Characterization And Genetic Analysis Of Near-isogenic Lines For Awn-inhibitor Gene B1 Of Common Wheat

Inheritance of'awnedness'in wheat, Triticum aestivum, has been well studied since the beginning of the twentieth century. As well known in barley, awns may play a major role in the elaboration of the yield in wheat. At the same time,it showed that awn is a beneficial trait of cultivation in production of wheat. Awns and the leaves have the same function of photosynthesis and the same way of carbon assimilation. In addition, awn is a high effective organ for photosynthesis.Compared with other photosynthetic organs, awn has a number of advantaged conditions for photosynthesis. Near-isogenic lines of common wheat with different awn length were produced in this study. Main results were as follows:(1) The results showed that SN051-1 (short awns) and SN051-2 (short awns) had no difference in heading and anthesis date, plant height, spike length, spike number per plant and kernels per spike, while awn lengths of them was the different. The results of cytological analysis show that SN051-1 and SN051-2 are composed of 42 chromosomes and the cytology is stable.(2) The results demonstrated that spike net photosynthetic rate of SN051-1 significantly was higher than SN051-2, although the difference of flagleaf in between the two materials was not remarkable. Thus, we believed that because of the presence of awn spike photosynthesis capability significantly enhanced. Besides, filling speed and thousand-grain weight (TGW) of SN051-1 were strikingly higher than SN051-2. Therefore, we concluded that awn played an important role of assimilate accumulation late in grain filling.(3) The results indicated that awn possessed xerophytic typical structural features and had a photosynthetic capacity. In addition, the awn stomatal density of SN051-1 was less than SN051-2,while the awn cross-sectional area, cell volume and volume ratio of chloroplast of SN051-1 were larger than SN051-2.(4) Genetic analysis showed that the awn length of these near-isogenic lines was controlled by single genes, long awn was dominant to the short awn. SSR marker Xgwm291150, which was located on the long arms of 5A chromosome, was found linked with the gene controlled the awn length, with the distance of 4.99 cM. The results indicated that SN051-1 and SN051-2 was the near-isogenic lines of common wheat for awn-inhibitor gene B1.(5) We analyzed genes differential expression of experimental materials by gene chip technology. The results showed that in these genes of differential expression, the number of signal more than twice the controls and meanwhile up-regulated and down-regulated expression at the same time was 56 and 45 respectively. We also annotated these genes of differential expression by virtue of access'Gene Ontology'. This laid the foundation for further study of searching for awn-related genes.