Genetic gains in tropical maize hybrids across moisture regimes with multi-trait-based index selection.

Unpredictable weather vagaries in the Asian tropics often increase the risk of a series of abiotic stresses in maize-growing areas, hindering the efforts to reach the projected demands. Breeding climate-resilient maize hybrids with a cross-tolerance to drought and waterlogging is necessary yet challenging because of the presence of genotype-by-environment interaction (GEI) and the lack of an efficient multi-trait-based selection technique. The present study aimed at estimating the variance components, genetic parameters, inter-trait relations, and expected selection gains (SGs) across the soil moisture regimes through genotype selection obtained based on the novel multi-trait genotype-ideotype distance index (MGIDI) for a set of 75 tropical pre-released maize hybrids. Twelve traits including grain yield and other secondary characteristics for experimental maize hybrids were studied at two locations. Positive and negative SGs were estimated across moisture regimes, including drought, waterlogging, and optimal moisture conditions. Hybrid, moisture condition, and hybrid-by-moisture condition interaction effects were significant (p ≤ 0.001) for most of the traits studied. Eleven genotypes were selected in each moisture condition through MGIDI by assuming 15% selection intensity where two hybrids, viz., ZH161289 and ZH161303, were found to be common across all the moisture regimes, indicating their moisture stress resilience, a unique potential for broader adaptation in rainfed stress-vulnerable ecologies. The selected hybrids showed desired genetic gains such as positive gains for grain yield (almost 11% in optimal and drought; 22% in waterlogging) and negative gains in flowering traits. The view on strengths and weaknesses as depicted by the MGIDI assists the breeders to develop maize hybrids with desired traits, such as grain yield and other yield contributors under specific stress conditions. The MGIDI would be a robust and easy-to-handle multi-trait selection process under various test environments with minimal multicollinearity issues. It was found to be a powerful tool in developing better selection strategies and optimizing the breeding scheme, thus contributing to the development of climate-resilient maize hybrids.

Genomic Regions Associated With Salinity Stress Tolerance in Tropical Maize (Zea Mays L.).

Being a widely cultivated crop globally under diverse climatic conditions and soil types, maize is often exposed to an array of biotic and abiotic stresses. Soil salinity is one of the challenges for maize cultivation in many parts of lowland tropics that significantly affects crop growth and reduces economic yields. Breeding strategies integrated with molecular approach might accelerate the process of identifying and developing salinity-tolerant maize cultivars. In this study, an association mapping panel consisting of 305 diverse maize inbred lines was phenotyped in a managed salinity stress phenotyping facility at International Center for Biosaline Agriculture (ICBA), Dubai, United Arab Emirates (UAE). Wide genotypic variability was observed in the panel under salinity stress for key phenotypic traits viz., grain yield, days to anthesis, anthesis-silking interval, plant height, cob length, cob girth, and kernel number. The panel was genotyped following the genome-based sequencing approach to generate 955,690 SNPs. Total SNPs were filtered to 213,043 at a call rate of 0.85 and minor allele frequency of 0.05 for association analysis. A total of 259 highly significant (P ≤ 1 × 10-5) marker-trait associations (MTAs) were identified for seven phenotypic traits. The phenotypic variance for MTAs ranged between 5.2 and 9%. A total of 64 associations were found in 19 unique putative gene expression regions. Among them, 12 associations were found in gene models with stress-related biological functions.

Synthesis of some N4-substituted isatin-3-thiosemicarbazones.

In this article, we describe a simple and new method for the synthesis of some N4-substituted isatin-3-thiosemicarbazones based on the reactions of the common intermediate, methyl 2-(2-oxo-1,2-dihydro-3H-indol-3-ylidene)-1-hydrazinecarbodithioate, prepared by condensing isatin with methyl 1-hydrazinecarbodithioate, and the readily available amines in essentially a one-step reaction. The synthesized thiosemicarbazones were fully characterized by their physical, analytical, and spectral (IR, 1H-NMR, EIMS) data.

Surgical approaches for inserting hemiarthroplasty of the hip.

BACKGROUND: The operation of insertion of a hemiarthroplasty to the hip refers to replacement of the femoral head with a prosthesis, whilst retaining the natural acetabulum and acetabular cartilage. The main surgical approaches to the hip for insertion of the prosthesis can be broadly categorised as either 'anterior' via the anterior joint capsule, or 'posterior' through the posterior joint capsule. OBJECTIVES: To evaluate, based on evidence from randomised controlled trials, the effects of different surgical approaches for the insertion of a hemiarthroplasty to the hip has on clinical outcomes. SEARCH STRATEGY: We searched the Cochrane Musculoskeletal Injuries Group specialised register (up to February 2002). Articles of all languages were considered. SELECTION CRITERIA: All randomised controlled trials comparing insertion of a hemiarthroplasty by different surgical approaches. DATA COLLECTION AND ANALYSIS: Both reviewers independently assessed trial quality, using a 10 item scale, and extracted data. Wherever appropriate and possible, the data are presented graphically. MAIN RESULTS: One randomised trial was identified involving 114 patients. The trial had poor methodology (particularly in susceptibility to selection bias), inadequate follow-up of patients who withdrew, and there was limited reporting of results. Medical complications and mortality from six months to two years appeared greater in the posterior group; this difference in mortality, within the structure of the poor methodology, was statistically significant. No other differences were claimed to be significant. REVIEWER'S CONCLUSIONS: There is currently insufficient evidence from randomised trials to determine the optimum surgical approach for insertion of a hemiarthroplasty to the hip.

Results of the long Gamma nail for complex proximal femoral fractures.

The results for a series of 35 patients with complex proximal femoral fractures treated with the long Gamma nail are presented. Fracture healing occurred in all surviving patients, but there were four technical problems associated with the implant. Two nails broke associated with delayed union of the fracture necessitating revision of the implant, one fracture of femur at the site of distal locking occurred during surgery and there was one later fracture at the tip of the nail. All but one failures of fixation were revised with another Gamma nail and healed uneventfully. Overall the number of fracture healing complications compares favourably to contemporary implants and improvements in the design and strength of the nail may further improve results.

Staphylococcus epidermidis with intermediate resistance to vancomycin: elusive phenotype or laboratory artifact?

The recent and troubling isolation of Staphylococcus aureus and coagulase-negative staphylococci that have increased resistance to glycopeptide antibiotics has prompted the use of aggressive surveillance measures in the clinical microbiology laboratory to aid in the recognition of these strains. Despite increasing awareness, the confirmation of glycopeptide resistance among staphylococci can be problematic; we present a case of catheter-associated peritonitis caused by Staphylococcus epidermidis to illustrate the dilemma.

Studies of the effect of anions (chloride, sulphate, nitrate, oxalate and acetate) on the pharmacological properties ofcobalt (ii) complexes with dithiooxamide-derived antibacterial agents.

A number of cobalt (II) complexes with dithiooramide derived antibacterial agents having different anions i.e., chloride, sulphate, nitrate, oxalate and acetate have been synthesised, and the effect of anions on antibacterial properties of these complexes against bacterial species Staphylococcus aureus, Streptococcus pneumoniae and Escherichia coli has been determined.