Stability for descriptors of Solanum aethiopicum Shum group (family Solanaceae)

The study is about Shum one of the four recognized morphological groups of the African eggplantSolanum aethiopicum Shum group is a nutrient-rich and income-generating crop enterprise in various sub-Saharan Africa countries. Despite its importance, the development of its improved varieties has not been prioritized. Until now, no field-based descriptor development reference for the crop is available for testing candidate varieties for distinctiveness, uniformity and stability. The purpose of this study is to identify morphological variables that provide identity of S. aethiopicum Shum group accessions across environments. With ten accessions across three test locations, it was observed that the highly polymorphic morphological variables were majorly vegetative and a few reproductive ones. They include plant height at flowering, plant canopy breadth, plant branching, petiole color, petiole length, leaf blade length, leaf blade width, leaf lobbing, leaf tip angle, flowering time, style length, fruit position, fruit flesh density, fruits per inflorescence and fruit flavor. A static stability analysis, a common selection technique for obtaining consistence in performance of genotypes, showed that accessions varied in their interaction with environments for different descriptors. The most statically stable accessions were 184P and 163P while the least stables were 168P, 148, 141, and 137. The findings indicate the potential for identifying unique and stable varieties of S. aethiopicum Shum group for the processing of official release to farmers

Morphological distinctiveness between Solanum aethiopicum Shum group and its progenitor

This paper invested on the use of morphological markers offers an alternative in germplasm discrimination of research-neglected crop species.Use of morphological markers offers an alternative in germplasm discrimination of research-neglected crop species. A collection of 25 accessions including five wild progenitors was evaluated in screen house to identify the morphological difference between Solanum aethiopicum Shum and Solanum anguivi. An Unweighted Pair Group Method with Arithmetic mean hierarchical clustering revealed presence of moderate structure with a cophenetic correlation coefficient of 0.73. Five distinct clusters were produced; the progenitor accessions for the S. aethiopicum Shum were grouped in their own cluster. The Richness, Shannon-Weaver and Simpson indices were also different among qualitative variable categories. A ‘prcomp’ function based Principal component analysis (PCA) in R on quantitative variables indicated that days to germination and emergence, cotyledonous leaf length, cotyledonous leaf width, shoot biomass, plant height, petiole length, days to first flowering opening, plant width, plant branching, and number of leaves per plant are the major drivers of variability in the study accessions. Further, results from canonical discriminant analysis to discern between the S. aethiopicum and its progenitor accession groups showed that the days to germination and emergence provide the best separation; with the former emerging earlier than the latter. The mean values for flowering time, leaves per plant, number of branches per plant and plant height were more favorable for the Shum than its wild progenitor accessions. The study revealed that morphological markers are useful in distinguishing between the S. aethiopicum Shum and its progenitor accessions

Amplicon sequencing identified a putative pathogen, Macrophomina phaseolina, causing wilt in African eggplant (Solanum aethiopicum) grown in Tanzania and Uganda

African eggplant (Solanum aethiopicum L.) is one of the most common traditional vegetables in Tanzania and Uganda, but its productivity is severely affected by wilt diseases caused by a number of pathogens. Plant stem and root samples were collected in several fields from many neighboring diseased and healthy plants of the Gilo group in Tanzania and from the Shum group in Uganda to identify putative pathogens causing wilt on African eggplants. Through amplicon sequencing of sampled diseased and healthy tissues, we identified putative causal pathogens for the wilt symptoms. Wilting of S. aethiopicum in Uganda is most likely caused by the bacterial pathogen Ralstonia solanacearum whereas, in Tanzania, wilt is most likely caused by the fungal pathogen Macrophomina phaseolina, infecting roots. Infection of stems by Fusarium solani may also contribute to the wilt symptoms in Tanzania. Further artificial inoculation under controlled conditions confirmed that M. phaseolina can cause typical wilting symptoms on S. aethiopcium genotypes. The discovery of different putative causal agents of wilt in the crop demonstrates the need for site specific etiological analysis of wilt before developing and implementing effective control methods. Further research is needed to confirm the results and develop appropriate management measures against specific wilt pathogens

Draft genome sequence of Solanum aethiopicum provides insights into disease resistance, drought tolerance, and the evolution of the genome

The African eggplant (Solanum aethiopicum) is a nutritious traditional vegetable used in many African countries, including Uganda and Nigeria. It is thought to have been domesticated in Africa from its wild relative, Solanum anguivi. S.aethiopicum has been routinely used as a source of disease resistance genes for several Solanaceae crops, including Solanum melongena. A lack of genomic resources has meant that breeding of S. aethiopicum has lagged behind other vegetable crops. Results: We assembled a 1.02-Gb draft genome of S. aethiopicum, which contained predominantly repetitive sequences (78.9%). We annotated 37,681 gene models, including 34,906 protein-coding genes. Expansion of disease resistance genes was observed via 2 rounds of amplification of long terminal repeat retrotransposons, which may have occurred ∼1.25 and 3.5 million years ago, respectively. By resequencing 65 S. aethiopicum and S. anguivi genotypes, 18,614,838 single-nucleotide polymorphisms were identified, of which 34,171 were located within disease resistance genes. Analysis of domestication and demographic history revealed active selection for genes involved in drought tolerance in both “Gilo” and “Shum” groups. A pan-genome of S. aethiopicum was assembled, containing 51,351 protein-coding genes; 7,069 of these genes were missing from the reference genome. Conclusions: The genome sequence of S. aethiopicum enhances our understanding of its biotic and abiotic resistance. The single-nucleotide polymorphisms identified are immediately available for use by breeders. The information provided here will accelerate selection and breeding of the African eggplant, as well as other crops within the Solanaceae family

Accuracy of using leaf blade length and leaf blade width measurements to calculate the leaf area of Solanum aethiopicum Shum group

Leaf area is an important parameter when determining growth response under normal as well as stressed environments. No attempt had been made to come up with an affordable but accurate alternative of measuring leaf size in research neglected leafy vegetable crops. Other techniques such as use of leaf area meters are either destructive, expensive or both. A study was conducted to determine leaf area in like-shaped leaves of research neglected crop plants, taking case of S. aethiopicum Shum group (SAS) germplasm. Data was collected on 552 individual plants (including pure lines and hybrids) at eight weeks after planting where a third fully open leaf from top of each plant was considered. Leaf blade length (LBL) and leaf blade width (LBW) were linearly measured while leaf area (LA) was measured using a leaf area meter. This was followed by correlation and regression analysis of LA with LBL, LBW, and LBL + LBW. Correlation coefficients at p < 0.001 ranged between 0.84 and 0.92, 0.79 and 0.88, 0.86 and 0.95 for total germplasm, pure lines and hybrids, respectively. The coefficient of determination (R2) ranged between 0.72 and 0.92. The best prediction for LA was obtained with hybrid plants (LA = -165.82 + 5.38LBL + 16.17LBW) at R2 of 92%. The implication is that we can accurately and affordably predict LA from duo measurements of LBL and LBW in SAS as well as in other crops having similar leaf shapes

Diversity and distribution of African indigenous vegetable species in Uganda

This article is about the African indigenous vegetable species (AIVS) which provide a means of livelihood to many urban and peri-urban dwellers in UgandaAfrican indigenous vegetable species (AIVS) provide a means of livelihood to many urban and peri-urban dwellers in Uganda. It was thus deemed necessary to understand the existing diversity and distribution of the traditional African vegetable species as a basis for recommending conservation and utilization strategies against biodiversity loss. A field survey was conducted in the four major agro-ecological zones of Uganda to provide information on a recent abundance of the various AIVS. Results from the survey showed that the Solanaceae (43.4%), Amaranthaceae (15.5%) and Malvaceae (11.6%) were the most prevalent families out of seven different families encountered. Twenty-three (23) species, a number lower than that initially reported in literature and distributed unevenly in the different regions were identified. Majority of the species were the indigenous rather than introduced vegetable species. Firstly, the study is informative of the superior importance of Solanaceous species compared to other AIVS. Secondly, the survey results indicate that the AIVS are becoming increasingly more important in Uganda than their introduced counterparts since all the 43.4% that composed the Solanaceae majority were of indigenous type. Research efforts should be devoted towards improved variety development and germplasm conservation to prevent a possible biodiversity loss of the most important AIVS for increased household incomes and nutrient security among the resource-poor majority in Uganda and other sub-Saharan Africa countrie

Farmer preferred traits and genotype choices in Solanum aethiopicum L., Shum group

Research articleBackground: Solanum aethiopicum L. is a nutrient dense African indigenous vegetable. However, advancement of its improved varieties that can increase productivity, household income, and food security has not been prioritized. Further still, studies on some of the crops that have been worked have indicated that it is not a guarantee that the improved varieties will be accepted by the end users and therefore there is need to identify and profile what genotypes are of interest to farmers and their preferred traits through inclusive participatory evaluations. Methodology: Farmer participatory evaluations were conducted to profile farmers’ traits of interest and preferred genotypes. A total of 24 genotypes were established in three replications in 6 farms in 3 districts; Wakiso, Mukono, and Luwero as these are the major producing districts of the vegetable in Uganda. A total of 177 sex-disaggregated farmers were engaged in scoring the genotypes for pest, disease and drought tolerance, general appeal, leaf yield, leaf texture, and seed yield for best 10 genotypes under each variable. Results: Non-significant differences in trait (p > 0.05) and genotype preferences (p > 0.05) were obtained between men and women. The most desired farmer traits were seed and leaf yield, followed by pest and disease resistance. The overall preferred genotype in terms of disease and pest resistance, leaf yield, leaf texture, and seed yield were E12 followed by E11. Conclusion: Gender does not seem to influence farmer choices for the S. aethiopicum, Shum group, indicating an opportunity for single variety prototype advancement by breeders and dissemination by seed companies

Draft genome sequence of Solanum aethiopicum provides insights into disease resistance, drought tolerance, and the evolution of the genome

The African eggplant (Solanum aethiopicum) is a nutritious traditional vegetable used in many African countries, including Uganda and Nigeria. It is thought to have been domesticated in Africa from its wild relative, Solanum anguivi. S. aethiopicum has been routinely used as a source of disease resistance genes for several Solanaceae crops, including Solanum melongena. A lack of genomic resources has meant that breeding of S. aethiopicum has lagged behind other vegetable crops