National Root Crops Research Institute Research Articles

Gender-inclusive consumer studies improve cassava breeding in Nigeria.

Including gender research in cassava breeding makes it easier for farmers to adopt new varieties that meet the specific needs and preferences of both male and female farmers, leading to increased adoption of new varieties, improved productivity, and better economic outcomes for the entire farming community. Gender was included in 2013 in variety development at the National Root Crops Research Institute (NRCRI), Umudike, Nigeria in response to the dis-adoption of some varieties by farmers who had not been part of varietal development from the start, and in light of social roles which influence the responsibilities, resources and livelihood outcomes of men, women and youths. Gender inclusion has given plant breeders accurate information about the cassava traits preferred by all end-users, not just male farmers. At NRCRI, gender studies intensified in the last 5 years, contributing to the development and release of improved varieties. Quantitative and qualitative research by the gender cross-cutting team modeled trait profiling and consumer preferences, to aid demand-led breeding. Some of the methods were acquired at several trainings on how to quantify qualitative responses for prioritization. Gender research techniques include participatory varietal selection (PVS), participatory plant breeding (PPB), mother-baby trials, focus group discussions (FGD), surveys, value chain mapping, G+ tools, experiments in farmer field schools (FFS), demonstration farms, and tricot. These gave the cross-cutting team a better understanding of gender relations, power, decision-making, ownership and control of resources, and have mitigated operational and field challenges during the surveys. These methods also elicited feedback from end-users that led to better naming of newly released varieties, reflecting perceptions of agronomic performance, and food qualities, which made the varieties easier to identify and remember.

Studies on Heavy Metal Accumulation and Quality of Irish Potato (Solanum Tuberosum) Tubers Grown with Inorganic and Organic Fertilizers in Jos, Plateau State, Nigeria

The aim of this work was to determine the nutritional quality and heavy metal concentration of irish potato tubers grown with inorganic and organic fertilizer. Forty five (45) tubers obtained from the National Root Crop Research Institute (NRCRI) Kuru were planted in a randomized complete block experimental design (RCBD). Three treatments were applied namely: inorganic fertilizer, poultry dung (positive control) and without treatment (negative control). Each treatment was replicated thrice in three different plots. At maturity, tubers were investigated for protein, lipid and calcium level while heavy metal contents were determined using the Atomic Absorption Spectrophotometer. Statistical analysis was carried out using ANOVA while mean separation was done using the LSD method at 95% confidence limit. Levels of three heavy metals (Cd, Zn and Co) in Irish potato tubers were higher than their respective permissible limits of 0.02, 1.3 and 0.06 in all samples. Fertilizer application (organic and inorganic) had no significant effect on the concentration of Pb, Cd, Cr, Zn, Co and Cu. Both organic and inorganic fertilizers had significant influence on Ni, As and Mn. Inorganic fertilizer significantly lowered the crude protein, lipid and calcium level in Irish potato tubers when compared with other treatments. This research has provided useful information to stakeholders in the Environmental and Health Science sectors to enlighten growers of Irish potato on the need to limit the use inorganic fertilizer and seek alternative yield enhancers that are effective and safer to the environment and human health.

Prioritizing preferred traits in the yam value chain in Nigeria: a gender situation analysis.

This study describes what did and did not work in the prioritization of preferred traits within the value chain of yam and associated food products (boiled and pounded yam) in Nigeria. Demand-led breeding protocols have enhanced participatory methods along gender lines to increase the clarity of information on the yam traits preferred by farmers and other end users. Drawing on the experience of the cross-cutting gender team at the National Root Crops Research Institute (NRCRI), Umudike, and partners, this study documents the successes and constraints in the use of gender-inclusive approaches for effective breeding. Methods in our gender studies involve critical assessment of the distinction between quantitative and qualitative research, with particular attention to measurement. Various techniques for data collection, such as interviews, observation, and archival studies, are assessed to locate their potential for constructing successful research projects. The methods used include participatory varietal selection, participatory plant breeding, focused discussions with farmer groups, value chain mapping, G+ tools, trait preferences (processing and consumption), triangulation of multi-disciplinary datasets, and social survey research. Yam production in southeast Nigeria is dominated by men, while women are the main processors. Gendered power play, access to resources, and decision-making have been found to constrain women's participation in yam production (and in yam research). Sex disaggregation was applied within the value chain studies to capture the complementarity and differences in the perceptions of women and men. The methods used facilitated the development and release to farmers in 2023 of three improved yam varieties with consumer-preferred characteristics such as high yield, high dry matter content, white tubers, and good boiling and pounding capability. The success stories also show that effective communication and cooperation within the gender cross-cutting team and farmer groups are important for better results. When gender specialists, food scientists, and breeders work together, innovations are created, challenges are overcome, and information is shared.

Relationship between Climate Variables (Rainfall and Temperature) and Ginger Yield Across the Climate Belts of Nigeria

Rainfall and temperature are very important elements and factors of weather and climate needed in the successful production of crops, including ginger. The relationship of these elements and ginger yield has not been given the due attention in Nigeria. Therefore, this study examined the relationship between Climate (Rainfall and Temperature) and Ginger Yield across the Climate Belts of Nigeria. Rainfall and Temperaturedata were obtained for the study from Nigerian Meteorological Agency (NiMet), Abuja while ginger yield data were collected from the experimental farms of National Root Crops Research Institute (NRCRI), Umudike, Agricultural Development Programme (ADP) and Nigerian Bureau of Statistics, Abuja. These data covered a period of 40 years (1980 -2019) and were analysed using simple linear regression, correlation and Analysis of Variance (ANOVA). Results obtained showed thatrainfall and temperature significantly predicted ginger yield across the four climate belts at p<0.05:Tropical Monsoon(TM) (F,12.0934)and jointly explained 45.2% of variation in ginger yield(r=.672and the R2=.452);Tropical Savanna (TS)(F,17.3452)and jointly explained 35.6% of variation in ginger yield (r = .597 and R2= .356);Warm Semi-Arid (WSA) (F,24.9501)and jointly explained 20.9% of variation in ginger yield (r= .457 and R2= .209); and Warm Desert (WD)(F,29.8517) and jointly explained 30.1% of variation in ginger yield(r =.549 and R2= .301).Based on these results, it is concluded here that there is a significant relationship between rainfall and temperature and ginger yields over the years and across the climate belts. The study recommends among others that planting and harvesting of ginger by farmers should align with the seasons as found in each of the four climate belts.

Physicochemical Analysis of Taro (Colocasia esculenta (L.) Schott) Accessions

Taro is an important staple meal for rural people in resource-poor nations in sub-Saharan Africa countries. This study looked at the proximate, mineral, and anti-nutrient content of whole taro corm. Understanding the extent and distribution of genetic diversity in taro is critical for creating conservation and enhancement initiatives. The aim of the study was to assess nutritional diversity and construct a taro pre-breeding population for high dry matter and low oxalate levels. One hundred and eighty eight taro accessions were procured and planted in alpha lattice design in 2019 at Ebonyi State University's teaching and experimental fields. The corms were picked from each accession, washed, and shipped to Nigeria's National Root Crop Research Institute Biochemistry Laboratory. The corms were freeze-dried, crushed, and analyzed for physiochemical parameters using the standard techniques of analysis provided by the Association of standard Analytical Chemists. Significant differences were observed among the taro populations in dry matter content at 22.53 %, ash at 2.46 %, crude lipid at 0.60 %, fibre at 1.74 %, crude protein at 7.79 %, carbohydrates at 9.97 %, and energy at 76.48 Kcal. Potassium content was at 638.91 mg/100 g, sodium at 28.39 mg/100g, calcium at 35.18 mg/100g, phosphorus at 117.61 mg/100g, iron at 7.78 mg/100g, zinc at 2.84 mg/100g, and manganese at 2.03 mg/100g. The soluble, insoluble, and total oxalate concentration was at 74.18 mg/100g, 218.76 mg/100 g, and 291.63 mg/100 g, respectively. A hierarchical cluster analysis of taro accessions revealed three distinct groupings, with cluster three distinguished by high dry matter content and an intermediate oxalate level. The findings revealed the existence of a considerable differential in nutritional content among the taro populations analyzed. Taro is divers in its dry matter and anti-nutrient content. Clustering the accessions according to their merit would aid breeders in sorting genotypes for eating quality metrics like high dry matter and low oxalate levels. These results, needs further work for reliability.

Evaluation of eight bambara groundnut (Vigna subterranea (L.) Verdcourt) accessions for agronomic characters and proximate composition in Uyo, Akwa Ibom State, Nigeria

Bambara groundnut (Vigna subterranea [L.] Verdc.) is a valuable but underutilised legume crop grown in sub-Saharan Africa. The objective of this study was to evaluate the yield and yield components of eight Bambara groundnut accessions obtained from the National Root Crops Research Institute in Umudike, Nigeria.  The experiment was conducted at the Teaching and Research farm of the University of Uyo, Uyo Southern Nigeria during the 2021 cropping seasons, using a randomised complete block design with three replications. Growth, yield and nutritional parameters were collected and subjected to analysis of variance, correlation and principal component analysis. Plant height, number of leaves, and leaf area were all significantly different (P≤0.05) among the accessions three months after planting. Number of pods per plant, seed weight, and 100-seed weight differed significantly (P≤0.05). Caly PSC (2853 kg/ha), Caly SK 46 (2803 kg/ha), Zeina (2538 kg/ha), and BNT (2488 kg/ha) were the top yielders among the accessions. Yields of Bambara groundnut differ significantly (P≤0.05) between accessions studied, ranging from 1624.67 kg/ha to 2853.33 kg/ha. Principal component (PC) analysis identified eight influential components, two of which, PC1 and PC3, contributed 27% and 17% of the total variation, respectively. In this study, the correlation analysis revealed that plant height and petiole length, plant height and number of seeds per plot were all negatively correlated. The leaf area and the number of pods per plot, the number of seeds per pod and the fibre content, the leaf area and seed weight, and the plant height and seed weight were all noted positively correlated. The nutritive value of the eight Bambara groundnut accessions varied significantly (P≤0.05). The mean protein levels of eight Bambara nut accessions studied ranged from 18.82 to 20.39%. Findings from this study clearly indicate that Bambara groundnut is suitable for production in Uyo, Akwa Ibom State. Thus, high yielding accessions identified in this study are recommended for increased production in Akwa Ibom State of Nigeria.

Assessment of X-ray Irradiation on the Morphological Performance of Sweet Potato (Ipomoea batatas [L.] Lam)

Aim: Sweet potatoes (Ipomoea batatas [L.] Lam) were studied to assess the influence of x-ray irradiation on the morphological performance.
 Place and Duration of Study: Samples were collected from National Root Crop Research Institute (NRCRI), Umudike, irradiation was done in the x-ray unit of a medical laboratory, planting and data analysis were done at the experimental farm and laboratory of the Department of Genetics and Biotechnology, University of Calabar.
 Methodology: Stems of Sweet potatoes were grouped and non-control groups irradiated at different x-ray doses, planted and morphological parameters analyzed.
 Results: The results showed no significant difference in the treatments for parameters such as number of leaves, leaf area, leaf length, plant height, leaf width and days to sprouting when kilo voltage (kV) was constant at 40kV and milli Amperes per second (mAs) varied from 1.6mAs to 3.2mAs. There was also no significant difference in the treatments for parameters such as leaf area, leaf length, leaf width and days to sprouting when mAs was constant at 1.6mAs and kilo voltage (kV) varied from 40kV to 100kV. The results also showed that the low doses of x-ray irradiation did not cause aberrations in the morphological performance of sweet potato.
 Conclusion: These findings necessitate the need for adequate irradiation doses in the use of ionizing radiations on crops in order to maintain and improve their varieties.

EFFECT OF TILLAGE PRACTICES AND FERTILIZER RATES ON GROWTH, AND YIELD OF SWEET POTATO (IPOMEA BATATA)

A field experiment was conducted at the Research Farm of National Root Crops Research Institute Sub-Station, Igbariam to study the effect of tillage practices and fertilizer application rates on the growth and productivity of sweet potato (var. Umuspo1) during the 2021 and 2022 cropping seasons. The experiment was set up as a 4 × 3 factorial fitted in a randomized complete block design (RCBD) with three replications. The main factor comprised four levels of fertilizer rates (0, 200, 400, and 600 NPK 20:10:10/ha) while the sub-factor consisted of three tillage methods (flats, mounds, and ridges). Data collected on the growth and yield of the crop were subjected to analysis of variance (ANOVA) using Genstat 4TH Edition statistical software. The significant means were separated using the least significant difference (LSD) at a 5% probability level. The result indicated that tillage practice had a significant effect on vine length in the 2021 and 2022 cropping seasons whereas the number of leaves showed no significant difference. On the other hand, tillage practice had significant effect on number of roots in the 2022 cropping season. The result obtained on the length of root indicated that both tillage practices and fertilizer application rates had no significant effect on sweet potato root length in the 2021 and 2022 cropping seasons. However, the results on the yield showed that ridges had the best performance in almost all the yield parameters while the application of fertilizer at the rate of 200 kg/ha gave the highest yield.

Molecular genotyping of sweet potato (Ipomoea batatas L. Lam) accessions using microsatellites

The experiment was conducted to ascertain the level of genetic diversity in sweet potato accessions using microsatellites. Thirty sweet potato accessions obtained from the International Potato Center (CIP), Kumasi, Ghana, Mozambique, and local germplasm of the National Root Crops Research Institute (NRCRI), Umudike, Abia State, Nigeria, as well as sweet potato vines from local farmers' fields in Jos, Plateau State, and Bauchi State, Nigeria, were analyzed for genetic diversity using five microsatellite markers. The results showed that the polymorphic SSR loci revealed diverse relationship among the sweet potato cultivars, which was grouped into four major clusters by unweighted pair group method analysis (UPGMA) method. Cluster analysis showed a Jaccard co-efficient ranging from 0.0 to 3.0 indicating high genetic diversity. The primers detected a total of 18 alleles and the number of alleles per locus was 4 for IBR-19, IBR-286, IBR-297 and 3 for IBR-16 and IBR-242 with an average of 3.67 alleles per locus. The polymorphic information content (PIC) of the markers varied from 0.35 to 0.72 with an average of 0.497. Marker IBR-19 revealed the highest PIC of 0.72, while marker IBR-297 had the lowest PIC of 0.35. Observed heterozygosity ranged from 0.32 to 0.89 with a mean of 0.675 across the five SSR loci. The results from the Analysis of molecular variance (AMOVA) which was used to quantify the diversity level and genetic relationship among the thirty sweet potato accessions indicated that a high diversity was mostly distributed within the populations for sweet potato accessions (75.12%) and (15.67%) among the populations.

Effects of Citrus aurantifolia Linn and Xylopia aethopica (Dunal) A. Rich Extracts on Leaf Blight Disease of Taro (Colocasia esculenta L. Schott)

Phytophthora colocasiae Raciborski, an Oomycete phytopathogen, has been known for several decades as the causal agent of the most infectious and devastating disease of Colocasia esculenta (L.) Schott, known as taro leaf blight (TLB). Investigations were conducted in a screenhouse to determine the effects of fruit extracts of Citrus aurantifolia and Xylopia aethiopica on the incidence and severity of TLB. The experiment was set up in a completely randomized design with three replicates.  Healthy taro seedlings obtained from the National Root Crops Research Institute (NRCRI), Umudike, were planted in plastic pots (5000 cm3) containing sterilized soil enriched with poultry manure. The plant extracts were applied as foliar spray on taro leaves with manually operated hand sprayer at 7 weeks after planting and continued at four days intervals for a period of 28 days. Positive check was maintained with the fungicide Ridomil (a.i. mefenoxam) applied at the rate of 0.67 mg.ml-1 while zero concentration in distilled water served as negative control. Data were subjected to one-way analysis of variance and means were separated using F-LSD.  Results showed very high reduction of disease with plant extracts (P < 0.05) and Ridomil compared to the control. Citrus aurantifolia juice was more efficient in reducing the incidence and severity of TLB compared to X. aethiopica extracts and was highly significant (P< 0.05). The overwhelmingly fungitoxic effects of  C. aurantifolia and X. aethiopica extracts on P. colocasiae as expressed in the reduction of disease suggests that these extracts can serve as alternative bio-fungicide for  the control of TLB. Hence, further studies under field conditions are required to reestablish their efficacy.

Diversity among Morphological Traits of Segregating Sweetpotato [Ipomoea batatas (L.) Lam] Genotypes in Umudike, Nigeria

Genotypes of the sweet potato (Ipomoea batatas (L.) Lam) normally exhibit high variability in their morphological characters. A field experiment was carried out in 2017 at the National Root Crops Research Institute, Umudike, Abia State, Nigeria to assess the morphological diversity among the population of 68 first filial generation (F1) sweet potato genotypes (Ligri PC) derived from seeds produced through poly cross systems from the International Potato Center, Kumasi, Ghana, including two local check varieties (UMUSPO3 and TIS87/0087). A randomized complete block design with three replicates was used to set up this experiment. The morphology descriptor was used to evaluate the genotypes of sweet potatoes on sixteen characters that covered both folial and fresh storage root morphology. The data were then subjected to an analysis of variance to identify any differences between the measured morphological parameters and agronomic variables. Using cluster analysis, it was established that all of the genotypes could be categorized into four distinct groups based on their physical characteristics. Consequent, a vast gene pool would provide for effective recombination to create a viable sweetpotato variety with high agricultural value.

Screening of some sweet potato (Ipomoea batatas (L.) Lam) genotypes for yield and damage by Cylas puncticollis under rainfed conditions in Umudike, Southeastern Nigeria

A field experiment was conducted at the National Root Crops Research Institute, Umudike, Southeastern Nigeria during the 2015 and 2016 cropping seasons to evaluate diversity among F1 population of sweet potato, namely: Sauti × 442162 (6), Ligri × Faara (17), Sauti × Bohye (17), including two checks (Umuspo 3 and TIS 87/0087). This experiment was laid out in a randomized complete block design with three replicates under rainfed condition. Data on fresh storage root yield were recorded at 120 days after planting. Analysis of variance, correlation and principal component analysis were utilized for data analysis. The study revealed that yield of fresh storage root showed significant differences (P< 0.05) among the sweet potato genotypes. Sauti X Bohye produced the highest storage root yield (19.33 t/ha) in 2015 and performed better than the national check TIS 87/0087 that recorded a storage root yield of 10.84 t/ha. The result from the study showed that out of the forty genotypes evaluated, twenty-six (26) genotypes recorded attack of C. puncticollis. The extent of the damge recorded among the genotypes attacked by C. puncticollis ranged from severe damage to little damage among the genotypes that recorded fresh storage root damage. SautiXBohye/11, SautiXBohye/13, SautiXBohye/17 recorded severe damage caused by C. puncticollis while LigriXFaara/15 recorded moderate damaged caused by C. puncticollis. Fifteen (15) genotypes did not record any infestation by Cylas puncticollis. All characters except unmarketable storage root weight at harvest exhibited positive and significant (P< 0.01) correlation with total roots weight (yield). Principal component analysis had three main principal components explaining 84.25% of the total variation with number of marketable roots, weight of marketable roots, storage root yield and Cylas incidence contributing the most to the first PCA. These genotypes could possess resistance genes to Cylas puncticollis and these genotypes could be incorporated in breeding programs for further trail.

English

The persistent low yield and farmers’ preference of their traditional yam varieties over the improved varieties necessitated this study to verify the adoption status of the released varieties in Nigeria. A total of 48 accessions of white yam (Dioscorea rotundata) were sampled from six states of Ebonyi, Enugu, Benue, Kogi, Nassarawa and Oyo within Nigeria yam-belt and were genotyped for relatedness to four released varieties from the National Root Crops Research Institute (NRCRI), Umudike yam breeding programme, while 14 accessions of water yam (D. alata) were sampled from four states of Benue, Kogi, Nassarawa and Oyo and were also genotyped for relatedness to three released varieties from International Institute for Tropical Agriculture (IITA), Ibadan. A total of 29 alleles were found in 5 sets of primers analyzed for 52 D. rotundata accessions and the number of alleles ranged from 5 (Dald08, SSR 51 and YM 34) to 8 (Dab2E07) with an average of 5.8 per locus. The observed heterozygosity ranged from 0.19 (YM34) to 0.77 (YM30). A total gene diversity of 0.63 according to Nei (1978) genetic distance coefficients was observed among the 52 D. rotundata accessions. Similarly, a total of 37 alleles were observed when 17 D. alata accessions were analysed with the 7 selected sets of primers. An average of 5.29 alleles was observed per locus. The observed heterozygosity varied from 0.47 (Dab2D06) to 0.82 (YM34). A total gene diversity of 0.58 was observed among 17 D. alata accessions according to Nei’ genetic distance coefficients. Cluster analysis showed that the D. rotundata accessions were classified into 8 clusters. While, 17 accessions of D. alata were classified into 4 clusters. There were relationships between some released varieties and farmers accessions and also among the farmers’ accessions from different locations, indicating that farmers might have given a preferred local name to the released varieties.   Key words: Verification, adoption, status, yam, microsatellites-markers.

First Report of Phytophthora sansomeana (E.M. Hansen) Causing Leaf Blight of taro (Colocasia esculenta (L.) Schott) in South Eastern Nigeria

Leaf blight and corm rot of taro (Colocasia esculenta (L.) Schott) caused by Phytophthora colocasiae Raciborski is the most disparaging disease of taro inducing severe losses in yield and quality of taro corms. Investigations were carried out in Umudike in 2016 and 2017 to determine the pathotypes present in that locality with a view to screening them on available taro genotypes for resistant cultivars. Symptomatic taro plant samples were collected from Taro Project Farm of the National Root Crops Research Institute, Umudike. Leaf tissue sections were excised from the periphery of lesions on symptomatic leaf, surface sterilized in 10% Sodium Hypochlorite solution for 2 minutes, rinsed in three changes of sterile distilled water and plated on Water Agar (WA). Mycelia emerging from diseased tissues after incubation were aseptically transferred to Corn Meal Agar (CMA). A total of 15 fungal isolates under 6 groups of species were obtained and these isolates were transferred to Carrot Agar (CA) from time to time until pure cultures were obtained. Based on varied cultural patterns, morphological characteristics and microscopic examination, the isolates were identified as Phytophthora sp, Fusarium sp FSSC, Fusarium solani, F. oxysporum and F. equiseti. Pathogenicity test confirmed that only Phytophthora sp induced leaf blight on detached leaf of taro plant. Molecular characterization of the isolates via Internal Transcribed Spacer (ITS) sequence analyses confirmed that the already implicated Phytophthora species was Phytophthora sansomeana. This is apparently the first report of P. sansomeana as a taro leaf blight pathogen in addition to the already known P. colocasisae.

Evaluation of Orange Fleshed Sweetpotato (Ipomoea batatas (L.) Lam) Genotypes for Growth and Yield related Characters under Rainfed Condition in Uyo Southeastern Nigeria

Five orange fleshed sweetpotato (Ipomoea batatas (L.) Lam) genotypes sourced from National Root Crops Research Institute, Umudike were evaluated under rainfed condition in 2020 and 2021 cropping seasons at the Teaching and Research Farm of the University of Uyo, Uyo, Akwa Ibom State, Nigeria to identify the high yielding and adaptable genotypes. The five genotypes; Umuspo-3, Umuspo-1, Naspot-12, Lourdes and Erica were used as treatments and the experiment was laid out in a randomized complete block design with three replications. Data on growth, yield and yield related characters were collected and analysis of variance, correlation and principal component analysis were performed. The result of the study indicated that the genotype differ significantly (P≤ 0.05) for number of marketable roots, weight of marketable roots and fresh roots yield. Umuspo-3 produced the highest storage root yield (29.22 t/ha, 28.78t/ha) in 2020 and 2021 cropping seasons, respectively. The result of the correlation analysis also revealed that vine length, number of marketable roots, weight of marketable were highly significantly and positively (P< 0.01) correlated with fresh root yield. Principal component analysis (PCA) had three main principal components explaining 82.41% of the total variation with number of marketable roots, weight of marketable tuber and storage root yield contributing the most to the first PCA. Umuspo-3 recorded high yield than the other four orange-fleshed sweetpotato. Therefore, Umuspo-3 was identified as a high yielding and adaptable orange-fleshed sweetpotato genotype and could be recommended mass cultivation in Uyo agro-ecology as a high yielding orange-fleshed sweetpotato.

Comparative Effect of NPK Fertilizer, Poultry Manure and Rice Mill Waste on Soil Chemical Properties, Nutrient Content and Performance of Ginger (Zingiber officinale Roscoe) in Umudike, Southeastern Nigeria

The study examined the comparative effect of NPK fertilizer, poultry manure and rice mill waste on soil chemical properties, nutrient content and performance of ginger in 2018 and 2019 at the National Root Crops Research Institute Farm, Umudike, Southeastern Nigeria, using ginger variety (UG 1) as the test crop. There were seven treatments consisting of sole and combinations of NPK15:15:15, poultry manure and rice mill waste with a rate of 45 kg N/ha regarded as a full dose. They were arranged in RCBD with three replications. Results showed that the application of the amendments significantly (p<0.05) increased soil chemical properties with the combined application of NPK and poultry manure, giving the highest value for most of the parameters determined. The NPK and poultry manure significantly reduced soil acidity from a very strong acidic level of 4.80 and 4.90 (initial values before the experiment) to 5.30 each year. It increased available phosphorus from 18.50 mg/kg to 23.50 mg/kg and exchangeable calcium from 3.60 cmol/kg to 4.40 cmol/kg in 2018 and it increased total nitrogen from 0.98 g/kg to 1.30 g/kg and exchangeable calcium from 3.20 cmol/kg to 4.00 cmol/kg in 2019. The combined treatment of NPK and poultry manure equally gave the highest nutrient content for both planting seasons; (N: 0.38%, P: 0.78%, K: 0.32%, Ca: 0.44% and Mg: 0.24%) in 2018 and (N: 0.34%, K: 0.31%, Ca: 0.31% and Mg: 0.19%) in 2019, except in the phosphorus content in 2019 was plot treated with the sole treatment of NPK gave the highest nutrient content of 0.72% and was significantly (p<0.05) higher than other treatments. The growth parameters were highest in the plot treated with NPK and poultry manure for both seasons. The highest yield of 49.6 t/ha and 51.0 t/ha were obtained from NPK and poultry manure in 2018 and 2019, respectively. Therefore, it can be concluded that the combination of NPK fertilizer and poultry manure is a promising amendment for increasing soil chemical properties, nutrient content, growth parameters and yield of ginger in Umudike.

High yield and pest resistant genotypes of sweet potato (Ipomoea batatas (L.) Lam.) for cultivation in Umudike, Southeastern, Nigeria

Newly developed progenies of sweet potato were evaluated to identify promising genotypes with high storage root yield, dry matter, starch content and susceptibility to Cylas spp. at the National Root Crops Research Institute, Umudike, Southeastern Nigeria during the 2015 and 2016 cropping seasons to evaluate variation among crosses of different sweet potato families, namely: LigriXFaara (17), LigriXApomoen (9) and LigrixSauti (8), including two check varieties (Umuspo 3 and TIS 87/0087). Analysis of variance, correlation and principal component analysis were employed for data analysis. In this study, four genotypes; LigriXFaara/3 (16.02t/ha), LigriXFaara/2 (14.67t/ha), LigriXFaara/1 (13.66t/ha) and LigriXFaara/6 (10.33t/ha) produced higher fresh storage root yield than the national check (TIS 87/0087). Four genotypes recorded starch content above 50mg100-1; LigriXApomoden/1 (69.71mg100-1), LigriXApomoden/3 (62.98mg100-1), LigriXApomoden/2 (60.89mg100-1), LigriXApomoden/4 (57.53 mg100-1). Among the thirty-four genotypes evaluated, twenty-nine genotypes were susceptible to the attack of C. puncticollis. LigriXFaara/1 recorded the highest attack of C. puncticollis, followed by LigriXApomoden/5, LigriXFaara/4, LigriXApomoden/3, LigriXSauti/3, LigriXFarra/5 while five genotypes; LigriXFaara/4, LigriXFaara/5, LigriXSauti/5, LigriXFaara/8, LigriXFaara/7 and LigriXFaara/14 did not show any sign of vulnerability of C. puncticollis. Promising genotypes that recorded high yield, dry matter and resistance to Cylas spp. could be subjected to advanced yield trail and incorporated into further breeding program.

Genome-Wide Association Study of Root Mealiness and Other Texture-Associated Traits in Cassava.

Cassava breeders have made significant progress in developing new genotypes with improved agronomic characteristics such as improved root yield and resistance against biotic and abiotic stresses. However, these new and improved cassava (Manihot esculenta Crantz) varieties in cultivation in Nigeria have undergone little or no improvement in their culinary qualities; hence, there is a paucity of genetic information regarding the texture of boiled cassava, particularly with respect to its mealiness, the principal sensory quality attribute of boiled cassava roots. The current study aimed at identifying genomic regions and polymorphisms associated with natural variation for root mealiness and other texture-related attributes of boiled cassava roots, which includes fibre, adhesiveness (ADH), taste, aroma, colour, and firmness. We performed a genome-wide association (GWAS) analysis using phenotypic data from a panel of 142 accessions obtained from the National Root Crops Research Institute (NRCRI), Umudike, Nigeria, and a set of 59,792 high-quality single nucleotide polymorphisms (SNPs) distributed across the cassava genome. Through genome-wide association mapping, we identified 80 SNPs that were significantly associated with root mealiness, fibre, adhesiveness, taste, aroma, colour and firmness on chromosomes 1, 4, 5, 6, 10, 13, 17 and 18. We also identified relevant candidate genes that are co-located with peak SNPs linked to these traits in M. esculenta. A survey of the cassava reference genome v6.1 positioned the SNPs on chromosome 13 in the vicinity of Manes.13G026900, a gene recognized as being responsible for cell adhesion and for the mealiness or crispness of vegetables and fruits, and also known to play an important role in cooked potato texture. This study provides the first insights into understanding the underlying genetic basis of boiled cassava root texture. After validation, the markers and candidate genes identified in this novel work could provide important genomic resources for use in marker-assisted selection (MAS) and genomic selection (GS) to accelerate genetic improvement of root mealiness and other culinary qualities in cassava breeding programmes in West Africa, especially in Nigeria, where the consumption of boiled and pounded cassava is low.

Varietal effects on Productivity of Potato (Solanum tuberosum L.) in Kuru, Northern Guinea Savanna, Nigeria

A study on varietal effects on the productivity of potato (Solanum tuberosum L.) was conducted during the 2017 and 2018 cropping seasons at the Research Farm of the National Root Crops Research Institute (NRCRI) Kuru, Jos in Plateau State, Nigeria. The study was aimed at assessing the effect of variety on productivity of potato. The treatments consisted of two varieties of potato (improved variety: Daimat, local variety). The experiment consisted of 4 that were laid out in a 2×2 split plot arrangement in a randomized complete block design (RCBD) and replicated three times. Crop data collected were percent germination, plant height, leaf area, number of leaves, number of branches, number of stems, stem girth, number of tubers per plant, number of seed tubers per plant, number of ware tubers per plant, weight of seed tubers per plant, weight of ware tubers per plant and total yield of potato (tons/ha). Although there was no significant effect of variety on the growth parameters of potato but the improved variety performed better than the local variety.  The improved variety is here by recommended for adoption in the study area. 

Physicochemical and microbial properties of orange-fleshed sweet potato flour produced with sun-drying and sulphiting agent

Many local Nigerian processors of sweet potato flour use sun-drying of the sliced roots in place of modern mechanical drying. This study used carotene-rich UMUSPO3 orangefleshed sweet potato (OFSP) variety that was newly bred at National Root Crop Research Institute (NRCRI), Umudike, Nigeria to evaluate the possible effect of sun-drying and sulphiting on the physicochemical and microbial properties of OFSP flour samples. Data were obtained for OFSP sun-dried flour samples processed by different pretreatment methods (blanching, sulphiting with sodium metabisulphite and a control). Results showed that the bacterial and fungal load of the sulphite-flour sample was 8.5×104 CFU/g and 4.00×104 CFU/g while that of the control flour sample was 12.00×104 CFU/g and 6.50×102 CFU/g respectively. The total carotenoid content (TCC) of the flour samples ranged from 10.73 – 11.68 mg/100 g while the TCC of the fresh (unprocessed) OFSP was 40.20 mg/100 g on dry matter basis. The proximate composition of the flour samples was 10.21 – 10.95% moisture, 8.18 – 8.20% protein, 2.40 -2.55% fibre, 0.95 -1.11% fat and 1.73 – 1.85% ash. Obtained physico-functional properties were 13.17 – 13.23 g/mL swelling power, 2.70 – 3.4 g/mL oil absorption capacity, 2.65 – 2.85 g/mL water absorption capacity, 77.50 – 88.000C gelatinization temperature and 0.65 – 0.66 g/mL bulk density