Genetic mapping,marker assisted selection and allelic relationships for the Pu6 gene conferring rust resistance in sunflower

Rust resistance in the sunflower line P386 is controlled by Pu₆, a gene which was reported to segregate independently from other rust resistant genes, such as R₄. The objectives of this work were to map Pu₆, to provide and validate molecular tools for its identification, and to determine the linkage relationship of Pu₆ and R₄. Genetic mapping of Pu₆ with six markers covered 24.8 cM of genetic distance on the lower end of linkage Group 13 of the sunflower consensus map. The marker most closely linked to Pu₆ was ORS316 at 2.5 cM in the distal position. ORS316 presented five alleles when was assayed with a representative set of resistant and susceptible lines. Allelism test between Pu₆ and R₄ indicated that both genes are linked at a genetic distance of 6.25 cM. This is the first confirmation based on an allelism test that at least two members of the R_adv/R₄/R₁₁/ R_13a/R_13b/Pu₆ cluster of genes are at different loci. A fine elucidation of the architecture of this complex locus will allow designing and constructing completely new genomic regions combining genes from different resistant sources and the elimination of the linkage drag around each resistant gene.     

‘Niigata S3’ is a new strawberry cultivar suitable for forcing culture under low temperature and insolation conditions

‘Niigata S3’ is a new strawberry (Fragaria × ananassa Duch.) cultivar that is early flowering and possesses high soluble solid content and good coloration. It was selected from a cross between Kei812 (seed parent) and ‘Asuka-Ruby’ (pollen parent). The first harvest date of ‘Niigata S3’ was December 27, 34 days earlier than ‘Echigohime’ and 9 days earlier than ‘Asuka-Ruby’ (means of 2007 and 2008). The marketable yield of ‘Niigata S3’ was 85% of ‘Echigohime’, 107% of ‘Asuka-Ruby’, while the early yield was 145% of ‘Echigohime’, 85% of ‘Asuka-Ruby’ (based on 2007 and 2008 means). The shape of the fruit is long conical, and its skin color medium-red. The fruit skin hardness of ‘Niigata S3’ was 31.5 g/mm², which was harder than ‘Echigohime’, and its average soluble solid content was 11.4%, which was higher than the values for ‘Echigohime’ and ‘Asuka-Ruby’ (2008). Furthermore, ‘Niigata S3’ did not bear apical overripe fruit. This new cultivar is adaptable to the climatic conditions of Niigata, as well as other regions that experience low winter temperatures and insolation.     

中国泰和乌骨鸡MHC与其繁殖性能相关的研究

实验采用四种限制性内切酶（ＨｈａＩ、ＥｃｏＲＶ、ＨａｅⅢ、Ｘｂａｉ）,运用ＰＣＲ－ＲＦＬＰＳ的方法,研究了泰和乌骨鸡ＭＨＣ分子遗传多态笥,探讨了各基因型与繁殖性能的相关关系,结果表明：四种酶切区别的Ｂ－ＬＩＩＢβ１外元的多态笥及ＭＨＣ基因组合型对蛋重及受精蛋孵化率影响差异均不显著。ＥｃｏＲＶ及ＸｂａＩ酶切多态性对产蛋数的多态性及ＭＨＣ基因组合型对蛋重及受精蛋孵化率影响差异均不显著。ＥｃｏＲＶ及Ｘｂ     

分子标记辅助选择改良杂交水稻的白叶枯病抗性

分子标记辅助选择技术以其对目标基因快速而精确的选择为回交育种提供了非常有效的工具。华中农业大学作物遗传改良实验室运用分子标记辅助的回交育种方法,将广谱高抗白叶枯病基因Ｚａ２１迅速导入到杂交水稻的两个优良恢复系明灰６３和６０７８之中,成功地完成了其抗生改良,并通过配组而达到了改良杂交水稻抗性的目的。本研究所运用的分子标记辅助的水稻回交育种程序是：通过一次杂交、二次回交改良杂交水稻抗性的目的。本研究所     

我国抗枯黄萎病棉花区试品种的纤维品质分析

本文对我国黄河、长江两流域1985—1986年(第6轮)抗病棉花区试品种的纤维品质进行了分析。结果指出,在参试品种中,“中棉12”和“冀合3016”的纤维品质综合表现较好,且在环境间的变异较小。品种纤维品质综合表现变异程度的大小与综合表现的优劣呈中度负相关(r=-0.409)。     

湘西瓜12号的选育

为选育优质、高产、抗病的无籽西反良种,以西瓜品种新８０４５７为母本,日本引进的“都三号”杂交一代经多代自交分离固定而成的自交系Ｄ３为父本,育成了早中熟无籽西瓜品种－湘西瓜１２号。该西瓜品种全生育期８８－８９ｄ,果实成熟期约３０ｄ,单果均重６ｋｇ,产量达６０ｔ／ｈｍ＾２,果心可溶固形物含量１２％－１３％,抗病耐湿性强,易坐易。     

大豆品种"吉农8号"选育报告

大豆新品种“吉农 8号”是以吉林 2 0号×长农 4号为母本 ,以公交 84- 5 181为父本 ,通过品种间有性杂交 ,多年系选而成。 3年区域试验结果比对照增产 7 6 % ,2年生产试验结果比对照增产 10 7%。 2 0 0 0年4月通过吉林省农作物品种审定委员会审定。其主要特点是单产水平高 ,抗倒伏 ,抗病性强     

3株烟草内生细菌促进作物生长作用的研究

通过漂浮育苗试验以及大田试验,研究了烟草内生细菌YN201408、YN201442和YN201448的促生长作用。结果表明:3个菌株的菌悬液均可促进烟草、番茄、白菜、玉米和油菜的生长,其中YN201448对烟草和番茄的促生长效果最好,YN201408促进白菜生长的作用较大,而YN201442对玉米和油菜的促生长作用最好。     

Genetic Diversity of European and Chinese Oilseed Brassica rapa Cultivars from Different Breeding Periods

The Brassica oilseed crops went through two major breeding bottlenecks during the introgression of genes for zero erucic acid and low glucosinolate content, respectively, which may lead to reduced genetic biodiversity of the crop. This study investigates the impact of these bottlenecks on the genetic diversity within and across European and Chinese winter B. rapa cultivars. We compared eight cultivars from Europe and China, representing three different seed qualities from three different breeding periods： （1） high erucic acid, high glucosinolates （＋＋）; （2） zero erucic acid, high glucosinolates（0＋）; （3） zero erucic acid, low glucosonolates （00, canola quality）. Diversity was estimated on 32 plants per cultivar, with 16 simple sequence repeat （SSR） markers covering each of the B. rapa linkage groups. The analysis of molecular variance （AMOVA） showed that genetic variations within cultivars, across cultivars and across regions （Europe and China） were significant, with about 60% of the total variation within cultivars. There was a slight, but non-significant loss in genetic diversity within cultivars when comparing the three breeding periods as indicated by effective number of alleles （2.39, 2.23, and 1.99 for breeding periods 1, 2, and 3, respectively）, Shannon information index （0.93, 0.90, 0.75）, and expected heterozygosity （0.51, 0.49, 0.42）. By cluster analysis （UPGMA dendrogram） and principal coordinate analysis, Chinese and European cultivars were clearly divided into two distinct groups. In conclusion, quality improvement did not significantly reduce the genetic diversity of European and Chinese B. rapa cultivars.     

Repetitive DNA Sequences in Wheat and Its Relatives

Repetitive DNA sequences form a large portion of eukaryote genomes. Using wheat ( Triticum )as a model, the classification, features and functions of repetitive DNA sequences in the Tritieeae grass tribe is reviewed as well as the role of these sequences in genome differentiation, control and regulation of homologous chromosome synapsis and pairing. Transposable elements, as an important portion of dispersed repetitives,may play an essential role in gene mutation of the host. Dynamic models for change of copy number and sequences of the repetitive family are also presented after the models of Charlesworth et al. Application of repetitive DNA sequences in the study of evolution, chromosome fingerprinting and marker assisted gene transfer and breeding are described by taking wheat as an example.