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-R-2 ratio value (diverse and representative) were 'Marbel F1' and Gy 14.

"USDA-ARS Multicolored Ornamental Festuca Grass Cultivars "Freedom Fire" 'Francy', 'Vida', 'Heidi', and 'Kim' for Low-input Applications in Semiarid Environments" published on Jun 2017 by American Society for Horticultural Science.

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.

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.

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.

Species of the genus Poa are taxonomically and genetically difficult to delineate owing 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 samples of P. pratensis and P. arachnifera to hone in on possible ancestral genomes in these two agronomic and highly polyploidy species. Relative to most species of Poa, 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 previously reported 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.

Quantitative trait locus mapping is often useful for understanding the number and the direction of effects for traits in germplasm of interest. New genotype-by-sequencing (GBS) methods are available for genetic mapping, but their application toward autopolyploid plants is limited. In this paper we discuss adapting semi-conductor sequencing to GBS of autotetraploid cocksfoot (Dactylis glomerata). Based on empirical results from a previous study, we selected 48 samples to pool on an Ion Torrent P1 sequencing chip. Whereas the Illumina-based SNP detection pipeline was designed to identify SNP markers in 64 bp sequence reads, the longer length of semi-conductor sequences was mined for additional SNPs. Using a small subset of plants from an F1 cocksfoot mapping population, a genetic linkage map was constructed with GBS-derived markers and previously mapped SSR markers, and between 25 and 29 homologous linkage groups were detected with high LOD probability. These data provide evidence of successful implementation of existing GBS pipelines when using semi-conductor sequencing on complex autotetraploid plants.

•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.

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.

Genetic transformation using foreign genes and the subsequent development of transgenic plants has been employed to develop enhanced elite germplasm. Although some skepticism exits regarding pollen tube-mediated gene transfer (PTT), reports demonstrating improved transformation efficiency with PTT systems are increasing and encouraging and the adoption of increasingly refined pollen-mediated methodologies may lead to species-dependent improvements in breeding. Here, we highlight PTT technology as an alternative to genetic transformation.

Native grasses planted or growing on sites contaminated by heavy metals should be safe for livestock and wildlife. Plant breeders seek to identify genes and quantitative trait loci (QTLs) controlling trace element variation among these grasses.

Environmental stresses such as chilling temperatures can reduce seed germination rate, seedling emergence rate, flower and fruit development, marketable yield, and postharvest fruit storage longevity in cucumber (Cucumis sativus L.) (Staub and Bacher, 1997;Staub and Wehner, 1996).Chilling temperatures occur in unpredictable patterns, making it difficult to implement management practices for crop protection.Moreover, response of cucumber seedlings to chilling depends on pre-and postchilling environment.Therefore, breeding for tolerance to chilling is an attractive management tool to minimize crop loss.Chilling injury at the first true-leaf stage in cucumber is controlled by simple plastidic (maternal; Chung et al., 2003) and nuclear (parental; Kozik and Wehner, 2008) factors.While Chung et al. (2007) identified three putative plastidic single-nucleotide polymorphisms (SNPs) associated with chilling tolerance in processing cucumber 'Chipper', Kozik and Wehner (2008) characterized one dominant nuclear gene, Ch, in line NC-76 (derived from PI 246930).The response of chilling tolerant 'Chipper' and line NC-76 seedlings challenged at 4 °C for 5.5 h under 270 mmol • m -2 • s -1 photosynthetic photon flux irradiance are similar (Gordon and Staub, 2011).No chilling-tolerant U.S.-processing cucumber varieties are commercially available.Although the processing cultivar Chipper (released in 1968 from Clemson University, Clemson, SC) possesses plastid genes for chilling tolerance in the seedling stage, its yield and quality are substantially lower than current cultivars.Therefore, experiments were undertaken to introgress the plastid chilling tolerance of 'Chipper' (donor parent) into the commercially acceptable processing cucumber line M29 [recurrent parent; experimental inbred line (S 11 ), North Carolina State University, Raleigh, NC] via backcrossing and self-pollination (Gordon and Staub, 2013).As a result, a series of three advanced backcross (ABL; BC 5 ) and 10 inbred backcross (IBL; BC 2 S 3-5 ) chilling-tolerant U.S.processing lines possessing acceptable yield and quality traits are being released by the Agricultural Research Service (ARS), U.S. Department of Agriculture (USDA).The chilling tolerance of backcross progeny is characterized by their response to chilling stress (5.5 h at 4 °C in 270 mmol • s -2 • m -2 cool white lighting) at the first true-leaf stage under controlled environmental conditions.These lines provide chilling-tolerant genetic stocks suitable for immediate use by cucumber improvement programs.

Compact and dwarfing vining habits in melon (Cucumis melo L.; 2n = 2x = 24) may have commercial importance since they can contribute to the promotion of concentrated fruit set and can be planted in higher plant densities than standard vining types. A study was designed to determine the genetics of dwarfism associated with a diminutive (short internodes) melon mutant line PNU-D1 (C. melo ssp. cantalupensis). PNU-D1 was crossed with inbred wild-type melon line PNU-WT1 (C. melo ssp. agrestis), and resultant F-1 progeny were then self-pollinated to produce an F-2 population that segregated as dwarf and vining plant types. Primary stem length of F-2 progeny assessed under greenhouse conditions indicated that a single recessive gene, designated mdw1, controlled dwarfism in this population. To identify the chromosomal location associated with mdw1, an simple sequence repeat (SSR)-based genetic linkage map was constructed using 94 F-2 progeny. Using 76 SSR markers positioned on 15 linkage groups spanning 462.84 cM, the location of mdw1 was localized to Chromosome 7. Using the putative dwarfing-associated genes, fine genetic mapping of the mdw1 genomic region was facilitated with 1,194 F-2 progeny that defined the genetic distance between mdw1 and cytokinin oxidase gene, a candidate gene for compact growth habit (cp) in cucumber, to be 1.7 cM. The candidate gene ERECTA (serin/threonine kinase) and UBI (ubiquitin) were also mapped to genomic regions flanking mdw1 at distances of 0.6 and 1.2 cM, respectively.

The responses to chilling temperature of 12 Korean cucumber varieties was compared to those of two U.S.A. (previously determined cold tolerant NC76 and 'Chipper'), and Chinese and Japanese germplasms. Seedlings of each entry were exposed to 4 degrees C (Experiment 1) and 1 degrees C (Experiments 2 and 3) at the first-true leaf stage for eight and nine hours, respectively, under 80% relative humidity (RH) and 149 mu moles.m(-2).s(-1) photosynthetic photon flux (PPF). The chilling response [damage rating (DR)] of each accession was based on visual ratings (1 to 5) after treatment, where 1 = no damage, 2 = slight, 3 = moderate, 4 = advanced, and 5 = severe damage. Predictably the cumulative average DR of chilling tolerant line NC76 and 'Chipper' after chilling was 1 and 1.1, respectively. Korean 'Nacdongchungjang' was most sensitive to chilling temperatures [DR = 2.3] when compared to the other entries examined. The sensitivity to chilling of 'Nacdongchungjang' was followed by Chinese 'Dongguan' [DR = 1.7]. In contrast, 'Saeronchungjang' (DR = 1) and 'Janghyungnachap' (DR = 1) were the most chilling tolerant of the Korean accessions examined and equivalent to the response of line NC76 and 'Chipper'. Nevertheless, chloroplast type genotyping of these accessions with known chilling-linked sdCAPS genomic markers revealed genotypic differences between chilling tolerant lines (NC76 and 'Chipper') and all Korean lines examined.

Environmental stresses such as chilling temperatures can decrease germination, emergence, flower and fruit development, marketable yield, and postharvest fruit storage longevity in cucumber (Cucumis sativus L.). While response to chilling injury in cucumber is controlled by simple plastidic (maternal) and nuclear (paternal) factors, no chilling tolerant U.S. processing varieties are commercially available. Furthermore, even though three single nucleotide polymorphic sites have been identified as plastid components associated with chilling tolerance in cucumber, it is not known how these factors interact with nuclear factors controlling economically important traits. Therefore, an experiment was designed to evaluate the rate of recovery of the chilling susceptible (cytoplasm) genotype during introgression backcrossing (IB), where it was used as a recurrent parent after the initial mating to a line possessing chilling tolerant cytoplasm (donor parent). Phenotypic yield and quality trait data were collected on processing type backcross progeny (BC1–5 and BC2S3) derived from an initial ‘Chipper’ (tolerant) × line M 29 (susceptible) mating, and rate of progression to the recurrent parent was determined by simple sequence repeat marker and morphological trait analyses. Substantial degrees of the recurrent parent phenotype and nuclear genome were recovered by the BC2 generation (P = 0.001), with nearly complete recovery of recurrent parental traits and its nuclear genome occurring by the BC3. General combining ability (GCA) of derived BC2S3 lines was significant for yield, yield/plant, length (L), diameter (D), and L:D ratios. The BC2S3 line GCA and rate of progression towards the recurrent parent for economically important traits suggests that elite chilling tolerant cucumber germplasm can be developed rapidly through IB and marker genotyping.

Continued reduction in limited natural resources worldwide increasingly necessitates the incorporation of low-maintenance and low-input plant materials into urban landscapes. Some fine-leaved Festuca grass species have been used in formal gardens and native urban landscapes because of their inherent tolerance to abiotic stresses, but native, ornamental types (tall and non-spreading with multicolored culms and panicles) are not common in landscapes of the western United States. A native fine-leaved Festuca collection made in Montana (designated FEID 9025897) by the U.S. Natural Resources Conservation Services possesses such ornamental characteristics but has not been evaluated for its horticultural potential. Therefore, a study was designed to assess its phenotypic and genotypic attributes by cloning 270 FEID 9025897 plants and evaluating them along with native F. idahoensis and F. ovina PIs (five) and commercial checks (five) for genetic diversity and plant morphology for 2 years (2010–11). Plant genetic constitution was determined using amplified fragment length polymorphism (AFLP) analysis. Plant height, width, biomass, relative vigor (visual rating of 0 = dead to 5 = green, abundant growth), persistence (number of plants alive per plot), and regrowth after clipping (visual rating of 0 = none to 5 = most) were estimated by evaluation of plants under replication at Hyde Park, UT. Based on AFLP-based coancestry analysis, FEID 9025897 plants possessed considerable genetic affinities with F. idahoensis. Morphological traits as averaged over both years varied in height (13.9 to 105.0 cm), width (9.9 to 66.2 cm), biomass (0 to 170.4 g), vigor (0.2 to 4.7), persistence (0 to 3.9), and regrowth (0 to 4.0). Based on these differences, 19 (7%) FEID 9025897 plants were identified for their ornamental potential that possessed multicolored (red, orange, and yellow) culms and varied in morphology with 2-year means of height (79.8 cm), width (45.2 cm), biomass (88.5 g), vigor (2.9), persistence (1.8), and regrowth (3.7).

Fine-leaved Festuca valesiaca Schleich. ex Gaudin (2n = 2x–4x) is native to heavily-grazed, cold, semi-arid, Asian rangelands. However, its potential for low-maintenance turf applications in the semi-arid western United States and its relatedness to other agriculturally important Festuca species have not been investigated. Therefore, a project was designed to identify F. valesiaca accessions that possess horticultural potential when grown under semi-arid growing conditions and to characterize their relatedness to other Festuca species. In 2008, 12 F. valesiaca accessions originating from Kyrgyzstan and eight US. Festuca and one Lolium cultivar were transplanted as replicated, spaced plants to a field nursery at Blue Creek, Utah. Relative vigor, height, width, total biomass (aboveground dry matter yield), seed weight, and seed number were evaluated between 2009 and 2011. Plant height, width, and total biomass of the F. valesiaca accessions examined were approximately equal to the commercial control, ‘Cascade’ (F. rubra L. subsp. commutata Gaudin; 6x; chewings fescue). Plant vigor and seed weight of F. valesiaca accessions PI 659923, PI 659932, W6 30575, and W6 30588 under semi-arid conditions (~300 mm annual precipitation) were significantly (P < 0.05) greater than ‘Cascade’. Moreover, principal component analysis based on all traits as loading factors indicated that these 12 F. valesiaca accessions were distinct from a majority of the other Festuca accessions examined. These F. valesiaca accessions produced abundant amounts of small seed, and this seed yield was significantly correlated with total aboveground biomass (dry weight; r 2  = 0.84, P < 0.001), plant height (r 2  = 0.58, P < 0.05), and plant vigor (r 2  = 0.83, P < 0.001). Amplified fragment length polymorphism (AFLP) analysis (1,454 polymorphic bands) was used to characterize F. valesiaca relatedness to other economically important Festuca species. The AFLP-based, neighbor-joining analysis differentiated F. valesiaca accessions from US Festuca cultivars examined, except for ‘Durar’ (F. ovina L.; 6x; sheep fescue), to which they had strong genetic affinities. Given their morphological attributes, F. valesiaca PI 659923, W6 30575, PI 659932, and W6 30588 should be considered for use in low-maintenance, semi-arid turf improvement programs in the western US.

Chilling temperatures (<10 C) may cause damages in cucumber plants (Cucumis sativus L) during winter and early spring seasons. Inheritance of chilling injury in U.S. processing cucumber is controlled by cytoplasmic (maternally) and nuclear factors. To understand inheritance of chilling injury in Korean market-type cucumber, reciprocal crosses between chilling tolerant (CT1) and susceptible (CT4) lines produced F1 (CT1 x CT4) and F-1 (CT4 x CT1) progenies. Reciprocal F2 (CT1 x CT4) and F-2 (CT4 x CT1) populations were subsequently derived. Seedlings in the first true leaf stage were subjected to 4 C for 8 h (08:00 to 16:00) and damage level was assessed visually using 1 (no damage) to 5 (severe damage) rating scale. Means of damage rating for reciprocal F1 (CT1 x CT4) and F-1 (CT4 x CT1) progenies were 1.1 and 1.1, respectively. This indicates that tolerance for chilling stress at 4 C in this germplasm is dominant. However, means of damage for F-2 (CTI x CT4) progenies and F-2 (CT4 x CT1) progenies were 3.2 and 1.2, respectively. These data indicate that genetic control of chilling injury in these progenies is paternal. Based on the data, we hypothesize that line CT1 possesses a dominant nuclear factor that conditions chilling tolerance in both reciprocal Els and a paternal factor(s) that lead chilling tolerance only in F-2 (CT4 x CTI). These putative nuclear and paternal genetic factors are designated as Ch-1 and Ch-p, respectively. (C) 2014 Elsevier B.V. All rights reserved.