Application of near infrared reflectance spectroscopy in screening of fresh cassava (Manihot esculenta crantz) storage roots for provitamin A carotenoids

A developed Near Infrared Reflectance Spectroscopy (NIRS) calibration equation was used for determining provitamin A carotenoids contents of different trials of fresh yellow root cassava genotypes using a total of 50 cassava genotypes scanned twice by NIRS from 400 nm to 2498 nm. The NIRS calibration equations were used to predict the β-cryptoxanthin, 13-cis β-carotene, trans β-carotene, 9-cis β -carotene, total β-carotene and total carotenoid concentrations of the samples. The predicted values for total carotenoids (TC-pred) ranged from 3.93 μg g–1 to 10.51 μg g–1 with mean of 7.07 ± 2.55 μg g–1 for International Collaborative Trials (ICT), 7.97–11.03 μg g–1 fresh weight with mean of 9.40 ± 0.76 μg g–1 for yellow root trial 8 (Multi-location Uniform Yield Trial) and 6.38–10.44 μg g–1 with mean of 8.74 ± 1.07 μg g–1 for yellow root trial 9 (Multilocation Advanced Yield Trial). Total carotenoids results using reference spectrophotometric method (TC-spec) ranged from 2.57 μg g–1 to 9.97 μg g–1 with mean of 5.66 ± 2.99 μg g–1 for ICT, 6.55–8.74 μg g–1 with mean of 7.74 ± 0.64 μg g–1 for yellow root trial 8 and 4.22–11.00 μg g–1 with mean of 7.57 ± 1.54 μg g–1 for yellow root trail 9. There is significant (P ≤ 0.001) positive correlation (r = 0.55) between TC-pred by NIRS and TC-spec. Also, significant (P ≤ 0.001) positive correlation (r = 0.52) exist between trans β-carotene predicted by NIRS and high-performance liquid chromatography reference. The developed NIRS calibration equations could be used to predict total carotenoids and trans β-carotene content of yellow root cassava and serve as rapid and cost-effective screening method for large cassava sample sets

Genetic variability, stability and heritability for quality and yield characteristics in provitamin A cassava varieties

Open Access Article; Published online: 25 Jan 2020Cassava is widely consumed in many areas of Africa, including Ghana, and is a major part of most household diets. These areas are characterized by rampant malnutrition, because the tuberous roots are low in nutritional value. Provitamin A biofortified cassava varieties have been developed by the International Institute for Tropical Agriculture, but adoption of these varieties in Ghana will largely depend on their agronomic performance, including fresh root yield, dry matter content, resistance to major pests and diseases, mealiness, starch content and the stability of these traits. Eight provitamin A varieties with two white checks were planted in three environments for two seasons to determine stability and variability among the varieties for important traits. There were significant variations in performance between varieties and between environments for cassava mosaic disease, root number, fresh root yield and starch content. High broad-sense heritability and genetic advance were observed in all traits, except for storage root number, and could be exploited through improvement programs. This study identified the best performing enhanced provitamin A varieties for traits that are key drivers of variety adoption in Ghana. In view of this, some varieties can be recommended for varietal release after on-farm testing. The study also showed the possibility of tapping heterosis after careful selection of parents

Popular biofortified cassava cultivars are heavily impacted by plant parasitic nematodes, especially Meloidogyne Spp.

Open Access Journal; Published online: 26 June 2020The development of new biofortified cassava cultivars, with higher micronutrient contents, offers great potential to enhance food and nutrition security prospects. Among the various constraints affecting cassava production are plant parasitic nematodes (PPN), especially root-knot nematodes. In this study, six popular biofortified cultivars were field-evaluated for their response to PPN in Nigeria. A field naturally infested with a diversity of PPN but dominated by root-knot nematodes was used. Application of the nematicide carbofuran significantly reduced PPN densities, and at harvest, no root galling damage was observed, compared with untreated plots, which had heavy galling damage. Plant height, stem girth, plant weight, marketable storage root number and weight were significantly lower for most cultivars in untreated plots. Percentage yield losses in the range of 21.3–63.7% were recorded from two separate trials conducted for 12 months each. Lower total carotenoid and dry matter contents were associated with higher PPN densities in some biofortified cultivars, resulting in a loss of as much as 63% of total carotenoid and 52% of dry matter contents. The number and weight of rotted storage roots were significantly greater in untreated plots across cultivars, reducing in-field and post-harvest storability. This study demonstrates that natural field populations of PPN can substantially affect yield, quality and nutritional value of released biofortified cassava cultivar

Effects of β-carotene biofortified cassava grits (Mahihot esculenta Crantz) based-diets on retinol bioavailability and performance of broiler chicks

The B-carotene content of five cassava varieties and products as well as B-carotene bioavailability in cassava grit from TMS 01/1371 were undertaken using 240 one-day old Arbor acre broiler strain randomly divided into eight groups of 30 birds each. Each group comprised a triplicate of 10 birds each assigned in a completely randomized design. The eight dietary treatments were: Diets 1 and 8 had yellow and white maize respectively as the main energy source, while diets 2, 3 and 4 had maize replaced with cassava grit from TMS 01/1371 at 25%, 50% and 75%. Diets 5, 6 and 7 also had the maize contents similarly replaced with 25%, 50% and 75% grits from TME 419 respectively. Yellow maize, white maize, grits from TME 419 and TMS 01/1371 contained 238.33, 13.33, 6.67 and 108.33. B-carotene in the peeled fresh tuber of TMS 01/1412 (468.33), unpeeled fresh tuber (425.00), dried peeled tuber (391.67) and dried unpeeled cassava (323.33) were significantly higher (P < 0.05) than the corresponding values in TMS 01/1371 (416.67, 371.67, 311.67 and 283.33) and TMS 01/1368 (401.67, 350.00, 295.00 and 258.33). TME 419 cassava and products (peeled fresh tuber, unpeeled fresh tuber, dried peeled tuber and dried unpeeled tuber, garri, garri flour, grit, grit flour, peeling, peels and leaves) contained significantly lower (P < 0.05) levels of B-carotene. The FCR of chicks on diet 1 (1.50) was lowest (P < 0.05) while those on diet 8 (2.24) was highest. The main and interactive effects of cassava varieties and inclusion levels of grits on all indices of performance were significantly different (P < 0.05). Dietary B-carotene only correlated negatively with grits inclusion levels (P < 0.05) from TMS 01/1371 (r = 0.40). The B-carotene content of the diets when related to the inclusion levels of grits from TMS 01/1371 were both significantly negative linearly and quadratically. Regression equations were: (1) Y = 15.333 – 0.0530x (R2 = 0.16); (2) Y = 13.667 + 0.147x – 0.003x2 (R2 = 0.36) Conclusively, processing methods adopted in this study reduced B-carotene content of cassava grits which may have affected the bioavailability of retinoic acid in broiler chicks’

Genetic by environment interaction on fresh root yield, dry matter content and total carotene concentration of yellow-fleshed cassava genotypes in five major cassava growing agroecological zones in Nigeria

Eighteen yellow-fleshed cassava genotypes and two released white-fleshed clones (check) were evaluated in five locations representing the major cassava growing agroecological zones of Nigeria to access their performance for fresh root yield, dry matter content, total carotene content and genotypes by environment interaction effects. The aim of the study was to identify stable cassava genotypes that combine high root yield, and high dry matter with high beta carotene content in storage root. The study was conducted in two cropping seasons (2008/2009 and 2009/2010) at Ikenne (humid forest), Ibadan (forest-savanna transition), Ubiaja (sub-humid forest), Mokwa (sub-humid southern-Guinea savanna) and Zaria (moist northern-Guinea savanna). At all locations, the trials were conducted in a randomised complete block design (RCBD) with four replications. The combined analysis of variance showed that fresh root yield (t ha-1), dry matter content (%) and total carotene content (μg g-1 fresh weight) was significantly affected (P &lt; 0.001) by Genotype (G), Environment E, and G × E interaction. For fresh root yield, the best genotype was IITA TMS I050024 followed by IITA TMS I050998 and IITA TMS I050286. For dry matter content of the storage roots, the genotype IITA TMS 1051570 had the highest score followed by IITA TMS 1051740 and IITA IMS I050998. For total carotene content, the best genotypes across the 10 environments in decreasing order of carotene content were IITA TMS I051601, IITA TMS I050311, IITA TMS I050998 and IITA TMS I050099. When combining fresh root yield and dry matter content (dry yield), the genotypes IITA TMS I050998 and IITA TMS I051740 ranked highest. The Environment effect accounted for most of the variation of the total sum of squares (SS) for fresh root yield (55.0%), dry matter content (42.3%) and dry yield (57.9%). The genotype accounted for most of the SS for total carotene content (67.9%)

Improving root characterisation for genomic prediction in cassava

Open Access Journal; Published online: 14 May 2020Cassava is cultivated due to its drought tolerance and high carbohydrate-containing storage roots. The lack of uniformity and irregular shape of storage roots poses constraints on harvesting and post-harvest processing. Here, we phenotyped the Genetic gain and offspring (C1) populations from the International Institute of Tropical Agriculture (IITA) breeding program using image analysis of storage root photographs taken in the field. In the genome-wide association analysis (GWAS), we detected for most shape and size-related traits, QTL on chromosomes 1 and 12. In a previous study, we found the QTL on chromosome 12 to be associated with cassava mosaic disease (CMD) resistance. Because the root uniformity is important for breeding, we calculated the standard deviation (SD) of individual root measurements per clone. With SD measurements we identified new significant QTL for Perimeter, Feret and Aspect Ratio on chromosomes 6, 9 and 16. Predictive accuracies of root size and shape image-extracted traits were mostly higher than yield trait prediction accuracies. This study aimed to evaluate the feasibility of the image phenotyping protocol and assess GWAS and genomic prediction for size and shape image-extracted traits. The methodology described and the results are promising and open up the opportunity to apply high-throughput methods in cassava

The differential impact of four tropical species of root-knot nematodes (Meloidogyne spp.) on biofortified cassava

Open Access ArticleCassava plays an important food security role in Africa. Although a hardy crop in general, average yields are low, while traditional cultivars tend to be low in nutrients and vitamins. Substantial efforts have therefore been made to improve the nutritional quality of cassava through the development of biofortified cultivars. Although root-knot nematodes (RKN) are among the various important constraints affecting production, details on the impact of different species of RKN on cassava productivity are scarce. In this study, six popular cultivars of biofortified cassava were evaluated for their response to M. arenaria, M. enterolobii, M. incognita, M. javanica and a combination of all four species, in pots. All tested cultivars were susceptible to the four Meloidogyne species, but some cultivars showed a tolerance to M. arenaria infection. Galling damage was observed on feeder roots of inoculated plants, with nematode reproduction factors ranging between 2.3 and 9.5. Plant height, stem girth and fresh plant mass were significantly lower for most cultivars by as much as 70% following RKN infection. The highest root galling and damage were observed in plants following inoculation with a combination of the four species. As individual species inoculations, M. incognita and M. javanica were the most damaging, with the least damage observed in plants inoculated with M. arenaria only. These results confirm the pathogenicity of M. arenaria, M. incognita and M. javanica and further illustrate the potential of M. enterolobii to impact cassava production, while combined species infections demonstrate the greater levels of damage that these may cause

The root-knot nematode, Meloidogyne incognita, profoundly affects the production of popular biofortified cassava cultivars

Open Access Article; Published online: 23 Jan 2020Despite being the single largest cassava-producing country, yields in Nigeria remain consistently poor and among the lowest. Regionally, yields are also particularly low across Africa. Pests and pathogens, including plant-parasitic nematodes, play an important role in this current yield deficit. African countries are not only faced with the problem of food security but also that of nutritional deficiency, due to limited micronutrients in the diet. In this study, six biofortified cultivars were evaluated for their response to inoculation with approximately 30 000 root-knot nematode (Meloidogyne incognita) eggs in 30 l pots in Nigeria. All cassava cultivars proved highly susceptible to M. incognita infection after 6 months, with nematode reproduction factor ranging from 7.0 to 44.8. Galling was common on feeder roots and gall index scores were recorded between 4 to 5 (on a scale of 1-5 where 5 ⩽ 100 galls). Meloidogyne incognita infection significantly reduced plant height, stem girth, fresh plant mass, fresh storage root number and storage root weight. Percentage yield loss of between 41.8-88.4% was recorded in M. incognita-infected plants compared with non-infected controls. Although M. incognita reduced storage root weight, it did not necessarily affect the nutritional quality (total carotenoid) or dry weight percentage of the biofortified cassava cultivars. Total carotenoid and dry weight contents of the control cultivar were similar to some of the biofortified cultivars. The high susceptibility of the biofortified cassava cultivars to M. incognita infection indicates that substantial yield losses are likely being experienced by farmers, as this nematode pest is prevalent across sub-Saharan Africa and the tropics