A correction to this paper has been published: https://doi.org/10.1007/s10681-021-02855-3

Twenty-five yellow fleshed cassava varieties including three checks (two improved and one local) were evaluated in a randomized complete block design with four replications in three locations in Nigeria. Tuber yield, dry matter content, root size, fiber content, harvest index, sprouting and vigor of the varieties evaluated were all significant at 0.05 significant levels across the locations. Taste, color of unexpanded leaves, height at branching, and internode length were not significant. In Ibadan, plant height, vigor and root size were not significant. In Mokwa, plant height was not significant. Traits such as dry matter, mealiness and taste were significant. In Onne, dry matter was not significant. Clones such as 01/1413, 01/1442, 01/1663, 98/2132, 01/1277, and 01/1235 were stable across locations, 94/0330 had the highest dry matter (38%) which was better than the best check 30572 (37%). All clones were resistant to cassava mosaic disease, cassava bacteria blight, cassava green mites and cassava anthracnose disease vector infection and to the spread of the pathogens within the plant and across locations. Clones 01/1115, 011413, 01/1663, and 01/1335 had high beta-carotene content of range 7 on a color chart. Clones 01/1368, 01/1371, 98/2132, 90/01554 and 94/0330 had dry matter values ranging from 30 to 38%; these were acceptable values. In terms of yield, the best clones were 01/1368 (26 t/ha), 98/2132 (25 t/ha) and 01/1663 (24.5 t/ha). For gari yield clone 01/1649 gave 25%; 94/0330 gave 23% and 90/01554 gave 23%. They were better than the best check, with 22% garri yield. Cultivating cassava with yellow pigmented root flesh is a valid strategy to solve the problem of improving the nutritional value of the diet in the region where cassava is a staple food. Key words: Agronomic performance, beta-carotene, clone, evaluation, cassava, yellow cassava, yield.

In an early yellow root cassava study in 2003 to 2004, we investigated agronomic performance of pro Vitamin A (yellow fleshed) cassava genotypes in three locations in Nigeria (Ibadan, Mokwa, and Onne). Twenty-two clones and three checks were evaluated. A randomized complete block design was used with four replications. Characteristics showing significant differences among genotypes across all locations included sprouting, vigor, harvest index, root size, storage root yield, dry matter content and fiber content. Plant height, root mealiness and taste were different in only selected locations. Six clones showed stable performance across locations including IITA TMS I011413, IITA TMS I011442, IITA TMS I011663, IITA TMS I982132, IITA TMS I011277 and IITA TMS I011235. Clones IITA TMS I940330 showed the highest dry matter content of 38%. All clones exhibited good resistant to cassava mosaic disease, cassava bacterial blight, cassava green mite, and cassava anthracnose disease. These genotypes ranged in total carotenoid content from 3.4 to 8.2 µg/g fresh weight. In terms of yield, the best clones were IITA TMS I011368 (26 t/ha), IITA TMS I011663 (22 t/ha) and IITA TMS I982132 (25 t/ha). For gari yield clone IITA, TMS I011649 gave 25%, IITA TMS I940330 gave 23%, and IITA TMS I9001554 gave 23%. They were better than the best check IITA TMS I30572, with 22% gari yield. This study showed the potential for biofortification of cassava as a valid strategy to approach the problem of micronutritient deficiencies of the population in the region where cassava is a staple food. Key words: cassava varieties, biofortification, pro Vitamin A, Nigeria, agronomic performance.

Iron (Fe) toxicity is recognized as one of the most widely spread soil constraints for rice production especially in West Africa. Oryza glaberrima the cultivated rice species that originated from West Africa is well-adapted to its growing ecologies. The aim of this study was to identify the promising O. glaberrima accessions tolerant to Fe toxicity from the 2106 accessions held at the AfricaRice gene bank. The screenings were conducted over a four-year period and involved evaluating the entries under Fe-toxic field conditions in West Africa, selecting good yielding accessions and repeating the testing with newly selected lines. Three accessions (TOG 7206, TOG 6218-B and TOG 7250-A) were higher yielding than O. sativa checks under stress but with similar yields under control conditions. These accessions yielded over 300g/m2 under both Fe toxicity and control conditions. In conclusion, these materials could be used as donors in breeding programs for developing high yielding rice varieties suited to Fe toxicity affected areas in West Africa.

A study was conducted during 2008 to 2009 in 12 environments in Nigeria, Benin Republic and Togo to evaluate genetic variation and heritability of yield and related traits in 48 rice genotypes. The experiments were laid out in a randomized complete block design (RCBD) with three replications. Genotypes differed significantly at p > 0.001 for all the traits studied, which implies that the genotypes contain adequate genetic variability. Phenotypic coefficients of variation (PCV) were higher than genotypic coefficients of variation (GCV) in all the characters across the 12 environments. High heritability estimates were obtained for days to flowering (91.37), days to maturity (86.86), plant height at maturity, number of tiller per meter square, panicle shattering, panicle threshability, panicle per meter and panicle length (72.21) suggesting that the traits are primarily under genetic control. High estimates of heritability, GCV and genetic advance (GA) observed for grain yield is an indication that selection for grain yield could be achieved through phenotypic performance. Furthermore, high estimates of heritability, GA and GCV recorded in these characters could be explained by additive gene action. Low estimates of heritability, GCV and GA recorded for grain yield and number of grains per panicle could be due to non-additive gene effect suggesting that these traits were less responsive to specific environment influences. Grain yield recorded highly significant positive correlation with panicle length (0.28), leaf width (0.40), grain length (0.30), number of panicles per meter square (0.19) and1000-grain weight (0.17). It correlated negatively with basal leaf sheath coloration (-0.33) and grain width (-0.20) in the 12 environments. The current study indicated that more number of tillers, panicles per meter square, long panicles, high number of primary and secondary branch panicles and large 1000-grain weight are important yield related traits and could be used for selection in rice breeding programs. Key words: Correlation coefficients, heritability, phenotypic coefficients, rice, variability, yield components.

Rice cultivation in Africa suffers from various biotic and abiotic constraints. The African rice, Oryza glaberrima, is a potential source of useful genes for resistance to a range of these stresses. The development of interspecific varieties based on crosses between the high yielding cultivated Asian rice species (Oryza sativa) and O. glaberrima showed some gaps in the resistance compared to O. glaberrima. In order to valorize its genetic potential, intraspecific lines were developed using three O. glaberrima lines Tog5681, Tog5672 and Tog7291 as parents. Phenotypic evaluation of the progeny (total of 55 F6 lines) and checks (O. glaberrima and O. sativa) using 18 quantitative characters, showed a higher degree of variation in plant height, leaf dimensions, panicle fertility and grain weight. Based on the discriminating characters proposed here for further exploitation, intraspecific lines were grouped into five clusters, two of which (G4 and G5) contained the best lines for vegetative (G4) and productive (G5) characters.

Two Outstanding Oryza glaberrima (2n = 24, AA) varieties TOG5681 and TOG5674 were used as male donor parents with IR64, the high-yielding improved Asian rice variety used as recurrent female parent by the International Rice Research Institute (IRRI) to develop 18 BC3F1 interspecific lowland rice progenies. The proportion of parental genomic contribution and the extent of genetic differences among these lines were assessing using 36 microsatellites markers. The average genomic contribution of the donor TOG5681 and that of the recurrent IR64 within their 12 interspecific lines derived from IR64xTOG5681 cross were estimated to 13.2% and 79.8% respectively. Using 33 out of the 36 SSR markers, the average genome introgression rate of TOG5674 and that of IR64 within their 6 progenies were estimated to 8.7% and 85.5% respectively. In addition, heterozygosity and non-parental alleles were also identified. Clustering analysis technique using NTSYS classified the progenies into six groups and group five is closely related to IR 64.

The aim of this study is to identify the phenotypic variability of 60 lowland NERICA varieties and 18 promising lines for better management of their genetic inheritance. The experimental design used was an augmented randomized complete block. Data on 23 agro-morphological traits were collected and analyzed. The analysis of variance showed highly significant differences (P<0.0001) between the variables and revealed the structure of the different genotypes from 11 quantitative discriminate traits. Cluster analysis and principal component analysis were carried out. The entries were grouped into three clusters irrespective of the level of backcrossing of genotypes. Eighty percent of lowland NERICA containing the desired characters adapted to lowland rice cultivation were grouped in cluster 1. The second cluster includes lowland NERICA varieties that can be grown in both upland and lowland ecologies, while the last group comprised only varieties close to their African parent and mainly adapted to the upland. Tillering at 60 days after sowing (DAS), plant height at maturity, maturity and spikelet fertility were the most discriminate and could therefore supplement a wide range of variables for genetic diversity study. Key words: Lowland NERICA, promising lines, agro-morphological descriptors, cluster

The objectives of this study were to estimate the phenotypic and genotypic coefficients of variation, broad sense heritability, genetic gain and correlations in rice (Oryza sativa L.). The experiment was laid out in a randomized complete block design (RCBD) with three replications in the International Institute of Tropical Agriculture, Ibadan, Nigeria during 2008/2009 cropping season. Genotypes differed significantly at (p>0.001) for all the traits studied, which implies that the genotypes constitute a pool of germplasm with adequate genetic variability. Genotypic coefficients of variation were lower than the corresponding phenotypic coefficients in all the traits studied, indicating considerable influence of the environment on the expression of the traits. High to medium broad sense heritability estimates observed on days to heading, days to maturity, plant height, grain yield and number of grains per panicle, panicle weight, number of panicles per m2 and panicle length suggests high component of heritable portion of variation, which is the portion exploited by breeder and that selection for these traits can be achieved directly based on their phenotypic performance. The low broad sense heritability observed for the number of tillers per plant and 1000 grain weight is indicative of the influence of the environment on these traits. Low heritability of these traits indicates the ineffectiveness of direct selection for these traits. High to medium heritability and genetic advance were recorded for the number of grains per panicle, grain yield, panicle weight and the number of panicles per plant. This suggests that these traits are primarily under genetic control and selection for them can be achieved through their phenotypic performance. Grain yield exhibited significantly positive correlation with the number of tillers per plant (r = 0.58**), panicle weight (r =0.60*) and number of grains per panicle (r= 0.52*). Therefore, the results suggest that these traits can be used for grain yield selection. Key words: Broad sense heritability, rice, genotypic coefficient of variation, phenotypic coefficient of variation, genetic gain, rice yield, yield components.

The immense potential of the lowlands in Burkina Faso for durable intensification of rice cropping have not been realised due to biotic and abiotic stress constraints.To this end, the rice research program in Burkina Faso evaluated 16 intra-and inter-specific lowland progenies in 2002 and 2003. The aim of the study is to introduce new lowland NERICAs through a participatory approach and to identify ideotypes that are adapted to lowland conditions. Variability was found among the 16 rice varieties with respect to the 9 variables that were evaluated. A principal components plot and clustering analysis technique were used to group 16 intra-and inter-specific lowland progenies. The inter-specific varieties formed the most interesting group and showed a better capacity for adaptation to the diversity of lowlands. They had good yields, sometimes higher than those of intra-specific varieties and check. Thus, the results obtained were quite satisfactory as the varieties possess good agronomic traits that are well adapted to intensified lowland rice farming. The recent naming of some of these inter-specific varieties as NERICA-L (New Rice for Africa Lowland) by Africa Rice Center confirmed their status. Thus from this study, a new set of inter-specific lines that are adapted to lowland conditions and which the national research programs in Burkina Faso can use in various tests for satisfying farmers’ needs are discussed. Key words: Hybridisation, inter-specific, insect, blast, NERICA, Oryza glaberrima, Oryza sativa, sterility, yield.

Rice is one of the major staple foods in Burkina Faso and in-country production covers about 60% of the demand and 40% is met from imports. The immense potential of the lowlands in Burkina Faso for durable intensification of rice cropping have not been realised due to biotic and abiotic constraints. Hence, there is an urgent need to increase and improve the production of rice in order to meet up with the high demand. To meet the demand, the rice research program in Burkina Faso evaluated intra and interspecific lowland progenies in 2002 and 2003. The aim of the study is to introduce new lowland NERICAs through a participatory approach and to identify ideotypes that are adapted to lowland conditions. Variations did exist among the 16 rice varieties with respect to the 9 variables that were evaluated. A principal components plot and clustering analysis technique were used to group the accessions. The interspecific varieties formed the most interesting group and have a better capacity for adaptation to the diversity of lowlands. They have acceptable yields, sometimes higher than those of intraspecific varieties and check. Thus, the results obtained were quite encouraging and showed that, the varieties possess good agronomic traits that are well adapted to intensify lowland rice farming. The recent naming of some of these interspecific varieties as NERICA-L (New Rice for Africa Lowland) by AfricaRice Center has confirmed that they compare well with the traditional varieties. Thus from this study, we now have a new set of interspecific lines that are adapted to lowland conditions that can be tested to meet farmers’ needs. Key words: Oryza glaberrima, Oryza sativa, hybridisation, inter-specific, NERICA, sterility, yields.

Field trials were conducted at the Teaching and Research Farm of University of Agriculture, Abeokuta (7 15 N, 3 25 E, altitude 144 m above sea level) located in the forest – savanna transition zone of south west Nigeria, to assess the agronomic and economic potentials of intercropping soybeans and cowpea with sunflower at three growth stages (simultaneously (SS) at planting, tenth true leaf stage, V10 and eighteenth true leaf stage, V18) in 2002 and 2003. Land use advantage in terms of land equivalent ratio (LER>1.00) ranged between 1.04 – 1.40 in 2002 and 1.05 – 1.24 in 2003 for the intercropping systems, whilst marginal intercrop compatibility in terms of land equivalent coefficient (LEC>0.25) ranged between 0.29 – 0.48 for sunflower/soybeans SS, at V10 and V18 in 2002 and sunflower/cowpea SS in 2003. These identified agronomic advantages did not guarantee substantial economic efficiency in terms of monetary equivalent ratio (MER>1.00) for some of the intercropping systems with LER>1.00 and LEC>0.25. Sunflower/cowpea SS in 2002 and sunflower/soybean V10 in 2003 recorded small monetary advantage over the most productive sole crop with MER=1.12 and 1.04 and sunflower yield equivalent (1349.2 and 1421.6 kg ha), respectively.

Morphological and molecular characterization of forty rice (Oryza sativa L.) accessions using 14 agro-botanical traits recommended by IRRI and 10 RAPD primers, respectively, was done in a field experiment in an augmented randomized complete block design. The aim of the work was to study variations and to select lines that can be used as potential parents in a future breeding programme. A principal components plot and, a dendrogram generated by cluster analysis using the unweighted pair group method with arithmetic mean (UPGMA) based on distance measures assessed for mean values of the morphological variables were used to group the accessions. Genetic relatedness among accessions based on RAPD molecular marker data (57 RAPD bands) was also presented in the bands form of a dendrogram generated by cluster analysis using (UPGMA). The relative effectiveness of the RAPD markers compared to botanical descriptors in assessing diversity among the accessions was investigated. A dendrogram was created by the UPGMA for morphological data and the 40 accessions classified into six morphological groups, whereas PCA re-ordered the accessions into four broad groups that had within cluster similarities and inter-cluster differences in morphological variation. Reaction products (bands) of the RAPD analysis were highly polymorphic, more discriminatory and informative as they were able to differentiate more pairs of accessions than the botanical descriptors. IITA rice accessions TOX 3052-46-3-3-2-1 and TOX 3027-44-1-E4-2-2 and Brazilian accessions (CL SELECCION 3B and 450) performed better in terms of yield, total tillers and number of filled tillers than accessions used as checks and could be selected for a future breeding programme.

Drought Frontiers in Rice, pp. 61-73 (2009) No AccessDrought research at WARDA: current situation and prospectsM. Sié, K. Futakuchi, H. Gridley, S. Mande, B. Manneh, M.N. Ndjiondjop, A. Efisue, S.A. Ogunbayo, M. Moussa, H. Tsunematsu, and H. SamejimaM. SiéAfrica Rice Center (WARDA), 01 B.P. 2031, Cotonou, BeninTel.: (229) 21 35 01 88; fax: (229) 21 35 05 56., K. FutakuchiAfrica Rice Center (WARDA), 01 B.P. 2031, Cotonou, BeninTel.: (229) 21 35 01 88; fax: (229) 21 35 05 56., H. GridleyAfrica Rice Center (WARDA), 01 B.P. 2031, Cotonou, BeninTel.: (229) 21 35 01 88; fax: (229) 21 35 05 56., S. MandeAfrica Rice Center (WARDA), 01 B.P. 2031, Cotonou, BeninTel.: (229) 21 35 01 88; fax: (229) 21 35 05 56., B. MannehAfrica Rice Center (WARDA), 01 B.P. 2031, Cotonou, BeninTel.: (229) 21 35 01 88; fax: (229) 21 35 05 56., M.N. NdjiondjopAfrica Rice Center (WARDA), 01 B.P. 2031, Cotonou, BeninTel.: (229) 21 35 01 88; fax: (229) 21 35 05 56., A. EfisueAfrica Rice Center (WARDA), 01 B.P. 2031, Cotonou, BeninTel.: (229) 21 35 01 88; fax: (229) 21 35 05 56., S.A. OgunbayoAfrica Rice Center (WARDA), 01 B.P. 2031, Cotonou, BeninTel.: (229) 21 35 01 88; fax: (229) 21 35 05 56., M. MoussaAfrica Rice Center (WARDA), 01 B.P. 2031, Cotonou, BeninTel.: (229) 21 35 01 88; fax: (229) 21 35 05 56., H. TsunematsuAfrica Rice Center (WARDA), 01 B.P. 2031, Cotonou, BeninTel.: (229) 21 35 01 88; fax: (229) 21 35 05 56., and H. SamejimaAfrica Rice Center (WARDA), 01 B.P. 2031, Cotonou, BeninTel.: (229) 21 35 01 88; fax: (229) 21 35 05 56.https://doi.org/10.1142/9789814280013_0004Cited by:1 PreviousNext AboutSectionsPDF/EPUB ToolsAdd to favoritesDownload CitationsTrack CitationsRecommend to Library ShareShare onFacebookTwitterLinked InRedditEmail Abstract: Drought is one of the major constraints to rice production in the rainfed ecology in sub-Saharan Africa (SSA). It occurs not only in uplands but also in lowlands; for example, 70% of lowland rice farmers experience a drought problem at the reproductive stage, which can reduce yield more severely than at the vegetative stage. At WARDA, therefore, drought is one priority area to be addressed. In WARDA's interspecific breeding between Oryza sativa and O. glaberrima for the rainfed ecology, one of the most important characteristics is short duration to evade drought that often occurs in the latter days of the cropping season. Several interspecific lines (NERICA: New Rice for Africa) with growth duration of 90–100 days have been developed. Apart from this escape type, NERICAs showing better drought resistance than local O. sativa checks have also been identified. Several O. glaberrima landraces showing high resistance were identified after collection from the flood plains of the Niger River and crossing of these landraces with O. sativa and existing NERICAs with high agronomic performance has already been done. Several O. sativa varieties were also screened for drought resistance at both vegetative and reproductive phases. Promising O. sativa varieties with good drought resistance have been used in crosses with susceptible genotypes for creating breeding and mapping populations. The populations being created are expected to segregate for root characteristics and/or osmotic adjustment, both of which are important drought-resistance traits in rice. A WARDA-JIRCAS joint project also aims to develop drought-resistant varieties. The project narrowed target characters down to root penetration into the deeper soil layers, which is very effective for growth maintenance in certain drought situations. Highly promising O. sativa lines have already been identified, and the next step is to identify genes/QTLs for this trait for use in marker-assisted selection. Past drought research at WARDA mostly concentrated on varietal improvement. However, an agronomic approach is also within our purview. We inventory farmers' existing cultural practices to minimize the risks of yield reduction by drought and test their true usefulness. Integrated drought management options for rainfed rice combining resistant varieties and cultivation practices will also be developed and evaluated. FiguresReferencesRelatedDetailsCited By 1Water Use and Growth of Rice (Oryza sativa L.) Cultivated on Saline Soils with Various Amounts of Soil and Waterburi Ha, Makoto Tsuda and Yoshihiko Hirai1 Jan 2014 | Japanese Journal of Crop Science, Vol. 83, No. 1 Drought Frontiers in RiceMetrics History PDF download

Morphological and molecular characterization of ninety-six landrace rice (Oryza sativa L.) accessions including six checks collected from four regions (North-West, North, West and Central-West) of Cote d’Ivoire were assessed using 14 agrobotanical traits and 10 Randomly Amplified DNA Polymorphisms (RAPDs) primers, respectively. Accessions were evaluated in a field experiment in an augmented experimental design with three replicates. The aim of the research was to study variations and to select lines that could be used as potential parents in future breeding programs. A principal components plot and a dendrogram based on distance between genotype cluster groups for mean values of the morphological variables were used to group the accessions. Genetic relatedness among accessions based on RAPD molecular marker was also presented in form of a dendrogram generated by clustering analysis using the Unweighted Pair Group Method with Arithmetic mean (UPGMA). The relative effectiveness of the RAPD markers compared to botanical descriptors in assessing diversity among the accessions was investigated. Clustering analysis technique using NTSYS classified the 96 landrace accessions into 8 morphological groups whereas PCA re-ordered the accessions into three broad groups that had within cluster similarities and inter-cluster differences in morphological variations. Reaction products (bands) of the RAPD analysis were highly polymorphic, more discriminatory and informative as they were able to differentiate more pairs of accessions than the botanical descriptors. Apart from checks, highest grain yield (2316 g/plot) was observed for accessions 46 (DNN 184) with an average of 12 filled tillers, plant height of 136 cm and medium maturity date of 136 days. It was observed that number of total and filled tillers per se was not a function of yield but rather, these traits were significantly associated with plant height and maturity date. Although, landrace rice accessions in Cote d’Ivoire is associated with relatively narrow genetic base, positive heterosis could be promoted if any of the Gagnoa (GGA) accessions from Central West of the country is used in a future hybridization program with Danane (DNN) accessions from west because of genetic distance between members of the two groups.

Field assessment of different rates and methods of three fungicide applications on delay in senescence (DS) and grain yield of cowpea during the early and late cropping season of 1999 respectively was conducted. The benomyl treatment applied via the combination of seed and foliar methods at the highest rate of 0.75 + 0.75kg a.i/ha gave the highest percentage delay in senescence (100%) as well as highest grain yield of (2.1 t/ha) which were significantly different (p<0.05) from the untreated control plots and mancozeb plots. Application via the seed gave the lowest percentage delay in senescence (20.3%) and the lowest grain yield of (0.24 t/ha), respectively, for early cropping season. Similar trends were recorded during late season for all these parameters, though they were lower than that of early cropping season.