Oxygen for the delivery room respiratory support of moderate-to-late preterm infants. An international survey of clinical practice from 21 countries.

AIM: The aim of this study was to determine clinician opinion regarding oxygen management in moderate-late preterm resuscitation. METHODS: An anonymous online questionnaire was distributed through email/social messaging platforms to neonatologists in 21 countries (October 2020-March 2021) via REDCap. RESULTS: Of the 695 respondents, 69% had access to oxygen blenders and 90% had pulse oximeters. Respondents from high-income countries were more likely to have oxygen blenders than those from middle-income countries (72% vs. 66%). Most initiated respiratory support with FiO2 0.21 (43%) or 0.3 (36%) but only 45% titrated FiO2 to target SpO2 . Most (89%) considered heart rate as a more important indicator of response than SpO2 . Almost all (96%) supported the need for well-designed trials to examine oxygenation in moderate-late preterm resuscitation. CONCLUSION: Most clinicians resuscitated moderate-late preterm infants with lower initial FiO2 but some cannot/will not target SpO2 or titrate FiO2 . Most consider heart rate as a more important indicator of infant response than SpO2 .Large and robust clinical trials examining oxygen use for moderate-late preterm resuscitation, including long-term neurodevelopmental outcomes, are supported amongst clinicians.

A QTL with major effect on reducing leaf rust severity on the short arm of chromosome 1A of wheat detected across different genetic backgrounds and diverse environments.

KEY MESSAGE: Selection for QLr.cau - 1AS (a major QTL detected in wheat for reducing leaf rust severity) based on the DNA marker gpw2246 was as effective as selection for Lr34 based on cssfr5. Leaf rust is an important disease of wheat worldwide. Utilization of slow-rusting resistance constitutes a strategy to sustainably control this disease. The American wheat cultivar Luke exhibits slow leaf-rusting resistance at the adult plant stage. The objectives of this study were to detect and validate QTL for the resistance in Luke. Three winter wheat populations were used, namely, 149 recombinant inbred lines (RILs) derived from the cross Luke × Aquileja, 307 RILs from Luke × AQ24788-83, and 80 F2:3 families selected from Lingxing66 × KA298. Aquileja and Lingxing66 are highly susceptible to leaf rust. AQ24788-83 shows high (susceptible) infection type but contains the slow-rusting gene Lr34 as diagnosed by the gene-specific marker cssfr5. KA298, an F9 RIL selected from Luke × AQ24788-83, contains Lr34 and QLr.cau-1AS (a major QTL originated from Luke, this study). These wheats were evaluated for leaf rust in 12 field and greenhouse environments involving four locations and five seasons. Genotyping was done using simple sequence repeat (SSR) and diversity arrays technology markers. Of the detected QTLs, QLr.cau-1AS was significant consistently across all the genetic backgrounds, test environments, and likely a wide range of pathogen races. QLr.cau-1AS explained 22.3-55.2% of leaf rust phenotypic variation, being comparable to Lr34 in effect size. A co-dominant SSR marker (gpw2246, http://wheat.pw.usda.gov/GG2/index.shtml ) was identified to be tightly linked to QLr.cau-1AS. Selection based on gpw2246 for QLr.cau-1AS was as effective as the selection based on cssfr5 for Lr34. QLr.cau-1AS will be helpful for increasing the genetic diversity of slow leaf-rusting resistance in wheat breeding programs.