Developing and Deploying Abiotic Stress-Tolerant Maize Varieties in the Tropics: Challenges and Opportunities

2016 ◽  
pp. 61-77 ◽  
Author(s):  
B. M. Prasanna
Keyword(s):  
Abiotic Stress ◽  
Maize Varieties ◽  
Challenges And Opportunities ◽  
The Tropics

scholarly journals Assessing the Potential of Extra-Early Maturing Landraces for Improving Tolerance to Drought, Heat, and Both Combined Stresses in Maize

Agronomy ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 318 ◽  
Author(s):  
Charles Nelimor ◽  
Baffour Badu-Apraku ◽  
Antonia Yarney Tetteh ◽  
Ana Luísa Garcia-Oliveira ◽  
Assanvo Simon-Pierre N’guetta
Keyword(s):  
Heat Stress ◽  
Abiotic Stress ◽  
Field Experiments ◽  
Yield Loss ◽  
Yield Potential ◽  
Genetic Base ◽  
Maize Varieties ◽  
Early Maturing ◽  
Maize Landraces ◽  
Landrace Accessions

Maize landrace accessions constitute an invaluable gene pool of unexplored alleles that can be harnessed to mitigate the challenges of the narrowing genetic base, declined genetic gains, and reduced resilience to abiotic stress in modern varieties developed from repeated recycling of few superior breeding lines. The objective of this study was to identify extra-early maize landraces that express tolerance to drought and/or heat stress and maintain high grain yield (GY) with other desirable agronomic/morpho-physiological traits. Field experiments were carried out over two years on 66 extra-early maturing maize landraces and six drought and/or heat-tolerant populations under drought stress (DS), heat stress (HS), combined both stresses (DSHS), and non-stress (NS) conditions as a control. Wide variations were observed across the accessions for measured traits under each stress, demonstrating the existence of substantial natural variation for tolerance to the abiotic stresses in the maize accessions. Performance under DS was predictive of yield potential under DSHS, but tolerance to HS was independent of tolerance to DS and DSHS. The accessions displayed greater tolerance to HS (23% yield loss) relative to DS (49% yield loss) and DSHS (yield loss = 58%). Accessions TZm-1162, TZm-1167, TZm-1472, and TZm-1508 showed particularly good adaptation to the three stresses. These landrace accessions should be further explored to identify the genes underlying their high tolerance and they could be exploited in maize breeding as a resource for broadening the genetic base and increasing the abiotic stress resilience of elite maize varieties.

Cross-breeding cattle for milk production in the tropics: achievements, challenges and opportunities

2013 ◽  
Vol 52 ◽  
pp. 111-125 ◽  
Author(s):  
E. Galukande ◽  
H. Mulindwa ◽  
M. Wurzinger ◽  
R. Roschinsky ◽  
A.O. Mwai ◽  
...  
Keyword(s):  
Milk Production ◽  
Cross Breeding ◽  
Challenges And Opportunities ◽  
The Tropics

scholarly journals Dairy science and health in the tropics: challenges and opportunities for the next decades

2019 ◽  
Vol 51 (5) ◽  
pp. 1009-1017 ◽  
Author(s):  
Lorenzo E. Hernández-Castellano ◽  
Jarlath E. Nally ◽  
Johanna Lindahl ◽  
Metha Wanapat ◽  
Ibrahim A. Alhidary ◽  
...  
Keyword(s):  
Challenges And Opportunities ◽  
Dairy Science ◽  
The Tropics

scholarly journals Multiple Beneficial Effects of Using Biochar (as a Great Organic Material) on Tolerance and Productivity of Rice under Abiotic Stress

2019 ◽  
Vol 6 (1) ◽  
pp. 40-51
Author(s):  
Gulaqa Anwari ◽  
Jin Feng ◽  
Abdourazak Alio Moussa
Keyword(s):  
Abiotic Stress ◽  
Plant Growth ◽  
Abiotic Stresses ◽  
Biological Properties ◽  
Breeding Method ◽  
Plant Growth Hormones ◽  
Crop Tolerance ◽  
Beneficial Effects ◽  
Challenges And Opportunities

Rice as a sensitive crop that usually affected by many harmful environmental stresses. Numerous policies are followed to increase plant growth-tolerance under abiotic-stresses in various plant species. The attempts to improve crop tolerance against abiotic stresses via common breeding method are needed to follow a long-term, and may also be non-affordable, these are due to the existing genetic variability of the plant. Current review analysis existing knowledge gaps, challenges, and opportunities in the biochar application as a beneficial and pyrogenic-C, material. Consequently, a review of the literature with a high focusing on the multiple beneficial effects of using biochar on tolerance and productivity of rice in abiotic stresses is needed. This review provides a summary of those efforts that would be beneficial in reducing inconvenienced abiotic-stresses, and also how using biochar could increase rice tolerance and production through the supporting of plant growth regulator's roles. Accordantly, present review findings showed that biochar is a great amendment and consisting of principally organic rich-C matter, which has multiple benefits on improving soil physicochemical and biological properties as well as increasing rice tolerance and its productivity through enhancing plant hormones roles under abiotic stressed conditions (heat/cold temperature, drought, salinity, heavy metal, and climate change stresses). Nevertheless, it is anticipated that further researches on the benefits of biochar will increase the comprehension of interactions between biochar and plant growth hormones, to accelerate our attempts for improving rice tolerance and productivity, under abiotic-stress conditions.

The Biology of Agroecosystems

2019 ◽  
Author(s):  
Nicola Randall ◽  
Barbara Smith
Keyword(s):  
Land Surface ◽  
Global Scale ◽  
Agroforestry Systems ◽  
Human Populations ◽  
Pest Species ◽  
Challenges And Opportunities ◽  
Future Challenges ◽  
Biological Impacts ◽  
The Tropics

The Biology of Agroecosystems provides an introduction to the biological and ecological attributes of ecosystems and the biological impacts of agriculture on the wider environment. Global human populations are rising and diets are becoming ever more complicated, leading to requirements for increased levels of food production. Natural biotopes are becoming increasingly fragmented as agricultural activities expand around them. Agroecosystems occur from the tropics to subarctic environments and comprise systems as varied as annual crops, perennial grasslands, orchards, and agroforestry systems. They presently cover almost 40 per cent of the terrestrial land surface and significantly shape landscapes at a global scale. The book outlines the origin and development of agriculture and summarizes the characteristics of different types of agroecosystems. The conflicts between management of land for productivity and conservation of natural resources are discussed, and some of the key biological issues (loss of biodiversity, instability, susceptibility to pests, for example) are explored. Individual chapters introduce the role of functional groups such as pollinators, nutrient cycling organisms, and pest regulators; the importance of soils and soil organisms for agriculture; and the biological impacts of water use in agroecosystems. Globalization of agriculture is explored, and includes drivers of change, such as shifting diets, and biological challenges, such as the spread of pest species. The final chapters outline different management methods for sustainable management of agroecosystems, and consider the future challenges and opportunities for agriculture and the biology of agroecosystems.

Breeding Rice Varieties for Abiotic Stress Tolerance: Challenges and Opportunities

2017 ◽  
pp. 339-361 ◽  
Author(s):  
Vishnu V. Nachimuthu ◽  
Robin Sabariappan ◽  
Raveendran Muthurajan ◽  
Arvind Kumar
Keyword(s):  
Abiotic Stress ◽  
Stress Tolerance ◽  
Abiotic Stress Tolerance ◽  
Rice Varieties ◽  
Challenges And Opportunities

scholarly journals Beat the stress: breeding for climate resilience in maize for the tropical rainfed environments

2021 ◽  
Author(s):  
Boddupalli M. Prasanna ◽  
Jill E. Cairns ◽  
P. H. Zaidi ◽  
Yoseph Beyene ◽  
Dan Makumbi ◽  
...  
Keyword(s):  
Insect Pests ◽  
Critical Role ◽  
Sub Saharan Africa ◽  
Tropical Maize ◽  
Maize Breeding ◽  
Genetic Gains ◽  
Maize Cultivars ◽  
Climate Resilience ◽  
Maize Varieties ◽  
The Tropics

Abstract Key message Intensive public sector breeding efforts and public-private partnerships have led to the increase in genetic gains, and deployment of elite climate-resilient maize cultivars for the stress-prone environments in the tropics. Abstract Maize (Zea mays L.) plays a critical role in ensuring food and nutritional security, and livelihoods of millions of resource-constrained smallholders. However, maize yields in the tropical rainfed environments are now increasingly vulnerable to various climate-induced stresses, especially drought, heat, waterlogging, salinity, cold, diseases, and insect pests, which often come in combinations to severely impact maize crops. The International Maize and Wheat Improvement Center (CIMMYT), in partnership with several public and private sector institutions, has been intensively engaged over the last four decades in breeding elite tropical maize germplasm with tolerance to key abiotic and biotic stresses, using an extensive managed stress screening network and on-farm testing system. This has led to the successful development and deployment of an array of elite stress-tolerant maize cultivars across sub-Saharan Africa, Asia, and Latin America. Further increasing genetic gains in the tropical maize breeding programs demands judicious integration of doubled haploidy, high-throughput and precise phenotyping, genomics-assisted breeding, breeding data management, and more effective decision support tools. Multi-institutional efforts, especially public–private alliances, are key to ensure that the improved maize varieties effectively reach the climate-vulnerable farming communities in the tropics, including accelerated replacement of old/obsolete varieties.

scholarly journals HETEROSIS OF SOME TROPICAL MAIZE GENOTYPES DERIVED FROM TWO DIFFERENT MAIZE BREEDING ERAS

2017 ◽  
Vol 30 (1) ◽  
pp. 01-10
Author(s):  
Ige AYODELE Sunday
Keyword(s):  
Grain Yield ◽  
Recurrent Selection ◽  
Stem Borer ◽  
Productivity Index ◽  
Gene Pools ◽  
International Institute ◽  
Maize Grain Yield ◽  
Maize Varieties ◽  
Maize Grain ◽  
The Tropics

Heterosis for maize grain yield was studied to identify cross combinations that may be useful sources for inbred line extraction, recurrent selection and, to estimate changes in the maize grain yield heterosis across two breeding eras in the tropics. Field studies were conducted at the International Institute of Tropical Agriculture (IITA), Ibadan during the cropping seasons of 2010, 2011 and 2012, with 10 open pollinated maize varieties (OPVs)  derived two breeding eras (1 and 2). The ten OPVs and the crosses generated from them were evaluated under stem borer infested and non-infested, high-N versus low-N and natural conditions. Mid and High-heterosis (MPH & HPH) were estimated from grain yield data from the tested environments. MPH & HPH under natural, optimum N-Fertilizer application, and borer infested environments were 37.20 and 25.38%, 19.85 and 12.3%, 30.98 and 18.94% respectively. Cross combination DMR-LSR-W (Era 1) x TZSR-Y-I (Era 1) expressed the highest magnitude of (MPH & HPH) (97.70 and 87.15%) for grain yield across the tested environments except low-N. It suggest the suitability of the hybrid for cultivation only in environments with high productivity index. Hybrid ACR99TZLCOMP4-DMRSR (Era 1) x BR9928DMRSR (Era 2) had highest HPH under low-N environments. Suggesting this combination as a good source of genes for the development of low nitrogen tolerance maize varieties in the tropics. Cross combinations that expressed better (HPH) under borer infestation are good gene pools for the development of stem borer tolerance maize varieties in stem borer endemic zone. These crosses hold promise as future candidates for commercial exploitation of heterosis or for the extraction of inbred lines in the tropics. Better (HPH) were derived from the crosses between Era 1 and & 2, indicates the older and newer maize varieties complement each other for (HPH) across environments. 

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