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101.
Johnie N. Jenkins Jack C. McCarty Martin J. Wubben Russell Hayes Osman A. Gutierrez Franklin Callahan Dewayne Deng 《Euphytica》2012,183(1):49-54
Cotton (Gossypium hirsutum L) cultivars highly resistant to the southern root-knot nematode (RKN) [Meloidogyne incognita (Kofoid and White) Chitwood] are not available. Resistant germplasm lines are available; however, the difficulty of selecting
true breeding lines has hindered applied breeding and no highly resistant cultivars are available to growers. Recently, molecular
markers on chromosomes 11 and 14 have been associated with RKN resistance, thus opening the way for marker assisted selection
(MAS) in applied breeding. Our study aimed to determine the utility of these markers for MAS. Cross one was RKN resistant
germplasm M240 RNR × the susceptible cultivar, FM966 and is representative of the initial cross a breeder would make to develop
a RKN resistant cultivar. Cross two consists of Clevewilt 6 × Mexico Wild (PI563649), which are the two lines originally used
to develop the first highly RKN resistant germplasm. Mexico Wild is photoperiodic. We phenotyped the F2 of cross one for gall index and number of RKN eggs per plant and genotyped each plant for CIR 316 (chromosome 11) and BNL
3661 (chromosome 14). From this, we verified that MAS was effective, and the QTL on chromosome 14 was primarily associated
with a dominant RKN resistance gene affecting reproduction. In the first F2 population of cross two, we used MAS to identify 11 plants homozygous for the markers on chromosomes 11 and 14, and which
also flowered in long days. Progeny of these 11 plants were phenotyped for RKN gall index and egg number and confirmed as
RKN highly resistant plants. Generally about 7–10 generations of RKN phenotyping and progeny testing were required to develop
the original RKN highly resistant germplasms. Our results show that commercial breeders should be able to use the markers
in MAS to rapidly develop RKN resistant cultivars. 相似文献
102.
Forsius M. Alveteg M. Jenkins A. Johansson M. Kleemola S. Lükewille A. Posch M. Sverdrup H. Walse C. 《Water, air, and soil pollution》1998,105(1-2):21-30
Three well-known dynamic acidification models (MAGIC, SAFE, SMART) were applied to data sets from five Integrated Monitoring sites in Europe. The calibrated models were used in a policy-oriented framework to predict the long-term soil acidification of these background forest sites, given different scenarios of future deposition of S and N. Emphasis was put on deriving realistic site-specific scenarios for the model applications. The deposition was calculated with EMEP transfer matrices and official emissions for the target years 2000, 2005 and 2010. The alternatives for S deposition were current reduction plans and maximum feasible reductions. For N, the NOx and NHy depositions were frozen at the present level. For NOx, a reduction scenario of flat 30% reduction from present deposition also was utilized to demonstrate the possible effects of such a measure. The three models yielded generally consistent results. The ‘Best prediction’-scenario (including the effects of the second UN/ECE protocol for reductions of SO2 emissions and present level for NOx-emissions), resulted in many cases in a stabilization of soil acidification, although significant improvements were not always shown. With the exception of one site, the ‘Maximum Feasible Reductions’ scenario always resulted in significant improvements. Dynamic models are needed as a complement to steady-state techniques for estimating critical loads and assessing emission reduction policies, where adequate data are available. 相似文献
103.
This paper expands on a short voluntary presentation, by the first two authors, to the 18th IUFRO World Congress held at Ljubljana, Yugoslavia, in September 1986. It describes management procedures and incorporates biological and economic data, from a number of agro-silvo-pastoral trials in the South West of Western Australia.The integration of pine timber and livestock production is shown to have a range of economic and environmental benefits available in the long-term. Ways in which the choice of tree density, planting pattern and silvicultural regime can each be directed towards the achievement of various objectives are indicated. 相似文献
104.
Jenkins PL Stack SG Earle-Richardson GB Scofield SM May JJ 《Journal of agricultural safety and health》2007,13(1):57-64
Dairy farmers may be exposed to high levels of noise and dust. Protections against these hazards exist, but many farmers do not use them. An intervention consisting of hearing and respiratory screenings combined with personalized education was implemented. This study evaluates the impact of this intervention on farmers' self-reported use of personal protective equipment (PPE) and implementation of noise and dust abatement. Participants were screened as to noise (n=209) or dust (n=392) hazards and use of PPE. Following this, they were counseled on PPE use, and identification and reduction of noise or dust hazards. Counselors sought a pledge from the farmers to eliminate hazards and increase PPE use. Farmers were subsequently surveyed and asked whether they had implemented the changes. At baseline, 70% (146/209) of farmers exposed to high levels of noise reported poor use ("sometimes", "rarely", or "never") of hearing protection. Results indicated that two months after intervention, 25.2% (28/111) of these subjects had successfully improved their PPE use. At baseline, 79% (311/392) offarmers reported poor use of respiratory protection, with 27.3% (41/150) showing improvement in PPE use within the same time. Strategies to reduce noise hazards were identified by 92.8% (194/209) of hearing screening attendees; 13.2% (18/136) successfully reduced or removed exposure. These values for dust screening attendees were 98.2% (385/392) and 30.7% (54/176), respectively. Use of this intervention appears to be an effective method for increasing PPE use on the farm. However, it is not effective for reducing noise hazards. 相似文献
105.
May JJ Sorensen JA Burdick PA Earle-Richardson GB Jenkins PL 《Journal of agricultural safety and health》2006,12(3):199-213
Tractor overturns contribute significantly to fatalities in New York State agriculture. On-site inspections a decade ago indicated that approximately 60% of tractors were without effective rollover protection. Our objectives were: to describe the current prevalence and distribution of rollover protective structures (ROPS) on New York farm tractors, to identify characteristics associated with the absence of ROPS, to explore segmenting the New York farm community on readiness for ROPS retrofitting, and to identify demographic characteristics that might assist in this segmenting. A random selection of 644 livestock, dairy, fruit, cash crop, vegetable, and organic farms were contacted for a telephone survey. Of 562 farms (87%) participating, 102 (18.1%) had all tractors equipped with ROPS and 138 (24.6%) had none. A disproportionate number of livestock, cash crop, and organic operations had no ROPS. Rates of ROPS-equipped tractors correlated directly with farm size and annual hours of tractor operation. Older farmers had a lower proportion of ROPS tractors. The presence of a child operator did not affect the proportion of ROPS tractors. After weighting the sample, the total number of non-ROPS tractors in New York is estimated at more than 80,000. In addition to providing key farm demographics, the survey enabled placement of farmers on a "stage of change" continuum related to readiness for retrofitting. Three-quarters of New York farmers are in the "precontemplation" stage of change relative to ROPS retrofitting, and this varies little by size of operation, age of farmer, or the presence of child tractor operators. Stage of change may relate to hours of tractor operation (p = 0.05) and does relate to commodity (p = 0.003) due primarily to the higher proportion of crop farmers in the earliest stage of change. The goal of retrofitting all New York farm tractors with ROPS appears nearly as daunting as it did a decade ago. 相似文献
106.
The Caenorhabditis elegans anteroposterior axis is established in response to fertilization by sperm. Here we present evidence that RhoA, the guanine nucleotide-exchange factor ECT-2, and the Rho guanosine triphosphatase-activating protein CYK-4 modulate myosin light-chain activity to create a gradient of actomyosin, which establishes the anterior domain. CYK-4 is enriched within sperm, and paternally donated CYK-4 is required for polarity. These data suggest that CYK-4 provides a molecular link between fertilization and polarity establishment in the one-cell embryo. Orthologs of CYK-4 are expressed in sperm of other species, which suggests that this cue may be evolutionarily conserved. 相似文献
107.
DL Jenkins LG Davis TW Stafford PF Campos B Hockett GT Jones LS Cummings C Yost TJ Connolly RM Yohe SC Gibbons M Raghavan M Rasmussen JL Paijmans M Hofreiter BM Kemp JL Barta C Monroe MT Gilbert E Willerslev 《Science (New York, N.Y.)》2012,337(6091):223-228
The Paisley Caves in Oregon record the oldest directly dated human remains (DNA) in the Western Hemisphere. More than 100 high-precision radiocarbon dates show that deposits containing artifacts and coprolites ranging in age from 12,450 to 2295 (14)C years ago are well stratified. Western Stemmed projectile points were recovered in deposits dated to 11,070 to 11,340 (14)C years ago, a time contemporaneous with or preceding the Clovis technology. There is no evidence of diagnostic Clovis technology at the site. These two distinct technologies were parallel developments, not the product of a unilinear technological evolution. "Blind testing" analysis of coprolites by an independent laboratory confirms the presence of human DNA in specimens of pre-Clovis age. The colonization of the Americas involved multiple technologically divergent, and possibly genetically divergent, founding groups. 相似文献
108.
Lina Tang Zhengji Piao Michael A. Jenkins Gang Wu Jingzhu Zhao 《Biological conservation》2010,143(5):1295-1298
Forest degradation in protected areas has been monitored around the world with remote sensing data, but degradation processes undetectable by widely used satellite sensors have been largely overlooked. Increased human pressures and socioeconomic development make forest protection more challenging, particularly for forest ecosystems that lie across national borders because of the differences in national socioeconomic policies and conditions within them. Here with Landsat data, Google Earth images, and field observations, we show that, in two adjacent biosphere reserves across the border of China and North Korea, over one half of primary forest landscapes have been deteriorated by exploitive uses, including seed harvesting and systematic logging. The combined effects of detectable and hidden degradation processes have further damaged forest ecosystems in the core areas in the two biosphere reserves, threatening sustainable biodiversity conservation in the region. It is urgent to develop cross-border collaborative conservation strategies that can help combat both detectable and hidden degradation processes at a regional scale. 相似文献
109.
Rio de Janeiro state in Brazil has one of the most diverse and most endangered avifaunas in the continental Americas. Many of these endangered birds are endemic to the Atlantic Forest biodiversity hotspot, and some even endemic to Rio de Janeiro itself. As with all other forested hotspots, little original forest remains. Much of that is outside formal protected areas and faces the risk of deforestation. These factors create special circumstances for setting conservation priorities — ones common to hotspots in general — but typically not to many conservation priority setting exercises.We mapped the distribution of the remaining habitat for the 189 birds in Rio de Janeiro state that are officially endangered and/or endemic to the Atlantic Forest. Using those habitat maps, we calculated the amount of habitat currently within protected areas for each species. We then prioritized all non-protected parts of the state for their avian conservation value and their potential contribution to a comprehensive protected area system. This analysis identified 10% of the remaining unprotected part of the state as the highest priority for avian conservation. We further highlight specific locations where conservation actions could create a more comprehensive protected area system for the avifauna of Rio de Janeiro state. 相似文献
110.
Buttrey EK Cole NA Jenkins KH Meyer BE McCollum FT Preece SL Auvermann BW Heflin KR MacDonald JC 《Journal of animal science》2012,90(13):5086-5098
Two hundred sixty-four crossbred heifers (initial BW = 354 kg ± 0.5) were used to determine effects of corn processing method and wet distillers grains plus solubles (WDGS) inclusion in finishing diets on animal performance, carcass characteristics, and manure characteristics. The study was conducted as a randomized complete block with a 2 × 2 factorial arrangement of treatments. Dietary treatments included steam-flaked corn (SFC)- and dry-rolled corn (DRC)-based finishing diets containing 0 or 20% WDGS (0SFC, 20SFC, 0DRC, and 20DRC, respectively). Heifers averaged 154 d on feed and were marketed in 3 groups. There were no interactions between corn processing method and WDGS detected (P ≥ 0.29) for any performance or carcass response variables. Heifers fed diets containing WDGS tended to have greater final BW (P = 0.10) and increased G:F (P = 0.08) compared with heifers fed diets without WDGS. Heifers fed SFC-based diets consumed 7% less feed (P < 0.01) and were 9% more efficient (P < 0.01) than heifers fed DRC-based diets. Carcass characteristics were not affected by corn processing method or WDGS inclusion (P ≥ 0.16). Intakes of OM, N, P, and K were greater (P ≤ 0.05) for heifers fed DRC-based diets than those fed SFC-based diets, which resulted in greater net accumulation of the nutrients in the manure (P ≤ 0.04). Heifers fed diets containing WDGS had greater (P < 0.01) intakes of N, P, and K than heifers fed diets without WDGS. As a result, a greater net accumulation of P and K (P ≤ 0.03) and N (P = 0.10) were present in the manure from cattle fed diets containing WDGS compared with those fed diets without WDGS. There was no interaction (P ≥ 0.16) between corn processing and WDGS on N volatilization losses. Nitrogen volatilization losses from manure (expressed as a percentage of intake and g·heifer(-1)·d(-1)) were greater (P < 0.01) for heifers fed SFC-based diets than heifers fed DRC-based diets. Feeding DRC-based finishing diets to heifers resulted in increased manure production and nutrient excretion and decreased N volatilization. Both corn processing method and WDGS inclusion affected animal performance and manure characteristics. 相似文献