Evaluation of performance of introduced yam bean (Pachyrhizus spp.) in Rwanda.

Root and tubers crops are key staple crops for both rural and urban populations in Rwanda and supporting more than nine million people living in densely populated areas and sustained on agriculture with diverse range of cultivated species. Yam bean (Pachyrizhus spp) was introduced for both its immediate utilization as a high-yielding root crop with high sugar, considerable micronutrient concentrations and protein content for subtropical regions compared to common grown tropical root and tuber crops (cassava, potato, sweetpotato and yam).The yields of these species are up to 100 tons fresh weight per hectare, with dry matter contents of up to 25%. Recent introduction of different yam bean accessions in different agro-ecological zones of Rwanda produced high yield storage roots. Higher storage roots yield with strict pruning was produced by Erosus genotype 209018 (111.33 t/ha) and genotype 209019 (108.00 t/ha) followed by Ahipa genotype 209029 with 76.33 t/ha respectively. Dry matter was relatively low with a range of 20.84-19.14 % for all introduced genotypes. As a root crop with capacity of fixing atmospheric nitrogen and which does not require good-quality soil and resists pests and diseases which can fix yields abundantly and produces well even in area with scanty rain, it might be well indicated for Rwand

Adaptation and stability of vegetable soybean genotypes in Uganda

Vegetable soybean ( Glycine max L. Merr.) is a specialty soybean, harvested as a vegetable when seeds are immature (R6 stage) and have expanded to fill 80 to 90% of the pod. The objective of the study was to assess the adaptation and stability of vegetable soybean genotypes in different agro-ecological zones of Uganda to enable selection of genotypes. A total of 21 genotypes were planted in Uganda for two consecutive seasons. Genotypes PI615437-B had the highest number of pods, while AGS 329 matured earliest in 64 days. Only AGS 292, AGS 329 and AGS 338 had 100 seeds weight above 30 g. G10427 was the ideal genotype in terms of adaptation and stability for fresh seed yield, with mean yield of 4281kg ha-1; followed by G2843 with 4039 kg ha-1. PI615437-B came third with fresh seed yield of 4024 kg ha-1. The least stable and adapted genotype was AGS 329 with only 1609 kg ha-1. Nakabango 1 and MUARIK 1 were the ideal environments, which were the most discriminative and representative. We recommend that G10427 be used as a test genotype and for improvement to produce a variety with good attributes, especially large seed, high yield and adaptable to Uganda.Le soja ( Glycine max L. Merr.) Est un soja de sp\ue9cialit\ue9, r\ue9colt\ue9 comme l\ue9gume quand les graines sont immatures (stade R6) et s\u2019est d\ue9velopp\ue9 pour remplir 80 \ue0 90% de la gousse. L\u2019objectif de l\u2019\ue9tude \ue9tait d\u2019\ue9valuer l\u2019adaptation et la stabilit\ue9 des g\ue9notypes de soja v\ue9g\ue9tal dans diff\ue9rentes zones agro-\ue9cologiques de l\u2019Ouganda pour permettre la s\ue9lection des g\ue9notypes. Au total, 21 g\ue9notypes ont \ue9t\ue9 plant\ue9s en Ouganda pendant deux saisons cons\ue9cutives. Les g\ue9notypes PI615437-B avaient le plus grand nombre de gousses, tandis qu\u2019AGS 329 est arriv\ue9 \ue0 maturit\ue9 plus t\uf4t en 64 jours. Seulement AGS 292, AGS 329 et AGS 338 avaient un poids de 100 graines sup\ue9rieur \ue0 30 g. G10427 \ue9tait le g\ue9notype id\ue9al en termes d\u2019adaptation et de stabilit\ue9 pour le rendement en semences fra\ueeches, avec un rendement moyen de 4281 kg ha-1; suivi de G2843 avec 4039 kg ha-1. Le PI615437-B est arriv\ue9 troisi\ue8me avec un rendement en graines fra\ueeches de 4024 kg ha-1. Le g\ue9notype le moins stable et le plus adapt\ue9 \ue9tait AGS 329 avec seulement 1609 kg ha-1. Nakabango 1 et MUARIK 1 \ue9taient les environnements id\ue9aux, les plus discriminants et les plus repr\ue9sentatifs. Nous recommandons que G10427 soit utilis\ue9 comme g\ue9notype de test et pour l\u2019am\ue9lioration afin de produire une vari\ue9t\ue9 en particulier des graines de grande taille, \ue0 haut rendement et adaptable \ue0 l\u2019Ouganda

Detection of cowpea aphid-borne mosaic virus (CABMV) in cowpea by reverse transcription polymerase chain reaction

The occurrence of CABMV on cowpea ( Vigna unguiculata L. Walp) in Uganda was described recently in several studies. This study developed and optimised a reverse transcription polymerase chain reaction (RT-PCR) based assay for the detection of CABMV in leaf samples, and compared it to previous RT-PCR and ELISA assays. Use of the forward primer (CABFF1, 5'- GGT AAC AAY AGT GGR CAA CC-3') and the reverse primer (CABRR1, 5'- CTG AGC ACT CMA ACC GGG-3') yielded a product of ~ 1,642 bp. Amplicon sequencing and subsequent BLASTN analysis showed that Ugandan isolates were 89.3-94.3% identical indicating they belong to the same strain of CABMV. Phylogenetic analysis also placed the Ugandan isolates in the same cluster different from other isolates but closer to those from Burkina Faso. However, the previously reported RT-PCR assay (GF/GR primer pair) did not give the expected PCR fragment (221 bp) and gave no virus hits upon amplicon sequencing and sequence analysis. The ELISA assay did not differentiate between positive and negative samples. The newly developed RT-PCR assay for detecting CABMV, described in this study, has important applications for plant quarantine, resistance breeding, host range studies as well as epidemiological studies for the control of CABMV in the country.L\u2019apparition de CABMV sur le ni\ue9b\ue9 ( Vigna unguiculata (L.)) en Ouganda a \ue9t\ue9 d\ue9crite r\ue9cemment dans plusieurs \ue9tudes. Cette \ue9tude a d\ue9velopp\ue9 et optimis\ue9 un essai bas\ue9 sur la transcription inverse- r\ue9action en cha\ueene par polym\ue9rase (RT-PCR) pour la d\ue9tection du CABMV dans les \ue9chantillons de feuilles, et la compar\ue9 aux essais pr\ue9c\ue9dents bas\ue9s sur la RT-PCR et ELISA. L\u2019usage de l\u2019amorce direct (CABFF1, 5'- GGT AAC AAY AGT GGR CAA CC-3\u2019) et d\u2019amorce r\ue9verse (CABRR1, 5'- CTG AGC ACT CMA ACC GGG-3') a donn\ue9 ~ 1,642 bp. Le s\ue9quen\ue7age d\u2019amplicon et l\u2019analyse subs\ue9quente de BLASTN ont montr\ue9 que les isolats d\u2019Ouganda \ue9taient \ue0 89,3-94,3% identiques indiquant qu\u2019ils appartiennent \ue0 la m\ueame souche de CABMV. Les analyses phylog\ue9n\ue9tiques ont aussi plac\ue9 les isolats Ougandais dans la m\ueame classe qui est diff\ue9rente des autres isolats mais proche de ceux du Burkina-Faso. N\ue9anmoins, les essais de RT-PCR (GF/GR paire d\u2019amorces) pr\ue9c\ue9dents n\u2019ont pas donn\ue9 les fragments PCR esp\ue9r\ue9s (221 bp) et n\u2019ont donn\ue9 aucune d\ue9tection de virus \ue0 partir du s\ue9quen\ue7age d\u2019amplicon et de l\u2019analyse de la s\ue9quence. L\u2019essai de l\u2019ELISA n\u2019a pas diff\ue9renci\ue9 entre les \ue9chantillons positifs et n\ue9gatifs. L\u2019essai RT-PCR nouvellement d\ue9velopp\ue9 pour d\ue9tecter le CABMV, d\ue9crit dans cette \ue9tude, a d\u2019importantes applications pour la mise en quarantaine de la plante, s\ue9lection pour la r\ue9sistance, les \ue9tudes des gammes d\u2019h\uf4tes ainsi que les \ue9tudes \ue9pid\ue9miologiques pour le contr\uf4le du CABMV dans le pays

Trait association and stability of virus resistance among cowpea genotypes in Uganda

Cowpea ( Vigna unguiculata L. Walp) grain constitutes an important source of protein for several households in Sub-Saharan Africa. However, widespread occurrence of viral diseases is a serious constraint to productivity of the crop and its nutritional value in terms of grain protein content. This study was carried out to identify cowpea genotypes with the best combination of virus resistance, maturity traits and yield stability. A screening trial for 105 genotypes was established in three locations (Budaka, Tororo and Serere) in Uganda for two consecutive seasons to assess for virus resistance, maturity traits and yield. Season and genotypic effects had a greater contribution to the variation in virus infection among genotypes. Eight genotypes (WC48, NE43, NE15, WC35A, WC39, WC33, WC35C, and WC18) showed low virus infection levels. The three locations formed a single mega-environment with WC51, NE48, and MU17 having the highest mean yield (1,384, 1,191.4 and 1,119.6 kg ha-1), respectively, as well as exhibiting yield stability across locations. Days to first flower, mid-bloom (days to 50% flowering) and days to maturity were positively associated. Virus severity, incidence and AUDPC also had a positive association indicating that indirect selection based on any of these traits is possible. Potential sources of resistance to virus infection exist among the evaluated genotypes. Further screening under high viral pressure is recommended. The high yielding genotypes are recommended for release for cultivation.Lesgrains du ni\ue9b\ue9 ( Vigna unguiculata L. Walp) constituent une source importante de prot\ue9ine pour un nombre important de m\ue9nages en Afrique Sub-Saharienne. Toutefois, la prolif\ue9ration des maladies virales est une contrainte s\ue9rieuse \ue0 la productivit\ue9 de la culture et sa valeur nutritionnelle en termes de la teneur en prot\ue9ine. Cette \ue9tude a \ue9t\ue9 conduite pour identifier les g\ue9notypes du ni\ue9b\ue9 avec une meilleure combinaison de r\ue9sistance au virus, traits de maturit\ue9 et la stabilit\ue9 du rendement en grain. Un essai de criblage de 105 g\ue9notypes a \ue9t\ue9 \ue9tabli dans trois localit\ue9s (Budaka, Tororo et Serere) en Uganda pendant deux saisons cons\ue9cutives pour \ue9valuer la r\ue9sistance au virus, traits de maturit\ue9 et le rendement. Les effets de la saison et du g\ue9notypeont contribu\ue9 beaucoup plus \ue0 la variation dans l\u2019infection du virus parmi les g\ue9notypes. Huit g\ue9notypes (WC48, NE43, NE15, WC35A, WC39, WC33, WC35C, et WC18) ont montr\ue9 de faibles niveaux d\u2019infection du virus.Les trois localit\ue9s ont form\ue9 un m\ue9ga-environnement avec WC51, NE48 et MU17 ayant les plus grands rendements moyens (1 384\ua0; 1 191,4 et1119,6 kg ha-1), respectivement, de m\ueame la stabilit\ue9 du rendement \ue0 travers les localit\ue9s. Le nombre de jours de la premi\ue8re floraison, mid-floraison (nombre de jours de 50% floraison) et le nombre de jours de maturit\ue9 \ue9taient associ\ue9s positivement. La s\ue9v\ue9rit\ue9 de virus, l\u2019incidence et l\u2019AUDPC ontaussi une association positive indiquant que la s\ue9lection indirecte bas\ue9e sur n\u2019importe quel de ces traits est possible. Des sources potentielles de r\ue9sistance \ue0 l\u2019infection des virus existent parmi les g\ue9notypes \ue9valu\ue9s. Un criblage sous une forte pression des virus est recommand\ue9. Les g\ue9notypes \ue0 haut rendement sont recommand\ue9s pour d\ue9livrance pour production

Effectiveness of pyramided genes in conferring resistance to anthracnose disease in common bean populations

Anthracnose disease (Colletotrichum lindemuthianum (Sacc. et. Magn) Lams. Scrib.) is one of the most devastating diseases that constrain common bean production in Uganda. A cascading pedigree pyramiding scheme was used to develop common bean populations to evaluate the effectiveness of pyramided and single resistance genes (Co-42, Co-43, Co-5, and Co-9) on disease development. Detached leaf trifoliates of F4:6 genotypes were screened with four C. lindemuthianum races (352, 713,767 and 2047). Disease severity data were subjected to ANOVA. Races, genotypes and Race x Genotype interaction were significant. Genes Co-42 and Co-5 conferred resistance to the four races and the gene pyramids Co-42+Co-5+Co-9 and Co-42+Co-5 had the lowest severity scores. Gene Co-43 conferred resistance to race 352 and weak resistance to race 713; whereas gene Co-9 conferred resistance to race 352. Co-43+Co-9 gene pyramid showed resistance only to race 352. The Co-42 and Co-5 genes conferred resistance to all the four races 352, 713, 767 and 2047. The single gene Co-42 was not significantly different from the pyramids Co-42+Co-5+Co-9 and Co-42+Co-5 (P<0.01). Similarly, the Co-5gene was not significantly different from Co-42+Co-5, Co-42+Co-9 and Co-5+Co-9 pyramids. The Co-9gene showed antagonism in all pyramids. These results indicate that pyramiding of resistance genes would be effective for disease management in Uganda, but pyramids with Co-9 gene would be less effective

Potential for yield loss reduction and profitability assessment of pesticide control of groundnut leaf miner among soybean genotypes

Groundnut leaf miner (GLM) is currently a threat to soybean production in Uganda due to the great yield losses as a result of the severe damage it causes on leaves leading to reduced photosynthetic area. GLM is a fairly new pest on soybean in Uganda, having initially been observed in soybean fields in 2011 in eastern Uganda. The objective of this study was to determine the yield loss caused by the groundnut leaf miner and effectiveness and profitability of commonly used pesticides for the control of the groundnut leaf miner ( Aproaerema modicella Deventer) (GLM), when tested with popular soybean ( Glycine max ) genotypes grown in Uganda. In a split plot RCBD design, pesticide protection (treated vs. untreated) formed the main plots; and six commercial soybean varieties (Maksoy 1N, 2N, 3N, 4N, 5N; and Namsoy 4M) as subplots. The study was done in two locations in eastern Uganda (Iki Iki District Agricultural Training and Information Centre (Iki Iki DATIC) and National Semi-Arid Resources Research Institute, Serere (NaSARRI) with two planting rounds at Iki Iki. These sites were chosen because they are hot spots for GLM. GLM severity and soybean yield were significantly affected by the pesticide protection. Overall, percentage grain yield losses caused by GLM on the different soybean varieties ranged from 37.3% to 65.7% and the highest loss was displayed by Maksoy 5N. Grain yield loss recorded at Iki Iki DATIC (53.1%) was remarkably higher than that recorded at the NaSARRI (49.1%). Economic analysis showed marginal returns to be dependent on location, with the Iki Iki DATIC having 0.6 and NaSARRI 1.1. This study has shown that the groundnut leaf miner, a recently emergent pest of soybean is becoming a big threat to soybean production and that chemical control alone may not be economical in managing the pest.La mineuse de feuilles d\u2019arachide (MFA) constitue actuellement une menace pour la production de soja en Ouganda en raison des pertes de rendement consid\ue9rables dues aux d\ue9g\ue2ts importants caus\ue9s aux feuilles, ce qui a entra\ueen\ue9 une r\ue9duction de la surface photosynth\ue9tique. Le MFA est un ravageur relativement nouveau sur le soja en Ouganda. Il avait d\u2019abord \ue9t\ue9 observ\ue9 dans des champs de soja en 2011 dans l\u2019est de l\u2019Ouganda. L\u2019objectif de cette \ue9tude \ue9tait de d\ue9terminer la perte de rendement caus\ue9e par la mineuse de feuilles d\u2019arachide et l\u2019efficacit\ue9 et la rentabilit\ue9 des pesticides couramment utilis\ue9s pour lutter contre la mineuse de feuilles d\u2019arachide ( Aproaerema modicella Deventer) (MFA), lorsqu\u2019il \ue9tait test\ue9 avec du soja tr\ue8s r\ue9pandu ( Glycine max ) g\ue9notypes cultiv\ue9s en Ouganda. L\u2019essai a \ue9t\ue9 install\ue9 suivant un dispositif split plot en parcelles divis\ue9es, la protection antiparasitaire (trait\ue9e ou non trait\ue9e) constituait les parcelles principales; et six vari\ue9t\ue9s commerciales de soja (Maksoy 1N, 2N, 3N, 4N, 5N; et Namsoy 4M) en sous-parcelles. L\u2019\ue9tude a \ue9t\ue9 r\ue9alis\ue9e dans deux regions de l\u2019est de l\u2019Ouganda (Centre de formation et d\u2019information agricoles du district d\u2019Iki Iki (Iki Iki DATIC) et Institut national de recherche sur les ressources semi-arides de Serere (NaSARRI), avec deux fois de plantation \ue0 Iki Iki. Ces sites ont \ue9t\ue9 choisis parceque ce sont des regions tr\ue8s menaces par MFA. La protection contre les pesticides a eu un effet important sur la s\ue9v\ue9rit\ue9 du MFA et le rendement du soja. Generalement, le pourcentage de pertes de rendement en grain caus\ue9es par la sur les diff\ue9rentes vari\ue9t\ue9s de soja variait de 37,3% \ue0 65,7% et la perte la plus \ue9lev\ue9e a \ue9t\ue9 montr\ue9e par Maksoy 5N. La perte de rendement en grains trouv\ue9e \ue0 Iki Iki DATIC (53,1%) \ue9tait remarquablement sup\ue9rieure \ue0 celle trouv\ue9e \ue0 NaSARRI (49,1%). L\u2019analyse \ue9conomique a montr\ue9 que les rendements marginaux d\ue9pendaient de la localisation, l\u2019Iki Iki DATIC \ue9tant \ue0 0,6 et NaSARRI \ue0 1,1. Une \ue9tude a montr\ue9 que la mineuse de feuilles d\u2019arachide, un ravageur du soja r\ue9cemment apparu, constituait une menace majeure pour la production de soja et que la lutte chimique \ue0 elle seule pouvait ne pas \ueatre rentable pour lutter contre ce ravageur

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

Morphological Diversity of Tropical Common bean Germplasm

Common bean ( Phaseolus vulgaris L.) landraces and varieties grown by farmers in the tropics are a major source of genes and genetic diversity for bean improvement. These materials are, however, threatened by genetic erosion. In this study, we sought to understand the current state of genetic diversity of common bean in Uganda, using the available collection consisting of 284 bean accessions. A field experiment was conducted at the National Crops Resources Research Institute in Namulonge, Uganda. The level of morphological variation estimated with the Shannon Weaver diversity index (H), ranged from 0.47 to 0.58, with an overall mean of 0.56\ub10.19, an indicator of moderate genetic diversity. Principal component analysis (PCA) clustered the germplasm into three major groups (G1, G2 and G3). The genotypes differed mostly for growth habit, pod cross-section, pod curvature, hypocotyl colour, days to flowering, node number on the main stem, number of flower buds, and 100 seed weight.Les cultivars et vari\ue9t\ue9s de haricot commun ( Phaseolus vulgaris L.) cultiv\ue9s par les fermiers dans les tropiques son tune source majeur de \ue8nes et diversit\ue9 g\ue9n\ue9tique pour l\u2019am\ue9lioration du haricot. Ce materiel est, par ailleurs, handicap\ue9 par une \ue9rosion g\ue9n\ue9tique. Le but de cette \ue9tude est de comprendre la situation courante de la diversit\ue9 g\ue9n\ue9tique du haricot commun en Ouganda, en utilisant la collection disponible de 284 accessions de haricots. Un essai \ue9tait conduit au National Crops Resources Research Institute \ue0 Namulonge, Ouganda. Le niveau de variation morphologique estim\ue9 \ue0 l\u2019aide de l\u2019indice de diversit\ue9 de Shannon Weaver (H),variait de 0.47 \ue0 0.58, avec une moyenne g\ue9n\ue9rale de 0.56\ub10.19, un indicateur de diversit\ue9 g\ue9n\ue9tique mod\ue9r\ue9. L\u2019analyse de la composante principale (PCA) a group\ue9 le germplasme en trois groupes majeurs (G1, G2 et G3). Les g\ue9notypes differaient plus par l\u2019habitude de croissance, la section des gousses, la courbature des gousses, la couleur de l\u2019hypocotyle, les jours \ue0 la floraison, le nombre de nodes sur la tige principale, le nombre de bourgeon des fleurs et le poids de 100 graines

NARROW SENSE HERITABILITY AND GENE EFFECTS FOR LATE LEAF SPOT RESISTANCE IN VALENCIA GROUNDNUTS

Late leaf spot (LLS), Phaeoisariopsis personata (Berk. and Curtis) Deighton, is one of the most important foliar diseases of groundnut ( Arachis hypogaea L.) worldwide. Effective chemical control is heavily reliant upon multiple fungicide applications which are costly for resource poor farmers in Sub-Saharan Africa. The deployment of resistant cultivars is a better option to control this disease in groundnut. A study was conducted to determine narrow sense heritability and gene action controlling LLS resistance in Valencia groundnut materials. The materials used included six generations; F1, F2, F1 backcrosses to the susceptible BC1P1 and resistant BC1P2 parents, and their respective parental lines of crosses between NuMex-M3 7 ICGV-SM 02501, Valencia C 7 ICGV-SM 02501and Redbeauty 7 ICGV-SM 03590. All the test materials were evaluated at the National Semi-Arid Resources Research Institute (NaSARRI) at Serere in Uganda. Narrow-sense heritability estimates were 12, 27 and 36%, for Redbeauty 7 ICGV-SM 03590, Valencia C 7 ICGV-SM 02501 and NuMex-M3 7 ICGV-SM 02501 crosses, respectively. Both additive and dominance gene effects contributed significantly to the inheritance of LLS resistance in all the crosses, except in Redbeauty 7 ICGV-SM 02501 where the effects of dominance were not significant.La tache fusarienne tardive (LLS), Phaeoisariopsis personata (Berk. and Curtis) Deighton, est l\u2019une des plus importantes maladies foliaires \ue0 l\u2019\ue9chelle mondiale au niveau de l\u2019arachide ( Arachis hypogaea L.). Une lutte chimique efficace contre cette maladie n\ue9cessite l\u2019utilisation en quantit\ue9 importante de plusieurs types de fongicides. Cette approche est tr\ue8s co\ufbteuse pour \ueatre adopt\ue9e par les petits paysans de l\u2019Afrique Sub-Saharienne. Le d\ue9veloppement de vari\ue9t\ue9s r\ue9sistantes est une meilleure option pour lutter contre cette maladie dont est sujette l\u2019arachide. Une \ue9tude a \ue9t\ue9 r\ue9alis\ue9e afin de d\ue9terminer l\u2019h\ue9ritabilit\ue9 au sens strict et l\u2019action des g\ue8nes contr\uf4lant la r\ue9sistance \ue0 LLS dans la vari\ue9t\ue9 d\u2019arachide Valencia. Les mat\ue9riels g\ue9n\ue9tiques utilis\ue9es comprennent six g\ue9n\ue9rations; F1, F2, F1 crois\ue9e en retour avec les parents susceptible BC1P1 et celui r\ue9sistant BC1P2\ua0; ainsi que les parents respectifs des croisements effectu\ue9s entre NuMex-M3 7 ICGV-SM 02501, Valencia C 7 ICGV-SM 02501 et Redbeauty 7 ICGV-SM 03590. Toutes ces vari\ue9t\ue9s ont \ue9t\ue9 \ue9valu\ue9es dans l\u2019institut de recherche des ressources nationales semi-arides (NaSARRI) \ue0 Serere en Ouganda. L\u2019h\ue9ritabilit\ue9 au sens strict \ue9tait estim\ue9e \ue0 12, 27 et 36%, respectivement pour les croisements entre Redbeauty 7 ICGV-SM 03590, Valencia C 7 ICGV-SM 02501 et NuMex-M3 7 ICGV-SM 02501. Dans tous les croisements, la r\ue9sistance \ue0 LLS est sous le control aussi bien de l\u2019action dominante que de l\u2019action additive des g\ue8nes\ua0; sauf dans le cas de Redbeauty 7 ICGV-SM 02501 o\uf9 les effets dominants des g\ue8nes ne sont pas significatifs

Genetic variability and gain for storage root yield and yield components in yam beans

There is limited information on the genetic parameters and genetic gain of yam bean ( Pachyrhizus species) accessions introduced to Rwanda. No comprehensive literature exists on the inheritance of yield and yield components, on segregating populations. This study investigated variability, heritability and genetic advance in F2 yam bean genotypes. Seven F2 yam bean hybrids were evaluated at the Rubona Research Station located in Southern Province of Rwanda, during growing season 2014B. Results revealed significant (P&lt;0.01) genetic variability in plant vigour (PV), pod weight (WOP), plant height (PHT), 100 seed weight (100SW), total biomass yield (TBY), storage root yield (SRY), dry matter content (DMC), and starch content (STA). High genetic (\u3c32g) and phenotypic (\u3c32p) variances, and genotypic coefficients of variation (GCV&gt; 25%) were observed for WOP, PHT, 100SW, TBY, DMC and STA. Estimates of heritability (H2) were high (greater than 50%) for all traits, except for seed yield, number of roots and number of pods. The GA and genetic advance, as percentage of the mean (GAM%), were high for PV, WOP, PHT, 100SW, TBY and DMC. There were positive and significant (P&lt;0.05) associations between PV and PHT, protein content (PRO), 100SW, TBY, SRY, and DMC. Dry matter content also had positive and significant (P&lt;0.01) correlations with STA. These results indicate presence of high genetic variability, heritability and expected genetic gain suggesting potential for genetic improvement of plant vigour, weight of pods, plant height, 100 seed weight, total biomass yield, storage root fresh yield, dry matter content and starch content of yam beans in Rwanda.Il existe peu d\u2019informations sur les param\ue8tres g\ue9n\ue9tiques et le gain g\ue9n\ue9tique des accessions de haricot-igname (esp\ue8ce Pachyrhizus ) introduites au Rwanda. Il n\u2019existe pas de litt\ue9rature compl\ue8te sur l\u2019h\ue9r\ue9dit\ue9 du rendement et des composantes du rendement, sur la s\ue9gr\ue9gation des populations. Cette \ue9tude a \ue9tudi\ue9 la variabilit\ue9, l\u2019h\ue9ritabilit\ue9 et l\u2019avanc\ue9e g\ue9n\ue9tique des g\ue9notypes de haricot-igname F2. Sept hybrides de haricot-igname F2 ont \ue9t\ue9 \ue9valu\ue9s \ue0 la Station de Recherche de Rubona situ\ue9e dans la Province M\ue9ridionale du Rwanda, pendant la saison agricole 2014B. Les r\ue9sultats ont r\ue9v\ue9l\ue9 une variabilit\ue9 g\ue9n\ue9tique significative (P &lt;0,01) de la vigueur de la plante (PV), du poids de la gousse (WOP), de la hauteur de la plante (PHT), du poids de 100 graines (100SW), du rendement total en biomasse (TBY), du rendement des racines de stockage (SRY), teneur en mati\ue8re s\ue8che (DMC) et teneur en amidon (STA). Des variances g\ue9n\ue9tiques (\u3c32g) et ph\ue9notypiques (\u3c32p) \ue9lev\ue9es et des coefficients de variation g\ue9notypiques (GCV&gt; 25%) ont \ue9t\ue9 observ\ue9s pour WOP, PHT, 100SW, TBY, DMC et STA. Les estimations de l\u2019h\ue9ritabilit\ue9 (H2) \ue9taient \ue9lev\ue9es (sup\ue9rieures \ue0 50%) pour tous les caract\ue8res, \ue0 l\u2019exception du rendement en graines, du nombre de racines et du nombre de gousses. Le GA et l\u2019avance g\ue9n\ue9tique, en pourcentage de la moyenne (GAM%), \ue9taient \ue9lev\ue9s pour PV, WOP, PHT, 100SW, TBY et DMC. Il y avait des associations positives et significatives (P &lt;0,05) entre PV et PHT, la teneur en prot\ue9ines (PRO), 100SW, TBY, SRY et DMC. La teneur en mati\ue8re s\ue8che avait \ue9galement des corr\ue9lations positives et significatives (P &lt;0,01) avec le STA. Ces r\ue9sultats indiquent la pr\ue9sence d\u2019une variabilit\ue9 g\ue9n\ue9tique, d\u2019une h\ue9ritabilit\ue9 et d\u2019un gain g\ue9n\ue9tique attendus \ue9lev\ue9s sugg\ue9rant un potentiel d\u2019am\ue9lioration g\ue9n\ue9tique de la vigueur des plantes, du poids des gousses, de la hauteur des plantes, du poids de 100 graines, du rendement total en biomasse, du rendement en racines fra\ueeches de stockage, de la teneur en mati\ue8re s\ue8che et en amidon de haricot-ignames au Rwanda