Jack E. Staub’s research while affiliated with University of Wisconsin–Madison and other places

Reliable yield performance is important in cucumber because seed companies prefer to market cultivars adapted to multiple rather than single regions of the U.S. Also, growers benefit by using a cultivar that performs well in many environments. Future performance of cultivars is also important. The objectives of the study were to (i) evaluate the yield of cucumber genotypes over successive years and in different locations, and (ii) identify cucumber genotypes with high stability for yield. A diverse set of 22 pickling genotypes was evaluated over 3 years (1986, 1987 and 1988) and in 7 locations across the United States. Yield traits were evaluated using once-over harvest and counting the number of fruit that were marketable, culled or oversize. Total yield, marketable yield (total minus culled fruit), early yield (number of oversize fruit), percent culls and fruit per plant were calculated. Data were analyzed with SASGxE and RGxE programs using SAS and R programming languages, respectively. There were strong effects of environment(E) as well as genotype(G) xE interaction for all traits. Genotypes ‘Regal F1’, ‘Calypso F1’, ‘Carolina F1’, ‘Gy 3’, ‘Gy 14’ and ‘Fremont F1’ had high marketable yield and medium to high stability for all traits. There was an advantage of hybrids over inbreds for trait performance. Hybrids fell into a single cluster with large prediction intervals. Based on the stability statistics and divisive clusters, it appears possible to breed stable cucumber genotypes with high yield. The genotype with highest performance for marketable yield, greatest stability for yield, lowest 1-R2 ratio value (diverse and representative) were ‘Marbel F1’ and Gy 14.

There is a need for drought tolerant grass germplasm for use in wildfire control on degraded landscapes of western US rangelands. In 2006, multi-national plant expeditions collected eight fine-leafed Festuca rubra L. (2n = 6x–8x) accessions from the harsh semi-arid rangelands of Kyrgyzstan (KGZ) and the People’s Republic of China (CHN) that may have potential for use in western U.S. rangelands. Morphological and marker-based genetic analyses compared these collections with nine commercial cultivars, and four previously described high performance KGZ F. valesiaca Schleich. ex Gaudin subsp. valesiaca plant introductions in the high desert of the U.S. Great Basin. Initially, accession morphology was evaluated over 3 years at Blue Creek, UT for relative vigor, height, width, total biomass, persistence, and seed yield. Subsequently, a subset of the F. rubra accessions and checks were evaluated at three locations (Malta, ID, Blue Creek, UT, and North Logan, UT) over 2 years. All entries differed for all traits over years and locations in both trials, and CHN PI 659984 was consistently the best performing F. rubra entry examined. Marker-based genetic comparisons differentiated the F. rubra from the F. valesiaca accessions and the Festuca checks examined, and the F. rubra accessions based on ploidy and geographic origin. Because the F. rubra accessions examined were erect (25.5–76.4 cm), green during summer months, and rhizomatous with substantial seed fecundity under harsh semi-arid growing conditions, they have potential for inclusion in plant improvement programs for increased sustainability and wildfire control of western U.S. rangelands.

Breeding of native cool-season grasses has the potential to improve forage production and expand the range of bioenergy feedstocks throughout western North America. Basin wildrye (Leymus cinereus) and creeping wildrye (Leymus triticoides) rank among the tallest and most rhizomatous grasses of this region, respectively. The objectives of this study were to develop interspecific creeping wildrye (CWR) × basin wildrye (BWR) hybrids and evaluate their biomass yield relative to tetraploid ‘Trailhead’, octoploid ‘Magnar’ and interploidy-hybrid ‘Continental’ BWR cultivars in comparison with other perennial grasses across diverse single-harvest dryland range sites and a two-harvest irrigated production system. Two half-sib hybrid populations were produced by harvesting seed from the tetraploid self-incompatible Acc:641.T CWR genet, which was clonally propagated by rhizomes into isolated hybridization blocks with two tetraploid BWR pollen parents: Acc:636 and ‘Trailhead’. Full-sib hybrid seed was also produced from a controlled cross of tetraploid ‘Rio’ CWR and ‘Trailhead’ BWR plants. In space-planted range plots, the ‘Rio’ CWR × ‘Trailhead’ BWR and Acc:641.T CWR × Acc:636 BWR hybrids displayed high-parent heterosis with 75% and 36% yield advantages, respectively, but the Acc:641.T CWR × ‘Trailhead’ BWR hybrid yielded significantly less than its BWR high-parent in this evaluation. Half-sib CWR × BWR hybrids of Acc:636 and ‘Trailhead’ both yielded as good as or better than available BWR cultivars, with yields similar to switchgrass (Panicum virgatum), in the irrigated sward plots. These results elucidate opportunity to harness genetic variation among native grass species for the development of forage and bioenergy feedstocks in western North America.

Species in the Poa genus are taxonomically and genetically difficult to delineate due to high and variable polyploidy, aneuploidy, and challenging breeding systems. Approximately 5% of the proposed species in Poa are considered to include or comprise diploids, but very few of those diploids are represented in seed collections. Recent phylogenetic studies of Poa have included some diploid species to elucidate Poa genome relationships. In this study we build upon that foundation of diploid Poa relationships with additional confirmed diploid species and accessions, and with additional chloroplast sequences. We also include a sample from P. pratensis and P. arachnifera to hone in on possible ancestral genomes in these two agronomic and highly polyploidy species. Relative to most of the Poa species, Poa section Dioicopoa (P. ligularis, P. iridifolia, and P. arachnifera) contained relatively large chromosomes. Phylogenies were constructed using the TLF gene region and five additional chloroplast genes, and the placement of new species and accessions fit within chloroplast lineages reported in Soreng et al. (2010) better than by taxonomic subgenera and sections. Low ploidy species in the "P" chloroplast lineage, such as P. iberica and P. remota, grouped closest to P. pratensis.

On the Ground • Climate change models for the western United States predict warmer winters in the Great Basin and hotter, drier summers in the Mojave Desert, increasing the already high rate of rangeland and pasture degradation, which in turn will increase annual grass invasion, escalate wildfire frequency, and reduce forage production. • These changes in western U.S. rangelands will continue to result in the emergence of novel ecosystems that will require different and/or improved plant materials for successful revegetation. • Traditional plant improvement of native and non-native rangeland plant species by the USDA, ARS Forage and Range Research Laboratory (FRRL, Logan, Utah) has been accomplished through rigorous evaluation of seed collections followed by recurrent selection and hybridization of unique plant types within selected populations to identify plants with superior establishment and performance characteristics. After such plant types have been selected, they are further evaluated in multiple ecologically diverse locations to identify broadly adapted superior germplasm for public release. • Plant improvement of perennial grasses, legumes, and forbs by the FRRL has provided and will continue to deliver plant materials that support sustainable rangeland management efforts to service productive and functionally diverse rangelands.

Poa badensis voucher PI 659654 trnT-L intergenic spacer, partial sequence; tRNA-Leu (trnL-UAA) gene and trnL-F intergenic spacer, complete sequence; and tRNA-Phe (trnF-GAA) gene, partial sequence chloroplast.

Poa chaixii voucher GR 11720 trnT-L intergenic spacer, partial sequence; tRNA-Leu (trnL-UAA) gene and trnL-F intergenic spacer, complete sequence; and tRNA-Phe (trnF-GAA) gene, partial sequence; chloroplast

Drought and heat tolerant fine-leaved fescue (Festuca ssp.) grasses have potential as components in rangeland greenstrips for wildfire control in semi-arid climates, although such grasses have not been evaluated under rangeland conditions. Therefore, 63 geographically diverse Festuca accessions of 11 species were evaluated for vigor, color, and biomass in 2009 and 2010 in North Logan, UT to identify grasses for use in U.S. western rangelands. Sixty-two plants representing eight species were selected in 2009 to intermate for further evaluation. Controlled biparental matings among these selections in 2010 produced 18 populations with sufficient seed to be evaluated with three commercial Festuca checks in replicated trials between 2012 and 2013 at Malta, ID, Blue Creek, UT, and North Logan, UT, where mean annual precipitation is 265, 362, and 484 mm, respectively. Plants were evaluated for color, relative vigor, biomass, seed yield, persistence, and regrowth over 2 years. Generally, four fine-leaved populations (R4S4, R4S6, R4S22, and R4S32) with parents originating from Turkey (F. valesiaca subsp. valesiaca), Russia (F. valesiaca, F. valesiaca subsp. valesiaca), Iran (F. valesiaca), and the U.S. (F. ovina) performed equal to or better than ‘Durar’ or ‘Covar’ checks. In Malta (harshest environment), the performance of these four populations compared to ‘Durar’ was 84–210 % for vigor, 79–90 % for color, 65–562 % for biomass, 64–296 % for seed yield, 92–117 % for persistence, and 164–454 % for regrowth, where R4S22 was superior. AFLP analysis indicated that all four populations were distinct, and that R4S4 and R4S6 grouped near ‘Covar’, R4S22 clustered near ‘Black Sheep’ and ‘Durar’, and R4S32 was genetically unique. These populations exhibit drought tolerance and green leaf color under harsh U.S. western desert conditions that make them amendable for use in greenstrips for wildfire control. © 2016, Springer Science+Business Media Dordrecht (outside the USA).

Most melon (Cucumis melo L.) breeding lines in South Korea display andromonoecious sex expression, which necessitates laborious hand emasculation during F1 hybrid seed production. Thus, there is a need to develop monoecious sex types in elite germplasm to obviate self-pollination. Sex expression is associated with floral ethylene production, which, in monecious melon plants, is associated with the A locus. Our study was conducted to develop molecular markers for selection of monoecious plants based on sequence variation inherent in the CmACS-7 gene [encoding 1-aminocyclopropane-1-carboxylic acid synthase (ACS)] that is associated with ethylene production. Full-length CmACS-7 sequences were cloned from a monoecious (MO23) and an andromonoecious (AM24) line. The alignment of those CmACS-7 sequences revealed a single nucleotide polymorphism (SNP; C170T) in exon 1 and an 18 bp indel in the 3′-untranslated region (UTR) of between MO23 and AM24, which was then used to develop a cleaved amplified polymorphic sequence (CAPS) (EX1-C170T) and a sequence characterized amplified region (SCAR) marker (T1ex), respectively. The sex expression and the T1ex SCAR-based genotype of 442 F2 plants derived from a MO23 × AM24 cross was determined. Monoecy and andromonoecy segregated in a 3:1 ratio in F2 progeny, where the sex type of 429 plants (13 plants not classified) co-segregated with the SCAR marker, demonstrating that sex expression regulated by CmACS-7 is controlled by a single dominant gene and that it confers monoecy in line MO23. Allelic variation in 112 geographically diverse melon lines for CmACS-7 as accessed by CAPS EX1-C170T and SCAR T1ex markers indicated that the: 1) exon 1 of CmACS-7 is highly conserved and the SNP/sex expression association detected is highly predictable making it potentially useful for marker-based selection of monoecious plants, and; 2) 18 bp indel mutation in the 3′-UTR was present in various lengths depending on different monoecious melon germplasm. © 2015, Korean Society for Horticultural Science and Springer-Verlag GmbH.