Crossability percentages of bread wheat collections from Tibet,China with rye

Summary The crossability percentages of 282 accessions of wheat (Triticum aestivum L.) collected in Tibet, China with rye (Secale cereale L.) have been tested. Five collections have a similar to and 277 accessions have a lower crossability percentage than Chinese Spring or are non-crossable with rye. The accessions with high crossability percentage occur along the highway near Lhasa. No landraces with higher crossability than Chinese Spring and rare landraces with similar crossability to Chinese Spring indicated that the landraces in Tibet region are different from those in Sichuan, Shaanxi and Henan provinces in the distribution frequency of high crossability, and there is no distribution of recessive kr4 alleles.     

Crossability percentages of bread wheat landraces from Shaanxi and Henan provinces,China with rye

Summary The crossability percentages of 118 landraces of wheat (Triticum aestivum L.) from Shaanxi and Henan provinces, China with rye (Secale cereale L.) have been tested. 14 landraces possess a higher crossability percentage than Chinese Spring, 30 landraces have a similar to and 74 landraces have a lower crossability percentage than Chinese Spring or are non-crossable with rye. Most landraces with high crossability percentage occur in south part of Shaanxi, and the west and southwest of Henan, their geographical distribution in these regions fits up with that in the Sichuan province.     

The introduction of the common bean (Phaseolus vulgaris L.) into Western Europe and the phenotypic variation of dry beans collected in The Netherlands in 1946

The first introduction of common bean from Central/South America into Western Europe most likely took place around 1500. The attractive bean seeds and their easy transportation warranted numerous additional introductions, not only from the Americas, but also from other areas where the common bean had been introduced. Bean seeds also must have been transported all over Europe both locally and internationally. Natural and human selection took place in and among introductions as well as in hybrid populations. Strong human selection may have led to pure garden forms which often occur in The Netherlands. In the period 1945–1948 a dry-bean collection of some 1500 accessions was made in The Netherlands. These have been classified into various criteria: 1. landraces, ‘primitive’ garden forms and cultivars, 2. (semi)climbing or bush types, 3. various seed colour types, including whitish, brownish, yellowish, black and variegated. This revised version was published online in July 2006 with corrections to the Cover Date.     

Estimation of outcrossing rate in landraces of tetraploid wheat (Triticum turgidum L.)

A study was undertaken to assess the amount of natural outbreeding in tetraploid wheat landraces of Ethiopian origin. The study consisted of two trials which were planted separately at two locations representing different environmental conditions for two consecutive seasons. The design employed was the randomized complete block with three replications. Two polymorphic loci, glume pubescence and awn condition were utilized as markers. The rate of outcrossing was based on the number of hybrids found in the recessive class of each marker. The overall level of outcrossing was higher in the pure stand trial than in the mixed stand trial. A higher rate of outcrossing occurred in the higher altitude area in the pure stand trial while the opposite was the case in the mixed stand trial. The average rate of outcrossing due to the marker loci was also different, with the long awn displaying more outbreeding tendency. Both locational and seasonal differences in the amount of outcrossing were observed. Generally, the study has revealed that there is a considerable amount of outbreeding in the landraces and that this genetic factor could play a role in preserving variation in the landrace populations. The level of outcrossing detected in this study could have a bearing on the maintenance of the genetic purity of diverse breeding lines being handled together in a breeding nursery and varietal purity in seed multiplication.     

Productivity and adaptive capacity of winter wheat landraces and modern cultivars grown under low-fertility conditions

In recent decades, most winter wheat (Triticum aestivum L.) breeding in the United States has been done in field nurseries in which the soil receives ample fertilization. To determine the effects of these breeding efforts on productivity under low-fertility conditions, we evaluated twenty-nine winter wheat genotypes (seven Asian landraces; thirteen standard-height U.S. cultivars released between 1874 and 1971; and nine semidwarf cultivars released between 1977 and 1988) under severe fertility stress at three Kansas, USA locations. Experiments included fertilized and unfertilized treatments. The modern, semidwarf cultivars yielded 18% and 20% more, on average, than landraces and standard-height cultivars under low and high fertility, respectively; however, only the latter difference reached the 5% significance level. At only one location (Hays) was there a significant genotype X fertility interaction: there, 89% of the semidwarf cultivars, only 8% of the standard cultivars, and 57% of the landraces responded to fertilization. The regression coefficient of mean grain yield (unfertilized) on year of introduction or release for standard and semidwarf cultivars was zero, indicating that a century of breeding has produced no genetic improvement in performance under these low-fertility conditions. Although we found that the usual yield advantage of modern cultivars is not expressed under very low fertility, we saw no evidence that older cultivars are superior under those conditions.     

Morphological characterization of kale populations from northwestern Spain

Crops belonging to the genus Brassicaare widely grown in Galicia (northwesternSpain). Kales (Brassica oleracea L.convar. acephala (DC.) Alef.) are oneof the most important Brassica cropsin this region where landraces aretraditionally grown by farmers on smallplots for either human or animal food.Fifteen kale populations from northwesternSpain were evaluated in two locations andtwo planting dates (early and late). Theobjectives were i) to study theirmorphological diversity, ii) to determinetheir relationships, and iii) to evaluatetheir morphological and agronomiccharacteristics that could be incorporatedto breeding programs in the future.Significant differences were found amongpopulations for all traits while genotype ×environment interaction was not significantfor most of them. Cluster and principalcomponent analysis were performed todetermine relationships among landraces andto obtain information on the usefulness ofthe characters for the definition ofgroups. The phenogram showed five groups,two groups including most of thepopulations and three small independentgroups. Groups of landraces were associatedwith the geographical origin and withmorphological differences amongpopulations, mainly with the length oftheir vegetative phase: north and earlypopulations (cluster A) and south and latepopulations (cluster B). Morphologicaldiversity was higher in coastal populationsthan in inland populations. As conclusion,the populations evaluated in this workdisplay a wide diversity of traits whichenable us to select and combine someinteresting landraces for important traitsin order to obtain improved varieties.     

IL‐12p40 gene expression in lung and hilar lymph nodes of MPS‐resistant pigs

Mycoplasma pneumonia of swine (MPS) is caused by Mycoplasma hyopneumoniae (M.hp) and is a common chronic respiratory disease of pigs. Recently, a genetically selected variant of the Landrace pig (Miyagino L2) has a lower incidence of pulmonary MPS lesions. We investigated the pathological and immunological characteristics of MPS resistance in these pigs (n = 24) by comparing with the normal landrace pig (control: n = 24). The pathological MPS lung lesion score in MPS‐selected landrace pigs was significantly lower than in the control. The gene expression of interleukin (IL)‐12p40, which acts as a chemoattractant and a component of the bioactive cytokines IL‐12 and IL‐23, was significantly higher at the hilar lymph nodes, lung, and spleen in MPS‐selected landrace pigs than in control landrace pigs, and these were negatively correlated with the macroscopic MPS lung lesion score. In summary, we demonstrate that resistance against MPS in Miyagino L2 pigs is associated with IL‐12p40 up‐regulation, in comparison with normal landrace pigs without the MPS vaccine. In addition, a comparative study of macroscopic MPS lung lesions and IL‐12p40 gene expression in lung and hilar lymph nodes may lead to beneficial selection traits for the genetic selection for MPS resistance in pigs.     

Variability in European Maize (<Emphasis Type="Italic">Zea mays</Emphasis> L.) Landraces under High and Low Nitrogen Inputs

An European maize (Zea mays L.) landrace core collection (EMLCC) was formed with samples from several countries. Evaluation of the EMLCC may contribute to broad the genetic base of maize breeding programs. The objective of this study was to assess the variability of EMLCC under low nitrogen (N) in relation to high N input. Eighty-five landraces of the EMLCC, grouped in four maturity groups, and three check hybrids were evaluated for response to low (0 kg ha⁻¹) and high (150 kg ha⁻¹) N in Spain and Greece. Five plant size traits (plant height, ear height, leaf length, leaf width and leaf area index), two grain traits (1000-kernel weight and grain yield), and two agronomic traits [growing degree units (GDU) and lodging] were studied. Overall means of plant size and grain traits increased when genotypes were grown at 150-N relative to 0-N input. The relative increase for grain traits was smaller in landraces than in hybrids. This suggests that landraces had lower grain yield response to N supply compared to hybrids. Linear regressions of plant size traits on GDU indicated that vegetative development was primarily associated with flowering lateness. The maturity group was the main source of variation for all traits. Landrace variability within maturity groups was significant for all traits across environments, despite significant landrace × environment interactions. Estimates of genetic and genotype × environment variances, and heritabilities at both high and low N inputs were not significantly different from each other. However estimates were generally larger at high N. Genetic and phenotypic correlation coefficients between the two N levels were very high for all traits.     

137份云南省地方稻抗白叶枯病多菌系多基因鉴定

为选育水稻抗性品种和发掘抗白叶枯病基因,以来自中国、日本和菲律宾的9株革兰氏阴性菌黄单胞菌水稻变种Xanthomonas oryzae pv. oryzae菌株为供试菌株评价137份云南省地方稻种质资源对白叶枯病菌的抗性,同时检测供试材料中含14个已克隆抗白叶枯病基因的情况。结果显示,供试材料中至少对1株黄单胞菌水稻变种菌株有抗性的材料有104份,抗1、2、3、4、5、6、7、8和9株黄单胞菌水稻变种菌株的材料分别有25、19、14、19、11、6、5、2和3份;其中白杂一号、珍白18、麻旱谷、老来红、晋糯、香谷、毫冷薅、齐头蚂蚱谷、九谷和来之不易10份材料抗谱较广。大部分抗性材料携带1～7个白叶枯病抗性基因或其同源基因,未检测到含有Xa7、xa13、Xa21和Xa45(t)基因或其同源基因的材料。供试材料携带的抗性基因数量与抗性水平均呈极显著相关。