Quantitative methods for sampling of germplasm collections : getting the best out of molecular markers when creating core collections

This thesis addresses the issue of how special players (crisis entrepreneurs) try to generate attention to a latent crisis and how government communication can contribute to identifying and interpreting such a crisis. In chapter 1, I show how crisis communication is an activity that is often associated with organizations. This study takes a different view. It is based on the concept that strategic crisis communication is used by those in the immediate environment to achieve certain goals. In society, certain individuals and groups can decide to oppose and denounce a given crisis. Some of those involved often start signalling the risk of an impending crisis before any such crisis has actually developed. In this study, I refer to individuals who generate signals of this kind as ‘crisis entrepreneurs’. These crisis entrepreneurs typically take the initiative when it comes to airing their concerns about a potential crisis situation. However, such individuals often have to deal with certain interactional problems that make it difficult for them to raise the issue of a crisis. They have to deal with certain ‘interactional’ challenges, while running the risk that their signals will not be picked up. For instance, they can be held responsible for raising the problem in question. They can be accused of bearing some degree of personal responsibility for the problem, through negligence, incompetence, or laziness, for example. In this study, I have explored the way in which crisis entrepreneurs issue signals. This is an attempt to identify the problems that they encounter as they attempt to draw people’s attention to a given crisis. The goal of this study is to enhance our understanding of crisis entrepreneurs’ interactional problems. The study makes use of the ‘discursive perspective’, which is based on the discursive psychological approach developed in the 1990s by two British social psychologists, Derek Edwards and Jonathan Potter. To date, this interaction-based approach has seldom been used in the context of crisis communication. Chapter 2 underlines the value of examining the way in which stakeholders within an organization’s environment raise the issue of a crisis. In terms of crises as a phenomenon, it is important to do justice to the dynamics of risks and crises. In essence, this is about what happens in the course of interactions. In such an environment, it is vital for an organization to keep pace with those in its surroundings if it is to observe signals in interaction with this dynamic environment. This requires a view of crisis communication that allows sufficient scope for the interactional dimension. Chapter 3 explores various elements that characterize crises in general, while describing a particularly significant phase - the latent crisis. I have identified two forms of latent crisis, a lingering form and a creeping form. These two forms differ chiefly in terms of the dynamics involved. While the dynamics of both types exhibit both peaks and troughs, there are differences. Lingering crises are entirely lacking in dynamism for extended periods of time. The dynamics of creeping crises, on the other hand, tend to increase gradually. After describing the theoretical framework of the study, chapter 4 proceeds to explore the theoretical and methodological scope of discursive psychology, in terms of an interactional approach to crisis communication. Discursive psychology offers the valuable option of using discourse analysis to examine the social context of risks from the standpoint of everyday reality. A discursive perspective characteristically focuses on a) everyday interactions that are not shaped by the study itself and b) the transactions that, either consciously or unconsciously, feature in such interactions. The discursive perspective offers a specific form of discourse analysis that communications professionals can use to understand how those in the environment express their ideas relative to others. The significance of this is that it can help professionals to understand the specific interactional problems facing crisis entrepreneurs. These involve dealing with certain ‘interactional’ challenges, while running the risk that their signals will not be picked up. Chapter 5 discusses the two cases selected for this study. The selected case domain is education in the Netherlands. I have investigated the ways in which crisis entrepreneurs have signalled problems in this sector. I used discourse analysis (Edwards, 1997; Potter, 1992) to first examine the interactional efforts of those behind collective social movements, then those of individual whistleblowers. To this end, I studied an interview with Matthé Sjamaar, the rector of a secondary school, which was published in Onderwijsblad (education journal) in May 1998. I also examined the manifesto of Beter Onderwijs Nederland (better education for the Netherlands; BON), which was published in the NRC Handelsblad newspaper in June 2006. Both sources raised the issue of a crisis. One of the criteria that I used in selecting these texts was whether the crisis entrepreneur in question had the ability to influence the public debate. In both cases, both local and national media responded to the statements made by these crisis entrepreneurs. Using a discursive response analysis, I explored the way in which newspapers dealt with the interactional problems faced by these crisis entrepreneurs. Chapters 6 and 7 form the empirical part of this study. The analysis identified three important discursive activities that are carried out by crisis entrepreneurs. These are: 1. demonstrating the validity of the problem, 2. establishing the messenger’s credibility, and 3. creating the belief in a solution. The analysis showed that Matthé Sjamaar creates indirectly undetermined others in the environment as being partly responsible for the cause of the problem, while exhibiting a degree of fatalism and holding out no prospect of a solution. He makes an indefinite-side group responsible for the problems. He shows he can not control the problem because it is too large. He creates the crisis as an isolated entity. They are merely the facts which he shows, which are independent of him. He suggests that he has done a lot of hard work and now others have to do something. The media portrayed Rector Sjamaar as symbolizing a problem that was primarily a personal issue. BON, on the other hand, presents itself as a collective that is committed to achieving better education in the Netherlands. The writers display insight and overview of the education problem and create the association to BON as a group consisting of ‘outspoken thinkers’ who are not hindered by doubts. The authors set themselves superior in their attitude towards the education reformers. The writers poses the problem as clear and relevant to everyone and so they create their own need for existence. So now they start a movement and give voice to something that has long been going on: BON is the solution to turn the tide. We can jointly fate a twist. Various media sources reinforced this image, portraying this social movement as the solution to the problem. The study has shown that crisis entrepreneurs may differ in terms of the strategies used and the interactional problems encountered. The solutions put forward by BON have proved more effective than those suggested by Rector Sjamaar. As a result, the discursive activities pursued by the former have been more successful than those of the latter. The diverse reactions exhibited by the media sources in this study serve to underline the precarious nature of a crisis entrepreneur’s operation. For instance, the analysis shows that rather than focusing on the authenticity of his signal, the responses to Matthé Sjamaar’s article dismiss his views as a purely private emotion. Based on this study, I show that the Rector’s initiative was undermined by his presentation of the problem. It failed to trigger a general sense of crisis as a result of segregation. BON fared very differently, as the problem of educational reform is already widely recognized. Moreover, as the analysis shows, BON’s spokespersons are important actors in this connection. Ad and Marijke Verbrugge have put forward polarizing arguments, in which they distance themselves from the New Learning concept. These views have clearly been taken on board by supporters and opponents in the debate triggered by these authors. The study has also shown that certain interactional problems are not necessarily inevitable, but that such problems can be triggered by crisis entrepreneurs themselves. Its content is inextricably linked to people’s goals in making specific comments. Chapter 8 summarizes the main observations in this thesis. It shows that the problems created by raising the issue of a latent crisis are not purely substantive in nature (‘is this crisis genuine?’), there is also an interactional aspect (for example, ‘how do I get people to accept the urgency and validity of the problem?’). My study provides a greater understanding of the course that crises can take. It also shows that crisis entrepreneurs can be seen as dynamic elements within society. They express dissenting views, and launch new initiatives through various forms of traditional and electronic media. This process can be very instructive. Communications professionals can better understand how crises develop among those in their environment if they are aware of the types of interactional problems, and the types of responses, that can result from raising the issue of a crisis. Moreover, this might also help communications professionals to achieve better outcomes in their dealings with crisis entrepreneurs. A discursive approach is valuable in this respect because it shows how certain themes in communication can deal with policy development. This approach can lead to a better hold on these themes in practice and can provide another perspective to widespread failure of interaction between government and citizens. The government is often unable to understand what the citizen means, because their interactional problems are not recognized. Knowledge of their doubts on an issue, can help the organization to acquire a better understanding of objections – from inside and out – against a particular policy. A discourse analysis of the interactional contributions of crisis entrepreneurs may give a rich and structured insight into latent crisis supply, including the strategies, interactional problems and reactions of the actors involved and how they are able to recognize a potential crisis. </p

Diversity and spatial distribution of sorghum on farmers’ fields in Uganda

Sorghum (Sorghum bicolor (L.) Moench) is a food security crop in sub-Saharan Africa, which requires constant breeding in response to changes in the fragility of agricultural production environments. Hence, understanding and tenacious use of genetic variation in sorghum germplasm is essential for improving the crop to cope with environmental changes. The objective of this study was to determine the levels of diversity and spatial distribution of sorghum on farmers’ fields in major sorghum growing regions in Uganda. A survey involving 180 fields was conducted in three districts, namely Agago and Apac (northern) and Serere (eastern) all in Uganda. Diversity was measured in terms of number of accessions per field, the Shannon-Weaver and Simpson diversity indices. In order to assess spatial distribution of sorghum diversity on the fields, correlation analysis was carried out between diversity and geographical distances between fields. Overall, Agago district had the highest number of accessions per unit area (4.47); while Apac had the lowest (1.62). The spatial distribution of sorghum diversity showed a positive correlation (r = 0.381 for Agago, 0.124 for Apac and 0.081 for Serere), between geographical distances and diversity across the three districts; implying that fields close together share similar sorghum varieties. This can be due to sharing seeds between farmers within a given location. Sorghum diversity was spatially distributed in the fields, with fields close to each other shared most sorghum types. The levels of sorghum diversity on fields were highest in Agago and lowest in Apac district. The existing on-farm sorghum diversity offers the opportunity for improving sorghum through natural breeding against biotic and abiotic stresses. &nbsp

Correlations and path analysis of yield traits in sorghum grown in southwestern highlands of Uganda

The study of relationships among traits is essential for assessing the feasibility of joint selection for two or more traits. Path coefficient analysis partitions correlation coefficient into direct and indirect contributions of various traits towards dependent variable, thus guiding effective selection. A study was conducted to determine the correlation and path coefficients for sorghum ( Sorghum bicolor L. Moench) grain yield and quantitative traits among 47 sorghum cultivars collected from southwestern highlands of Uganda. The study was conducted at Kachwekano Research Farm in Kabale District in southwestern Uganda, at an altitude of 2,223 metres above sea level, during the two successive sorghum growing seasons of December 2014 to August 2015 and December 2015 to August 2016. Correlations revealed strong significant trait associations (P&lt;0.001) for grain yield with panicle weight (r=0.938), and moderately strong relationships with panicle width (r=0.619), stem girth (r= 0.674), and leaf width (r=0.576). Grain yield revealed a non-significant negative correlation with days to 50% flowering (r=-0.011). Regression analysis revealed that panicle weight and plant height had the highest direct effect on grain yield of 1.085 and 0.2097, respectively. Path coefficient analysis revealed that stem girth (0.814), leaf width (0.74901) and panicle width (0.713) had the highest indirect contributions to grain yield. The residual effect was low (R=0.11), with high adjusted R2 value (0.89).L\u2019\ue9tude des relations entre les traits est essentielle pour \ue9valuer la faisabilit\ue9 d\u2019une s\ue9lection conjointe de deux traits ou plus. L\u2019analyse du coefficient de consanguinit\ue9 partage le coefficient de corr\ue9lation en contributions directes et indirectes de divers traits \ue0 la variable d\ue9pendante, guidant ainsi la s\ue9lection effective. Une \ue9tude a \ue9t\ue9 faite pour d\ue9terminer les coefficients de corr\ue9lation et de consanguinit\ue9 pour le rendement en grain de sorgho ( Sorghum bicolor L. Moench) et les caract\ue8res quantitatifs parmi 47 cultivars de sorgho collect\ue9s dans les hautes altitudes du sud-ouest de l\u2019Ouganda. L\u2019\ue9tude a \ue9t\ue9 faite \ue0 la ferme de recherche Kachwekano, dans le district de Kabale, dans le sud-ouest de l\u2019Ouganda, \ue0 2 223 m\ue8tres d\u2019altitude, au cours des deux saisons de culture de sorgho successives de D\ue9cembre 2014 \ue0 Ao\ufbt 2015 et de D\ue9cembre 2015 \ue0 Ao\ufbt 2016. Les corr\ue9lations ont r\ue9v\ue9l\ue9 un trait associations (P &lt;0,001) pour le rendement en grain avec le poids de la panicule (r = 0,938) et des relations mod\ue9r\ue9ment fortes avec la largeur de la panicule (r = 0,619), la circonf\ue9rence de la tige (r = 0,674) et la largeur de la feuille (r = 0,576). Le rendement en grains a r\ue9v\ue9l\ue9 une corr\ue9lation n\ue9gative non significative avec la floraison en jours \ue0 50% (r = -0,011). Une analyse de r\ue9gression a r\ue9v\ue9l\ue9 que le poids de la panicule et la hauteur de la plante avaient l\u2019effet direct le plus \ue9lev\ue9 sur le rendement en grain, \ue0 savoir 1,085 et 0,2097, respectivement. L\u2019analyse du coefficient de consanguinit\ue9 a r\ue9v\ue9l\ue9 que la circonf\ue9rence de la tige (0,814), la largeur des feuilles (0,74901) et la largeur de la panicule (0,713) avaient les contributions indirectes les plus \ue9lev\ue9es au rendement en grain. L\u2019effet r\ue9siduel \ue9tait faible (R = 0,11), avec une valeur de R2 ajust\ue9e \ue9lev\ue9e (0,89)

Revisiting application of statistics in Agricultural Research in sub-Saharan Africa: Entry points for improvement

The importance of statistics in empowering the agricultural research process and sharpening interventions cannot be over-emphasized. Undocumented evidence points to misconceptions, misuse or underuse of statistics among agricultural researchers in sub-Saharan Africa (SSA); pointing to the possibility that the subject has been part of the causes the unfulfilled targets in the agricultural sector in the region. The objective of this study was to analyse and document weaknesses in statistical practice in agricultural research, with a view to identifying entry points for strengthening the performance of the sector for SSA to be able to achieve its set goals. A desk study involving 165 research articles published in the African Crop Science Journal over the period of 17 years (2000 to 2017) was conducted through a rigorous SWOT analysis for issues related to the use of statistics in the implementation of agricultural research in SSA. A checklist consisting of key elements related to study design; data collection, analysis and exploitation; and presentation, was used to guide the interrogation. Findings indicated that researchers generally made explicit description of treatment structures that fairly matched the study objectives and hypotheses (in the few cases where they were stated), with a few weaknesses in the description of factorial treatment structure. The Randomised Complete Block Design was most commonly used among the designs, with 3-4 replicates. However, there was hardly any justification for its use, as the blocking factors were never mentioned and thus their role in determining the precision of the results was difficult to determine. Analysis of Variance was the main method for data analysis, followed by correlations. The F-test and the associated P-values were the basis for decisions on treatment differences. Most researchers had problems with presentation and interpretation of P-values and significance level. Post adhoc tests mostly used the Least Significant Difference (LSD) for pairwise mean comparisons, with little consideration for the treatment structure, the number of treatments and the nature (qualitative or quantitative). Generally, estimates of treatment means were presented together with various measures of precision, in both tables and graphical forms. In several cases, LSD was used or misused interchangeably with standard error (SE) or standard error of difference (SED). Several statistical software were used for data analysis and presentation, with the main ones being SAS, Genstat and MSTAT-C. Key entry points for improvement heavily lie in human and infrastructural resource capacity improvement, most specifically in (i) periodic review of university and other tertiary institutions\u2019 curricula to provide sufficient time allocation, physical space and relevant infrastructure for true hands on practice; (ii) more effective utilisation of the few statisticians available in the region, (iii) short term staff in-service retooling courses, (iv) sustained statistical service units wherever necessary, and (v) provision for periodic interactive statistician-researcher platforms (such as conferences and workshops) for sharing notes on challenges and achievements during implementation of their research programmes.L\u2019importance des statistiques pour renforcer le processus de recherche agricole et affiner les interventions ne saurait \ueatre trop soulign\ue9e. Des preuves non document\ue9es font ressortir des id\ue9es fausses, un usage abusif ou un usage insuffisant des statistiques parmi les chercheurs en agriculture en Afrique subsaharienne (ASS); soulignant la possibilit\ue9 que le sujet ait fait partie des causes des objectifs non atteints dans le secteur agricole de la r\ue9gion. L\u2019objectif de cette \ue9tude \ue9tait d\u2019analyser et de documenter les faiblesses de la pratique d\u2018 utilization de la statistique en mati\ue8re de recherche agricole, en vue d\u2019identifier les points d\u2019entr\ue9e permettant de renforcer les performances du secteur afin que l\u2019ASS puisse atteindre ses objectifs fix\ue9s. Une \ue9tude th\ue9orique comprenant 165 articles de recherche publi\ue9s dans le journal African Crop Science Journal dans une p\ue9riode de 17 ans (2000 \ue0 2017) qui ont \ue9t\ue9 r\ue9alis\ue9es au moyen d\u2019une analyse SWOT rigoureuse des probl\ue8mes li\ue9s \ue0 l\u2019utilisation des statistiques dans la mise en \u153uvre de la recherche agricole en ASS. Une liste de contr\uf4le comprenant des \ue9l\ue9ments cl\ue9s li\ue9s \ue0 la conception de l\u2019\ue9tude; collection, analyse et exploitation de donn\ue9es; et pr\ue9sentation, a \ue9t\ue9 utilis\ue9 pour guider l\u2019interrogatoire. Les r\ue9sultats ont indiqu\ue9 que les chercheurs avaient g\ue9n\ue9ralement d\ue9crit de mani\ue8re explicite les structures de traitement correspondant assez bien aux objectifs et hypoth\ue8ses de l\u2019\ue9tude (dans les cas rares o\uf9 elles avaient \ue9t\ue9 \ue9nonc\ue9es), avec quelques faiblesses dans la description de la structure de traitement factoriel. Le dispositif en bloc (fisher) randomis\ue9 \ue9tait le plus couramment utilis\ue9 parmi les dispositifs, avec 3 \ue0 4 r\ue9plicats. Cependant, son utilisation n\u2019\ue9tait gu\ue8re justifi\ue9e, car les facteurs de blocage n\u2019\ue9taient jamais mentionn\ue9s et leur r\uf4le dans la d\ue9termination de la pr\ue9cision des r\ue9sultats \ue9tait donc difficile \ue0 d\ue9terminer. L\u2019analyse de la variance \ue9tait la principale m\ue9thode d\u2019analyse des donn\ue9es, suivie par les corr\ue9lations. Le test F et les valeurs P associ\ue9es constituaient la base des d\ue9cisions sur les diff\ue9rences de traitements. La plupart des chercheurs ont eu des probl\ue8mes de pr\ue9sentation et d\u2019interpr\ue9tation des valeurs de p et du niveau de signification. Les tests post adhoc ont principalement utilis\ue9 la diff\ue9rence la moins significative (DMS) pour les comparaisons moyennes par paires, en prenant peu en compte la structure du traitement, le nombre de traitements et la nature (qualitative ou quantitative). En g\ue9n\ue9ral, les estimations des moyennes de traitement \ue9taient pr\ue9sent\ue9es avec diverses mesures de pr\ue9cision, sous forme de tableaux et de graphiques. Dans plusieurs cas, le DMS a \ue9t\ue9 utilis\ue9 ou utilis\ue9 de mani\ue8re interchangeable avec l\u2019erreur standard (ES) ou l\u2019erreur standard de diff\ue9rence (ESD). Plusieurs logiciels statistiques ont \ue9t\ue9 utilis\ue9s pour l\u2019analyse et la pr\ue9sentation des donn\ue9es, les principaux \ue9tant SAS, Genstat et MSTAT-C. Les points principaux d\u2019am\ue9lioration d\ue9pendent essentiellement de l\u2019am\ue9lioration de la capacit\ue9 des ressources humaines et infrastructurelles, plus particuli\ue8rement de (i) la r\ue9vision p\ue9riodique des programmes d\u2019\ue9tudes des universit\ue9s et autres \ue9tablissements d\u2019enseignement sup\ue9rieur afin de pr\ue9voir suffisamment de temps, un espace physique et une infrastructure appropri\ue9e pour une v\ue9ritable mise en pratique; (ii) une utilisation plus efficace des quelques statisticiens disponibles dans la r\ue9gion, (iii) des cours de r\ue9outillage en cours \ue0 court terme pour le personnel, (iv) des unit\ue9s de services statistiques durables, le cas \ue9ch\ue9ant, et (v) la mise en place de plates-formes interactives interactives de statisticiens et de chercheurs ( conf\ue9rences et d\u2019ateliers d\u2019\ue9criture) pour partager des notes sur les d\ue9fis et les r\ue9alisations au cours de la mise en \u153uvre de leurs programmes de recherche

Mode of inheritance of promiscuous nodulation and combining abilities in soybean genotypes

Article purchasedKnowledge of the mode of inheritance of a trait can be a powerful decision-making tool in a breeding program, as it helps predicting selection gain, defining breeding strategy and choosing parental lines. This study aimed at estimating genetic parameters to infer the mode of inheritance of promiscuous nodulation in soybean. Half diallel crosses were made among nine parental lines. F2 progenies were field evaluated together with parents for nodulation characteristics and grain yield in response to Bradyrhizobium sp. strain USDA 3456. Data on nodule number (NN), percent of effective nodules (NE), fresh and dry weight of nodules (NFW and NDW), and grain yield were subjected to analysis of variance, and progenies’ means regression against parents’ was performed following Griffing’s Method2/Model 1. General and specific combining abilities, broad and narrow sense heritabilities, and Baker’s ratio were estimated. The study showed predominant GCA effect for all measured traits except NE. Broad and narrow sense heritabilities were high for grain yield and NDW, moderate for NN and NFW, and low for NE. Baker’s ratio was high for all measured traits except for NE. Overall, additive gene action was more important for all measured traits, except NE where non-additive gene action was more important. The high to moderate heritabilities for most traits showed that substantial gain can be achieved through selection

Kernel morphometric characteristics and oil content among Shea tree genotypes in Uganda

Shea tree (Vitellaria paradoxa subsp. nilotica) is an important commercial tree for domestic oil and industrial products of cosmetics, chocolate and other confectionaries traded grown worldwide. We studied seed morphometric characteristics and crude oil content of Shea nuts in Uganda. Five populations, comprising of 16 ethnovarieties, were selected from Eastern, Northern and West Nile Sub-regions of Uganda, based on their attributes as judged by the farmers. Fresh kernel weight ranged from 2 to 18.85 mg per seed. Kernel weight increased with Shea fruit weight (y = 0.1499x + 6.1887, R² = 0.306). Moyo district had the highest oil content (54.37 ± 0.32%); while Amuru district had the lowest oil content (50.5 ± 1.32%). Oil content decreased with increasing kernel size (y = -0.4541x + 57.303, R² = 0.2116) and dry matter content (y = 0.635x - 9.863, R²= 0.011); and varied between ethnovarieties and Shea tree populations, p&nbsp;=&nbsp;0.003 and P&lt;&nbsp;0.001, respectively. Tinny seeded (45.7 - 65.49%), Round fruited (45.41 - 65.91%), Dwarf tree (45.19 - 64.19%), Elliptical fruited (45.32 - 64.19%) and Soft pulped (42.16 - 69.77%) ethnovarieties had the highest oil content. Narrow sense heritability (h2) for oil yield was 1.72; while response to selection (R) was 16.48 with genetic gain (Gs) of 2.21%, given 10% top selection intensity

SCREENING SOYBEAN GENOTYPES FOR PROMISCUOUS SYMBIOTIC ASSOCIATION WITH Bradyrhizobium STRAINS

The current low soybean ( Glycine max L. Merrill) yields in Sub-Saharan Africa can be alleviated by developing promiscuous genotypes. The research trend in Africa is towards developing promiscuous varieties for less labour and high yields in soybean production. A greenhouse experiment was conducted at Makerere University Agricultural Research Institute, Kabanyolo (MUARIK) with the aim of screening of soybean germplasm for promiscuous symbiotic association with Bradyrhizobium sp. in order to identify genotypes with potential to be used as parents to initiate a breeding programme focusing on promiscuous nodulation. The response of 65 soybean genotypes from different origins to cowpea-type inoculant, Bradyrhizobium sp. strain USDA 3456 were evaluated. Soybean seeds inoculated with both Bradyrhizobium sp. strain USDA 3456 and Bradyrhizobium japonicum strain USDA 110 were planted in buckets filled with steam-sterilised soil. Significant differences in the number of nodules, effective nodules, fresh and dry weight of nodules were observed among genotypes (P&lt;0.001). Twelve of the 65 genotypes were highly responsive to Bradyrhizobium sp., with over 10 nodules per plant, over 50 mg dry weight of nodules, and 50% effective nodules. A highly positive correlation was shown between dry weight of nodules and nodule number. This study proposes the soybean genotypes NamII, WonderSoya, Bulindi 48C, NamSoy 4M, MakSoy 3N, NamSoy 3, K-Local, Kabanyolo 1, UG 5, Soprano, MakSoy 2N, and MakSoy 5N as potential parental materials for subsequent breeding work.La s\ue9lection de vari\ue9t\ue9s de soja \ue0 nodulation facile peut contribuer grandement \ue0 l\u2019am\ue9lioration des rendements de production en Afrique sub-Saharienne. Les vari\ue9t\ue9s de soja \ue0 nodulation facile rendent superflus l\u2019utilisation d\u2019engrais azot\ue9s, l\u2019application d\u2019inoculum aux fins de fixation biologique d\u2019azote, am\ue9liorent le rendement de soja, ainsi que la qualit\ue9 du sol pour les cultures subs\ue9quentes. Une exp\ue9rimentation en serre a \ue9t\ue9 conduite \ue0 l\u2019Institut de Recherche Agricole de l\u2019Universit\ue9 de Makerere \ue0 Kabanyolo (MUARIK). L\u2019objectif \ue9tait d\u2019\ue9valuer l\u2019habilet\ue9 des accessions de soja \ue0 r\ue9aliser la symbiose avec Bradyrhizobium sp. En vue d\u2019identifier les cultivars qui peuvent constituer de potentiels parents \ue0 utiliser pour initier un programme d\u2019am\ue9lioration g\ue9n\ue9tique du soja visant la nodulation facile. 65 accessions d\u2019origines diverses ont \ue9t\ue9 \ue9valu\ue9es pour leur r\ue9action en pr\ue9sence de rhizobium de type ni\ue9b\ue9 (Bradyrhizobium sp. souche USDA 3456). Les graines de soja inocul\ue9es avec le rhizobium de type ni\ue9b\ue9 (Bradyrhizobium sp. souche USDA 3456) ou de type soja ( Bradyrhizobium japonicum souche USDA 110) ont \ue9t\ue9 plant\ue9es dans des pots en plastic soigneusement remplis de terre arable st\ue9rilis\ue9e \ue0 base de vapeur surchauff\ue9e. Des diff\ue9rences significatives ont \ue9t\ue9 observ\ue9es entre accessions, au niveau des nombres de nodules, pourcentages de nodules actives, poids frais et secs des nodules (P&lt;0.001). Douze accessions ont notablement r\ue9agi face \ue0 Bradyrhizobium sp. avec chacune plus de 10 nodules par plante, 50 mg comme poids sec de nodules, et 50% de nodules actives. Une corr\ue9lation positivement tr\ue8s significative a \ue9t\ue9 observ\ue9e entre poids sec et nombre de nodules. Cette \ue9tude propose les accessions NamII, WonderSoya, Bulindi 48C, NamSoy 4M, MakSoy 3N, NamSoy 3, K-Local, Kabanyolo 1, UG 5, Soprano, MakSoy 2N, and MakSoy 5N comme potentiels parents \ue0 utiliser dans un programme ult\ue9rieur d\u2019am\ue9lioration g\ue9n\ue9tique

Quality of core collections for effective utilisation of genetic resources review, discussion and interpretation

Definition of clear criteria for evaluation of the quality of core collections is a prerequisite for selecting high-quality cores. However, a critical examination of the different methods used in literature, for evaluating the quality of core collections, shows that there are no clear guidelines on the choices of quality evaluation criteria and as a result, inappropriate analyses are sometimes made leading to false conclusions being drawn regarding the quality of core collections and the methods to select such core collections. The choice of criteria for evaluating core collections appears to be based mainly on the fact that those criteria have been used in earlier publications rather than on the actual objectives of the core collection. In this study, we provide insight into different criteria used for evaluating core collections. We also discussed different types of core collections and related each type of core collection to their respective evaluation criteria. Two new criteria based on genetic distance are introduced. The consequences of the different evaluation criteria are illustrated using simulated and experimental data. We strongly recommend the use of the distance-based criteria since they not only allow the simultaneous evaluation of all variables describing the accessions, but they also provide intuitive and interpretable criteria, as compared with the univariate criteria generally used for the evaluation of core collections. Our findings will provide genebank curators and researchers with possibilities to make informed choices when creating, comparing and using core collection

STABILITY AND EXTENT OF RESISTANCE OF COWPEA LINES TO FLOWER BUD THRIPS IN UGANDA

Cowpea ( Vigna unguiculata (L.) Walp.) is a legume attacked by several field insect pests, with flower thrips ( Megalurothrips sjostedti Trybom) being the most damaging. It causes 20 to 100% yield losses. Cowpea constitutes an important source of protein for resource poor households in Africa. The objective of this study was to identify cowpea lines that are resistant to flower thrips as a step in developing sustainable thrips management strategies. Seventy two cowpea cultivars were screened in three locations and two rainy seasons in Uganda, for thrips damage and yield components. Up to 11 cultivars (IT2841*Brown (1.50), MU20B (1.58), EBELAT*NE39 (1.61), WC17 (1.63), WC29 (1.65), MU24C (1.65), WC5 (1.66), NE46 (1.67), WC30 (1.68), NE67 (1.69), and NE51 (1.71)) were the most resistant and stable across locations. However, thrips damage was negatively correlated with the number of days to flowering (r = -0.32), indicating that the resistance in the cultivars was explained by the flower thrips infestation escape due to later flowering. Cultivar MU9 was high yielding (813.87 kg ha-1) and the most adapted genotype to all the locations; while cultivars WC26, NE48, and NE5 were the most adapted to Arua and Serere, and WC48A was the most adapted to Makerere University Agricultural Research Institute, Kabanyolo (MUARIK). There is potential of finding resistance sources in the cultivars tested.Le ni\ue9b\ue9 ( Vigna unguiculata (L.) Walp.) est une l\ue9gumineuse attaqu\ue9e par plusieurs insectes au champ avec thrips ( Megalurothrips sjostedti Trybom) le plus nuisible causant 20-100% de perte de rendement. Le ni\ue9b\ue9 constitue une source de prot\ue9ine bon-march\ue9 pour beaucoup de pauvres m\ue9nages en Afrique. L\u2019objectif de cette \ue9tude \ue9tait d\u2019identifier des vari\ue9t\ue9s plus r\ue9sistantes au thrips pour le d\ue9veloppement des strat\ue9gies de lutte durable. Soixante-douze vari\ue9t\ue9s du ni\ue9b\ue9 ont \ue9t\ue9 \ue9valu\ue9es dans trois environnements pendant deux saisons en Uganda pour les dommages, le rendement et ses composantes. Les donn\ue9es ont \ue9t\ue9 soumises aux analyses de variance et biplot de l\u2019effet de g\ue9notype et l\u2019interaction entre g\ue9notype et environnement (GGE). Les r\ue9sultats ont montr\ue9 un effet significatif (P&lt;0.001) de l\u2019interaction entre g\ue9notype, environnement pour les scores de dommages caus\ue9s par thrips. Les vari\ue9t\ue9s les plus r\ue9sistantes et stables \ue9taient IT2841*Brown (1.50), MU20B (1.58), EBELAT*NE39 (1.61), WC17 (1.63), WC29 (1.65), MU24C (1.65), WC5 (1.66), NE46 (1.67), WC30 (1.68), NE67 (1.69), and NE51 (1.71). Toutefois, une corr\ue9lation n\ue9gative (r = -0.32) a \ue9t\ue9 observ\ue9e entre les scores de dommage et le nombre de jours de floraison indiquant que la r\ue9sistance observ\ue9e, \ue9tait due \ue0 un \ue9chappement par une floraison tardive. Le cultivar MU9 avait le rendement le plus \ue9lev\ue9 (813, 87 kg ha-1) et constituait le plus adapt\ue9 aux diff\ue9rents environnements alors que les cultivars WC26, NE48, and NE5 \ue9taient les plus adapt\ue9s \ue0 Arua et Serere, et WC48A \ue9tait le plus adapt\ue9 \ue0 l\u2019Institut de Recherches Agricoles de l\u2019Universit\ue9 de Makerere, Kabanyolo (MUARIK). Il y a potentiel de trouver de source de r\ue9sistance parmi les vari\ue9t\ue9s \ue9valu\ue9es

Resistance of Uganda soybean germplasm to Adzuki bean bruchid

Soybean ( Glycine max (L.) Merrill) is among the major food and industrial crops grown globally for its high protein and oil content. Lately, in Uganda, soybean reportedly faces challenges with a storage pest, Callosobruchus chinensis . This study was carried out to quantify the damage caused by the pest and identify the sources of resistance in the germplasm in Uganda. The study was conducted at Makerere University Agricultural Research Institute, Kabanyolo (MUARIK) in Uganda, during 2015 and 2016. Callosobruchus chinensis was used to challenge 498 soybean lines under no choice condition, in the laboratory. Results showed no significant differences in eggs laid amongst the different genotypes; however the genotypes performed significantly different (P&lt; 0.05) for adult insect emergence, median development period (MDP), Dobie susceptibility index (DSI), growth index (GI), insect percent emergence (% IE) and seed weight loss (%WL). Genotype AVRDC G8527 had the lowest % IE (6.31), DSI (0.7), % WL (0.02) and GI (0.07), suggesting high resistance. Weight loss of up to 27% was recorded in genotype USA 7. There was a strong positive correlation between number of adults that emerged with DSI (r=0.87), eggs (r=0.88), % weight loss (r=0.73), and growth index (r=0.996). Cluster analysis revealed that AVRDC G8527, a resistant genotype was closely related to S-line 13.2A, a moderate resistant genotype. Regression analysis, revealed that adult bruchid emergence explain seed weight loss with 62% coefficient of determination; while seed colour could be used to determine genotype DSI with up to 74% coefficient of determination. Genotypes AVRDC G8527 and G89 were identified as the most resistant genotypes based on levels of DSI.Le soja ( Glycine max (L.) Merrill) est parmi les cultures alimentaires majeures et industrielles cultiv\ue9es g\ue9n\ue9ralement pour sa grande teneur en prot\ue9ine et en huile. R\ue9cemment, en Ouganda, le soja fait face \ue0 des d\ue9fis avec une peste de stockage, Callosobruchus chinensis . Cette \ue9tude a \ue9t\ue9 conduite pour quantifier les dommages caus\ue9s par la peste et identifier les sources de r\ue9sistance dans le germplasm en Ouganda. L\u2019\ue9tude a \ue9t\ue9 conduite \ue0 l\u2019Institut de Recherche Agricole de l\u2019Universit\ue9 de Makerere, Kabanyolo (MUARIK) en Ouganda, en 2015 et 2016. Callosobruchus chinensis a \ue9t\ue9 utilis\ue9 pour \ue9valuer 498 lign\ue9es du soja sous une condition sans choix, dans le laboratoire. Les r\ue9sultats ont montr\ue9 qu\u2019il n\u2019y a pas de diff\ue9rences significatives dans la ponte des \u153ufs parmi les diff\ue9rents g\ue9notypes; toutefois, les g\ue9notypes ont montr\ue9 des performances significativement diff\ue9rentes (P&lt;0,05) pour l\u2019\ue9mergence des insectes adultes, la p\ue9riode moyenne de d\ue9veloppement (MDP) l\u2019indice de sensibilit\ue9 de Dobie (DSI), l\u2019indice de croissance (GI)\ua0; le pourcentage d\u2019\ue9mergence de l\u2019insecte (%IE) et la perte du poids (%WL). Le g\ue9notype AVRDC G8527 a eu le plus faible %IE (6,31), DSI (0,7), %WL (0.02) et (0.07) sugg\ue9rant une grande r\ue9sistance. Une perte de poids jusqu\u2019\ue0 27% a \ue9t\ue9 observ\ue9e sur le g\ue9notype USA 7. Il y a une forte et positive corr\ue9lation entre le nombre d\u2019adultes qui ont \ue9merg\ue9 avec DSI (r=0,88), la perte du poids (r=0.73), et l\u2019indice de croissance (r=0,996). L\u2019analyse hi\ue9rarchique a r\ue9v\ue9l\ue9 que AVRDC G8527, un g\ue9notype r\ue9sistant a \ue9t\ue9 li\ue9 \ue0 la lign\ue9e S-line 13.2A, un g\ue9notype mod\ue9r\ue9ment r\ue9sistant. L\u2019analyse en r\ue9gression lin\ue9aire a r\ue9v\ue9l\ue9 que l\u2019\ue9mergence du bruche adulte explique la perte du poids avec un coefficient de d\ue9termination de 62%\ua0; alors que la couleur des graines pourrait \ueatre utilis\ue9e pour d\ue9terminer le DSI jusqu\u2019\ue0 74% de coefficient de d\ue9termination. Les g\ue9notypes AVRDC G8527 et G89 ont \ue9t\ue9 identifi\ue9s comme g\ue9notypes les plus r\ue9sistants sur la base des niveaux de DSI