Drought tolerance assessment of African cowpea accessions based on stomatal behaviour and cell membrane stability

2008 ◽  
Vol 146 (6) ◽  
pp. 689-694 ◽  
Author(s):  
M. T. LABUSCHAGNE ◽  
R. VERHOEVEN ◽  
M. NKOUANESSI
Keyword(s):  
Cell Membrane ◽  
Drought Tolerance ◽  
Membrane Stability ◽  
Sub Saharan Africa ◽  
Cell Membrane Stability ◽  
Drought Tolerant ◽  
Stomatal Behaviour ◽  
Wide Range ◽  
Drought Conditions ◽  
Sub Saharan

SUMMARYIn Sub-Saharan Africa, cowpea is well known for its ability to survive under conditions of water stress and it plays an important role in regions where drought is the factor most limiting to crop yield. In the present study, the drought tolerance levels of 20 African cowpea accessions from three countries were evaluated. A number of the genotypes showed drought tolerance, the merits of stomatal behaviour and cell membrane stability to assess drought tolerance was demonstrated. Damage to the cell membranes caused by drought was less in tolerant accessions. Stomatal opening was also better regulated; the opening was smaller under drought conditions, thus reducing transpiration (T). The wide range of drought tolerance observed among the accessions suggests the possibility of breeding drought-tolerant cultivars in cowpea. Drought-tolerant accessions included Bafoussam 1, M.66, Bafoussam 3, Hluhluwa, Bafoussam 4, Balen, Makueni, Bafoussam 2 and Okhalweni and these could be recommended to breeders as valuable material for drought tolerance improvement in cowpea.

Evaluation of polyethylene glycol test of measuring cell membrane stability as a drought tolerance test in wheat

1988 ◽  
Vol 110 (3) ◽  
pp. 429-433 ◽  
Author(s):  
G. S. Premachandra ◽  
T. Shimada
Keyword(s):  
Polyethylene Glycol ◽  
Cell Membrane ◽  
Drought Tolerance ◽  
Tolerance Test ◽  
Membrane Stability ◽  
Measuring Cell ◽  
Cell Membrane Stability ◽  
Drought Tolerant ◽  
Leaf Tissues ◽  
Wheat Lines

SummaryEffectiveness of the polyethylene glycol (PEG) test for measuring cell membrane stability (CMS) to select drought-tolerant genotypes in wheat was investigated. PEG test was compared with two other tests. Genetic variability of CMS was also investigated.Drought was induced artificially in pot-grown plants and in excised leaves, and percentage injury in leaf tissues by drought stress as measured by CMS was compared with that by PEG test. Percentage injury in leaf tissues of pot-grown plants was not correlated significantly with that by PEG test. However, percentage injury in excised leaves was well correlated with that in PEG test. The results suggest that the PEG test has merit in measuring drought tolerance in wheat. Frequency distribution of CMS in winter wheat lines was closely related to the characteristic pattern of quantitative inheritance and therefore CMS of wheat seems to be controlled by polygene action.

Evaluation of cowpea (Vigna unguiculata (L.) Walp.) germplasm lines for tolerance to drought

2012 ◽  
Vol 10 (3) ◽  
pp. 171-176 ◽  
Author(s):  
Christian A. Fatokun ◽  
Ousmane Boukar ◽  
Satoru Muranaka
Keyword(s):  
Drought Tolerance ◽  
Sub Saharan Africa ◽  
Grain Legume ◽  
International Institute ◽  
Breeding Lines ◽  
Germplasm Collections ◽  
Legume Crop ◽  
Drought Tolerant ◽  
Cowpea Varieties ◽  
Sub Saharan

Cowpea is an important grain legume crop in sub-Saharan Africa (SSA) where, on a worldwide basis, the bulk is produced and consumed. The dry savanna area of SSA is where cowpea is mostly grown under rain-fed conditions. The crop is therefore prone to drought which may occur early, mid and/or late in the cropping season. Compared with many other crops, cowpea is drought tolerant, even though drought is still a major constraint limiting its productivity in SSA. Increasing the level of drought tolerance in existing cowpea varieties grown by farmers would enable them to obtain more and stable yield from their cowpea fields. As a first step towards enhancing drought tolerance in existing cowpea varieties, 1288 lines were selected randomly from cowpea germplasm collections maintained at the International Institute of Tropical Agriculture, and evaluated for their drought tolerance at Ibadan. Drought was imposed by withdrawal of irrigation from 5 weeks after sowing. On average, drought reduced the number of days to flower by 12 d, and the mean grain yield per plant was also reduced by 67.28%. A few of the cowpea lines stayed green for up to 6 weeks after irrigation was stopped, even though some of these produced no pods when the study was terminated. Further evaluation in the screenhouse of 142 selected drought-tolerant lines helped to identify six lines that could be potential parents for developing breeding lines with enhanced drought tolerance.

scholarly journals Evaluation of advanced back cross lines for drought tolerance in rice (Oryza sativa L.)

2021 ◽  
Vol 17 (AAEBSSD) ◽  
pp. 245-251
Author(s):  
P. Venkata Ramana Rao ◽  
M. Girija Rani ◽  
K.S.N. Prasad ◽  
P. Naga Kumari ◽  
B.N.V.S.R. Ravi Kumar ◽  
...  
Keyword(s):  
Drought Tolerance ◽  
Oryza Sativa L ◽  
Seedling Survival ◽  
Direct Selection ◽  
Rice Varieties ◽  
Back Cross ◽  
Drought Tolerant ◽  
Wide Range ◽  
Drought Conditions ◽  
Secondary Traits

Drought is the largest abiotic constraint to rice production which cause significant yield loss depending upon the severity. Development of rice varieties with tolerance to drought and high use water use efficiency is the need of the hour. Despite the importance of drought as major abiotic constraint, the efforts to develop drought tolerant rice varieties are very low. Breeding efforts until recent past were focused on understanding and improvement of secondary traits that are putatively associated with drought tolerance. However, the genetic gain in yield by improvement of secondary traits is very low. Hence, improvement of yield per se under drought conditions will be better solution. Introgression of yield QTLs under drought in the genetic background of high yielding varieties will be helpful to overcome the problem to a certain extent. In the present study, 31 advanced back cross lines (BILs) derived from drought susceptible mega variety Samba Mahsuri (BT 5204) and a drought tolerant tolerant land race Azucena were evaluated under drought. Thirty one advanced back cross inbred lines (BC2F4) lines having yield QTLs viz., qDTY3.1 on chromosome 3 and qDTY2.1 on chromosome 2 were phenotyped under drought conditions. The results suggested that wide range of variation was observed for yield and its component traits in the BILs generated in the background of BPT 5204 and direct selection for yield under water stress coupled with marker assisted screening would help in development of drought tolerant version of mega varieties with improved yield under stress. Thermo tolerance studies indicated that high variability was observed for the BILs in terms of % seedling survival, % reduction in root and shoot growth under stress.

scholarly journals Drought Tolerance and Application of Marker-Assisted Selection in Sorghum

Biology ◽  
2021 ◽  
Vol 10 (12) ◽  
pp. 1249
Author(s):  
Andekelile Mwamahonje ◽  
John Saviour Yaw Eleblu ◽  
Kwadwo Ofori ◽  
Santosh Deshpande ◽  
Tileye Feyissa ◽  
...  
Keyword(s):  
Drought Tolerance ◽  
Qtl Mapping ◽  
Marker Assisted Selection ◽  
Sub Saharan Africa ◽  
Stay Green ◽  
Qtl Pyramiding ◽  
Drought Tolerant ◽  
Sub Saharan ◽  
Food And Nutritional Security ◽  
Marker Assisted Backcrossing

Sorghum is an important staple food crop in drought prone areas of Sub-Saharan Africa, which is characterized by erratic rainfall with poor distribution. Sorghum is a drought-tolerant crop by nature with reasonable yield compared to other cereal crops, but such abiotic stress adversely affects the productivity. Some sorghum varieties maintain green functional leaves under post-anthesis drought stress referred to as stay-green, which makes it an important crop for food and nutritional security. Notwithstanding, it is difficult to maintain consistency of tolerance over time due to climate change, which is caused by human activities. Drought in sorghum is addressed by several approaches, for instance, breeding drought-tolerant sorghum using conventional and molecular technologies. The challenge with conventional methods is that they depend on phenotyping stay-green, which is complex in sorghum, as it is constituted by multiple genes and environmental effects. Marker assisted selection, which involves the use of DNA molecular markers to map QTL associated with stay-green, has been useful to supplement stay-green improvement in sorghum. It involves QTL mapping associated with the stay-green trait for introgression into the senescent sorghum varieties through marker-assisted backcrossing by comparing with phenotypic field data. Therefore, this review discusses mechanisms of drought tolerance in sorghum focusing on physiological, morphological, and biochemical traits. In addition, the review discusses the application of marker-assisted selection techniques, including marker-assisted backcrossing, QTL mapping, and QTL pyramiding for addressing post-flowering drought in sorghum.

scholarly journals Addressing Pediatric HIV Pretreatment Drug Resistance and Virologic Failure in Sub-Saharan Africa: A Cost-Effectiveness Analysis of Diagnostic-Based Strategies in Children ≥3 Years Old

Diagnostics ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 567
Author(s):  
Mutita Siriruchatanon ◽  
Shan Liu ◽  
James G. Carlucci ◽  
Eva A. Enns ◽  
Horacio A. Duarte
Keyword(s):  
Drug Resistance ◽  
Cost Effectiveness ◽  
Virologic Failure ◽  
Pediatric Hiv ◽  
Sub Saharan Africa ◽  
Financial Investment ◽  
Switching Strategy ◽  
Wide Range ◽  
Sub Saharan ◽  
Living With Hiv

Improvement of antiretroviral therapy (ART) regimen switching practices and implementation of pretreatment drug resistance (PDR) testing are two potential approaches to improve health outcomes for children living with HIV. We developed a microsimulation model of disease progression and treatment focused on children with perinatally acquired HIV in sub-Saharan Africa who initiate ART at 3 years of age. We evaluated the cost-effectiveness of diagnostic-based strategies (improved switching and PDR testing), over a 10-year time horizon, in settings without and with pediatric dolutegravir (DTG) availability as first-line ART. The improved switching strategy increases the probability of switching to second-line ART when virologic failure is diagnosed through viral load testing. The PDR testing strategy involves a one-time PDR test prior to ART initiation to guide choice of initial regimen. When DTG is not available, PDR testing is dominated by the improved switching strategy, which has an incremental cost-effectiveness ratio (ICER) of USD 579/life-year gained (LY), relative to the status quo. If DTG is available, improved switching has a similar ICER (USD 591/LY) relative to the DTGstatus quo. Even when substantial financial investment is needed to achieve improved regimen switching practices, the improved switching strategy still has the potential to be cost-effective in a wide range of sub-Saharan African countries. Our analysis highlights the importance of strengthening existing laboratory monitoring systems to improve the health of children living with HIV.

Cassava Processing in Sub-Saharan Africa: the Implications for Expanding Cassava Production

1994 ◽  
Vol 23 (3) ◽  
pp. 197-205 ◽  
Author(s):  
Felix Izu Nweke
Keyword(s):  
Food Security ◽  
Water Supply ◽  
Sub Saharan Africa ◽  
Wide Range ◽  
Intensive Use ◽  
Cassava Production ◽  
Sub Saharan ◽  
Processing Techniques ◽  
Technical Solutions ◽  
Poor Soil

Cassava makes an important contribution to improving food security and rural incomes in sub-Saharan Africa, as it is tolerant of drought and poor soil and its cultivation does not require much labour. However, the fresh roots are bulky and perishable and need to be processed before they can be marketed; processing also removes the cyanogens which make many varieties poisonous in their raw form. Cassava roots are turned into granules, flours, pastes and chips, with a wide range of flavours and appearances for different areas and markets. Many different processing techniques are used, some of which make intensive use of fuelwood while others require a plentiful water supply. These requirements, as well as the need for a good transport and marketing infrastructure, limit the expansion of cassava production in sub-Saharan Africa, but technical solutions are being found.

scholarly journals Comparative Area Studies and the Study of the Global South

2020 ◽  
Vol 20 (2) ◽  
pp. 279-287
Author(s):  
Rudra Sil ◽  
Ariel I. Ahram
Keyword(s):  
Social Science ◽  
Science Inquiry ◽  
Global South ◽  
Sub Saharan Africa ◽  
Theory Building ◽  
Spatial And Temporal Variation ◽  
Area Studies ◽  
Wide Range ◽  
Range Theory ◽  
Sub Saharan

Comparative Area Studies (CAS) offers a template to bring the Global South back into the foreground of social science inquiry. CAS urges researchers to grapple directly with empirical variations derived from across the seemingly different global regions. CAS offers three comparative modes: intra-regional, cross-regional, and trans-regional. A number of scholars have used CAS’s comparative rubrics, even without knowing about the wider CAS agenda and program. CAS unsettles assumptions about discrete, fixed “regional” or civilizational blocks as well as about nomothetic theory-building aimed at universal or general laws. At the same time, CAS engages in the idea of medium-range theory-building, focusing empirical rigor and induction in order to create concepts and analyses that are portable yet contextualized. These macro-historical theories must be attentive to spatial and temporal variation in the social world. Claims of universalism are suspect. For the study of the Global South, in particular, CAS provides a path for aggregating and leveraging the wide range of observations and interpretations area specialists have to offer on regions as diverse as South Asia, the Middle East, Latin America, and sub-Saharan Africa. CAS thus changes the division of labor within social science to allow greater input for scholarship derived from and originating in the developing world.

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