Distribution of Grain Hardness in Chinese Wheats and Genetic Analysis

A hundred winter wheat and 41 spring wheat cultivars and advanced lines were used to investigate the distribution of grain hardness in Chinese wheats and correlations between grain hardness and other kernel traits. P1, P2, F1 , F2 and F3 from three crosses, i. e. , Liken2/Yumai2, 85Zhong33/Wenmai6 and 85Zhong33/95Zhong459 were sown to study the genetics of grain hardness. Significant correlation was observed between hardness measured by Single Kernel Characteristic System 4100 (SKCS 4100) and Near Infrared (NIR) Spectroscopy, r ranging from 0.85 to 0.94. Chinese wheat is a mixed population in terms of hardness, ranging from very soft to very hard. For autumn-sown wheat, on average, grain hardness decreases from north to south and spring-sown wheat is dominant with hard type. Hardness is negatively associated with flour color, and its associations with flour yield and ash content differ in winter and spring wheats. Grain hardness is controlled by a major gene and several minor genes with additive effect mostly, but dominant effect is also observed, with heritability of 0.78.

Comparative Analysis of Hina Gene Sequences in Wild (Hordeum spontaneum) and Cultivated (H. vulgare) Barleys

The Hina gene is one of the two known Hin genes for hardness, and its RNA expression is correlated with grain hardness and dry matter digestibility variation. In this study, only one clone ofHina gene was obtained from one barley accession. A total of 121 Hina gene sequences were isolated from 121 wild barley （Hordeum spontaneum） accessions in Israel, Iran, and Turkey, and then their molecular characteristics were compared with 97 Hina gene sequences from 74 cultivated barley （H. vulgare） lines in Europe and 23 landrace （H. vulgare） with global distribution and other 26 Hina gene sequences from cultivated barleys （H. vulgare） with unknown global distribution. Cis-acting regulatory element （CARE） searching revealed that there were different types of regulatory element for the Hina gene in wild and landrace/cultivated barleys. There were six consistent cis-acting binding sites in wild and landrace/cultivated barleys, whereas 8 to 16 inconsistent TATA-boxes were observed. In addition, three special elements （E2Fb, Spl, and boxS） were only observed in wild barley, while one （AT1-motif） was only found in landrace/cultivated barley. Forty-four deduced amino acid sequences of HINA from wild and landrace/cultivated barleys were obtained by deleting repetitive amino acid sequences, and they were clustered into two groups on the basis of Neighbor-Joining analysis. However, there was no obvious difference in the amino acid sequences of HINA between wild and landrace/cultivated barleys. Comparing to protein secondary structure of wheat PINA, it was indicated that HINA also existed a signal peptide. In addition, HINA was a hydrophilic protein on the basis of the protein properties and composition.

Comparison of microstructure and property of high chromium bearing steel with and without nitrogen addition

Microstructure and property of bearing steel with and without nitrogen addition were investigated by microstructural observation and hardness measurement after different heat treatment processing. Based on the microstructural observation of both 9Cr18 steel and X90N steel, it was found that nitrogen addition could effectively reduce the amount and size of coarse carbides and also refine the original austenite grain size. Due to addition of nitrogen, more austenite phase was found in X90N steel than in 9Cr18 steel. The retained austenite of X90N steel after quenching at 1050℃ could be reduced from about 60% to about 7 9% by cold treatment at -73℃ and subsequent tempering, and thus finally increased the hardness up to 60 HRC after low temperature tempering and to 63 HRC after high temperature tempering. Furthermore, both the wear and corrosion resistance of X90N steel were found much more superior than those of 9Cr18 steel, which was attributed to the addition of nitrogen. It was proposed at last that nitrogen alloying into the high chromium bearing steel was a promising way not only to refine the size of both carbides and austenite, but also to achieve high hardness, high wear property and improved corrosion resistance of the stainless bearing steel.