Fairway crested wheatgrass, which is identified taxonomically as Agropyron cristatum (L . ) Gaertn. (45 ), A. cristatiforme (38) , or A. pectiniforme Roem. and Schult (22), is an economically important range grass belonging to the "crested wheatgrass complex" (24, 38). The crested wheatgrass complex includes diploid, 2n = 14, tetraploid, 2n = 28, and hexaploid, 2n = 42, forms (1, 11, 22). The variety Fairway and Fairway-like derivatives are the only known diploid members of the species complex (24, 38). Meiotic chromosome behavior of Fairway diploids appears to be typical of other diploid species; however, the number of plants examined cytologically has been relatively small. Although Fairway crested wheatgrass is a good seed producer, interplant variation in fertility is high (13, 22, 25, 42). Irregular chromosome behavior is a common source of sterility and may be contributing to the variable seed set in diploid crested wheatgrass. No information is available concerning the relation of meiotic chromosome behavior to fertility in Fairway crested wheatgrass. Polyploid crested wheatgrasses are generally considered to be of autoploid origin, i.e., they are derived by duplication of the chromosome complement of a diploid prototype. Chromosome pairing in the polyploid species (31), in interspecific hybrids (12), and in polyhaploid plants (11) substantiate the autoploid derivation of polyploid crested wheatgrass. Diploid and tetraploid forms of crested wheatgrass have been hybridized by Knowles (24), and chromosome pairing in the hybrids suggest a close relation between the diploid and tetraploid genomes. Colchicine-induced tetraploids of Fairway crested wheatgrass have been produced by Knowles, 1 and these artificial tetraploids are currently being utilized in his crested wheatgrass breeding program. If the full breeding and cytogenetic potentials of diploid crested wheatgrass are to be realized, the meiotic chromosome behavior and the cytotaxonomic status of this species must be fully understood. The present investigation was designed to provide further information concerning the cytogenetic characteristics of Fairway crested wheatgrass and its autotetraploid derivatives. This investigation was established with the following objectives: 1. To examine meiotic chromosome behavior of Fairway crested wheatgrass. 2. To determine the relation of meiotic chromosome behavior to fertility in Fairway crested wheatgrass. 3. To evaluate the effectiveness of several colchicine treatments in doubling the chromosome complement of Fairway crested wheatgrass. 4. To determine the effect of induced polyploidy on plant morphology in colchicine-induced tetraploids of Fairway crested wheatgrass. 5. To determine the meiotic chromosome behavior and fertility of induced tetraploids of Fairway crested wheatgrass.

Western prairie clover [Dalea ornata (Douglas ex Hook.) Eaton & J. Wright] is a perennial legume that occurs in the northern Great Basin, Snake River Basin, and southern Columbia Plateau, whereas Searls prairie clover [Dalea searlsiae (A. Gray) Barneby], also a perennial legume, occurs in the southern Great Basin and surrounding areas. Understanding the genetic and ecotypic variation of these prairie clovers is a prerequisite for developing populations suitable for rangeland revegetation in the western USA. DNA sequences of internal transcribed spacer (ITS/5.8S) and trnK/matK were used to study the phylogeny of these species. The species were distinguished by DNA sequences from both regions and conserved haplotypes were observed between and within species. Common-garden plots of 22 collections of western prairie clover from Idaho, Oregon, and Washington and 20 collections of Searls prairie clover from Utah and Nevada were established in northern Utah for phenotypic evaluation. Significant variation was detected among the collections for all traits measured in the common gardens for both species. Flowering date was correlated with collection-site temperature and elevation in western prairie clover collections, whereas biomass-related traits were closely related with collection-site precipitation in Searls prairie clover. Population structure from amplified fragment length polymorphism (AFLP) markers resulted in two distinct, genetically differentiated groups and a third admixed group in western prairie clover, and flowering date played a significant role in discriminating those genetic-based groupings of collections. For western prairie clover, two populations are recommended for development, one from the Deschutes River watershed and another from the remaining collections. For Searls prairie clover, two genetically different groups of collections were identified from southern Utah and eastern Nevada and from northwestern Utah. Three western Nevada collections exhibited close association with eastern Nevada and southern Utah groups for AFLP-markers but with collections from northwestern Utah for phenotypic traits. Strong isolation by distance was observed for Searls prairie clover collections suggesting that genetic drift and gene flow are major factors for determining population structure in this species. As a result, two regional seed sources should be developed for Searls prairie clover, one from northwestern Utah and the other from eastern Nevada and southern Utah.

Understanding the biotic factors influencing invasive plant performance is essential for managing invaded land and preventing further exotic establishment and spread. I studied how competition between both conspecifics and native co-habitants and arbuscular mycorrhizal fungal (AMF) impacted the success of the invasive bunchgrass Brachypodium sylvaticumin early growth stages. I examined whether invasive plants performed and competed differently when grown in soil containing AMF from adjacent invaded and noninvaded ranges in order to determine the contribution of AMF to both monoculture stability and spread of the invasive to noninvaded territory. I also directly manipulated common mycelial network (CMN) formation by AMF to determine hyphal network contribution to competitive interactions. I found that invasive plants performed most poorly (as indicated by decreased chlorophyll content, size and shoot dry mass) in invaded range soil against conspecifics. This could be two-pronged evidence for existing biotic pressure on the invasives to expand into adjacent noninvaded ranges. I also found a negative effect of AMF colonization and invasive plant performance, potentially indicating deleterious plant-soil feedbacks which could help maintain plant biodiversity at a community level. CMN effects were found to be interactive with root competition and directly affected the performance and nutrient status of B. sylvaticum. Although no direct correlations between AMF colonization levels and competition were found, CMN presence contributed significantly to plant growth and nutrient status. Therefore AMF, through infection and CMN formation, may be able to influence invasive plant growth and spread in the field.

Fleshy fruits in different species can display large variation in color. A link between fruit color and seed dispersal success is suggested by previous studies showing that high intensity of fruit color increases the visitation rate in seed-dispersing birds. Wild tomato species (Solanum spp.) are excellent model organisms for research on genetic basis of differential fruit color development during the ripening process. Despite polymorphism in fruit color, all tomato species have yellow flowers due to accumulation of carotenoid pigments, which suggests that the carotenoid pathway is intact. Thus, regulatory changes controlling enzymes activity during fruit maturation are likely to have played a role in fruit color evolution. Our transcriptome analysis of wild tomato species revealed that differences in cyc-b and crtr-b2 expression could explain the diversity of fruit color. Additionally, co-expression analysis elucidated regulators of the carotenoid pathway. Combined with Sanger sequencing of carotenoid pathway genes, we identified genes that may underlie differences in fruit color during tomato evolution.

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