Phenotypic Diversity in Tef [Eragrostis Tef (Zucc.) Trotter] Accessions from Different Regions of Ethiopia

Seventy nine tef landraces collected from ten administrative zones and seven altitude classes were planted with two improved varieties in simple lattice design at Gute and Bako in 2007 and 2008, respectively to assess the patterns of genetic variation for quantitative and qualitative traits. Loose and fairly loose panicle forms; gray lemma color and brown seed color were abundant across all regions and altitude classes while compact and semi-compact panicles, red and purple lemma color and white seed color were less frequent. Higher Shannon diversity indices were observed for East Gojam, East Wollega, Horro Guduru Wollega, Illubabor and Jimma collections. Mean squares due to genotypes were significantly different for all traits except number of culm internodes, number of spikelet per panicle and number of fertile floret/spikelet at top of the panicle. Genotypes and environments interacted highly significantly (P≤0.01) for number of panicle branches, lodging index, above ground biomass weight, grain yield per plant and harvest index. About 73% of the entire diversity among population was explained by the first six principal components (PCs), of which the first PC explained about 31% of the variation. This originated mainly due plant height, panicle length, culm length, first and second culm internode diameters, days to panicle emergency and days to maturity. Similarly, about 91% and 90% of the variations among regions of origin and altitude classes were explained by the first five and three PCs, respectively. At 50% similarity level, 11 clusters were formed, containing 2-33 landrace populations per cluster, while six tef landraces remain solitary. There is no cluster formed solely either from tef populations of a given region, tef populations collected from similar agro-ecological zones or populations collected from areas with similar soil type. Some neighboring regions were grouped together in one cluster, implying that there are extensive informal seed exchanges or inter-regional migration of farmers with their seed. Some other regions show strong similarity while they are geographically very far away from each other (for instance, South Wello and Horro Guduru Wollega). Six altitude classes were grouped in to two main clusters at about 50% similarity level. However, tef landraces collected from altitude class below 1576 m.a.s.l (class I) remain un-grouped

GENERATION MEANS ANALYSIS FOR SOME QUANTITATIVE TRAITS IN SESAME (SESAMUM INDICUM L.) CROSSES FROM ETHIOPIA

The nature of gene action governing the expression of various traits is very helpful in formulating an effective and sound breeding program. The objective of the present study was to determine the type and magnitude of gene action in sesame using generation means analysis to provide a basis for an evaluation of selection methods for the improvement of sesame. The six basic generations parent 1(P1), parent 2 (P2),  hybrid (F1), F2, back cross 1(BC1) and  back cross (BC2) of five crosses such as cross-1 (EW002 x BG006), cross-2 (Dicho x EW006), cross-3 (EW002 x Dicho), cross-4 (Obsa x Dicho) and cross-5 (EW002 x Obsa) were planted in 2012 and 2013 at Uke trial site of Bako Agricultural Research Center in a randomized complete block design, with three replications. The combined analysis of variance indicated highly significant differences among generations for all the traits in all crosses. Simple additive-dominance model exhibited lack of good fit for all the characters studied in all the crosses, except days to maturity in cross 2. The result of the generation means analysis showed that days to flowering, plant height, branches per plant, and capsules per plant and yield per plant were found to be under the control of additive and non-additive gene effects, coupled with duplicate type of epitasis. Biparental mating followed by selection of desired recombinants from the segregating population is the most applicable breeding methodology for traits under the influence of duplicate type of epitasis. Complementary type of epitasis was only observed for plant height in cross 1 and capsules per plant in cross 3, which appeared to be desirable and would be helpful in further improvement of these traits

Combing Ability for Seed Yield and Agronomic Traits of Sesame Genotypes (Sesamum indicum L.) from Western Ethiopia

Knowledge of the genetic control of characters is essential for breeders to decide on the breeding procedure to follow. The aim of this study was to  determine the nature of gene action in the inheritance of major quantitative traits in sesame. Ten parents of sesame were crossed in year 2011 in a 10 x  10 full diallel mating system. Data were collected for major agronomic traits, grain yield and oil content. F1 progenies along with their parents were  evaluated during 2012 cropping season in a randomized complete block design with three replicates at Uke and Wama trial sites of Bako Agricultural  Research Center. For all traits, general (GCA) and specific (SCA) combining abilities were highly significant. Mean square for reciprocal effects were  significant for all traits except plant height. Inbred lines Dicho, EW002, BG006, Obsa and EW003-1 had positive GCA effects for seed yield per plant.  Parental line BG006 had high GCA for oil content. For seed yield per plant, direct crosses BG006 x EW003-1, EW023-2 x Wama, EW003-1 x EW019 and  EW003-1 x EW010-1 had high SCA effects, while EW019 x Dicho and Obsa x Dicho had high SCA for oil content. For seed yield per plant, reciprocal crosses  EW010-1 x EW002, EW006 x BG006, EW003-1 x EW023-2 and Dicho x EW006 were good combiners. Reciprocal cross Wama x EW019 was the best for its  high SCA for oil content. The predominance of non-additive gene actions in all traits considered in this study suggested the exploitation of hybrid vigor as  the best approach in sesame breeding. The result of this experiment indicated that maternal effects were important in sesame breeding for high seed  yield.&nbsp

Genetic diversity and population structure among sorghum (Sorghum bicolor, L.) germplasm collections from Western Ethiopia

The Western Ethiopian region harbors a unique set of sorghum germplasm adapted to conditions not conventional to sorghums grown in other parts of the world. Accessions from the region possess unique resistance to multiple leaf and grain diseases. This study is aimed at exploring the extent of genetic variation and population structure among accessions of this region. A total of 123 accessions comprising 111 from Western Ethiopia (62 from Asosa and 49 from Pawe) and 12 U.S. adapted lines were genotyped using 30 sorghum simple sequence repeat markers (SSR). Genetic diversity and population structure were analyzed using PowerMarker and STRUCTURE software, respectively, based on 23 polymorphic SSR markers. Principal component analysis (PCA) was performed to view the variability in multi-dimensional space. Population structure analysis revealed considerable admixtures between Pawe and Asosa accessions, while the PowerMarker analysis grouped the accessions into three distinct clusters largely based on collection regions. The PCA did not clearly differentiate Asosa and Pawe accessions, but U.S. adapted lines were clearly separated from the rest. The study indicated the presence of marked genetic variability among accessions from Western Ethiopia and also provided clues on shared genetic events among accessions adapted to the two areas in Western Ethiopia.Keywords: Sorghum, genetic diversity, population structure, SSR, Ethiopi

Designing self-sustaining early generation seed supply systems: The must-dos

Shortages in the supply of quality early generation seed (EGS) of new and improved varieties, particularly of dryland cereals and legumes is a major challenge because of the business models.This triggers the following questions: what EGS business models would sustainably avail quality parent seed? To investigate this, we documented 16 EGS interventions. We found that pre-securing seed market ahead of production played important role in the successful seed business. Taking different forms (e.g., pre-orders, demand forecasting, pre-aggregation of demand, joint planning,contractual agreement), it brings confidence to EGS producers to continuously invest in the business and make it profitable. For sustainable EGS production and supply in sub-Saharan Africa, we advocate for market assurance in advance. Two guiding principles are also suggested and four recommendations formulated

Combining Ability Analysis for Bread Wheat (Triticum Aestivum L.)

 Choice of promising genotypes from a diverse genetic base and subsequent utilization for hybridization is one of the strategies for improving productivity of bread wheat. The data from eight parents and their F1 progenies of half-diallel crosses were analyzed for combining ability for yield and yield related traits in triplicate randomized complete block design in 2005 at Sinana, south-east Ethiopia. Significant differences among all the genotypes were apparent for all traits, except for biomass per plant. Both GCA and SCA mean squares revealed significant differences in plant height, harvest index, grain yield per plant, 1000-kernel weight and maturity traits, indicating the important of both additive and non-additive gene actions in the inheritance of these traits with the predominant effect of non-additive gene action. For the remaining traits, only mean square due to GCA showed significant variation, indicating the greater importance of additive gene action in controlling the inheritance of these characters. Abola gave highly significant GCA effects in the desirable direction and was the best general combiner for most of the traits,followed by Galema and Sofumer, while Dashen was the only parentwhich showed significant positive GCA effect for grain yield per plant. Cross combinations of Dashen x Galema, Abola x Dure, Dashen x Meda-Welabu, Abola x Galema, and Galema x Dure, exhibited significant SCA effects in the desired direction for at least two and, at most, for four traits, for which SCA variance showed significant differences. Hence, these crosses revealed possibility for commercial exploitation of heterosis as well as selection of potential homozygous lines from transgressive segregants for improvement of yield levels of bread wheat