 population had good yields and seasonal distribution of yield, but that yields of FL4X were below the
experiment mean yields at Gainesville and Marianna.
Impacts
The new root-knot nematode ladino white clover cultivar should result in more usefullness for whit clover in forage systems and decrease stand decline in white clover areas impacted by the southern root-knot nematode.
Publications
- Wofford, D. S. and E. Ostmark. 2006. White Clover Response to Root-Knot Nematode Isolates. Agronomy Abstracts.
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Progress 10/01/04 to 09/30/05
Outputs
Field yield trials and greenhouse evaluation test were finalized for a white clover population selected from the cultivar Osceola for tolerance to the southern root-knot nematode (Melodoigyne incognita). Field data from three locations and several years indicated that the selected material did not differ in forage production in the absence of the nematode. Flowering capacity was also evaluated and no differences were detected between the source population (Osceola) and the selected population. The original objective was to develop a root-knot nematode population that did not differ in other traits from Osceola and this has been accomplished. Over one thousand progeny from crosses involving multifoliate white clover plants were evaluated during 2005. Many of these crosses also involved various leaf mark types. Selections were made within these segregating groups to continue the work on developing novel combinations of leaf marks and the multifoliate leaf trait. Future
crosses are planned to continue this work. White clover plants with a unique leaf mark were observed in Gainesville during the spring growing season and individual plants were collected during early summer. Plants were grown in the greenhouse and evaluated for growth habit, leaf mark, and intensity of leaf mark. Forty individuals were selected and transplanted in the field for seed production during the 2005-2006 growing season. From an interpollination of entries representing the US germplasm collection of crimson clover, 400 plants were transplanted to the field during the 2004-2005 growing season. Seeds were harvested from each of these four hundred, resulting in the production of 400 half-sib families. Twenty one individuals from 377 of these families were planted in the greenhouse as the next step in the long term objective of estimating genetic parameters for both vegetative and reproductive traits found in the current US germplasm collection of crimson clover. Much of this
material was lost due to flowering induced by an external light source which induced flowering of the material about 4 weeks after planting. The 47 families that were not visibly reproductively induced were transplanted to a field plot for evaluation during the 2005-2006 growing season.
Impacts
The anticipated release of a root-knot nematode tolerant ladino white clover will address stand decline problems associated with these types of white clover.
Publications
- Gwata, E. T., D. S. Wofford, K. J. Boote, A. R. Blount, and P.L. Pfahler. 2005. Inheritance of promiscuous nodulation in soybean. Crop Science 45: 635-638.
- D. S. Wofford and E. Ostmark. 2005. Comparisons Among Cycles of Selection for Root-knot Nematode Tolerance in White Clover. Agron. Abstr.
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Progress 10/01/03 to 09/30/04
Outputs
A greenhouse test was conducted to compare two white clover populations for tolerance to the southern root-knot nematode (Melodoigyne incognita). Two hundred plants of Osceola and a population selected from Osceola for nematode tolerance (Cycle 5) were inoculated with larvae of three nematode isolates each. An equal number of seedlings were grown of each population for use as an uninoculated check. Response variables evaluated included top growth, root mass, gall score, egg mass score, and nematode reproduction. All variables were collected on 100 plants of each entry eight weeks after inoculation and again at 16 weeks after inoculation. For all response variables, inoculated Cycle 5 was significantly better than inoculated Osceola (greater top growth, greater root mass, fewer gall, fewer egg masses, lower nematode reproduction), however, no differences were detected for growth variables between the two populations. These results were the same as prior tests that only
used one isolate of the nematode. Yield tests were conducted at Gainesville and Ona to compare Cycle 5, Osceola, and other commercially available white clovers. At both locations, there were no differences found for production between Osceola and Cycle 5. Additionally, these two entries were either the same or significantly out yielded the other entries in the tests. This data, in addition to the nematode test previously presented, will be compiled to support the release of Cycle 5 as a nematode tolerant white clover. Crosses continued to be made in the multifoliate white clover breeding population. Over 800 progeny were evaluated and several selections were made for inclusion as parents in future crosses. Crosses were also made in mutant leaf-mark populations to increase the frequency of the mutant genes responsible for the leaf mark variants. Progeny will be evaluated in 2005 to further develop new mutant leaf-mark populations. Work on the promiscuous trait in soybean was completed
and manuscripts were prepared and submitted for publication.
Impacts
The development of cultivars for these species will have a direct effect on stand productivity and longevity, both of which will be economically beneficial to producers.
Publications
- Gwata, E. T., D. S. Wofford, and K. J. Boote. 2004. Genetics of promiscuous nodulation in soybean: nodule dry weight and leaf color score. Journal of Heredity 95: 154-157.
- Gwata, E. T., D. S. Wofford, and H. Mushoriwa. 2004. Determination of effective nodulation in early juvenile soybean plants for genetic and biotechnology studies. African Journal of Biotechnology. 2: 417-420.
- Gwata, E. T., D. S. Wofford, and K. J. Boote. 2004. Inheritance of promiscuous nodulation in soybean. Crop Science. (In Press).
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Progress 10/01/02 to 10/01/03
Outputs
A white clover population selected for root-knot nematode tolerance was subjected to a greenhouse study evaluating growth characteristics. Compared to the original source population, the selections had significantly more top growth, root growth, less gall formation, less egg mass formation, and less plant mortality. This population will be evaluated for response to other isolates of the pathogen. A study investigating the inheritance of promisuous nodulation in soybean was successful in identifying the number of loci and the mode of gene action controlling the trait. Several selection criteria were evaluated for use in the subsequent transfer of the trait and from this group some were identified as being useful in the incorporation of the trait into other germplasm. An experimental diploid red clover population FLMR7 was developed and released in 2002 and foundation seed was produced in 2003. A tetraploid red clover (T. pratense) population was produced, has undergone
three cycles of selection, and breeder seed is currently being increased in Oregon. Primary selection criteria were seedling vigor, adaptation to Florida conditions, and improved seed production. A mid-dormant diploid red clover was developed by four cycles of recurrent phenotypic selection and a breeder seed increase is currently underway. Field evaluation at Gainesville of a segregating population of Lotononis bainesii developed by a Uruguayan cooperator showed potential for use as a forage legume. However, reliance on native rhizobia resulted in ineffective nodulation with poor growth and persistence. A subsequent experiment in 2003 using effective rhizobium, resulted in vigorous growth during the summer and fall, but questions regarding winter persistence remain. Thirty plant introductions of pintoi perennial peanut (A. pintoi) have been evaluated for morphological and molecular variability. Agronomic performance of these accessions grown on a flatwoods soil at Gainesville, FL
suggests large variability for forage and seed yields, but a general lack of adaptation to north central Florida.
Impacts
The development of cultivars for these species will have a direct effect on stand productivity and longevity, both of which will be economically beneficial to producers.
Publications
- Gwata, E. T., D. S. Wofford, P. L. Pfahler, and K. J. Boote. 2003. Pollen morphology and in vitro germination characteristics of nodulating and nonnodulating soybean (Glycine max L. ) genotypes. Theoretical and Applied Genetics. 106: 837-839.
- Gwata, E. T., D. S. Wofford, and H. Mushoriwa. Determination of effective nodulation in early juvenile soybean plants for genetic and biotechnology studies. 2003. African Journal of Biotechnology. Vol 2 (11).
- Carvalho, M.A., K.H. Quesenberry, D.W. Gorbet.2003 Seed production and fatty acid profile in Arachis pintoi. Agron Abstr. CD-ROM, C08-carvalho237434-P.
- Quesenberry, K.H., J. M. Mullaney, A.R. Blount, R.S. Kalmbacher, and J.G. Norcini. 2003. Characterization of physiological and morphological variability in buffalo clover. Soil Crop Sci. Soc. Fla Proc. 62:66-69.
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