Genetic Diversity Analysis of Lowland Sorghum [Sorghum Bicolor (L.) Moench) Landraces Under Moisture Stress Conditions and Breeding for Drought Tolerance in North Eastern Ethiopia PDF Download

Author: Amelework Beyene Assefa
Publisher:
ISBN:
Category : Farmers
Languages : en
Pages : 364

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Author: Karen Ruth Harris
Publisher:
ISBN:
Category :
Languages : en
Pages :

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Sorghum (Sorghum bicolor [L.] Moench) is the fifth most economically important cereal grown worldwide and is a source of food, feed, fiber and fuel. Sorghum, a C4 grass and a close relative to sugarcane, is adapted to hot, dry adverse environments. Some genotypes of sorghum called stay-green have delayed leaf senescence during grain ripening under drought stress conditions which allows normal grain filling whereas most sorghum lines senesce early under post-anthesis drought. Eight sources of stay-green have been identified in the sorghum germplasm collection, most originating from Sudan and Ethiopia. The diversity of the eight sources of staygreen was analyzed using 55 simple sequence repeats (SSR) markers with genome coverage. This analysis showed that the sources of stay-green are quite diverse and can be divided into five groups based on race or working group. Three sources of stay-green have been used to identify 12 major quantitative trait loci (QTL) that modulate this trait. The origin of favorable alleles for stay-green was traced backward to ancestral lines and forward into breeding materials derived from stay-green germplasm. The analysis of the origin of favorable alleles for stay-green helped explain why subsets of stay-green QTL were identified in different studies and provided evidence that there may be more than one favorable allele in the sorghum germplasm for several of the stay-green QTL. Analysis of stay-green breeding lines from three public sorghum-breeding programs revealed that one of the main QTL identified in mapping studies was not being used in the breeding programs (0/13), most likely due to its association with an allele for lemon yellow seeds. In addition, a subset of the regions containing favorable alleles for staygreen from the genotype BTx642 were over represented in stay-green breeding lines. Nearly isogenic lines containing favorable alleles from BTx642 for Stg1, Stg2, Stg3, and Stg4 in a RTx7000 (senescent) background were characterized and each NIL was shown to exhibit a stay-green phenotype. Based in part on this information, fine-mapping of Stg1 was undertaken by crossing the Stg1 NIL to RTx7000. Overall, these results revealed the origin of favorable alleles for stay-green and the current utilization of alleles for stay-green in public breeding programs. In addition, this study identified additional stay-green sources that could be used for further QTL analysis and highlighted the genetic complexity of the stay-green trait.

Author: Hailemichael Shewayrga Desmae
Publisher:
ISBN:
Category : Sorghum
Languages : en
Pages : 246

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Author: Kahiu Ngugi
Publisher: LAP Lambert Academic Publishing
ISBN: 9783846544365
Category :
Languages : en
Pages : 92

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Sorghum bicolor (L) Moench is the fifth most important cereal crop globally and in Africa, it is the second most important after Maize. In Kenya, Sorghum is an important food security crop mainly cultivated in semi-arid agro-ecological zones on area of about 150,000 ha where annual rainfall is about 250mm . The major constraint to low yields is due to prolonged drought stress and frequent drought occurrence. In order to alleviate the low yields in the face of continuing climate change, there is need to identify germ-plasm that possesses drought tolerance genes/alleles and that can be harnessed to improve sorghum adaptation to drought stress. This study assessed the phenotypic and genotypic performance of sorghum local land-races grown in Kenya and characterized their genetic diversity under drought stress conditions. The results reported here showed that Kenyan sorghum germ-plasm is highly polymorphic and genetically diverse.The land-races can be categorized as having been selected for earliness or drought escape, drought tolerance as represented by the many newly identified stay-green genotypes and has also been selected for high yielding but drought susceptible alleles.

Author: Malik Muhammad Khan
Publisher: LAP Lambert Academic Publishing
ISBN: 9783847343400
Category :
Languages : en
Pages : 80

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Drought is the most common adverse environmental condition that can seriously reduce crop productivity. Increasing crop resistance to drought stress would be the most economical approach to improve agricultural productivity and to reduce agricultural use of fresh water resources. As a result, understanding the drought tolerance and breeding for drought resistant crop plants has been the major goal of plant breeders. Sorghum is well-known for its capacity to tolerate conditions of limited moisture and to produce during periods of extended drought. Twenty sorghum (Sorghum bicolor L. Moench) genotypes with known drought tolerance traits were used in this study. The present study will be conducted to evaluate the genetic variability for drought tolerance in sorghum genotypes at molecular level.

Author: Yi-Hong Wang
Publisher: CRC Press
ISBN: 1482210096
Category : Science
Languages : en
Pages : 366

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Sorghum is one of the hardiest crop plants in modern agriculture and also one of the most versatile. Its seeds provide calorie for food and feed, stalks for building and industrial materials and its juice for syrup. This book provides an in-depth review of the cutting-edge knowledge in sorghum genetics and its applications in sorghum breeding. Each

Author: Mohammad Shafiqurrahaman
Publisher:
ISBN:
Category :
Languages : en
Pages : 6

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Author: Anuj Chiluwal
Publisher:
ISBN:
Category :
Languages : en
Pages :

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Sorghum (Sorghum bicolor (L.) Moench) is one of the hardiest crop to abiotic stresses compared with other grain crops. However early stage chilling, terminal heat and drought stress are three most damaging abiotic stresses that have limited sorghum productivity in the US Great plains and other locations having similar environmental conditions. Three studies were conducted with an overall goal aimed at increasing grain sorghum's resilience to harsh climatic conditions. In the first study, four promising chilling stress tolerant sorghum advanced breeding lines, a known early stage chilling tolerant Chinese landrace (Shan Qui Red - SQR) and a susceptible US elite cultivar (RTx430) as checks were assessed for chilling tolerance during emergence and early growth under field and controlled environments. Aerial phenotyping using unmanned aircraft systems (UAS) fitted with multispectral camera was used to capture reflectance-based vegetation indices (NDVI and NDRE) in field experiments. Some advanced breeding lines with superior agronomic background also recorded significantly better emergence, seedling growth and vigor compared to SQR under chilling conditions. Aerial phenotyping indices from images taken between 30 and 60 days after emergence were consistently correlated with destructive measurements under early plantings, indicating their effectiveness in differentiating chilling responses. Second study was conducted to understand physiological mechanisms inducing heat stress resilience in sorghum during flowering. A diverse set of sorghum inbreds and selected hybrids were tested under greenhouse, growth chamber facilities and field conditions. A highly conserved early-morning-flowering mechanism was observed across all the inbreds and hybrids, with the peak anthesis wherein >90% of florets completed flowering within 30 min after dawn. The conserved response was consistent even under drought stress and heat stress exposure imposed at different times of the day. Our findings report a novel heat escaping early-morning-flowering mechanism effectively employed by sorghum to minimize heat stress impact at anthesis. Another experiment with sequential increase in daytime temperature treatments suggest heat stress induced loss in pollen viability to be a key factor resulting in reduced seed-set and grain yield. The findings suggest heat stress could have a greater impact on post-pollen germination processes such as fertilization, embryo formation and development. We identified a heat tolerant genotype "Macia" which appears to be a promising donor for developing improved heat tolerant sorghum hybrids. In the third study, a bi-parental recombinant inbred lines (RILs) mapping population developed from elite post flowering drought susceptible cultivar (RTx430) and a known drought tolerant cultivar (SC35) were evaluated under wide spectrum of environments and moisture conditions. Several novel and major QTL for grain yield, panicle neck diameter, effective quantum yield of photosystem II and chlorophyll content were identified. The genomic regions and the candidate genes within these regions can potentially help in improving source and sink dynamics in sorghum under diverse environments. The findings from these studies will complement ongoing efforts in developing future sorghum with enhanced resilience to different abiotic stresses that continue to limit sorghum productivity.

Author: Jan Engels
Publisher: Cambridge University Press
ISBN: 9780521384568
Category : Science
Languages : en
Pages : 404

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One of the world centers of crop evolution and origin, Ethiopia has long been recognized as an important area of diversity for several major and various minor crops. Based on an international conference held in Addis Ababa, this book describes how plant genetic diversity in Ethiopia is of vital importance in breeding new varieties of crops with desirable characteristics, such as increased resistance to pests and diseases and greater adaptation to heat and drought. The three main sections in the book consider the Ethiopian center of diversity, germ plasm or genetic material collection and conservation in Ethiopia, and the evaluation and utilization of Ethiopian genetic resources. A broad range of food and feed crops and plants of medicinal and industrial importance are discussed, both at a national and international level. A brief account of conservation strategies and gene bank problems unique to Ethiopia is also given. The importance of Ethiopia's plant genetic resources to world agriculture has been demonstrated on more than one occasion. Plant breeders, geneticists, and botanists throughout the world will, therefore, find this unique book a valuable source of information and an essential reference work.

Author: Fantaye Belay
Publisher:
ISBN: 9783330081031
Category :
Languages : en
Pages : 64

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