Growing Soybean Varieties from Multiple Maturity Groups Can Reduce Yearly Yield Volatility

In the Kentucky Soybean Performance Test program, varieties of maturity groups (MG) 3, 4 and 5 are tested to provide information on their relative yields. The difference in maturity between the earliest and the latest maturing variety in the test in any year is approximately 30 days. In general, although some regional differences appear, the long-term state-wide and within region yield of the different maturity groups (average yield of a 11 varieties in a maturity group) is equal (Table 1). As I\u27ve inspected results from the Kentucky Soybean Performance Tests for the last decade, it appeared that some of the variation in yield among varieties at a particular location in a particular year was due solely to the maturity of the variety. Furthermore, large deviations in maturity group yield occurred during consecutive years even within the same testing region. These points are illustrated in Table 1 by specific years from the Lexington, Wickliffe, and Nebo tests. The purpose of this note is to illustrate and discuss reducing soybean yield volatility by growing varieties from different maturity groups

Using Performance Test Results in Soybean Variety Selection in Kentucky

Many soybean varieties are available to, soybean producers in Kentucky each year. Information is available from company advertisements, private yield tests, and public performance tests which producers can use when selecting a variety. The question arises as to how this information relates to variety performance on a particular farm. The value of yield test data lies in the predictive ability of that data. How well does data from a set of environments predict relative performance among varieties over the wide range of possible environments in which those varieties can be grown? The first objective of this note is to discuss the best subset of environments to use for predicting future variety performance. This discussion involves variety selection for yield where no predictable yield reducing factor, .such as soybean cyst nematode, is present. Soybean varieties of maturity group (MG) 3, HG 4 and MG 5 are grown successfully in Kentucky. Thus, a second objective of this report is to discuss how maturity group affects soybean variety performance in Kentucky

Stubble Losses of Kentucky Soybeans

Double crop soybeans in Kentucky tend to be shorter than plants from full season plantings. Since lowest pod height is related to plant height, double crop soybeans may be subject to greater harvest losses due to pods remaining below the level at which the combine header is operated. While it would be possible to lower the header closer to the soil to pick up some of those pods, that would slow down harvest and increase the risk of picking up stones and other trash. Although the actual cutting heights used in Kentucky are not known, some producers use combines with flexible ground-hugging headers, and others use nonflexible headers. Regardless of header type, some producers cut higher to avoid stones or to complete harvest more quickly

Does Chemical Leaf Burn of Double Crop Soybeans Reduce Yield?

Most farmers who have applied acifluorfen (sold as Blazer or Tackle) for postemergence control of broadleaf weeds in soybean fields are aware that leaf crinkling, bronzing, and necrosis can result. Despite this, studies in Kentucky, Illinois, Arkansas, and South Carolina have shown that full season soybeans have plenty of time to recover from leaf burn caused by this herbicide, and no yield losses have been found. However, double crop soybeans are usually planted much later than the full season crop. This delay in planting may reduce the time for plants to complete vegetative growth before beginning the seed production process. Therefore, double crop soybeans may be limited in their ability to recover from acifluorfen injury in time to produce as much grain as nonsprayed soybeans. Our objective was to determine if yields of double crop soybeans are reduced by leaf burn due to the use of acifluorfen

Evaluation of a Skip-Row Planting System or Plant Run-Over as Management Practices on Full Season Soybeans in Narrow Rows

In recent years there has been an increased interest in narrow row and solid seeded soybeans in Kentucky. Soybeans seeded in narrow rows have an earlier canopy closure which allows a longer time for the soybean plants to intercept the maximum amount of sunlight. The shading effect which results from earlier canopy closure also aids in weed suppression. More farmers are now seeding full season soybeans in narrow rows or solid seeded stands; because cultivation is eliminated, however, some are hesitant to adopt narrow row production practices for fear of inadequate chemical weed control. With the recent increase in effective postemergence herbicides for weed control in soybeans, farmers now have several opportunities to achieve adequate weed control using only herbicides. The objective or this research was to evaluate the effect on soybean yields of leaving skip-rows for equipment passage or of plant damage from running over the soybeans at various stages. In narrow row systems postemergence herbicide application will result in plant damage to those plants run over during application

Row Widths for Full Season Soybeans in Kentucky

Soybean yields in Kentucky have increased steadily in the past 20 years as a result of improved varieties and production practices. To achieve even higher yields new varieties and better production practices need to be developed and tested. One possibility for increasing soybean yields is to plant in narrow rows using varieties which respond to this practice. Although previous research in Kentucky has not shown a yield advantage for full season soybeans planted in narrow rows, researchers in other states have recently shown increases in yield with narrowing row widths. A number of new varieties have also been developed specifically for narrow row plantings. These varieties are shorter, lodge less, and have a high yield potential. This study was designed to answer the question: Will narrow row widths provide higher yields for these soybean varieties when grown under full season conditions in Kentucky

Chiral Modes at Exceptional Points in Exciton-Polariton Quantum Fluid

We demonstrate the generation of chiral modes-vortex flows with fixed handedness in exciton-polariton quantum fluids. The chiral modes arise in the vicinity of exceptional points (non-Hermitian spectral degeneracies) in an optically induced resonator for exciton polaritons. In particular, a vortex is generated by driving two dipole modes of the non-Hermitian ring resonator into degeneracy. Transition through the exceptional point in the space of the system's parameters is enabled by precise manipulation of real and imaginary parts of the closed-wall potential forming the resonator. As the system is driven to the vicinity of the exceptional point, we observe the formation of a vortex state with a fixed orbital angular momentum (topological charge). This method can be extended to generate higher-order orbital angular momentum states through coalescence of multiple non-Hermitian spectral degeneracies. Our Letter demonstrates the possibility of exploiting nontrivial and counterintuitive properties of waves near exceptional points in macroscopic quantum systems

Direct measurement of polariton-polariton interaction strength in the Thomas-Fermi regime of exciton-polariton condensation

Bosonic condensates of exciton polaritons (light-matter quasiparticles in a semiconductor) provide a solid-state platform for studies of non-equilibrium quantum systems with a spontaneous macroscopic coherence. These driven, dissipative condensates typically coexist and interact with an incoherent reservoir, which undermines measurements of key parameters of the condensate. Here, we overcome this limitation by creating a high-density exciton-polariton condensate in an optically-induced "box" trap. In this so-called Thomas-Fermi regime, the condensate is fully separated from the reservoir and its behaviour is dominated by interparticle interactions. We use this regime to directly measure the polariton-polariton interaction strength, and reduce the existing uncertainty in its value from four orders of magnitude to within three times the theoretical prediction. The Thomas-Fermi regime has previously been demonstrated only in ultracold atomic gases in thermal equilibrium. In a non-equilibrium exciton-polariton system, this regime offers a novel opportunity to study interaction-driven effects unmasked by an incoherent reservoir.Comment: 11 pages, 5 figure

Herd-level animal management factors associated with the occurrence of bovine neonatal pancytopenia in calves in a multicountry study

Since 2007, mortality associated with a previously unreported haemorrhagic disease has been observed in young calves in several European countries. The syndrome, which has been named ‘bovine neonatal pancytopenia’ (BNP), is characterised by thrombocytopenia, leukocytopenia and a panmyelophthisis. A herd-level case-control study was conducted in four BNP affected countries (Belgium, France, Germany and the Netherlands) to identify herd management risk factors for BNP occurrence. Data were collected using structured face-to-face and telephone interviews of farm managers and their local veterinarians. In total, 363 case farms and 887 control farms were included in a matched multivariable conditional logistic regression analysis. Case-control status was strongly associated with the odds of herd level use of the vaccine PregSure® BVD (PregSure, Pfizer Animal Health) (matched adjusted odds ratio (OR) 107.2; 95% CI: 41.0–280.1). This was also the case for the practices of feeding calves colostrum from the calf’s own dam (OR 2.0; 95% CI: 1.1–3.4) or feeding pooled colostrum (OR 4.1; 95% CI: 1.9–8.8). Given that the study had relatively high statistical power and represented a variety of cattle production and husbandry systems, it can be concluded with some confidence that no other herd level management factors are competent causes for a sufficient cause of BNP occurrence on herd level. It is suggested that genetic characteristics of the dams and BNP calves should be the focus of further investigations aimed at identifying the currently missing component causes that together with PregSure vaccination and colostrum feeding represent a sufficient cause for occurrence of BNP in calves

Finishing a whole-genome shotgun: Release 3 of the Drosophila melanogaster euchromatic genome sequence

BACKGROUND: The Drosophila melanogaster genome was the first metazoan genome to have been sequenced by the whole-genome shotgun (WGS) method. Two issues relating to this achievement were widely debated in the genomics community: how correct is the sequence with respect to base-pair (bp) accuracy and frequency of assembly errors? And, how difficult is it to bring a WGS sequence to the accepted standard for finished sequence? We are now in a position to answer these questions. RESULTS: Our finishing process was designed to close gaps, improve sequence quality and validate the assembly. Sequence traces derived from the WGS and draft sequencing of individual bacterial artificial chromosomes (BACs) were assembled into BAC-sized segments. These segments were brought to high quality, and then joined to constitute the sequence of each chromosome arm. Overall assembly was verified by comparison to a physical map of fingerprinted BAC clones. In the current version of the 116.9 Mb euchromatic genome, called Release 3, the six euchromatic chromosome arms are represented by 13 scaffolds with a total of 37 sequence gaps. We compared Release 3 to Release 2; in autosomal regions of unique sequence, the error rate of Release 2 was one in 20,000 bp. CONCLUSIONS: The WGS strategy can efficiently produce a high-quality sequence of a metazoan genome while generating the reagents required for sequence finishing. However, the initial method of repeat assembly was flawed. The sequence we report here, Release 3, is a reliable resource for molecular genetic experimentation and computational analysis