Genetic diversity of maize genotypes with variable resistance to Striga asiatica based on SSR markers

Genetic diversity among breeding populations is key in plant breeding programs. This study aimed to determine the extent of genetic diversity among 37 diverse maize genotypes using simple sequence repeat (SSR) markers. The maize genotypes were selected based on their variable resistance to Striga asiatica. Maize genotypes were fingerprinted using 18 polymorphic SSR markers. Marker and population diversity parameters were computed. A total of 191 alleles were detected and the number of effective alleles varied from 2 to 21 per locus with a mean of 11. The polymorphic information content (PIC) of the SSR markers varied from 0.59 to 0.96, with a mean of 0.80. Significant differences were observed among populations, individuals and within individuals. Within and among individual variances accounted for 85% and 13% of the total gene diversity. The genotypes were grouped into three main genetic clusters, which were not influenced by genotype origin. Mean genetic distance (0.43) and low geneflow (0.18) were observed among the populations. High mean genetic identity (0.65) was recorded, indicating potential genetic ‘bottleneck’ among the selected germplasm. The following open pollinated varieties; Border King, Colorado, CIMMYT’s ZM OPVs, Mac Pearl, Shesha, Nel Choice, Natal 8Lines, Nel Choice QPM, Hickory King, Kep Select, Obatanpa and the Striga resistant synthetic variety DSTRYSYN15 were selected from different clusters for breeding

Perception of climate change and coping strategies among smallholder irrigators in Zimbabwe

IntroductionAcross sub-Sahara Africa, governments and international aid agencies are making huge investments in smallholder irrigation schemes to enhance food security, climate resilience and economic transformation in rain-fed farming systems. Unfortunately, a majority of the smallholder irrigation schemes have performed dismally on these fronts. Climate change is a major exacerbating factor to existing challenges resulting in the poor performance of the schemes. Hence, it is crucial to understand smallholder irrigators' perceptions of climate change and current adaptation strategies to co-design appropriate and acceptable adaptation strategies to address water stress in the schemes. This area had received less significant research attention. This study aims to determine the perception of climate change and coping strategies in smallholder schemes.MethodsA mixed-method research strategy was used to collect data from 317 irrigation scheme farmers in three schemes (Exchange, Insukamini, and Ruchanyu) in Midlands Province. A binary logistic regression (BLR) method was used for data analysis.ResultsThe results suggest that scheme farmers have noticed changes in temperature and rainfall patterns. Results obtained from the model show that climate change perception was mainly influenced by age, gender, location, irrigation experience, and plot size. Farmers perceived that climatic change has resulted in decreased irrigation water availability, thus leading to poor yields. This study also shows that the main adaptation strategies to water stress include improving soil moisture conservation, construction of small-scale reservoirs, water charging and trade, setting clear water use priorities, and adoption of climate-resilient and short-season crop varieties. Perception of high temperatures, long dry periods, late rainfall, increase in the frequency of drought, shortening of cold season, and shortening of rain season influence adaptation strategies adopted by scheme farmers.ConclusionThis study offered useful data for policymakers and irrigation developers to develop appropriate policies and programs to improve the sustainability of schemes given current and projected water stress in Zimbabwe and sub-Sahara Africa in general

Breeding groundnut for rust resistance: A review

Sustainable groundnut production can be realised through development and adoption of high yielding cultivars possessing durable rust resistance. Integrating conventional breeding with genomic tools in identifying candidate rust resistance genes, and introgressing the genes into adapted elite germplasm, with the aid of molecular makers, could enhance breeding for rust resistance. This review highlights breeding approaches for groundnut rust resistance, with emphasis on integrating conventional breeding with marker-assisted selection. The life cycle, symptoms and epidemiology of the pathogen are also discussed to understand the host-pathogen interaction and guide groundnut rust resistance breeding

Socio-Economic Factors and Water Footprint in Smallholder Irrigation Schemes in Zimbabwe

Despite the need to grow crops with low water consumption needs, given the increasing water stress across many regions of the globe, assessments of crop water footprint (WFP) values have not received significant research attention in Zimbabwe. This unique study is the first of its kind to assess the mediation effect between socio-economic factors and crop WFP among smallholder irrigation schemes in Zimbabwe. A total of 317 farmers from three schemes in Midlands Province in Zimbabwe participated in this study. The following were the main findings in terms of the examined variables: (1) Schemes (p p p < 0.1) all decreased WFP_Maize; (2) education showed a reduction effect on the link between scheme maintenance and WFP_Maize; (3) secondary education has a higher impact on the magnitude of Maint on WFP_Maize; and (4) Maint and WFP_Maize have a positive correlation. This study illustrates the interaction of socio-economic factors on WFP and has substantial implications for simultaneously addressing the sustainable consumption of water for crop production, food security, and malnutrition in a changing climate

Socio-Economic Factors and Water Footprint in Smallholder Irrigation Schemes in Zimbabwe

Despite the need to grow crops with low water consumption needs, given the increasing water stress across many regions of the globe, assessments of crop water footprint (WFP) values have not received significant research attention in Zimbabwe. This unique study is the first of its kind to assess the mediation effect between socio-economic factors and crop WFP among smallholder irrigation schemes in Zimbabwe. A total of 317 farmers from three schemes in Midlands Province in Zimbabwe participated in this study. The following were the main findings in terms of the examined variables: (1) Schemes (p &lt; 0.01), Gender (p &lt; 0.05), and Maint (p &lt; 0.1) all decreased WFP_Maize; (2) education showed a reduction effect on the link between scheme maintenance and WFP_Maize; (3) secondary education has a higher impact on the magnitude of Maint on WFP_Maize; and (4) Maint and WFP_Maize have a positive correlation. This study illustrates the interaction of socio-economic factors on WFP and has substantial implications for simultaneously addressing the sustainable consumption of water for crop production, food security, and malnutrition in a changing climate

Variance components and heritability of traits related to root: shoot biomass allocation and drought tolerance in wheat

Enhanced root growth in plants is fundamental to improve soil water exploration and drought tolerance. Understanding of the variance components and heritability of root biomass allocation is key to design suitable breeding strategies and to enhance the response to selection. This study aimed to determine variance components and heritability of biomass allocation and related traits in 99 genotypes of wheat (Triticum aestivum L.) and one triticale (X. Triticosecale Wittmack) under drought-stressed and non-stressed conditions in the field and greenhouse using a 10x10 alpha lattice design. Days to heading (DTH), days to maturity (DTM), number of tillers (NPT), plant height (PH), spike length (SL),shoot and root biomass (SB, RB), root to shoot ratio (RS), thousand kernel weight (TKW) and yield (GY) were recorded. Analyses of variance, variance components, heritability and genetic correlations were computed. Significant (p70%) for RS observed in this population constitute several bottlenecks for improving yield and root mass simultaneously. However, indirect selection for DTH, PH, RB, and TKW, could help optimize RS and simultaneously improve drought tolerance and yield under drought-stressed conditions

Variance components and heritability of traits related to root : shoot biomass allocation and drought tolerance in wheat

Enhanced root growth in plants is fundamental to improve soil water exploration and drought tolerance. Understanding of the variance components and heritability of root biomass allocation is key to design suitable breeding strategies and to enhance the response to selection. This study aimed to determine variance components and heritability of biomass allocation and related traits in 99 genotypes of wheat (Triticum aestivum L.) and one triticale (X. Triticosecale Wittmack) under drought-stressed and non-stressed conditions in the field and greenhouse using a 10x10 alpha lattice design. Days to heading (DTH), days to maturity (DTM), number of tillers (NPT), plant height (PH), spike length (SL),shoot and root biomass (SB, RB), root to shoot ratio (RS), thousand kernel weight (TKW) and yield (GY) were recorded. Analyses of variance, variance components, heritability and genetic correlations were computed. Significant (p70%) for RS observed in this population constitute several bottlenecks for improving yield and root mass simultaneously. However, indirect selection for DTH, PH, RB, and TKW, could help optimize RS and simultaneously improve drought tolerance and yield under drought-stressed conditions

Unpacking the value of traditional African vegetables for food and nutrition security

Published online: 16 Mar 2021There is a need for agriculture in sub-Saharan Africa to diversify into more nutrient-rich crops to meet the subcontinent’snutritional needs in terms of micronutrients and reduce health risks related to high and rising rates of overweight/obesity.Many traditional African vegetables (TAVs) are nutrient-dense and have much potential to reduce malnutrition. These vegetablescan also provide sustainable incomes to rural, urban and peri-urban farming communities. In addition to their high economicvalues and health benefits, most TAVs are amenable to be grown under low input conditions and even organically. However,TAVs are under-researched and underutilized across the vegetable value chain. This paper provides a detailed account of thevalue of TAVs, focusing on their importance, research and development progress, and future needs. To exploit the potential ofTAVs, there is need for a more concerted research and development efforts including effective characterization of the nutritionand genetic profiles; enhancing adaptability and yield gains; and capacity development in value addition, postharvest handling,processing, marketing, and seed system development. Success in these areas depends on effective collaborations among nationaland international partners including the private seed sector, and government and non-governmental organizations working in theareas of agriculture, nutrition and health

Analysis of population structure and genetic diversity in a Southern African soybean collection based on single nucleotide polymorphism markers

Abstract Soybean is an emerging strategic crop for nutrition, food security, and livestock feed in Africa, but improvement of its productivity is hampered by low genetic diversity. There is need for broadening the tropical germplasm base through incorporation and introgression of temperate germplasm in Southern Africa breeding programs. Therefore, this study was conducted to determine the population structure and molecular diversity among 180 temperate and 30 tropical soybean accessions using single nucleotide polymorphism (SNP) markers. The results revealed very low levels of molecular diversity among the 210 lines with implications for the breeding strategy. Low fixation index (FST) value of 0.06 was observed, indicating low genetic differences among populations. This suggests high genetic exchange among different lines due to global germplasm sharing. Inference based on three tools, such as the Evanno method, silhouette plots and UPMGA phylogenetic tree showed the existence of three sub-populations. The UPMGA tree showed that the first sub-cluster is composed of three genotypes, the second cluster has two genotypes, while the rest of the genotypes constituted the third cluster. The third cluster revealed low variation among most genotypes. Negligible differences were observed among some of the lines, such as Tachiyukata and Yougestu, indicating sharing of common parental backgrounds. However large phenotypic differences were observed among the accessions suggesting that there is potential for their utilization in the breeding programs. Rapid phenotyping revealed grain yield potential ranging from one to five tons per hectare for the 200 non-genetically modified accessions. Findings from this study will inform the crossing strategy for the subtropical soybean breeding programs. Innovation strategies for improving genetic variability in the germplasm collection, such as investments in pre-breeding, increasing the geographic sources of introductions and exploitation of mutation breeding would be recommended to enhance genetic gain