Breeding for cob traits in maize

The advantages of maize cobs as cellulosic feedstock are based on their compact architecture and high fraction of cellulose and hemicellulose. Cobs are low in ash content, nutrients, and minerals and their harvest will likely not deplete the soil. Dual-purpose maize, with larger cob biomass and high tissue density, could reduce transport costs providing more farmers with additional income from cob sales. The objective of this study was to lay the foundation for developing dual-purpose maize, combining high cob biomass and grain yield. This included a morphological and genetic analysis of cob characters under varying environments, as well as their relationships to grain yield. In addition, as starting point for further research of cob biomass traits, novel germplasm was developed including a biparental doubled haploid population. Overall, grain yield was positively correlated with all cob architecture traits but independent from cob density. Gene mapping experiments were performed in two different two intermated B73 x Mo17 (IBM) populations under varying nitrogen managements. For cob tissue density, two of the largest QTL were identified in both IBM populations on chromosomes 5 and 7 each explaining 7.7-10.7% of the phenotypic variation. These regions are known to contain candidate genes ra1 and ba2, involved in branching and branch elongation. Available maize accessions with extreme cob architecture likely carry novel alleles or genes for cob size and tissue density. Using this potential from new resources in combination with the findings and summarized information for cob biomass genetics from this research further progress with developing dual purpose maize varieties can be accomplished

NAVIGATING ETHICAL AND MORAL CHALLENGES LEADERS FACE IN STAKEHOLDER CAPITALISM

One can assume that the ethical business leader of the 21st century will need to become a leader of community in which they operate, answering to all stakeholders, guiding all stakeholders, mediating all stakeholders’ concerns. A virtuous position at first glance and one leader wants to aspire to in theory but frequently fail at in practice. The current paper strives to underline the need of ethical conduct at both leader and stakeholders’ level and proposes the introduction of a code of ethical principles to be followed and introduced by the leader and all stakeholders in an organization. Such a code should promote a set of well-established principles to be agreed and followed by the parties involved. A five criteria set is proposed for the development of further codes of conduct, that will lead to more appropriate judgements and findings

Genetic and Morphometric Analysis of Cob Architecture and Biomass-Related Traits in the Intermated B73 × Mo17 Recombinant Inbred Lines of Maize

Expected future cellulosic ethanol production increases the demand for biomass in the US Corn Belt. With low nutritious value, low nitrogen content, and compact biomass, maize cobs can provide a significant amount of cellulosic materials. The value of maize cobs depends on cob architecture, chemical composition, and their relation to grain yield as primary trait. Eight traits including cob volume, fractional diameters, length, weight, tissue density, and grain yield have been analyzed in this quantitative trait locus (QTL) mapping experiment to evaluate their inheritance and inter-relations. One hundred eighty-four recombinant inbred lines of the intermated B73 × Mo17 (IBM) Syn 4 population were evaluated from an experiment carried out at three locations and analyzed using genotypic information of 1,339 public SNP markers. QTL detection was performed using (1) comparison-wise thresholds with reselection of cofactors (α = 0.001) and (2) empirical logarithm of odds score thresholds (P = 0.05). Several QTL with small genetic effects (R2 = 2.9–13.4 %) were found, suggesting a complex quantitative inheritance of all traits. Increased cob tissue density was found to add value to the residual without a commensurate negative impact on grain yield and therefore enables for simultaneous selection for cob biomass and grain yield

Coarse Projective kMC Integration: Forward/Reverse Initial and Boundary Value Problems

In "equation-free" multiscale computation a dynamic model is given at a fine, microscopic level; yet we believe that its coarse-grained, macroscopic dynamics can be described by closed equations involving only coarse variables. These variables are typically various low-order moments of the distributions evolved through the microscopic model. We consider the problem of integrating these unavailable equations by acting directly on kinetic Monte Carlo microscopic simulators, thus circumventing their derivation in closed form. In particular, we use projective multi-step integration to solve the coarse initial value problem forward in time as well as backward in time (under certain conditions). Macroscopic trajectories are thus traced back to unstable, source-type, and even sometimes saddle-like stationary points, even though the microscopic simulator only evolves forward in time. We also demonstrate the use of such projective integrators in a shooting boundary value problem formulation for the computation of "coarse limit cycles" of the macroscopic behavior, and the approximation of their stability through estimates of the leading "coarse Floquet multipliers".Comment: Submitted to Journal of Computational Physic

Why leadership fails? Few causes for why good leaders do bad things:

The six factors considered for achieving success in leadership are clarity, role modeling, achievability, commitment, transparency and openness. The article analyzes the factors that generate a failure of leadership, even for the so-called widely renewed good leaders, precisely the behavior causes and developments that lead to failure and not their acquiring process. The chosen target population is represented by the leaders ruling large organizations, which need an integrated vision to produce effective leadership. The perspective will have a theoretical basis but also an empirical one. The quantitative part relies on a survey conducted among leaders for three different industries (pharmaceutical, IT and telecom). They were asked questions regarding the causes, which produce leadership failure and finally produce misconduct and breaches of the compliance rules and regulations. In addition, the survey asked the participants to develop their proposals for preventing leadership failure. It was established the importance of the tone from the top, leading by example, a clear mechanism for checking the health of the organization from a leadership perspective. The article will also show that the way to prevent leadership failure and avoid behaviors that lead to misconduct is a permanent journey

Evaluation of strategies to optimize training populations for genomic prediction in oat (Avena sativa)

publishedVersio

Evaluation of strategies to optimize training populations for genomic prediction in oat (Avena sativa)

publishedVersio

Genotypic variation and relationships between seedling and adult plant traits in maize (Zea mays L.) inbred lines grown under contrasting nitrogen levels

Genotypes with better root development have good nutrient acquisition capacity and may yield better under limited nitrogen (N) conditions and consequently can help reduce the N fertilization rate and hence mitigate some economic and ecological problems. This study focused on the genotypic variation among diverse maize inbred lines for seedling and adult plant traits under contrasting N levels. Seventy four lines were screened under high and low N levels in a climate chamber and in the field. High phenotypic diversity was observed for seedling and adult plant traits together with moderate to high broad-sense heritability estimates. Seedling total root length and root dry weight were significantly correlated with other root traits in maize. Of the adult plant traits evaluated in the field, the anthesis-silking interval and the leaf chlorophyll contents were significantly correlated with grain yield under both low and high N levels. In one location, the seminal root length was correlated with grain yield both under low and high N levels and the root dry weight was correlated with grain yield under high N. Selection indices based on secondary root traits along with grain yield could lead to an increase in selection efficiency for grain yield under N stress condition. By identifying lines with better root development, particularly lines with longer SRL, it may be possible to select inbred lines with higher grain yield particularly under low N condition

Association analysis of genes involved in maize (Zea mays L.) root development with seedling and agronomic traits under contrasting nitrogen levels

Genotypes with large and well distributed root system might have the potential to adapt to soils with limited nutrient availability. For this purpose, an association study (AS) panel consisting of 74 diverse set of inbred maize lines were screened for seedling root traits and adult plant root traits under two contrasting nitrogen (N) levels (low and high N). Allele re-sequencing of RTCL, RTH3, RUM1, and RUL1 genes related to root development was carried out for AS panel lines. Association analysis was carried out between individual polymorphisms, and both seedling and adult plant traits, while controlling for spurious associations due to population structure and kinship relations. Based on the SNPs identified in RTCL, RTH3, RUM1, and RUL1, lines within the AS panel were grouped into 16, 9, 22, and 7 haplotypes, respectively. Association analysis revealed several polymorphisms within root genes putatively associated with the variability in seedling root and adult plant traits development under contrasting N levels. The highest number of significantly associated SNPs with seedling root traits were found in RTCL (19 SNPs) followed by RUM1 (4 SNPs) and in case of RTH3 and RUL1, two and three SNPs, respectively, were significantly associated with root traits. RTCL and RTH3 were also found to be associated with grain yield. Thus considerable allelic diversity is present within the candidate genes studied and can be utilized to develop functional markers that allow identification of maize lines with improved root architecture and yield under N stress conditions

Genetic and agronomic assessment of cob traits in corn under low and normal nitrogen management conditions

With rising energy demands and costs for fossil fuels, alternative energy from renewable sources such as maize cobs will become competitive. Maize cobs have beneficial characteristics for utilization as feedstock including compact tissue, high cellulose content, and low ash and nitrogen content. Nitrogen is quantitatively the most important nutrient for plant growth. However, the influence of nitrogen fertilization on maize cob production is unclear. In this study, quantitative trait loci (QTL) have been analyzed for cob morphological traits such as cob weight, volume, length, diameter and cob tissue density, and grain yield under normal and low nitrogen regimes. 213 doubled-haploid lines of the intermated B73 × Mo17 (IBM) Syn10 population have been resequenced for 8575 bins, based on SNP markers. A total of 138 QTL were found for six traits across six trials using composite interval mapping with ten cofactors and empirical comparison-wise thresholds (P = 0.001). Despite moderate to high repeatabilities across trials, few QTL were consistent across trials and overall levels of explained phenotypic variance were lower than expected some of the cob trait × trial combinations (R2 = 7.3–43.1 %). Variation for cob traits was less affected by nitrogen conditions than by grain yield. Thus, the economics of cob usage under low nitrogen regimes is promising