Tuber Flesh Colour Research Articles

Genetic Characterization of Water Yam (Dioscorea alata L.) and Production Constraints of Yam in Pwani Region and Unguja Island, Tanzania

Yam (Dioscorea spp.) is a tuber crop cultivated in over 30% of all regions in Tanzania, contributing to the carbohydrate needs of many households. The morphological and genetic diversity of water yam (D. alata L.) local cultivars collected from Pwani region and Unguja Island were evaluated using 26 agro-morphological characters and 10 Short Sequence Repeat (SSR) markers. Cluster analysis using morphological characters classified nine water yam local cultivars into two main clusters with three subclusters. Tuber flesh and leaf colour were the main descriptors for clustering. The genetic diversity of 128 water yam genotypes using ten polymorphic SSR markers generated a total of 40 alleles that ranged from 2 to 7 per SSR marker. The mean polymorphic information content (PIC) ranged from 0.3 to 0.9, with a mean of 0.56. Cluster analysis separated 128 yam genotypes into two main clusters with five subclusters. The findings revealed relatively high genetic diversity of D. alata in the study areas. A structured questionnaire revealed drought (29.3%) and lack of planting materials (23.3%) as the major constraints to yam production in the study areas. Information reported in this study is useful in improving, reviving and promoting yam through breeding and conservation programs.

Morphological Characteristics and Similarity Analysis of Cassava (Manihot esculenta Crantz) in Wonosobo, Temanggung, and Magelang Regencies

The diversity of cassava in Wonosobo, Temanggung and Magelang districts must be investigated. The objective of the study was to analyze the diversity of cassava based on morphological characteristics. The cassava of each accession was planted in Bandongan, Magelang Regency. Morphological characters observed after six months of planting included apical leaf color, apical leaf hair, leaf lobe shape, petiole color, leaf color, number of leaf lobes, leaf length, leaf width, petiole length, vein color, petiole orientation, color epidermis of stem, color of outer appearance of stem, distance between nodes, stem growth, color of mature branch tip, branching type, tuber, tuber shape, outer tuber skin color, tuber flesh color, and tuber inner skin color. Analysis of the morphological characteristics of cassava is presented in the form of a dendrogram using the MVSP (Multi Variate Statistical Package) version 3.22. The results of the study obtained 39 accessions of cassava which showed different morphological characteristics. The lowest morphological similarity (0.735) was found in Group I only consisted of 2 acquisitions that did not have tubers, namely Red Vegetables and Green Vegetables and Group II ( Groups III and IV) have a similarity of 0.92. The highest similarity was in groups IIIa and IIIb and Groups IVa and IVb have a similarity coefficient value of 0.95. The morphological diversity of 39 accessions is a source of cassava germplasm: 37 accessions are harvested for tubers and 2 accessions areharvested explicitly for leaves as vegetables. This research was useful for the development of cassava-based food industry bioproducts.

Molecular and phenotypic profiling of white Guinea yam (Dioscorea rotundata) breeding lines

Phenotypic and genotypic profiling helps identify genotypes with suitable and complementary traits for genetic improvement in crops. A total of 32 traits were assessed in 36 genotypes of white Guinea yam established in a 6 × 6 triple lattice design. The objective was to evaluate an array of plant traits that define the genetic merits of breeding lines for yam improvement. Different analytical tools were used to identify and prioritize relevant traits defining the genetic merits of breeding lines in the yam improvement program. Out of the 32 traits measured, the linear combination of 14 traits that minimize within-group variance and maximize between-group variance for discriminating the genetic values of yam breeding lines were identified. When best linear unbiased prediction with genomic relationship matrix (GBLUP) was used, the accuracies of genomic breeding values were higher (r=0.87 to 0.97) for the seven traits (dry matter content, intensity of flesh oxidization of shredded tuber, pasting temperature, pasting time, tuber flesh colour, yam mosaic virus and fresh tuber yield) with high broad-sense heritability values (H2m>0.6). While, for the remaining seven traits with low (H2m<0.3) to medium (H2m=0.3 to 0.54) broad-sense heritability values, the accuracies of genomic estimated breeding values (GEBV) were low (r<0.4) to medium (r=0.4-0.8). The genotype–trait (GT) biplot display revealed superior clones with desirable genetic values for the key traits. These results are relevant for parental selection aimed at improving key agronomic traits in white Guinea yam.

IDENTIFICATION OF MORPHOLOGY AND RELATIONSHIPS OF PORANG PLANTS (AMORPHOPHALLUS MUELLERI BLUME) IN KUMPEH ULU DISTRICT, MUARO JAMBI REGENCY

Porang (Amorphophallus muelleri Blume) is a group of tuber plants that are useful as food and medicine so that they have bright prospects for development. In Jambi Province, especially in Muaro Jambi Regency, porang plants are found growing wild among duku trees. This study aims to determine the morphological character of porang plants and to determine the level of diversity and kinship of porang plants found in Kumpeh Ulu District, Muaro Jambi Regency. The research was carried out from August to September 2021, in 18 villages located in the Kumpeh Ulu District. The research was conducted using a non-experimental descriptive method with proportionate stratified random sampling, and the sample was measured quantitatively and qualitatively. The morphological identification of porang plants from 18 villages in Kumpeh Ulu District showed similarities in bulbil shape, bulbil surface colour, bulbil surface texture, bulbil flesh colour, leaf shape and petiole colour. However, there were differences in leaf colour, tuber flesh colour, tuber surface texture and tuber shape.

Genome-wide association studies reveal novel loci controlling tuber flesh color and oxidative browning in Dioscorea alata.

Consumers' preferences for food crops are guided by quality attributes. This study aimed at deciphering the genetic basis of quality traits, especially tuber flesh color (FC) and oxidative browning (OB) in Dioscorea alata, based on the genome-wide association studies (GWAS) approach. The D. alata panel was planted at two locations in Guadeloupe. At harvest, the FC was scored visually as white, cream, or purple on longitudinally sliced mature tubers. The OB was scored visually as the presence or absence of browning after 15 min of exposure of the sliced samples to ambient air. Phenotypic characterization for FC and OB of a diverse panel of D. alata genotypes highlighted significant variation within the panel and across two locations. The genotypes within the panel displayed a weak structure and could be classified into three subpopulations. GWAS identified 14 and 4 significant associations for tuber FC and OB, respectively, with phenotypic variance, explained values ranging from 7.18% to 18.04%. Allele segregation analysis at the significantly associated loci highlighted the favorable alleles for the desired traits, i.e., white FC and no OB. A total of 24 putative candidate genes were identified around the significant signals. A comparative analysis with previously reported quantitative trait loci indicated that numerous genomic regions control these traits in D. alata. Our study provides important insights into the genetic control of tuber FC and OB in D. alata. The major and stable loci can be further utilized to improve selection in breeding programs for developing new cultivars with enhanced tuber quality. © 2023 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

The Relationship of Sweet Potato Germplasm Based on Morphological Characters

Information about the morphological and genetic characteristics of sweet potato (Ipomoea batatas) is important in the variety development program. This experiment aimed to determine the diversity and genetic relationship of sweet potato accessions from NTT based on morphological character data. The research was carried out at Kendalpayak Research Station, Malang, East Java from April - September 2019. The materials used were seventy-one sweet potato germplasm from the ILETRI collection (collected from NTT). Each accession was planted on a 1 m × 5 m plot size, with a spacing of 100 × 20 cm (single row). Fertilization was carried out using a dose of “100 kg urea + 100 kg SP36 + 200 kg KCl ha-1”. The observed characters were the vines length, growth type, internode length, leaf length, leaf width, leaf size, leaf bone color, leaf shape, leaf characteristics, lobes number, lobe shape, mature leaf color, shoot color, pigmentation of petiole, young stems pigmentation (dominant and secondary color), young leaves feathers, tuber skin color, tuber flesh color, weight of canopy, number of tubers perplot, weight of tubers perplot, number and weight of tubers perplot. Cluster analysis was carried out using the Minitab 17 program. There was morphological diversity in seventy-one accessions of sweet potato germplasm from NTT. Principal component analysis resulted in seven main components with the proportion of diversity 76.3%. cluster analysis, seventy-one accessions of sweet potato germplasm were divided into fifteen accession groups on the basis of 80% degree. Characteristics of shoot color, mature leaf color, leaf size, petiole pigmentation, and leaf bone color contributed greatly to the total diversity.

IDENTIFIKASI JENIS-JENIS UBI KAYU (Manihot esculenta) DI KECAMATAN TOMIA TIMUR KABUPATEN WAKATOBI

This study aims to identify and describe the types of cassava in Tomia Timur District, Wakatobi Regency. The research was carried out in Tomia Timur Subdistrict, Wakatobi Regency, in December 2021 January 2022. This research is a survey research that is analyzed descriptively by statistics that is describing, describing, and describing the object being studied. The variables observed were stem color, branched and unbranched, stem height, stem diameter, distance between stem segments, leaf color, petiole color, leaf lobe length, tuber shape, wet tuber weight per tree, outer skin color of tuber, color inner skin of tubers, tuber flesh color, benefits of cassava plants, cultivation techniques, and soil conditions. The results showed that there were 10 types of cassava in Tomia Timur District, Wakatobi Regency, namely Kalambe cassava, Kalambe Fanse cassava, Ndoke cassava, Bogoro cassava, Bogoro Mohoro cassava, Makuri cassava, Andapatua cassava, Salbia cassava, cassava English wood, and Andabula cassava.

Phenolic Acid Content and Antioxidant Properties of Edible Potato (Solanum tuberosum L.) with Various Tuber Flesh Colours.

The aim of the paper was to evaluate the phenolic acid content and antioxidant properties in potato cultivars with coloured flesh and bright flesh. The study material included eight cultivars of edible potato grown in a temperate climate in Poland. Five cultivars were potato tubers with coloured flesh: "Rote Emma", "Blue Salad", "Vitelotte", "Red Emmalie", and "Blue Congo"; and three were potato tubers with bright flesh: "Bella Rosa", "Lord", and "Tajfun". In all potato samples under study, four phenolic acids were identified: chlorogenic acid, gallic acid, p-coumaric acid, and caffeic acid. The predominant acid was chlorogenic acid, the levels of which ranged from 62.95 mg·100 g-1 FM to 126.77 mg·100 g-1 FM. The total concentration of the identified phenolic acids was diverse and depended on the genotype of the cultivar and the tuber flesh colour, with coloured-fleshed potatoes having higher phenolic acid contents in comparison to bright-fleshed potato cultivars. The average concentration of phenolic acids in the samples was 89.19 mg∙100 g-1 FM, and the average concentrations of the individual phenolic acids identified were as follows: chlorogenic acid (86.19 mg∙100 g-1 FM), gallic acid (1.18 mg∙100 g-1 FM), p-coumaric acid (0.64 mg∙100 g-1 FM), and caffeic acid (1.18 mg∙100 g-1 FM). In addition, three groups of anthocyanins were identified: pelargonidin-3,5-di-O-glucoside, peonidin-3,5-di-O-glucoside, and petunidin-3,5-di-O-glucoside. Anthocyanins were not found in the "Lord" or "Tajfun" varieties characterised by white tuber flesh. The predominant pigment was petunidin-3,5-di-O-glucoside, with an average content of 23.15 mg∙100 g-1 FM, and the highest value was observed in the "Vitelotte" variety (51.27 mg∙100 g-1 FM). The antioxidant activity of the flesh of the potatoes under study was diverse depending on flesh colour. The FRAP (Ferric Reducing Antioxidant Power) assay indicated higher antioxidant activity of coloured-fleshed potato cultivars. The highest concentration was identified in the "Vitelotte" cultivar flesh and was 114% higher than in the "Lord" cultivar. Similar dependencies were found in the case of the DPPH (2,2-diphenyl-1-picrylhydrazyl) assay; however, in this case, the "Vitelotte" cultivar flesh demonstrated nearly 6.4 times higher antioxidant activity than the "Lord" cultivar. Summarizing our own research, we can conclude that potato varieties with coloured flesh are characterised by a higher content of biologically active substances, including phenolic acids, and antioxidant properties compared to potato tubers with bright flesh.

Tuber Flesh Colour, Enzymatic Discolouration, Dormancy and Late Blight Resistance of 29 Tuber-Bearing Accessions of Solanum spp.

Potato relatives adapted to many different habitats are promising sources of desirable agricultural traits for potato breeding. Wild potato relatives are preserved in different collections around the world, and their detailed description is key to their exploitation in practice. We described 29 seed accessions of 26 Solanum species originating from the VIR potato collection (Institute of Plant Industry – VIR, Saint Petersburg, Russia) and preserved in Poland. The description included resistance to Phytophthora infestans, tuber flesh colour, enzymatic discolouration and tuber dormancy (sprouting). Up to 13 genotypes were evaluated per accession. The evaluation was repeated in three years for each trait. Two P. infestans isolates were used in late blight resistance tests. Amongst all the tested accessions, five were resistant to both P. infestans isolates, including genotype 13_A2. Twenty-one accessions had white tuber flesh, and 13 accessions showed a lack of or weak enzymatic discolouration. Additionally, we found accessions that were whiter than the standard white-fleshed Polish potato cultivar Irys. In our material, we observed a large variation in the length of the sprouts after storage, indicating differences in the dormancy period length. Four accessions showed a lack of sprouting after 28 weeks of storage at 5–6 °C. The tested material is preserved as in vitro plants in the National Centre for Plant Genetic Resources: Polish Genebank (IHAR-PIB, Radzików, Poland), which will facilitate their use in breeding programs.

EARLY GENERATION SELECTION IN DIFFERENT LOCATIONS IN POTATO BREEDING PROGRAM

In variety development studies through hybridization, it is necessary to make hybridization with the parents suitable for the purpose, to obtain the tubers in seedling generation from the hybrid seeds obtained, and then to proceed to the clonal selection process. In this study, it was aimed to select clones suitable for tuber shape, earliness, table and industrial use in different locations in the first clonal generation stage from the variation created by hybridization between some commercially registered potato varieties, local potato varieties and some clones with superior characteristics. The study was conducted with 3316 clones in Artova and Kazova districts in Tokat province in Turkey. In this year, which was the first clonal selection stage, besides phenotypic characteristics such as breeder's preference, maturity group, tuber defects, skin roughness, skin and tuber flesh color, characteristics such as the number of tubers per hill, tuber yield per hill, average tuber weight, depth of lateral (eye) and apical buds were examined and data on clones belonging to each hybrid family were obtained. Thus, it was decided to proceed to the next selection stage with 918 clones selected due to their compliance with the criteria determined in the first clonal generation stage.

Review on Breeding Potato (Solanum tuberosum L.) Genotypes for Processing Quality Traits

Potato (Solanum tuberosum L .) is a rich source of protein, energy, vitamins and minerals. Potato is in the family Solanaceae with chromosome numbers vary from diploid (2n = 2x = 24) to hexaploid (2n = 6x = 72). In Ethiopia, the major objectives of potato breeding was targeted at selection of clones for high yield, wide adaptability and resistance for late blight, hence processing qualitative traits were not the main targets in potato breeding program still near future. Therefore, the objective of this review article is to discuss breeding potato genotypes for desirable processing quality traits. Tuber shape is a syndrome of many characters that considers the length/width ratio for describing the overall shape; it varies from compressed/round to long. The yellow pigment in potato tuber flesh is caused by various carotenoids that may protect against cancer, cardiovascular disease, and macular eye degeneration. The genetics of morphological traits are Tuber flesh color, skin color and tuber shape and eye depth. To minimize waste, varieties with long tubers are preferred for French fries and varieties with round tubers are ideal for crisps. Eye depth is an important trait of tuber quality because deep eyes affect the appearance of tubers and add to the cost of peeling in processing factories. Tuber quality traits in potato are specific gravity, dry mater content, starch content, Glycolalkaloids and tuber size uniformity. Specific gravity of potatoes is commonly used by the potato processing industry as a tool for quick estimation of dry matter content, as both are highly correlated. Tuber dry matter content and specific gravity significantly influenced by the interaction effect of growing environment and cultivars. Processing quality usually has relatively low to moderately high heritability, depending on the progenitor materials. Therefore, multiple location tests over several years are often required in order to determine whether a clone has indeed a high processing quality. Keywords: Potato breeding; Tuber quality; Dry mater content; Specific gravity; Processing. DOI: 10.7176/JNSR/12-13-03 Publication date: July 31 st 2021

Farmers’ perceptions on varietal diversity, trait preferences and diversity management of bush yam (Dioscorea praehensilis Benth.) in Ghana

Bush yam (Dioscorea praehensilis Benth.) is an important food and cash crop species in some West and Central African countries. Unfortunately, several socioeconomic, cultural, nutritional, and agronomic constraints hinder its cultivation, and thus lead to its underutilization and gradual disappearance. To effectively promote its cultivation and utilization, knowledge of its diversity, distribution, management, and farmers’ varietal preferences is necessary. This study, therefore, used a participatory rural appraisal survey to assess such information in 23 villages from three regions of Ghana. A total of 42 D. praehensilis morphotypes were recorded and grouped in seven classes based on the tuber flesh colour. The Shannon diversity index (H’ = 1.88), equitability (0.65), and Margalef species richness (2.53) revealed the presence of moderate diversity and distribution in the surveyed regions. Farmers’ variety trait preferences included mainly the early maturity (21.1%), smooth tuber texture (16.5%), stability in tuber flesh colour (7.86%), good storage aptitude (7.6%), and high tuber productivity (12.8%). In contrast, D. praehensilis production and utilization rates have declined mainly due to poor culinary quality (39.9%) and poor agronomic traits (20.7%) of most morphotypes. Survey results showed that D. praehensilis is largely an in-situ conserved species in Ghana (60.0%). This study provided an insight on D. praehensilis diversity, distribution and farmers’ varietal preferences in Ghana which will guide its genetic resource conservation and plant breeding interventions.

Extracting knowledge networks from plant scientific literature: potato tuber flesh color as an exemplary trait

BackgroundScientific literature carries a wealth of information crucial for research, but only a fraction of it is present as structured information in databases and therefore can be analyzed using traditional data analysis tools. Natural language processing (NLP) is often and successfully employed to support humans by distilling relevant information from large corpora of free text and structuring it in a way that lends itself to further computational analyses. For this pilot, we developed a pipeline that uses NLP on biological literature to produce knowledge networks. We focused on the flesh color of potato, a well-studied trait with known associations, and we investigated whether these knowledge networks can assist us in formulating new hypotheses on the underlying biological processes.ResultsWe trained an NLP model based on a manually annotated corpus of 34 full-text potato articles, to recognize relevant biological entities and relationships between them in text (genes, proteins, metabolites and traits). This model detected the number of biological entities with a precision of 97.65% and a recall of 88.91% on the training set. We conducted a time series analysis on 4023 PubMed abstract of plant genetics-based articles which focus on 4 major Solanaceous crops (tomato, potato, eggplant and capsicum), to determine that the networks contained both previously known and contemporaneously unknown leads to subsequently discovered biological phenomena relating to flesh color. A novel time-based analysis of these networks indicates a connection between our trait and a candidate gene (zeaxanthin epoxidase) already two years prior to explicit statements of that connection in the literature.ConclusionsOur time-based analysis indicates that network-assisted hypothesis generation shows promise for knowledge discovery, data integration and hypothesis generation in scientific research.

Potato biodiversity: A linear discriminant analysis on the nutritional and physicochemical composition of fifty genotypes

Fifty potato genotypes from twenty-four different countries of origin, four different flesh colours (yellow, purple, red and marble) and different cultivation types (Andean accessions, landraces, breeder lines and cultivated varieties) were studied in terms of their nutritional and physicochemical characteristics. In general, cultivated varieties and breeder lines showed the highest similarity (slight differences only in some particular fatty acids distributions: C10:0, C12:0 and C22:0) concerning the physicochemical parameters assayed in this work, independently of the geographical origin or tuber flesh colour of these genotypes. Nonetheless, some of the studied landraces and Andean accessions proved to be similar enough to be considered as genotypes with good potential for commercial cultivation. These results can contribute to the supply of new potato genotypes into sustainable farming systems, supporting the protection of potato biodiversity, particularly Andean accessions, landraces and coloured genotypes (red or purple flesh) which are not widely cultivated so far.

Genome-wide Analysis of MYB Gene Family in Potato Provides Insights into Tissue-specific Regulation of Anthocyanin Biosynthesis

The MYB transcription factor is one of the largest gene families in plants, playing an important role in regulating plant growth, development, response to stress, senescence, and especially the anthocyanin biosynthesis. In this study, A total of 217 MYB genes, including 90 1R-MYBs, 124 R2R3-MYBs, and 3 R1R2R3-MYBs have been identified from the potato genome. The 1R-MYB and R2R3-MYB family members could be divided into 20 and 35 subgroups respectively. Analysis of gene structure and protein motifs revealed that members within the same subgroup presented similar exon/intron and motif organization, further supporting the results of phylogenetic analysis. Potato is an ideal plant to reveal the tissue-specific anthocyanins biosynthesis regulated by MYB, as the anthocyanins could be accumulated in different tissues, showing colorful phenotypes. Five pairs of colored and colorless tissues, stigma, petal, stem, leaf, and tuber flesh, were applied to the transcriptomic analysis. A total of 70 MYB genes were found to be differentially expressed between colored and colorless tissues, and these differentially expressed genes were suspected to regulate the biosynthesis of anthocyanin of different tissues. Co-expression analysis identified numerous potential interactive regulators of anthocyanins biosynthesis, involving 39 MYBs, 24 bHLHs, 2 WD-repeats, and 29 biosynthesis genes. Genome-wide association study (GWAS) of tuber flesh color revealed a major signal at the end of Chromosome 10, which was co-localized with reported I gene (StMYB88), controlling tuber peel color. Analyses of DEGs (Differentially Expression Genes) revealed that both StMYB88 and StMYB89 were closely related to regulating anthocyanin biosynthesis of tuber flesh. This work offers a comprehensive overview of the MYB family in potato and will lay a foundation for the functional validation of these genes in the tissue-specific regulation of anthocyanin biosynthesis.

Identification of Ethiopian Yam (<i>Dioscorea</i> spp.) Collections and Their Phenotypic Diversity Study

Yam plant has a major role in Ethiopia particularly in densely populated areas of south, southwestern, and western parts of the country. It grows in a wide range of soils with an altitude range of 1140 to 2200 masl. This study was done to identify yam species collected from major producing areas of the country. The total of sixty yam accessions from ten different geographic origins of South and Oromiya region of Ethiopia were used. The collected samples were planted in complete randomized block design at two research sites of South Agricultural Research Institute. Forty-five qualitative morphological characterizations were used to characterize and identify Dioscorea species. Among these qualitative characters observed in the study presence and absence of spines on stems and roots, number of male and female inflorescence, stem length, twining direction, and flesh color were the major traits considered for species identification. The organoleptic properties evaluation was carried out using fifteen selected local farmers. Statistical analysis was done using Numerical Taxonomy and Multivariate Analysis System Version 2.02 NTSYpc software program and the data reduction function of SPSS for windows. Based on this study, sixty yam germplams of ten major growing areas of the country were identified into six Dioscorea species. These identified Dioscorea species were again subjected to qualitative morphological characterization and 33 morphological traits revealed variability. This implies presence of high diversity in yam (Dioscorea species) of Ethiopia. Most of the morphological variations among the yam genotypes were contributed by young petiole color, tendency of tuber to branch, and tuber flesh color. Hence, these morphological traits could be taken as useful traits for identification of yam cultivars.

Morphological characteristics and yields of several sweet potato (Ipomoea batatas L.) tubers

This study aims to evaluate certain tubers of new sweet potato clones for their morphological characters of and yield under low input conditions in the middle highland. This study was conducted at Saree, Aceh Besar, the Province of Aceh (485 m ASL) from February to July 2015. The study used a Completely Randomized Block Design of non-factorial with 12 sweet potato clones consisting of nine clones passed by CIP-SEA Bogor, Indonesia (CIP-LSQ, CIP-1945, CIP-MAN, CIP-513, CIP-BDG, CIP-WHI-5, CIP-W86P, CIP-B9, and CIP-204), one national variety (Antin-1), and two local clones (Orange Saree and Purple Saree). The results showed that there were differences in the characters of 12 sweet potato clones in terms of their tuber shapes, skins and flesh colors. Sweet potato tuber shape being studied consisted of an oval, round and long. Tuber flesh color generally was white, cream, yellow, orange and purple. Meanwhile, CIP-1945, CIP-W86P, Local Orange Saree clones, and Antin-1 variety have orange tuber flesh. CIP-WHI5 clone has the highest number of tubers, while CIP-204 clone has the largest diameter and length of tubers, and the highest in tuber yield.

Phenotypic and genetic characterisation revealed the existence of several biotypes within the Neorautanenia brachypus (Harms) C.A. wild accessions in South East Lowveld, Zimbabwe

BackgroundLocal communities in the South Eastern Lowveld of Zimbabwe have adopted the feeding of livestock with Neorautanenia brachypus (Harms) C.A. tuber to mitigate against climate change. Differences within Neorautanenia brachypus (Harms) tuber flesh colour and preferences by cattle have been observed, suggesting possible diversity within the N. brachypus plant community. This study aimed at distinguishing the N. brachypus wild plant species through phenotypic and genetic characterization using morphological descriptors and random amplified polymorphic (RAPD) markers respectively. Leaf samples were selected using judgmental sampling techniques from wards 11–15 in Sengwe (Chiredzi district) for leaf morphology and molecular characterization. RAPD-PCR analysis was done using 18-screened random decamer primers to confirm the diversity in the plant population. The similarity of the biotypes was evaluated using binary coding on the basis of the presence or absence of a morphological indicator as well as distinct DNA amplicon fragments. Primer 7.0.13 was used to estimate morphological and genetic similarities using the unweighted pair group method with arithmetic average (UPGMA). The cluster number was estimated using the Elbow method part of the R package.ResultsInitially, 14 biotype groups were identified from 96 accessions visually characterized basing of leaf characteristics. All the leaf biotypes displayed arcuate venation with differences observed for leaf shape, tip shape and leaf margins. The 14 biotypes clustered into six groups based on the binary data of the morphological characteristics. RAPD primers generated three hundred and sixty eight distinct amplicons with 77.5% being polymorphic from the 14 biotypes. The number of bands produced per primer ranged from four (OPF-02) to 44 (UBC-746). The PIC value ranged from 0.1327 to 0.1873 for the RAPD primers. Use of molecular markers collapsed the biotypes into five clusters. Both the leaf descriptors and RAPD markers showed the existence of genetic diversity within the wild accessions of N. brachypus.ConclusionsA combination of morphological and RAPD markers effectively refined the resolution of the genetic diversity within the N. brachypus wild accessions to nine biotypes. These findings have indicated to the existence of more than one biotype of N. brachypus with potentially different properties. The favorable biotypes can further be promoted through incorporation in pastures as alternative feed or complementary feed to livestock. As such the output of this study will serve as a guide for N. brachypus germplasm management and improvement.

The evaluation of selected qualitative parameters of sweet potato (Ipomoea batatas L.) in dependence on its cultivar

The sweet potato (Ipomoea batatas L.) is relatively known vegetable species, but it is grown only on small area in the Middle European region. Its cultivars are characterized by different colour of tuber flesh which can be white, beige, yellow, orange and purple. The aim of this study was to determine and compare selected qualitative parameters of tubers (total carotenoids, vitamin C and total soluble solids) among orange, white and purple sweet potato cultivars. The field experiments were established at Slovak University of Agriculture in Nitra in 2016 and 2017. Sweet potatoes were grown by hillock system with using of black non-woven textile for soil mulching. The tuber harvest was realised on the 6th October 2016 and 13rd September 2017. The highest content of total carotenoids was found in orange sweet potato cultivars (78.47 - 122.89 mg.kg-1 fresh weight) and its values were multiple-fold higher in comparison with purple (4.22 mg.kg-1 f. w.) and white (10.71 mg.kg-1 f. w.) cultivars. Orange cultivars were also richer source of vitamin C (246.31 - 325.99 mg.kg-1 f. w.) compared to white (179.66 mg.kg-1 f. w.) and purple (187.75 mg.kg-1 f. w.) cultivars of sweet potatoes. The total soluble solids, expressing mainly sugar content, was higher in purple (10.13 °BRIX) cultivar of sweet potatoes, followed by cultivars with orange (8.52 - 9.72 °BRIX) and white (5.57 °BRIX) tuber flesh. Obtained results showed the significant effect of cultivar, characterized by different tuber flesh colour, on the composition and contribution of sweet potatoes for human health.

Ascorbic acid content in potato tubers with coloured flesh as affected by genotype, environment and storage

The aim of the study was to evaluate the effect of genotype, tuber flesh colour, site conditions, year of cultivation and storage on the content of ascorbic acid (AAC) in the tubers of twelve potato cultivars with coloured flesh, compared with the yellow-flesh cv. Agria. AAC ranged from 88.6 to 282.0 mg/kg fresh matter (FM) and it was significantly influenced by genotype. A significantly highest AAC, on a three-year average, was achieved by cv. Rosemarie with red flesh (218.9 mg/kg FM; 1.10–1.84-fold more than the other cultivars). Position number two was achieved by the control cv. Agria (199.4 mg/kg FM). The purple or red colour of the cultivars with coloured flesh did not have a significant effect on the AAC. A significantly higher (1.17 times) AAC was determined at the Uhříněves site with warmer climate and drier weather before the harvest, compared with the other site in Valečov. The AAC was also significantly affected by year of cultivation. Cold storage (4°C, 180 days) resulted in a significant decrease in AAC, which varied in dependence on the genotype of the cultivars (34.6% to 65.1%). However, no link to the colour of the tuber flesh was found.