Genetic by environment interaction on fresh root yield, dry matter content and total carotene concentration of yellow-fleshed cassava genotypes in five major cassava growing agroecological zones in Nigeria

Eighteen yellow-fleshed cassava genotypes and two released white-fleshed clones (check) were evaluated in five locations representing the major cassava growing agroecological zones of Nigeria to access their performance for fresh root yield, dry matter content, total carotene content and genotypes by environment interaction effects. The aim of the study was to identify stable cassava genotypes that combine high root yield, and high dry matter with high beta carotene content in storage root. The study was conducted in two cropping seasons (2008/2009 and 2009/2010) at Ikenne (humid forest), Ibadan (forest-savanna transition), Ubiaja (sub-humid forest), Mokwa (sub-humid southern-Guinea savanna) and Zaria (moist northern-Guinea savanna). At all locations, the trials were conducted in a randomised complete block design (RCBD) with four replications. The combined analysis of variance showed that fresh root yield (t ha-1), dry matter content (%) and total carotene content (μg g-1 fresh weight) was significantly affected (P < 0.001) by Genotype (G), Environment E, and G × E interaction. For fresh root yield, the best genotype was IITA TMS I050024 followed by IITA TMS I050998 and IITA TMS I050286. For dry matter content of the storage roots, the genotype IITA TMS 1051570 had the highest score followed by IITA TMS 1051740 and IITA IMS I050998. For total carotene content, the best genotypes across the 10 environments in decreasing order of carotene content were IITA TMS I051601, IITA TMS I050311, IITA TMS I050998 and IITA TMS I050099. When combining fresh root yield and dry matter content (dry yield), the genotypes IITA TMS I050998 and IITA TMS I051740 ranked highest. The Environment effect accounted for most of the variation of the total sum of squares (SS) for fresh root yield (55.0%), dry matter content (42.3%) and dry yield (57.9%). The genotype accounted for most of the SS for total carotene content (67.9%)

Information and Design: Book Symposium on Luciano Floridi’s The Logic of Information

Purpose – To review and discuss Luciano Floridi’s 2019 book The Logic of Information: A Theory of Philosophy as Conceptual Design, the latest instalment in his philosophy of information (PI) tetralogy, particularly with respect to its implications for library and information studies (LIS). Design/methodology/approach – Nine scholars with research interests in philosophy and LIS read and responded to the book, raising critical and heuristic questions in the spirit of scholarly dialogue. Floridi responded to these questions. Findings – Floridi’s PI, including this latest publication, is of interest to LIS scholars, and much insight can be gained by exploring this connection. It seems also that LIS has the potential to contribute to PI’s further development in some respects. Research implications – Floridi’s PI work is technical philosophy for which many LIS scholars do not have the training or patience to engage with, yet doing so is rewarding. This suggests a role for translational work between philosophy and LIS. Originality/value – The book symposium format, not yet seen in LIS, provides forum for sustained, multifaceted and generative dialogue around ideas

Molecular markers associated with a new source of resistance to the cassava mosaic disease

The predominant source of resistance to the cassava mosaic disease (CMD) is known to be polygenic requiring evaluation in multiple environments to characterise resistant genotypes, which makes the detection of genes for resistance using segregation analysis inefficient. Recently, some landraces have been identified which exhibit high levels of resistance to CMD. In this study, molecular markers associated with resistance to CMD in a resistant landrace were identified, using F1 progenies derived from a cross between the CMD resistant landrace TME7 and the susceptible line TMS30555, as a first step in marker assisted breeding for CMD resistance. Bulk segregant analysis (BSA) on the parents, resistant and susceptible DNA pools, using simple sequence repeat (SSR) and amplified fragment length polymorphism (AFLP) markers revealed that an SSR marker, SSRY28-180, donated by the resistant parent was linked with resistance to CMD. Marker-trait association detected by regression analysis showed that the marker, accounted for 57.41% of total phenotypic variation for resistance. The analysis furthershowed that another SSR marker, SSRY106-207 and an AFLP marker, E-ACC/M-CTC-225, accounted for 35.59% and 22.5% of the total phenotypic variation for resistance, respectively. The implication of the results in breeding for resistance to CMD is discussed

One-vortex moduli space and Ricci flow

The metric on the moduli space of one abelian Higgs vortex on a surface has a natural geometrical evolution as the Bradlow parameter, which determines the vortex size, varies. It is shown by various arguments, and by calculations in special cases, that this geometrical flow has many similarities to Ricci flow.Comment: 20 page

Constraints on Finite Soft Supersymmetry-Breaking Terms

Requiring the soft supersymmetry-breaking (SSB) parameters in finite gauge-Yukawa unified models to be finite up to and including two-loop order, we derive a two-loop sum rule for the soft scalar-masses. It is shown that this sum rule coincides with that of a certain class of string models in which the massive string states are organized into N=4 supermultiplets. We investigate the SSB sector of two finite SU(5) models. Using the sum rule which allows the non-universality of the SSB terms and requiring that the lightest superparticle particleis neutral, we constrain the parameter space of the SSB sector in each model.Comment: 34 page

Stringy origin of non-Abelian discrete flavor symmetries

We study the origin of non-Abelian discrete flavor symmetries in superstring theory. We classify all possible non-Abelian discrete flavor symmetries which can appear in heterotic orbifold models. These symmetries include D_4 and Delta(54). We find that the symmetries of the couplings are always larger than the symmetries of the compact space. This is because they are a consequence of the geometry of the orbifold combined with the space group selection rules of the string. We also study possible breaking patterns. Our analysis yields a simple geometric understanding of the realization of non-Abelian flavor symmetries.Comment: 27 pages, 4 figures, v2: matches version published in Nuclear Physics

A passive transmitter for quantum key distribution with coherent light

Signal state preparation in quantum key distribution schemes can be realized using either an active or a passive source. Passive sources might be valuable in some scenarios; for instance, in those experimental setups operating at high transmission rates, since no externally driven element is required. Typical passive transmitters involve parametric down-conversion. More recently, it has been shown that phase-randomized coherent pulses also allow passive generation of decoy states and Bennett-Brassard 1984 (BB84) polarization signals, though the combination of both setups in a single passive source is cumbersome. In this paper, we present a complete passive transmitter that prepares decoy-state BB84 signals using coherent light. Our method employs sum-frequency generation together with linear optical components and classical photodetectors. In the asymptotic limit of an infinite long experiment, the resulting secret key rate (per pulse) is comparable to the one delivered by an active decoy-state BB84 setup with an infinite number of decoy settings.Comment: 10 pages, 4 figures. arXiv admin note: substantial text overlap with arXiv:1009.383