Inheritance of Boron Efficiency in Oilseed Rape

Field experiments were conducted to study the inheritance of boron efficiency in oilseed rape (Brassica napus L.) by evaluating the boron (B) efficiency coefficient (BEC, the ratio of the seed yield at below the critical boron level to that at the boron-sufficient level) with 657 F2:3 lines of a population derived from a cross between a B-efficient cultivar, Qingyou 10, and a B-inefficient cultivar, Bakow. Qingyou 10 had high BEC as well as high seed yield at low available soil B. On the contrary, Bakow produced low seed yield at low B status. Boron deficiency decreased the seed yield of the F2:3 lines to different extents and the distribution of BEC of the population showed a bimodal pattern. When the 657 F2:3 lines were grouped into B-efficient lines and B-inefficient lines according to their BEC, the ratio of B-efficient lines to B-inefficient lines fitted the expected ratio (3:1), indicating that one major gene controlled the B-efficiency trait. 127 F2:3 lines selected from the population at random, with distribution of BEC similar to that of the overall population, were used to identify the target region for fine mapping of the boron efficiency gene.

解读“五普”的少数民族人口

全国第五次人口普查资料显示,在20世纪90年代的10年间,中国各民族在人口数量、构成、分布和素质等方面都发生了很大变化,出现良性发展态势。这是中国政府实践符合国情的民族政策和人口政策,促进各民族共同繁荣的具体体现。这为21世纪在我国全面建设小康社会,实现各民族人口与经济、社会、资源、环境的可持续发展打下了良好的基础。