Effects of the Fhb1 gene on Fusarium head blight resistance and agronomic traits of winter wheat

The gene Fhb1 has been used in many countries to improve wheat Fusarium head blight(FHB) resistance. To make better use of this gene in the Yellow-Huai River Valleys Winter Wheat Zone(YHWZ), the most important wheat-producing region of China, it is desirable to elucidate its effects on FHB resistance and agronomic traits in different genetic backgrounds. Based on a diagnostic marker for Fhb1, six BC2 populations were developed by crossing dwarf-male-sterile(DMS)-Zhoumai 16 to three Fhb1 donors(Ningmai 9, Ningmai 13, and Jianyang 84) and backcrossing to Zhoumai 16 and Zhoumai16’s derivative cultivars(Lunxuan 136 and Lunxuan 13) using marker-assisted backcross breeding. The progenies were assessed for FHB resistance and major agronomic traits.The Fhb1 alleles were identified using the gene-specific molecular marker. The plants with the Fhb1-resistant genotype(Fhb1-R) in these populations showed significantly fewer infected spikelets than those with the Fhb1-susceptible genotype(Fhb1-S). When Lunxuan 136 was used as the recurrent parent, Fhb1-R plants showed significantly fewer infected spikelets per spike than Fhb1-R plants produced using Lunxuan 13 as the recurrent parent, indicating that the genetic backgrounds of Fhb1 influence the expression of FHB resistance. Fhb1-R plants from the DMS-Zhoumai 16/Ningmai 9//Zhoumai 16/3/Lunxuan 136 population showed the highest FHB resistance among the six populations and a significantly higher level of FHB resistance than the moderately susceptible control Huaimai 20. No significant phenotypic differences between Fhb1-R and Fhb1-S plants were observed for the eight agronomic traits investigated. These results suggest that it is feasible to improve FHB resistance of winter wheat withoutreducing yield potential by introgressing Fhb1 resistance allele into FHB-susceptible cultivars in the YHWZ.

Influencing factors of the neurodevelopment of high-risk infants

Background High-risk infants refer to newborns exposed to high-risk factors in the prenatal, natal or postnatal period. High-risk infants are at high risk of developmental retardation, and early identification of developmental abnormalities plays a vital role in improving high-risk infants' quality of life.Aims To describe the neurodevelopment of high-risk infants aged less than 1 year old, and to analyse the incidences and influencing factors of neurodevelopmental abnormalities in order to provide a basis for neurodevelopment monitoring and management of highrisk infants.Methods High-risk infants born between January 2016 and December 2016 in the maternity and infant health hospitals of three districts in Shanghai were followed up.The Gesell Developmental Scale was used to assess the neurodevelopmental level at the time of recruitment(0-2 months) and at 9 months. Univariate and multivariate analyses of the influencing factors were conducted.Results 484 high-risk infants(male 51 %, female 49%)with an average gestation age of 36.5±2.2 weeks were recruited. At the time of recruitment, the average age was2.1(0.8) months, and the developmental quotient(DQ)scores of full-term high-risk infants in motor(t=3.542,p=0.001), cognitive(t=3.125, p=0.002), language(t=3.189, p=0.002) and social(t=3.316, p=0.001) areas were higher than those of preterm infants. The incidences of developmental abnormalities of full-term high-risk infants in motor(χ~2 =9.452, p=0.002), cognitive(χ~2=6.258, p=0.012), language(χ~2 =12.319, p =0.001) and social(χ~2 =6.811, p=0.009) areas were lower than the preterm infants. At 9 months, there was no difference in the DQ scores and incidences of developmental abnormalities in four areas between full-term and preterm high-risk infants, and the incidence of developmental abnormalities was around 10%.Conclusion The incidence of neurodevelopmental abnormalities in high-risk infants aged less than 1 year old is high. Preterm birth and parental bad habits are significant factors affecting the neurodevelopment.Monitoring and early interventions help to improve highrisk infants' neurodevelopment.

Variation in allelic frequencies at loci associated with kernel weight and their effects on kernel weight-related traits in winter wheat

Knowledge of allelic frequencies at loci associated with kernel weight and effects on kernel weight-related traits is crucial for yield improvement in wheat. Kernel weight-related traits were evaluated in 200 Chinese winter wheat cultivars(lines) grown at the Xinxiang Experimental Station, Chinese Academy of Agricultural Sciences, Xinxiang in Henan Province, for three consecutive years from 2014 to 2016. Alleles associated with kernel weight at nine loci, TaCKX6-D1, TaCwi-A1, TaCWI-4A, TaGS1a, TaGS5-A1, TaGS3-3A, TaGW2-6A, TaSus2-2B, and TaTGW6-A1, were determined for all cultivars(lines). ANOVA showed that genotypes, years and their interactions had significant effects on thousand-kernel weight(TKW), kernel length(KL) and kernel width(KW). The overall mean frequencies of alleles conferring high and low TKW at the nine loci were 65.9% and 33.4%, with the ranges of 37.0%–85.0% and 13.5%–63.0% for single loci. The frequencies of high-TKW alleles were over 50.0% at eight of the loci. Genotypes at each locus with the high-TKW allele had higher TKW than those with the low-TKW allele. The high-TKW allele Hap-H at the TaSus2-2B locus can be preferably used to increase grain yield due to its high TKW(49.32 g). A total of 18 main allelic combinations(ACs) at nine loci were detected. Three ACs(AC1–AC3) had significantly higher TKW than AC6 with high-TKW alleles at all nine loci even though they contained some low-TKW alleles. This indicated that other loci controlling kernel weight were present in the high-TKW cultivars. This work provides important information for parental selection and marker-assisted selection for breeding.