Expansion of the crop ontology by adding cassava trait ontology

Poster presented at CGIAR Generation Challenge Programme, General Research Meeting. Hyderabad (India), 21-25 Sep 201

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

Support from Parents, Peers, and Teachers is differently associated with Middle School Students’ Well-Being

Parents, peers, and teachers provide a powerful context for school students’ well-being. However, a detailed and systematic analysis of how parental, teacher, and peer support relate to students’ well-being, measured by the dimensions self-worth, psychological and physical well-being, is still missing. To address this research gap, the following study investigates 733 adolescent German students from grades 7 and 8 (Mage = 13.97, SD = 0.41, 52% girls) with respect to their perceived supportive relationships at home and within the school context. The study considers gender, socioeconomic status, and school form as potential confounders. The results of the structural equation model, analyzed with the statistical software R, indicate that perceived teacher support was positively related to students’ self-worth and physical well-being, while peer support was related to psychological well-being. Students who perceived their parents as supportive reported higher well-being with respect to all three dimensions investigated

Cassava improvement in the era of "agrigenomics": the road to nextgeneration breeding.

In the last 45 years, IITA has played a pivotal role in the genetic improvement of cassava for resourcepoor farmers in sub-Saharan Africa (SSA). More than 400 varieties have been developed that are not only high yielding but also resistant to diseases and pests. Many of these improved varieties have been extensively deployed in SSA and have helped to avert humanitarian crises caused by the viral disease pandemics that devastated local landraces in East and Central Africa

Marker-based estimates reveal significant non-additive effects in clonally propagated cassava (Manihot esculenta): implications for the prediction of total genetic value and the selection of varieties

Open Access JournalIn clonally propagated crops, non-additive genetic effects can be effectively exploited by the identification of superior genetic individuals as varieties. Cassava (Manihot esculenta Crantz) is a clonally propagated staple food crop that feeds hundreds of millions. We quantified the amount and nature of non-additive genetic variation for key traits in a breeding population of cassava from sub-Saharan Africa using additive and non-additive genome-wide marker-based relationship matrices. We then assessed the accuracy of genomic prediction of additive compared to total (additive plus non-additive) genetic value. We confirmed previous findings based on diallel populations, that non-additive genetic variation is significant, especially for yield traits. Further, we show that we total genetic value correlated more strongly to observed phenotypes than did additive value, although this is constrained by low broad-sense heritability and is not beneficial for traits with already high heritability. We address the implication of these results for cassava breeding and put our work in the context of previous results in cassava, and other plant and animal species

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’