摘要：Seven parents and their 21 Fl diallel crosses of maize were grown under field conditions in the 2001 and 2002 growing seasons on two soils mutually air-distanced 800 m （BI = fluvisol and B2 = stagnic albeluvisol; pH in KCI = 7.02 and 3.85, humus = 2.75 and 2.02, CaCO3 = 11.4% and 0, for B 1 and B2, respectively）. Also, the B 1 and B2 were differently in NH4Acetate-EDTA soluble fraction （***： calcium 25,500 and 2,300; zinc 1.61 and 0.53; cadmium 0.195 and 0.064, respectively）. The experiments were conducted in four replicates （the basic plot 16.8 m2） in a randomized complete block design. The ear-leaf was taken at the beginning of silking and grain samples at maturity. Mean leaf-Cd （mg ***-t in dry matter） were 0.102 and 0.072, for 2001 and 2002; 0.064 and 0.195, for BI and B2, while differences in level of genotype were from 0.040 to 0.581 （the parents） and from 0.046 to 0.171 （the hybrids）. Six hybrids of Bc707-1 had considerably higher leaf-Cd in comparison with six hybrids of Bc265-1 （means 0.100 and 0.050 respectively）. Grain-Cd was under detectable range （〈 0.040） with exception of Bc707-1 parent on the B2 soil （0.17 mg Cd-kg^-1）.

摘要：The effects ol different genotypes and planting densities on main agronomic traits, storage root traits and yield were studied with 6 high-quality sweetpotato varieties as study objects by 2-factor completely random design. The results showed that there were significant differences in stem diameter, length of the longest vine and top/root （T/R） between different genotypes, T/R differed significantly under dif- ferent planting densities, and number of basal branches decreased with planting density increasing. genotype and genotype x density showed significant or very sig- nificant effects on fresh root yield per plant, dry matter content and fresh root yield per hectare, fresh root yield per plant gradually decreased with planting density in- creasing, while fresh root yield per hectare increased with planting density increas- ing. Numbers of storage roots in different sizes of the 6 sweetpotato cultivars all exhibited an order of number of large-sized storage roots〈number of medium-sized storage roots〈small-sized storage root; and there were very significant differences in ratio of large-sized storage roots between different genotypes. The number of large- sized storage roots, ratio of large-sized storage roots and number of commercial storage roots deceased with planting density increasing, while there were no signifi- cant differences in number of medium-sized storage roots, number of small-sized storage roots, ratio of medium-sized storage roots and ratio of small-sized storage roots between different densities. Correlation analysis showed that there was signifi- cant positive correlation between number of basal branches and fresh root yield per plant; dry matter content in storage roots was in significant positive correlation with stem diameter, and in significant negative correlation with length of the longest vine; fresh root yield per hectare was in significant positive correlation with fresh root yield per plant, and in very significant negative correlation

摘要：Stability among 50 accessions of West African okra （Abelmoschus caillei） was assessed under three diverse ecological environments at Abeokuta, Ibadan and Mokwa in Nigeria during 2005 and 2006 cropping season. The accessions were grown in a Randomized Complete Block Design with three replications; data were collected on 5-10 randomly selected plants from each plot. Only 20 accessions were subjected to stability analysis on the basis of yield across the three environments. The joint regression analysis, deviation means square were computed using Eberhart and Russell method and complemented with Francis and Kannenberg method. The regression coefficients of accessions mean yields on the environmental index resulted in regression coefficients ranging in values from 0.5549 to 1.6667. OAA/96/175-5328, NGAE-96-011 and NGAE-96-0060 were among the superior genotypes with high yield performance. The large variation in regression values indicated large differences in genotype response to different environments. It suggests that stability concept of Ebelhart and Russell could be modified to use any yield components that has strong correlation with yield for stability analysis. The two promising accessions ofA. caillei （NGAE-96-011 and NGAE-96-0060） needed to be further tested on farmers＇ field to obtain on-farm data, alter which it should be recommended for official registration and released by the National Committee on Naming, Registration and Release of Crop varieties in Nigeria.

摘要：参考GenBank中多个BVDV毒株基因组序列,利用生物软件primer5.0设计两对引物,扩增出BVDV牦牛株P20基因和P14基因.结果表明,克隆得到的P20基因序列为504bp,与GenBank上发表的BVDV P20大小一致,P14基因序列为312 bp,与GenBank上发表的BVDV毒株比较有6个插入碱基.核苷酸序列的同源性及系统发生分析的结果表明,牦牛(Yak)株属于BVDV-1.