A Novel Modified Endosperm Texture in a Mutant High‐Protein Digestibility/High‐Lysine Grain Sorghum (Sorghum bicolor (L.) Moench)

Development of high‐protein digestibility (HPD)/high‐lysine (hl) sorghum mutant germplasm with good grain quality (i.e., hard endosperm texture) has been a major research objective at Purdue University. Progress toward achieving this objective, however, has been slow due to challenges posed by a combination of genetic and environmental factors. In this article, we report on the identification of a sorghum grain phenotype with a unique modified endosperm texture that has near‐normal hardness and possesses superior nutritional quality traits of high digestibility and enhanced lysine content. These modified endosperm lines were identified among F₆ families developed from crosses between hard endosperm, normal nutritional quality sorghum lines, and improved HPD/hl sorghum mutant P721Q‐derived lines. A novel vitreous endosperm formation originated in the central portion of the kernel endosperm with opaque portions appearing both centrally and peripherally surrounding the vitreous portion. Kernels exhibiting modification showed a range of vitreous content from a slight interior section to one that filled out to the kernel periphery. Microstructure of the vitreous endosperm fraction was dramatically different from that of vitreous normal kernels in sorghum and in other cereals, in that polygonal starch granules were densely packed but without the typically associated continuous protein matrix. We speculate that, due to the lack of protein matrix, such vitreous endosperm may have more available starch for animal nutrition, and possibly have improved wet‐milling and dry‐grind ethanol processing properties. The new modified endosperm selections produce a range that approaches the density of the vitreous parent, and have lysine content and protein digestibility comparable to the HPD/hl opaque mutant parent.     

Geographical patterns of morphological variation in sorghum (Sorghum bicolor (L.) Moench) germplasm from Ethiopia and Eritrea: Quantitative characters

A total of 415 sorghum (Sorghum bicolor (L.) Moench) accessions representing different regions of Ethiopia, Eritrea and a group of introduced lines were evaluated for 15 quantitative characters to determine the extent and geographical pattern of morphological variation. The extent of variation was highly pronounced for agronomically important characters for sorghum. These characters included plant height, days for 50% flowering, peduncle exsertion, panicle length and width, number and length of primary branches per panicle and thousand seed weight. Significant regional variation was also observed for most of the characters. The results implied that environmental factors such as altitude, rainfall, temperature and growing period are important in regional variation. Mean for plant height and for days for 50% flowering showed clinal variation along the gradients of rainfall pattern and growing period in Ethiopia. Moreover, there were significant positive correlation coefficients between most of the characters. This included the correlation between agronomic characters of primary interest in sorghum breeding such as plant height and days for 50% flowering and also between various characters and the altitude of the collection sites. The implications of the results in plant breeding, germplasm collection and conservation as well as the probable sources of the wide range of variation are discussed. This revised version was published online in July 2006 with corrections to the Cover Date.     

Species of Ticks on Camels and Their Seasonal Population Dynamics in Eastern Ethiopia

A study was conducted to identify the species of ticks found on camels (Camelus dromedarius) and their seasonal population dynamics in Eastern Ethiopia. Collection and identification of the ticks were undertaken at 2-month intervals from December 1997 to August 1999. On each occasion, all the visible adult ticks were collected from one side of the body of each of the same 17 camels. The most abundant species of ticks on the camels were Rhipiephalus pulchellus (85.2%), Hyalomma dromedarii (5.9%), Amblyomma gemma (4.0%) and Amblyomma variegatum (1.8%). The average tick load per camel was higher during rainy months than during dry months. The smallest number of ticks per camel was observed during the driest month (December), whereas the highest was recorded in the wettest month (August). Any strategy intended to mitigate problems of tick infestation of camels in this area should take into account the identified tick species and their season of abundance.     

非洲主要国家竹种资源与利用

非洲是世界第3大竹资源分布区，竹资源量仅次于亚洲和拉丁美洲。东部非洲的埃塞俄比亚、肯尼亚等国家的竹种资源比较单一，以高地竹和低地竹为主；南部非洲的马达加斯加、中部非洲的喀麦隆和西部非洲的尼日利亚等国家竹种资源较为丰富。埃塞俄比亚、尼日利亚、喀麦隆、马达加斯加、刚果、莫桑比克、塞内加尔、加纳的竹林面积位居非洲前列。非洲竹资源加工利用主要以传统产品为主，现代加工水平不高，竹产品进出口水平有限。近年来，非洲主要竹资源分布国的竹产业战略与政策发展以及国际合作日渐活跃并取得积极进展。文章分析了非洲21个国家的竹资源及利用现状，以期为开发利用非洲竹资源提供参考。     

Geomorphological evolution and present-day processes in the Dessie Graben (Wollo,Ethiopia)

This paper presents a detailed geomorphological overview of the landforms and processes characterizing the Dessie basin, a small graben located on the western Afar Margin (Ethiopia), which is a physiographic province characterized by small, closed basins and mountain ranges produced by regional extension. Large-scale geomorphological survey and mapping of the basin allowed to point out the noteworthy morphodynamic role of the present-day slope processes, including numerous landslides of different typology and size. These processes heavily interact with the built-up area of Dessie town, one of the most important cities of Ethiopia with ca. 200,000 inhabitants, which occupies a large part of the basin floor. The potential incidence of landslides of different typology in the basin and their possible impact on the urban settlement are put in relation with the distribution of the different landform units which make up the basin surface.     

Plant community and ecological analysis of woodland vegetation in Metema Area, Amhara National Regional State, Northwestern Ethiopia

We studied woodland vegetation in broad-leaved deciduous woodlands of Metema in northwestern Amhara regional state,Ethiopia to determine plant community types and species distribution patterns and their relationships with environmental variables,including altitude,pH,cation exchange capacity,electrical conductivity(EC),and moisture.We used a selective approach with a systematic sampling design.A total of 74 quadrats,each 25m × 25m at intervals of 150 200 m were sampled along the established transect lines.For herbaceous vegetation and soil data collection,five subquadrats each 1m × 1m were established at the four corners and the center of each quadrat.Three community types were identified using TWINSPAN analysis.All three community types showed high diversity(Shannon-Weiner index),the highest in community type II at 3.55.The highest similarity coefficient was 0.49(49%) between community types II and III,reflecting 0.51(51%) dissimilarity in their species richness.The canonical correspondence ordination diagram revealed that the distribution pattern of community type I was explained by moisture while that of community types III and II was explained by EC and altitude and moisture,respectively.Altitude was the most statistically significant environmental variable,followed by moisture and EC in determining the total variation in species composition and distribution patterns while pH and cation exchange capacity were non significant.In conclusion,we recommend that any intervention should take into account these three discrete community types and their environmental settings to make the intervention more successful.     

Investigation into association and expression of PLCz and COX-2 as candidate genes for boar sperm quality and fertility

Phospholipase C zeta (PLCz) and cyclooxygenase isoenzyme type 2 (COX-2) are important in spermatogenesis, but their effect has not yet confirmed in pigs. Therefore, this study was aimed to analyse their association with sperm quality and fertility and to identify the mRNA and protein expression in boars reproductive tissues. DNA samples from 231 Pietrain (PI) and 109 Pietrain × Hampshire (PIHA) pigs with records of sperm quality [sperm concentration (SCON), motility, semen volume, plasma droplet and abnormal spermatozoa rate] and fertility (non-return rate and number of piglet born alive) traits were available. A SNP in non-coding region of PLCz g.158 A > C was associated with SCON (p < 0.05) in PIHA population while the polymorphism of COX-2 g.68 G > A in 3' UTR was not associated with any traits. For mRNA and protein expression study, a total of six boars were divided into two groups with G-I and G-II, where G-I was characterized for relatively better sperm quality. Both genes expressed higher in reproductive tissues compared with non-reproductive tissues. Phospholipase C zeta mRNA expressed higher in testis (p < 0.01), all parts of epididymis and spermatozoa from G-I, while COX-2 expressed higher in testis (p < 0.05), head and body of epididymis (p < 0.01), and spermatozoa from G-II boar. Both proteins were localized in Leydig cells and spermatozoa. These results might shed light on roles of these genes in spermatogenesis as candidate for boar sperm quality and fertility, but still the lack of association across populations should be considered.