Impact of MYOD family genes on pork traits in Large White and Landrace pigs

Summary Porcine myogenic differentiation genes ( MYOD ) family play a key role in growth and muscle development and are therefore considered as candidate genes for meat production traits. The objective of the study was to investigate the polymorphisms at four loci belonging to the MYOD genes family and analyse their associations with variation in meat production traits in Czech pig breeds. To verify the associations between the polymorphisms and the selected meat traits, altogether 254 pigs, including full- and half-sibs, of Large White and Landrace breeds were tested. The studied meat characteristics were weight of neck, loin, shoulder and ham, lean meat content (LMC), backfat thickness, intramuscular fat (IMF), remission, dry matter content and test daily gain. Statistically significant associations were observed between MYOG gene and fat and neck weight, and between MYF5 gene and IMF and LMC. High significant differences were observed between genotypes AA and AB of MYOD1 in IMF and between genotypes AB and BB of MYF5 in loin weight.     

五指山猪与长白猪妊娠期65d猪胎儿肌纤维差异比较研究

为寻找五指山猪与长白猪肌肉发育关键时期(妊娠期65d)肌纤维发育差异情况,采用石蜡切片、HE染色、Image-Pro Plus软件测量及SAS软件统计分析多种技术对两猪种骨骼肌肌纤维的表观组织学特征、数目和横截面积差异进行分析。结果表明,五指山猪和长白猪妊娠期65d胎儿肌纤维组织学外观有明显差异;并且长白猪猪胎儿骨骼肌肌纤维数目和横截面积均显著高于五指山猪(P0.05)。试验结果确定两猪种肌肉发育关键时期肌纤维发育差异,为日后深入研究影响肌肉发育的机制提供了参考。     

Variation of grain iron content in a local upland rice germplasm from the village of Huai Tee Cha in northern Thailand

Crown rust caused by Puccinia coronata Cda. f. sp. avenae Eriks., is a major fungal disease of cultivated oats (Avena sativa L.) in Tunisia. Six landrace oats (M_tK₂, JT₅, BJ₃₅, GT₁, ZN₃ and JT₀) locally collected and previously screened for their relative oat crown rust resistance were used in this experiment. These accessions were evaluated during a two cropping season in field plots under heavy natural oat crown rust infection. Assessment criteria to crown rust reactions were AUDPC, latent period, uredinia size and number of uredinia per cm² of infected leaf area. Principal components analysis showed that the variables were grouped in two components. These two principal components explained 83.56% of the total variance. The projection of the point-cloud representing the populations on the plan formed by the principal components ‘Fact 1’ (63.83%), in abscissa, and ‘Fact 2’ (19.73%) in ordinate, permitted to distribute the accessions in several groups. Three landrace oats (M_tK₂, JT₅, and JT₀) showed the lowest value of all the components used. These landrace oats might be good sources of effective and durable resistance to crown rust.     

Diversity and distribution patterns of enset landraces in Sidama, Southern Ethiopia

Diversity and distribution of enset landraces (clones) were investigated in 300 randomly selected peasant households at ten different locations in the Sidama region of Ethiopia using presence-or-absence data. A total of 86 named landraces were recorded, making the region an area of remarkably high enset landrace diversity. A substantial fraction of the landraces had a restricted distribution range and low abundance while a number were moderately common with the remaining few being cosmopolitan. Regional distribution was positively correlated with local abundance, such that more widespread landraces were also typically more abundant (r = 0.78, p < .01). Landrace diversity was not evenly distributed throughout the region, the highest diversity being recorded in mountain areas (r = 0.71, p < .05). Farmers exchange planting materials extensively, resulting in a fairly high (up to 70%) coefficient of similarity among sites. Implications for the collection and conservation of enset genetic resources are discussed.     

Extent and Pattern of Genetic Diversity for Morpho-agronomic Traits in Ethiopian Highland Pulse Landraces: I. Field Pea (<Emphasis Type="Italic">Pisum sativum</Emphasis> L.)

An experiment was conducted in 2001 at Holetta and Kulumsa, Ethiopia, to study the extent and pattern of genetic diversity in Ethiopian field pea (Pisum sativum L.) landraces. One hundred forty-eight germplasm accessions were grown in an alpha lattice design with 2 replications. Data on 12 traits were collected and analyzed. Differences among the accessions were significant for most of the traits (except number of seeds/ pod) at each location even though differences pooled over location were mostly non-significant. The accessions were grouped into five clusters of different sizes. Accessions from the southern part of the country (Arsi) distributed overall clusters while those from the northern half (North and South Wello, North Gonder and North Shewa) fell into clusters C₁ to C₃. Cumulative effects of a number of characters dictated differentiation of the accessions into clusters. There was no definite relationship between geographic diversity and genetic diversity as overlapping was encountered in clustering pattern among accessions from different parts of the country. Accessions from different regions might have similar genetic background and those from the same origin might also have different genetic background. Therefore, geographic diversity should not necessarily be used as an index of genetic diversity and parental selection should be based on a systematic study of genetic diversity in a specific population. Genetic distances among most of the clusters were significant that crosses between parents selected out of them are expected to generate desirable genetic recombination. Selection should also consider the special advantages of each cluster and each accession within a cluster. Future germplasm collection, conservation and breeding efforts should focus not only on inter-regional diversity but also on intra-regional diversity.     

Extent and Pattern of Genetic Diversity for Morpho-agronomic Traits in Ethiopian Highland Pulse Landraces II. Faba Bean (<Emphasis Type="Italic">Vicia faba</Emphasis> L.)

A field experiment was conducted in 2001 at Holetta and Kulumsa, Ethiopia, to study genetic diversity in Ethiopian faba bean (Vicia faba L.) landraces. One hundred sixty random germplasm accessions were grown in an alpha lattice design with two replications. Data on 12 traits were collected and analyzed. Significant differences were observed among the accessions for most of the traits (except number of pods/podding nodes) at each location even though differences pooled over location were mostly non-significant. Cluster analysis distinguished seven diversity classes of different sizes. Accessions from the northern half of the country (North and South Wello, North Gonder and North Shewa) were closely related while those from the southern part of the country (Arsi) were highly diverse. Cumulative effects of a number of characters dictated differentiation of the accessions into clusters. Some overlapping were encountered between accessions from the northern and those from the southern parts of the country. The study revealed that accessions from different regions might have similar genetic background and those from the same origin might also have different genetic background. Therefore, geographic diversity should not necessarily be used as an index of genetic diversity and parental selection should be based on a systematic study of genetic diversity in a specific population. Genetic distances between most of the clusters were significant that crosses between parents selected out of them are expected to generate desirable progenies. Future germplasm collection, conservation and utilization strategies should put more focus not only on inter-regional diversity in the country as a whole but also on intra-regional diversity in Arsi.     

天津白和长白成年母猪在发情期间和妊娠早期的生殖激素变化规律

用放免法测定了天津白和长白各6头成年母猪从发情-2 d到妊娠30 d之间外周血清中促黄体素(LH)、促卵泡素(FSH)、雌二醇和孕酮浓度的动态变化。结果显示,整个试验期内天津白猪血清中平均LH,FSH与孕酮浓度均一直高于长白猪。其中,在妊娠早期的LH浓度、发情后的FSH浓度与其二次峰值、妊娠4,9,12,16 d的孕酮浓度及其最大峰值,天津白猪都显著高于长白猪(P<0.05)。血清雌二醇浓度,仅在发情-1 d时呈现出品种差异,天津白猪显著高于长白猪。结果表明,在发情前后与妊娠早期,成年天津白与长白母猪血清中4种生殖激素浓度的变化规律都基本相似,但在浓度值变化方面存在明显差异。     

Sampling strategy to develop a core collection of Uruguayan maize landraces based on morphological traits

Core collections were suggested to improve germplasmutilization. A core collection is a subset chosen to represent thediversity of a collection with a minimum of redundancies. Becausediversity is distributed between and within groups with differentdegrees of organization, an adequate classification of accessionsinto related groups should be performed prior to the selection of acore collection. Different classification strategies for theUruguayan Maize Collection were compared, and the best one was usedto select a core collection. The following classification strategieswere compared following a multivariate approach using the availablemaize data base: i) racial classification, ii) geographicorigin (south and north of the country), and iii) acombination of kernel type and geographic origin. The third optionwas considered the best classification rule, since it takes intoaccount two points which are closely related to the distribution ofdiversity: genotypic composition and geographic origin. The followingfive groups were identified in the collection: a) pop, b)floury, c) dent, d) southern flint-semiflints, ande) northern flint-semiflints. Eight core collections,each of 90 accessions, were selected, using different strategies toweight the groups in the core and to select the accessions from thegroups. The P, C, and L strategies were used and combined with eitherrandom selection within the group or the Relative Diversity method.Two samples of 90 accessions were obtained at random withoutconsidering the classification. The Relative Diversity methodcombined with the L strategy produced the best core collection, as itretained the highest percentage of the ranges for the 17 variablesincluded in the analysis. On average, 91% of the ranges wereretained in the core, confirming its representativeness.     

Effect of Developmental Stages Length on Yield and some Quality Traits of Turkish Durum Wheat (<Emphasis Type="Italic">Triticum turgidum</Emphasis> L. Convar. <Emphasis Type="Italic">durum</Emphasis> (Desf.) Mackey) Landraces: Influence of Developmental Stages Length on Yield and Quality of Durum Wheat

The study aimed at exploring durum wheat landraces to be utilized in breeding programs. 566 single durum wheat plants selected from 117 populations collected from 12 provinces were studied. The selected material was planted for characterizing their some qualitative and quantitative traits such as percent vitreousness, pearling index, grain protein content, seed yield and thousand kernel weight; as well as determining time frame for germination-tillering, germination-shooting, germination-heading, germination-maturity, tillering-shooting (T-S), tillering-heading (T-H), tillering-maturity, shooting-heading, shooting-maturity, and heading-maturity. Mean, coefficient of variation, and confidence intervals (0.95) were computed for each of 12 provinces, for altitudinal origins with 200 m of ranges and, for each of two geographical regions separately. The highest variation existed for number of days between T-H and the lowest for number of days between T-S. The highest variation within developmental stages was observed in samples from Diyarbakir with a CV of 32.96%, from 600 to 799 altitude range with a CV of 18.86%, and from Southeast Anatolia with a CV of 20.12%.