Defining a Multiple‐Use Germplasm Collection for the Genus <i>Trifolium</i>

Morris, J. B.; Greene, Stephanie L.

doi:10.2135/cropsci2001.413893x

Cited by 23 publications

(16 citation statements)

References 45 publications

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“…medium belongs to the tertiary gene pool of T. pratense relatives (Morris & Greene, 2001) along with T. alpestre. Plant breeders use the secondary gene pool if they cannot find desirable alleles in primary gene pool (cultivars, landraces, wild/naturalised, botanical varieties) and they turn to the tertiary gene pool only after exhausting the secondary pool (Fehr, 1987).…”

Section: Discussionmentioning

confidence: 99%

Identification of barriers to interspecific crosses in the genus Trifolium

2006

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A study of pre-and post-fertilisation barriers after interspecific crosses of diploid and tetraploid Trifolium pratense L. and wild species T. alpestre L., T. medium L. and T. sarosiense Hazsl. was aimed at finding of a promising cross combination for obtaining hybrids. The growth of pollen tubes was arrested in interspecific crosses mainly when T. pratense was at a diploid level. To investigate the post-fertilisation barriers in detail, the hybrid embryo viability was traced by two clearing treatments of immature seeds: (1) using chloral hydrate (which proved to be most appropriate); and (2) a mixture of benzyl benzoate and dibutly phthalate. In interspecific combinations T. pratense (4×) × either T. alpestre or T. sarosiense, enlargement of immature seeds occurred, but no hybrid embryo was traced. Of the wild species used as a male parent for crosses, T. medium was the only exception from the point of view of fertilisation. Globular, heart and the early torpedo stages of hybrid embryos were observed 7 days after pollination (DAP) but only when T. pratense was at a tetraploid level. When T. pratense (2×, 4×) was used as a male parent for interspecific crosses with T. alpestre, T. medium and T. sarosiense, strong defects in various stages of embryogenesis were observed, particularly wrinkled and narrowing embryo sacs caused by an expansion of endothelial cells. We conclude with the following finding: (1) to make crosses only in one direction with T. pratense as a female parent and T. medium as a male; (2) to use tetraploid plants of T. pratense; (3) and to excise hybrid embryos at an early torpedo stage, about 7 DAP.

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Section: Discussionmentioning

confidence: 99%

Identification of barriers to interspecific crosses in the genus Trifolium

2006

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“…The species is ranked as globally imperiled [25] and wild clover species, especially native to the US, have been identified as important to conserve in the USDA National Plant Germplasm System collection [26]. The species is a dominant forb in early seral communities that are disturbed by fire or grazing [27].…”

Section: Introductionmentioning

confidence: 99%

Conserving Plants in Gene Banks and Nature: Investigating Complementarity with Trifolium thompsonii Morton

Greene

Kisha

et al. 2014

PLoS ONE

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A standard conservation strategy for plant genetic resources integrates in situ (on-farm or wild) and ex situ (gene or field bank) approaches. Gene bank managers collect ex situ accessions that represent a comprehensive snap shot of the genetic diversity of in situ populations at a given time and place. Although simple in theory, achieving complementary in situ and ex situ holdings is challenging. Using Trifolium thompsonii as a model insect-pollinated herbaceous perennial species, we used AFLP markers to compare genetic diversity and structure of ex situ accessions collected at two time periods (1995, 2004) from four locations, with their corresponding in situ populations sampled in 2009. Our goal was to assess the complementarity of the two approaches. We examined how gene flow, selection and genetic drift contributed to population change. Across locations, we found no difference in diversity between ex situ and in situ samples. One population showed a decline in genetic diversity over the 15 years studied. Population genetic differentiation among the four locations was significant, but weak. Association tests suggested infrequent, long distance gene flow. Selection and drift occurred, but differences due to spatial effects were three times as strong as differences attributed to temporal effects, and suggested recollection efforts could occur at intervals greater than fifteen years. An effective collecting strategy for insect pollinated herbaceous perennial species was to sample >150 plants, equalize maternal contribution, and sample along random transects with sufficient space between plants to minimize intrafamilial sampling. Quantifying genetic change between ex situ and in situ accessions allows genetic resource managers to validate ex situ collecting and maintenance protocols, develop appropriate recollection intervals, and provide an early detection mechanism for identifying problematic conditions that can be addressed to prevent further decline in vulnerable in situ populations.

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“…Landraces and ecotypes of red clover not only form a valuable source for breeding, they substantially contribute to the biodiversity of natural and managed grasslands. Changes in land-use patterns and the increased use of elite cultivars threaten the genetic diversity of native and naturalised ecotypes and emphasises the need for an efficient management of genetic resources (Morris and Greene 2001).…”

Section: Introductionmentioning

confidence: 99%

Swiss Mattenklee landraces, a distinct and diverse genetic resource of red clover (Trifolium pratense L.)

et al. 2003

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Genetic variability within and among 19 landraces and cultivars of red clover ( Trifolium pratense L.) was investigated by means of amplified fragment length polymorphism (AFLP) analysis in order to assess the potential value of Swiss Mattenklee landraces as genetic resources for plant breeding and the preservation of biodiversity. Populations were classified into three groups according to their origin and agronomic features: Mattenklee landraces (8), Mattenklee cultivars (8) and field clover cultivars (3). Analysis of molecular variance based on 276 polymorphic AFLP markers revealed 80% of total variability to be due to variability within populations while 12% were attributed to variability among groups. Stepwise discriminant analysis identified a subset of 126 AFLP markers which best separated individual plants into the three respective groups. Genetic distances between populations were considerably larger among groups than among populations within the same group, providing further evidence for the genetic distinction between Mattenklee landraces, Mattenklee cultivars and field clover cultivars. AFLP markers identified two landrace clusters, containing three and four populations respectively, which, together with one additional landrace, may sufficiently represent the genetic variability of all eight landraces investigated. The results of this study strongly suggest that Swiss Mattenklee landraces form a genetically distinct group of red clover. The data obtained provide criteria on how to efficiently manage, preserve and exploit Mattenklee germplasm.

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Defining a Multiple‐Use Germplasm Collection for the Genus Trifolium

Cited by 23 publications

References 45 publications

Identification of barriers to interspecific crosses in the genus Trifolium

Identification of barriers to interspecific crosses in the genus Trifolium

Conserving Plants in Gene Banks and Nature: Investigating Complementarity with Trifolium thompsonii Morton

Swiss Mattenklee landraces, a distinct and diverse genetic resource of red clover (Trifolium pratense L.)

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