Impact of early seed quality selection on maize inbreds and hybrids

Seed composition, genetic background, and environment influence seed quality. Plant breeders selecting for improved seed composition seldom select their inbreds for improved seed quality traits. The standard germination test evaluates seed viability, but it often overestimates field performance. Therefore, seed vigor tests are used to predict seed germination under stressful environments. There is little information on the possible genetic improvement of seed selected for both, improved seed composition and vigor. The objectives of this study were 1) to evaluate the seed quality attributes of a group of maize (Zea mays L.) inbreds selected for high protein content; 2) to assess whether early selection improves the seed quality and decreases the phenotypic variability of seed vigor in a group of inbreds; and 3) to calculate the breeding parameters of general (GCA) and specific combining ability (SCA). During summer 2002 and 2003, related sets of inbred lines were grown in replicated nurseries near Clinton, IL, and Ames, IA. Seed from each inbred was produced by self pollination. Some of the inbred lines grown in 2002 and all grown in 2003 were high-protein white lines that also had been selected for germination cold tolerance and high post-accelerated aging field emergence. In 2002, the mean percentage of standard germination test, saturated cold test, accelerated aging test, soak test, and fast green test for the group of selected high-protein white inbreds were significantly (P ≤ 0.05) higher than the corresponding average values of the yellow inbred checks. There was genetic variability for seed quality in these sets of high protein white inbreds even after a very intense selection process for improved seed quality traits. GCA effects for seed quality were more important than the SCA effects, indicating that the additive effect of the inbreds was more important than the dominant effect to the final seed quality of the hybrids. Selecting inbreds for high seed quality early in the breeding program is beneficial and important for improving germination and field performance

Isolation and characterization of the aconitate hydratase 4 (Aco4) gene from soybean

Aconitase catalyzes the reversible isomerization of two tricarboxylic acids, citrate and isocitrate, during the Krebs cycle. Five aconitase genes, namely, Aco1, Aco2, Aco3, Aco4, and Aco5, have been identified in soybean. Previously, Aco4 was mapped on chromosome 11. The purpose of this investigation was to isolate and sequence the candidate gene for Aco4. We mapped the Aco4 gene to a 148 kb region on chromosome 11 that contained 19 predicted genes. One of these, Glyma.11G080600, codes for aconitate hydratase. Sequencing of two isozyme variants (A-line and B-line) for Glyma.11G080600 revealed three synonymous and two non-synonymous substitutions. Perhaps, the two non-synonymous substitutions resulted in a variable isozyme pattern between the variants. Glyma.11G080600 contains a catalytic domain and a swivel domain that are known to catalyze isomerization of citrate to isocitrate and swiveling conformational change in the enzyme mechanism, respectively. Conservation of both the domains implies the role of Glyma.11G080600 in the interconversion of citrate and isocitrate. Glyma.11G080600 is expressed in most tissues, with maximum expression in leaves. Phylogenetic analysis of 25 genes from different species displayed three major clusters. Glyma.11G080600 (Aco4) and Glyma.01G162800, which are conserved in Glycine max (L.) Merr. and Glycine soja Siebold. & Zucc., may have common ancestry before G. max and G. soja split

Thin Plate Spline Regression Model Used at Early Stages of Soybean Breeding to Control Field Spatial Variation

Yield variation observed in Soybean (Glycine max) progeny‐row yield trial (PRYT) is the final result of line genotypic merit, field spatial pattern, and experimental error. The spatial variation in field tests could confound the estimates of genetic merits. The objectives of this research were to: i) quantify non‐genetic yield variation in a soybean breeding PRYT; and ii) determine efficiency of the Thin Plate Spline Regression (TPSR) model in adjusting yield because of variation caused by field spatial pattern. The 3rd objective was to evaluate if the use of the TPSR model could improve the selection accuracy of PRYT unreplicated yield tests. Uniformity Study, Early Generation Test, and Confirmation Study were conducted. Our results indicated that large spatial variations in soybean PRYT field could be present as evaluated by the Uniformity Study conducted with two commercial lines. In this experiment, the use of the TPSR proved to be effective in reducing the error variance and the coefficient of variability, with an improvement in relative efficiency (IRE) of 37.9%. In Early Generation Tests, 2565 lines were evaluated within test‐sets along with three checks. The TPSR model also was effective in the Early Generation Tests, the IRE was 40.4%. The correlation coefficients calculated between yield estimates obtained in two-year Early Generation Tests and Confirmation Study improved by 0.21 points compared with results from the non‐TPSR experiments. The results indicated that the use of TPSR model was effective in accounting for some of the spatial variation in field tests

Tallaba

Ġabra ta’ poeżiji u proża li tinkludi: Il-Bravi fid-Dar ta’ Luċija ta’ Dun Pawl – X’Qasma ta’ Qalb ta’ C. M. D – Innu ta’ G. M. A. – Ġens il-Malti ta’ R. Briffa – It-Tallaba minn ta’ Matilde Serao ta’ Ġużè Micallef GoggiN/

Candidate Gene Identification for a Lethal Chlorophyll-Deficient Mutant in Soybean

Chlorophyll-deficient mutants have been studied persistently to understand genetic mechanisms controlling metabolic pathways. A spontaneous chlorophyll-deficient lethal mutant was observed in self-pollinated progeny of a soybean cultivar “BSR 101”. Observed segregation patterns indicated single-gene recessive inheritance for this lethal-yellow mutant. The objectives of this investigation were to develop a genetic linkage map of the region containing the lethal-yellow (YL_PR350) gene and identify putative candidate genes for this locus. The YL_PR350 gene was mapped to chromosome 15 and is flanked by BARCSOYSSR_15_1591 and BARCSOYSSR_15_1597. This region physically spans ~153 kb and there are 14 predicted genes that lie in this region. The predicted gene Glyma.15g275900 is an excellent candidate for the YL_PR350 gene as it is homologous to an Arabidopsis gene, At3g08010, which codes for a chloroplast-localized protein (ATAB2) involved in the biogenesis of Photosystem I and II. This thylakoid membrane protein is crucial for photosynthesis in Arabidopsis. Future characterization of the candidate gene may enhance our knowledge about photosynthesis, a complex metabolic process critical for sustainability of plants

Raising children on a vegan diet: Parents’ opinion on problems in everyday life

A growing number of Italian families are adopting a vegan diet (VD) for their offspring from infancy for various reasons, with health benefits and ethics being the most common reasons. Barriers to effective communication with primary care pediatricians (PCPs) are perceived by many parents and, depending on the actors involved and the environment, a VD may affect social interactions in everyday life. A national cross‐sectional survey was conducted between July and September 2020. Parents of children following a VD completed an online questionnaire. Data from 176 Italian parents were collected. About 72% (71.8%) of the children included in this study had been on a VD since weaning. Parents did not inform their primary care pediatricians (PCP) about the VD in 36.2% of the cases. In 70.8% of the cases, PCPs were perceived as skeptical or against a VD. About 70% (71.2%) of the parents relied on medical dietitians, and 28.2% on nutritionists/dietitians for dietary counseling. Parents administered an individual B12 supplement in 87.2% of the cases. To the best of our knowledge, this survey is the first which explores the relationship between vegan parents and their PCPs, the parental management of their children’s diet and problems regarding the implementation of a VD in everyday life

Readout system test benches

We propose to develop and exploit versatile multi-purpose Personal Computer-based Test Benches to support the evaluation and design of the basic elements required for digital front-end readout and data transmission systems for an LHC experiment. These test benches will have modular hardware facilities for the operation of new readout system components under realistic conditions, and will implement advanced modern software engineering concepts. They will support components such as fast ADCs, hybrid fibre-optic transceivers, and the prototype VLSI systolic array and data-flow processors currently being developed in national research laboratories and by the emerging European HDTV industry. These efforts would also lay the foundations for projects involving the development of custom-designed VLSI circuits