High Levels Of Provitamin Research Articles

Suitability of testers to characterize provitamin a content and agronomic performance of tropical maize inbred lines.

Vitamin A deficiency poses health risks for children, pregnant women, and nursing mothers in sub-Saharan Africa (SSA) and Southeast Asia. Provitamin A–biofortified maize varieties can contribute to minimizing the adverse effects of vitamin A deficiency in areas where maize is a staple food crop. Identifying suitable testers is important to breed provitamin A–biofortified hybrid maize. This study was therefore conducted to 1) assess the suitability of maize inbred lines with contrasting levels of provitamin A (one with high and one with low provitamin A concentration) to assess the combining ability of maize inbred lines in accumulating provitamin A and other carotenoids, and grain yield, 2) confirm the mode of inheritance of provitamin A and grain yield, and 3) identify promising inbred lines with desirable combining ability effects for use to develop high-yielding provitamin A–biofortified hybrids. The inbreds crossed to the two inbred testers were evaluated in four environments for the carotenoid content and eight environments for the agronomic performance. The combined analysis of variance revealed a significant genetic variation among the testcrosses for all carotenoids, grain yield, and other agronomic traits. The mode of inheritance for grain yield, other agronomic traits, provitamin A, and other carotenoids was regulated by both additive and non-additive gene effects with a prominence of additive gene effects. The high provitamin A tester that displayed positive GCA effects for β-carotene and provitamin A content, broader agronomic performance of testcrosses, and higher levels of provitamin A in testcrosses can be considered suitable for breeding programs developing provitamin A–biofortified hybrids. The inbred lines TZI2012, TZI2142, TZI2130, TZI2065-2, TZI2161, TZI2025, TZI1278, TZI1314, TZI1304, and TZI2032 with positive GCA effects for grain yield and provitamin A content could be used as parental lines to develop source population of new inbred lines and high-yielding hybrids with elevated levels of provitamin A. The best performing hybrids are promising for release as high-yielding provitamin A maize hybrids after further evaluations.

PERTUMBUHAN DAN HASIL SAWI (Brassica juncea) DENGAN KOMBINASI BAHAN ORGANIK BERBAHAN AMPAS TEBU PADA DUA PERIODE TANAM

Mustard greens is a type of leaf vegetable that is favored by consumers because it contains high levels of pro-vitamin A and ascorbic acid which are beneficial for health. However, the production of mustard greens is still relatively low due to the limited availability of fertilizers. Bagasse is the first waste produced from the industrial processing of sugar cane, the volume reaches 30 - 34% of milled sugar cane. This research was conducted in the experimental field of Ratu Samban University. The purpose of this study was to determine the growth and yield of mustard greens against a combination of organic matter made from bagasse in two planting periods. This study used a single factor Completely Randomized Block Design (RAKL) with 10 replications. The treatment used in this study consisted of 4 levels, namely: P0 = control without treatment, P1 = 200g bagasse + 75g chicken manure, P2 = 250g bagasse + 50g chicken manure, P3 = 300g bagasse + 25g chicken manure. The results showed that the planting of the first and second periods, all treatments, namely P0, P1, P2, P3 had a very significant effect on all observation variables at all plant ages. P3 treatment (300g bagasse + 25g chicken manure) gave the best results on all variables observed yotu plant height, number of leaves, plant production, shoot wet weight, and root wet weight.

Multinutrient Biofortification of Maize (Zea mays L.) in Africa: Current Status, Opportunities and Limitations

Macro and micronutrient deficiencies pose serious health challenges globally, with the largest impact in developing regions such as subSaharan Africa (SSA), Latin America and South Asia. Maize is a good source of calories but contains low concentrations of essential nutrients. Major limiting nutrients in maize-based diets are essential amino acids such as lysine and tryptophan, and micronutrients such as vitamin A, zinc (Zn) and iron (Fe). Responding to these challenges, separate maize biofortification programs have been designed worldwide, resulting in several cultivars with high levels of provitamin A, lysine, tryptophan, Zn and Fe being commercialized. This strategy of developing single-nutrient biofortified cultivars does not address the nutrient deficiency challenges in SSA in an integrated manner. Hence, development of maize with multinutritional attributes can be a sustainable and cost-effective strategy for addressing the problem of nutrient deficiencies in SSA. This review provides a synopsis of the health challenges associated with Zn, provitamin A and tryptophan deficiencies and link these to vulnerable societies; a synthesis of past and present intervention measures for addressing nutrient deficiencies in SSA; and a discussion on the possibility of developing maize with multinutritional quality attributes, but also with adaptation to stress conditions in SSA.

Assessing inbred-hybrid relationships for developing drought-tolerant provitamin A-quality protein maize hybrids.

Drought‐tolerant early‐maturing maize (Zea mays L.) inbred lines with high levels of provitamin A (PVA) and quality protein (QPM) are urgently needed for development of superior hybrids to mitigate malnutrition and to intensify maize production and productivity in sub‐Saharan Africa (SSA). This study was designed to identify early‐maturing inbred lines with combined tolerance to drought, elevated tryptophan, and PVA contents; to examine inbred–hybrid relationships for tryptophan and PVA accumulation; and to select hybrids with outstanding grain yield (GY) performance. A total of 64 inbred lines and six checks, plus 96 hybrids and four checks, were evaluated under drought and well‐watered environments in Nigeria for 2 yr. Eighteen parental lines and 54 derived hybrids were assayed for tryptophan and PVA contents. Ten drought‐tolerant inbred lines with high tryptophan and elevated PVA levels were identified in the top 10 hybrid combinations across managed drought and well‐watered conditions. The inbred–hybrid relationship was significant for GY under each and across the two contrasting environments. Significant average heterosis was found for tryptophan and PVA under well‐watered conditions. This indicated that the selected inbred lines could be used for developing high‐yielding PVA‐QPM hybrids tolerant to drought stress in SSA. The 10 top‐performing PVA‐QPM hybrids identified are being extensively evaluated in different locations and subsequently in on‐farm trials for commercialization throughout SSA.

Delaying the harvest induces bioactive compounds and maintains the quality of sweet potatoes.

We have identified the best harvesting periods, related to higher bioactive compound content and post-harvest quality, for minimally processed sweet potatoes with orange pulp and cream pulp. Quality loss in minimally processed sweet potatoes occurred due to browning in cv. Mãe de Familia and ESAM1 and to whitening in cv. Paraná. Both Mãe de Família and ESAM1 presented higher peroxidase and polyphenol oxidase activities at 120days, and cv. Paraná contained high levels of provitamin A. β-carotene was the major carotenoid (up to 99%) in orange pulp. All cultivars harvested at 150 and 180days and minimally processed showed the best visual quality, the highest bioactive compound content, and no microbial infection. Delaying the harvest also increase the antioxidant activity in orange roots, which was associated with a high content of carotenoids and phenolic compounds, resulting in an increase in the nutritional quality of the product. PRACTICAL APPLICATIONS: Postharvest techniques can improve the visual and phytochemical quality of vegetables and extend their shelf life. The present research provides the best harvesting periods for minimally processed cream and orange sweet potato roots with higher postharvest qualities. Delaying the harvest resulted in a product with better visual quality, higher levels of bioactive compounds, which are highly beneficial to health, for example, ß-carotene, and no microbiological contamination. Our results may contribute to improvements in the current knowledge about harvesting times for sweet potato growers who aim to produce high quality, minimally processed products with a longer shelf life.

Molecular and Functional Characterization of GR2-R1 Event Based Backcross Derived Lines of Golden Rice in the Genetic Background of a Mega Rice Variety Swarna

Homozygous Golden Rice lines developed in the background of Swarna through marker assisted backcross breeding (MABB) using transgenic GR2-R1 event as a donor for the provitamin A trait have high levels of provitamin A (up to 20 ppm) but are dwarf with pale green leaves and drastically reduced panicle size, grain number and yield as compared to the recurrent parent, Swarna. In this study, we carried out detailed morphological, biochemical and molecular characterization of these lines in a quest to identify the probable reasons for their abnormal phenotype. Nucleotide blast analysis with the primer sequences used to amplify the transgene revealed that the integration of transgene disrupted the native OsAux1 gene, which codes for an auxin transmembrane transporter protein. Real time expression analysis of the transgenes (ZmPsy and CrtI) driven by endosperm-specific promoter revealed the leaky expression of the transgene in the vegetative tissues. We propose that the disruption of OsAux1 disturbed the fine balance of plant growth regulators viz., auxins, gibberellic acid and abscisic acid, leading to the abnormalities in the growth and development of the lines homozygous for the transgene. The study demonstrates the conserved roles of OsAux1 gene in rice and Arabidopsis.

A foundation for provitamin A biofortification of maize: genome-wide association and genomic prediction models of carotenoid levels.

Efforts are underway for development of crops with improved levels of provitamin A carotenoids to help combat dietary vitamin A deficiency. As a global staple crop with considerable variation in kernel carotenoid composition, maize (Zea mays L.) could have a widespread impact. We performed a genome-wide association study (GWAS) of quantified seed carotenoids across a panel of maize inbreds ranging from light yellow to dark orange in grain color to identify some of the key genes controlling maize grain carotenoid composition. Significant associations at the genome-wide level were detected within the coding regions of zep1 and lut1, carotenoid biosynthetic genes not previously shown to impact grain carotenoid composition in association studies, as well as within previously associated lcyE and crtRB1 genes. We leveraged existing biochemical and genomic information to identify 58 a priori candidate genes relevant to the biosynthesis and retention of carotenoids in maize to test in a pathway-level analysis. This revealed dxs2 and lut5, genes not previously associated with kernel carotenoids. In genomic prediction models, use of markers that targeted a small set of quantitative trait loci associated with carotenoid levels in prior linkage studies were as effective as genome-wide markers for predicting carotenoid traits. Based on GWAS, pathway-level analysis, and genomic prediction studies, we outline a flexible strategy involving use of a small number of genes that can be selected for rapid conversion of elite white grain germplasm, with minimal amounts of carotenoids, to orange grain versions containing high levels of provitamin A.

Genetic Analysis of Visually Scored Orange Kernel Color in Maize

Increasing levels of provitamin A carotenoids in maize (Zea mays L.) grain through plant breeding has potential to help humans suffering from vitamin A deficiency. In parts of Africa where this deficiency is prevalent, there is a consumer preference for white maize grain and an avoidance of yellow maize grain. White grain has minimal levels of carotenoids whereas yellow grain can have appreciable levels of carotenoids. There is a new effort to introduce orange maize that contains high levels of provitamin A, which appears to be a more acceptable color than yellow to consumers in Africa. The implementation of this program requires backcross selection to convert African‐adapted germplasm with white grain to orange. We conducted a study to assess the heritability of visual scores for relative intensity of orange kernel color and identify genetic markers associated with orange color across and within 10 families of the maize nested association mapping population. We found visually scored kernel color to have a moderately high heritability and identified five common quantitative trait loci (QTL) and six rare QTL for intensity of orange color. Notably, half of them coincided with carotenoid biosynthetic genes. Our results indicate that breeders in Africa, Asia, and throughout the world would have flexibility to select for orange kernel color visually and/or with gene‐specific markers. Such selection can be combined with marker‐assisted selection efforts to increase provitamin A levels in maize grain.

Diallel analysis of maize inbred lines for carotenoids and grain yield

Vitamin A deficiency causes xerophthalmia in preschool-aged children worldwide. The objective of this study was to estimate the genetic parameters that would be useful in selecting parent plants for developing productive hybrids with higher levels of provitamin A in the maize kernel. A complete 7 × 7 diallel mating scheme was used to generate 21 single-cross hybrids. The F1 crosses and check hybrids were evaluated in complete block design across three different Brazilian environments, and carotenoid content was analyzed by high performance liquid chromatography. General combining ability effects were significant for all traits except α-carotene This result indicates that the contribution of the additive effect was more important for provitamin A and other carotenoids and, consequently that there is high chance of improving this trait through recurrent selection methods. Line 3 produced the highest level of kernel provitamin A among the inbred lines evaluated and also demonstrated the potential to contribute to the development of genetic materials with a good performance for provitamin A. Inbred lines 1, 6, and 7 showed a higher concentration of favorable alleles for grain yield, and inbred lines 3 and 6 exhibited a higher concentration of favorable alleles for β-carotene. Hybrid 1 × 3 performed well in terms of provitamin A and grain yield and combination 2 × 3 was the best performer in terms of lutein content.

Vitamin A content of traditional leafy vegetables consumed by the Luo people of western Kenya

Vitamin A deficiency (VAD) causes numerous health problems in developing countries, including the sub-Saharan Africa. VAD is one of the major causes of morbidity and mortality in children, and also affects lactating mothers and the elderly. The main objectives of the study were to identify, collect and analyse traditional, leafy vegetables for pro-vitamin A carotenoids and tocopherols. A total of 15 domesticated and 36 wild traditional leafy vegetable species were collected and analysed. The species that contained the highest amounts of β-carotene, lutein and α-tocopherol was Erythrococca bongensis Pax (5.3, 60.7 and 220.7 mg/kg DM, respectively). The results showed that wild plant species generally contained higher levels of pro-vitamin A carotenoids than the domesticated vegetable species and varieties. The study concluded that traditional, leafy vegetables (domesticated and wild) have the potential to prevent or combat VAD amongst the general rural population in developing countries.

Ensuring the Supply of and Creating Demand for a Biofortified Crop with a Visible Trait: Lessons Learned from the Introduction of Orange-Fleshed Sweet Potato in Drought-Prone Areas of Mozambique

Orange-fleshed sweet potato (OFSP) is a promising biofortified crop for sub-Saharan Africa because it has high levels of provitamin A carotenoids, the formed vitamin A is bioavailable, and white-fleshed sweet potato is already widely grown. To examine whether farmers will adopt varieties with a distinct visible trait, young children will eat OFSP in sufficient quantities to improve vitamin A intake, OFSP can serve as an entry point for promoting a more diversified diet, and lessons can be drawn to assure sustained adoption. The 2-year quasi-experimental intervention study followed households and children (n = 741; mean age, 13 months at baseline) through two agricultural cycles in drought prone-areas of Mozambique. OFSP is acceptable to farmers when introduced by using an integrated approach. In the second year, intervention children (n = 498) were more likely than control children (n = 243) to have consumed OFSP (54% vs. 4%), dark-green leaves (60% vs. 46%), or ripe papaya (65% vs. 42%) on 3 or more days in the previous week (p < .001 for all comparisons). Their vitamin A intakes were nearly eight times higher than those of control children (median, 426 vs. 56 1g RAE [retinol activity equivalents], p < .001). Diet diversification was limited by difficult agroecological conditions and low purchasing power. However, dietary diversity was higher among intervention than control children (32% vs. 9% consuming food from more than four groups; p < .001). An integrated OFSP-based approach had a positive impact on the vitamin A intake of young children. A market development component and improved vine multiplication systems are recommended to assure sustained adoption.

Quick screening of maize kernels for provitamin A content

Improving the micronutrient content of foods by bio-fortification is one of the strategies to alleviate micronutrient deficiencies. One of the target crops being bred for increased provitamin A content is maize. In order to estimate the success of these activities, we developed a quick screening method that allows distinction between low, medium and high levels of provitamin A carotenoids in maize by semi-quantitative analysis. Carotenoids in 13 lines of maize were extracted with acetone/hexane and carotenes and monohydroxy carotenoids were separated on a de-activated alumina column. The two fractions were quantified separately by absorption at 450 nm. Regression lines were constructed between the spectrophotometrically determined carotenoids in the fractions and the amount of retinol equivalents (RE) determined by HPLC in the full extract. Total carotene (μg/100 g)=7.62 RE+176; r = 0.97 , P < 0.01 ; SEE=10 RE/100 g. Total monohydroxy carotenoids (μg/100 g)=15.36 RE+374; r = 0.86 , P < 0.01 ; SEE=12 RE/100 g. The method described allows fast screening of maize kernels on levels of pro-vitamin A without the need of a full HPLC analysis of all samples, and hence reduces the cost of analyses.

Cortical, but not posterior subcapsular, cataract shows significant familial aggregation in an older population after adjustment for possible shared environmental factors

To quantify the risk for age-related cortical cataract and posterior subcapsular cataract (PSC) associated with having an affected sibling after adjusting for known environmental and personal risk factors. Sibling cohort study. Participants in the ongoing Salisbury Eye Evaluation (SEE) study (n = 321; mean age, 78.1+/-4.2 years) and their locally resident siblings (n = 453; mean age, 72.6+/-7.4 years) were recruited at the time of Rounds 3 and 4 of the SEE study. INTERVENTION/TESTING METHODS: Retroillumination photographs of the lens were graded for the presence of cortical cataract and PSC with the Wilmer grading system. The residual correlation between siblings' cataract grades was estimated after adjustment for a number of factors (age; gender; race; lifetime exposure to ultraviolet-B light; cigarette, alcohol, estrogen, and steroid use; serum antioxidants; history of diabetes; blood pressure; and body mass index) suspected to be associated with the presence of cataract. The average sibship size was 2.7 per family. Multivariate analysis revealed the magnitude of heritability (h(2)) for cortical cataract to be 24% (95% CI, 6%-42%), whereas that for PSC was not statistically significant (h(2) 4%; 95% CI, 0%-11%) after adjustment for the covariates. The model revealed that increasing age, female gender, a history of diabetes, and black race increased the odds of cortical cataract, whereas higher levels of provitamin A were protective. A history of diabetes and steroid use increased the odds for PSC. This study is consistent with a significant genetic effect for age-related cortical cataract but not PSC.

Multivariate analysis of the sensory changes in the dehydrated cowpea leaves

Processing of foods, especially dehydration is known to result in alteration of sensory and nutritional qualities. Cowpea leaves is one of the common leafy vegetables consumed in Kenya that contain high levels of pro-vitamin A compounds and has good carotene retention during processing. A tasting panel was trained using a quantitative descriptive analysis (QDA) test that was developed and used to characterize the sensory properties of dehydrated cowpea leaves. The panel identified sensory attributes in dehydrated cowpea leaves that were important in discriminating the dehydrated samples from the fresh material. Principal component analysis (PCA) was used to analyze the QDA scores. The first principal component (PC1) which accounted for 85% of the variance was an index of the interrelationship among variables in differentiating the samples while PC2, which accounted for the remaining variance measured the attributes influence in discriminating samples. The results of the sensory attributes mean scores showed that aroma, texture and appearance had high influence in discriminating between the fresh, the sun-dried and the solar-dried samples. The solar dried products were close to the fresh material, which was characterized, as soft and tender with an appealing dark green color, than the sun dried product. The sun dried products differed from the other products more on appearance.

Combining Ability of Maize Inbreds for Carotenoids and Tocopherols

Carotenoids (provitamin A) and tocopherols (vitamin E) are lipid soluble antioxidants associated with decreased risk of several degenerative diseases. Both vitamins occur naturally in corn (Zea mays L.) grain. Corn grain is a major component in diets of humans and animals, and may have added value with increased levels of carotenoids and tocopherols. To estimate genetic variation among a group of inbreds and their breeding potential, we estimated combining abilities of four carotenoids and two tocopherols in a diallel of 45 corn hybrids. Ten inbreds were chosen that varied in endosperm color (yellow to orange), tocopherol levels and oil content. Plants were grown for two years (1998, 1999) at Urbana, IL, in an RCB design with three replications. High pressure liquid chromatography was used to assay for four carotenoids (lutein, zeaxanthin, β‐cryptoxanthin, and β‐carotene) and two tocopherols (α‐tocopherol and γ‐tocopherol). Good agreement between year means for the six compounds was observed indicating minor environmental effects. Diallel analyses indicated, between 72 to 87% of the total sums of squares for hybrids for the six compounds was attributable to GCA effects. Significant SCA effects were found for several crosses. Estimates of GCA effects indicated A619 had high values for lutein, β‐cryptoxanthin, and total carotenoids. Inbred R84 was a poor genotype for xanthophyll pigments but a significant contributor for β‐carotene and γ‐tocopherol, and total tocopherol. These genetic stocks indicate corn hybrids can be developed with higher levels of provitamin A and vitamin E.

Combining Ability of Maize Inbreds for Carotenoids and Tocopherols

Carotenoids (provitamin A) and tocopherols (vitamin E) are lipid soluble antioxidants associated with decreased risk of several degenerative diseases. Both vitamins occur naturally in corn (Zea mays L.) grain. Corn grain is a major component in diets of humans and animals, and may have added value with increased levels of carotenoids and tocopherols. To estimate genetic variation among a group of inbreds and their breeding potential, we estimated combining abilities of four carotenoids and two tocopherols in a diallel of 45 corn hybrids. Ten inbreds were chosen that varied in endosperm color (yellow to orange), tocopherol levels and oil content. Plants were grown for two years (1998, 1999) at Urbana, IL, in an RCB design with three replications. High pressure liquid chromatography was used to assay for four carotenoids (lutein, zeaxanthin, β-cryptoxanthin, and β-carotene) and two tocopherols (α-tocopherol and γ-tocopherol). Good agreement between year means for the six compounds was observed indicating minor environmental effects. Diallel analyses indicated, between 72 to 87% of the total sums of squares for hybrids for the six compounds was attributable to GCA effects. Significant SCA effects were found for several crosses. Estimates of GCA effects indicated A619 had high values for lutein, β-cryptoxanthin, and total carotenoids. Inbred R84 was a poor genotype for xanthophyll pigments but a significant contributor for β-carotene and γ-tocopherol, and total tocopherol. These genetic stocks indicate corn hybrids can be developed with higher levels of provitamin A and vitamin E.

Factors influencing the conversion of carotenoids to retinol: bioavailability to bioconversion to bioefficacy.

Vitamin A (retinol) is a necessary nutrient for vision, reproduction, growth, and immune function. Pro-vitamin A carotenoids are an important source, especially in developing countries. While preformed vitamin A is readily available from foods, carotenoids are much more difficult to assimilate. A number of factors have been identified that either enhance or hinder the bioavailability of carotenoids. These have been presented in the literature and given the mnemonic SLAMENGHI by some researchers. The following factors are summarized: Species of carotenoid, molecular Linkage, Amount in the meal, Matrix Properties, Effectors, Nutrient status, Genetics, Host specificity, and Interactions between factors. Identifying which of these are key issues for the general public, and promoting the increased consumption of fruits and vegetables with moderate and high levels of pro-vitamin A carotenoids, are important to vitamin A status and overall good health.