Why farmers use so many different maize varieties in West Kenya

2021 ◽  
Vol 50 (4) ◽  
pp. 406-417
Author(s):  
Conny J.M. Almekinders ◽  
Paul Hebinck ◽  
Wytze Marinus ◽  
Richard D. Kiaka ◽  
Wycliffe W. Waswa
Keyword(s):  
Systematic Study ◽  
Good Yield ◽  
System Development ◽  
Maize Breeding ◽  
Seed Sources ◽  
Use Of Data ◽  
Crop Varieties ◽  
Maize Varieties ◽  
Seed System ◽  
Hybrid Maize

In this article we reflect on the discussions as to whether breeding and seed system development should proceed along its current well established route of developing varieties with a higher agricultural productivity or if the diversity of farmers, their contexts and rationales requires broader approaches. We make use of data from a recently held survey (2018) in West Kenya. The data show that some 80% of the households in the survey planted both local and hybrid maize varieties. The choices that people make about which variety to plant are many. Apart from rainfall, the availability of cash, the promise of a good yield, the presence of projects and programs and the culture of seed also influences these choices. We argue that an inclusive demand-oriented maize breeding and seed system needs to include a range of varieties and seed sources and to develop and support different delivery pathways to fit farmers’ diverse use of seeds and varieties. Our findings also indicate the need for more systematic study of the diversity of farmers’ rationales and the performance of crop varieties. This would provide useful information for all the actors involved.

scholarly journals Analysis of Genetic Diversity within Nepalese Maize Populations Using SSR Markers

1970 ◽  
Vol 11 ◽  
pp. 1-8 ◽  
Author(s):  
Dil Bahadur Gurung ◽  
Maria Luz C George ◽  
Quirino D Dela Cruz
Keyword(s):  
Genetic Diversity ◽  
Ssr Markers ◽  
Gene Diversity ◽  
Genetic Distances ◽  
Maize Breeding ◽  
Maize Populations ◽  
Maize Varieties ◽  
Ssr Loci ◽  
Average Gene ◽  
Hybrid Maize

Information on genetic diversity and relationships among breeding materials is necessary for hybrid maize breeding. Four open-pollinated varieties were analyzed using SSR markers to determine the genetic diversity within the varieties. In each variety, 15 individuals were genotyped with 30 SSR markers. Average heterozygosity percentage of the varieties was 45.07%, ranging from 35.23% in Rampur Composite to 54.64% in Khumal Yellow, indicating the higher level of heterozygosity in these two varieties. An average PIC value across all the polymorphic SSR loci was 0.50; which ranged from 0.47 in Manakamana-2 to 0.52 in Khumal Yellow and Arun-4. At the genotype level, the range was from 0.07 in umc1161 to 0.84 in umc1136. The total number of alleles detected was 415 for 30 SSR markers in 60 genotypes. The unique and common alleles detected respectively were 27 and 71. The average number of alleles per locus was 3.45 among the varieties, ranging from 3.21in Manakamana-2 to 3.76 in Khumal Yellow. Average gene diversity across the varieties was 0.54 and ranged from 0.51 in Manakamana-2 to 0.56 in Khumal Yellow and Arun-4. The genetic similarity coefficient of all individuals among the varieties was seen at 0.35.The MRD values were higher between Arun-4 and Manakamana-2 (0.290) and low between Khumal Yellow and Rampur Composite (0.221). Estimate of genetic distances among the varieties showed that Rampur Composite, Khumal Yellow, and Manakamana-2 were closely related sharing the similar genetic backgrounds, whereas Arun-4 was genetically more distantly related. Efforts are being made for the development and evaluation of inbred lines from these distantly related maize varieties for developing high yielding maize hybrids. Key Words: genetic diversity; maize hybrid; SSR markers DOI: 10.3126/njst.v11i0.4082Nepal Journal of Science and Technology 11 (2010) 1-8

scholarly journals Performance of different crops productivity enhancement through adaptation of crop varieties at charland in Bangladesh

2016 ◽  
Vol 40 (4) ◽  
pp. 629-640
Author(s):  
MN Islam ◽  
MS Rahman ◽  
MS Alom ◽  
M Akhteruzzaman
Keyword(s):  
Climate Change ◽  
Crop Production ◽  
Production Systems ◽  
Crop Productivity ◽  
River Channel ◽  
Local Cultivar ◽  
Crop Varieties ◽  
Maize Varieties ◽  
Erosion And Accretion ◽  
Hybrid Maize

Charland that are emerged as islands within the river channel or as attached land to the riverbanks as a result of erosion and accretion. In crop production systems, screening of adaptable crop varieties for charland is necessary to address the climate change issues. Hence, five separate experiments were conducted at charland of the Padma River in Kushtia district during November 2012 to May 2013 to select suitable varieties of lentil, hybrid maize, soybean, potato and mustard for increasing crop productivity. The experiment comprised of four lentil varieties viz. BARI Masur-4, BARI Masur-5, BARI Masur-6 and a local cultivar; four hybrid maize varieties namely BARI Hybrid maize-5, BARI Hybrid maize-7, BARI Hybrid maize-9 and Pacific-11; three soybean varieties like BARI Soybean-5, BARI Soybean-6 and Shohag; four potato varieties viz., BARI Alu-7, BARI Alu-8, BARI Alu-31 and Belgium; and five mustard varieties viz., BARI Sarisha-11, BARI Sarisha-13, BARI Sarisha-14, BARI Sarisha-15 and BARI Sarisha-16 were evaluated separately in five trials for their adaptation in charland. Among the studied crops, lentil var. BARI Masur-6, maize var. BARI Hybrid maize-9, soybean var. BARI Soybean-6, potato var. BARI Alu-7 and mustard var. BARI Sarisha-11performed better in the charland under climate change situation in Bangladesh.Bangladesh J. Agril. Res. 40(4): 629-640, December 2015

Hybrid maize breeding with doubled haploids: Comparison between selection criteria

2006 ◽  
Vol 54 (3) ◽  
pp. 343-350 ◽  
Author(s):  
C. F. H. Longin ◽  
H. F. Utz ◽  
A. E. Melchinger ◽  
J.C. Reif
Keyword(s):  
Selection Criteria ◽  
Doubled Haploids ◽  
Optimum Allocation ◽  
Finite Sample ◽  
Sample Sizes ◽  
Maize Breeding ◽  
Selection Gain ◽  
Breeding Programmes ◽  
Hybrid Maize ◽  
Breeding Resources

The optimum allocation of breeding resources is crucial for the efficiency of breeding programmes. The objectives were to (i) compare selection gain ΔGk for finite and infinite sample sizes, (ii) compare ΔGk and the probability of identifying superior hybrids (Pk), and (iii) determine the optimum allocation of the number of hybrids and test locations in hybrid maize breeding using doubled haploids. Infinite compared to finite sample sizes led to almost identical optimum allocation of test resources, but to an inflation of ΔGk. This inflation decreased as the budget and the number of finally selected hybrids increased. A reasonable Pk was reached for hybrids belonging to the q = 1% best of the population. The optimum allocations for Pk(q) and ΔGkwere similar, indicating that Pk(q) is promising for optimizing breeding programmes.

THE DEVELOPMENT AND SYSTEMATIC STUDY OF THE PROGRAM OF MEASURES ON IMPROVEMENT OF ORGANIZATION OF TRANSPORT SERVICE OF THE POPULATION IN THE METROPOLIS

2020 ◽  
Vol 4 (26) ◽  
pp. 91-95
Author(s):  
D. A. Smirnov ◽  
Keyword(s):  
Transport System ◽  
Systematic Study ◽  
Public Transport ◽  
Road Network ◽  
System Development ◽  
Transport Service ◽  
Transport Services ◽  
The City

The article reveals the content of measures to improve the organization of transport services in the metropolis. The key directions of the city transport system development are considered. The analysis of the offered offers is carried out. Keywords: metropolis, transport development, public transport, street and road network.

scholarly journals Selection Signatures Underlying Dramatic Male Inflorescence Transformation During Modern Hybrid Maize Breeding

Genetics ◽  
2018 ◽  
Vol 210 (3) ◽  
pp. 1125-1138 ◽  
Author(s):  
Joseph L. Gage ◽  
Michael R. White ◽  
Jode W. Edwards ◽  
Shawn Kaeppler ◽  
Natalia de Leon
Keyword(s):  
Selection Signatures ◽  
Maize Breeding ◽  
Male Inflorescence ◽  
Hybrid Maize

scholarly journals Trehalose Protects Maize Plants from Salt Stress and Phosphorus Deficiency

Plants ◽  
2019 ◽  
Vol 8 (12) ◽  
pp. 568
Author(s):  
Md. Motiar Rohman ◽  
Md. Robyul Islam ◽  
Mahmuda Binte Monsur ◽  
Mohammad Amiruzzaman ◽  
Masayuki Fujita ◽  
...  
Keyword(s):  
Glutathione Peroxidase ◽  
Root Length ◽  
Phosphorus Deficiency ◽  
Monodehydroascorbate Reductase ◽  
Maize Seedlings ◽  
Combined Stress ◽  
Ros Scavenging ◽  
Sod Activity ◽  
Maize Varieties ◽  
Hybrid Maize

This study is undertaken to elucidate the role of trehalose (Tre) in mitigating oxidative stress under salinity and low P in maize. Eight-day-old maize seedlings of two maize varieties, BARI Hybrid Maize-7 and BARI Hybrid Maize-9, were subjected to salinity (150 mM NaCl), low P (5 µM KH2PO4) and their combined stress with or without 10 mM Tre for 15 d. Salinity and combined stress significantly inhibited the shoot length, root length, and root volume, whereas low P increased the root length and volume in both genotypes. Exogenous Tre in the stress treatments increased all of the growth parameters as well as decreased the salinity, low P, and combined stress-mediated Na+/K+, reactive oxygen species (ROS), malondialdehyde (MDA), lipoxygenase (LOX) activity, and methylglyoxal (MG) in both genotypes. Individually, salinity and low P increased superoxide dismutase (SOD) activity in both genotypes, but combined stress decreased the activity. Peroxidase (POD) activity increased in all stress treatments. Interestingly, Tre application enhanced the SOD activity in all the stress treatments but inhibited the POD activity. Both catalase (CAT) and glutathione peroxidase (GPX) activity were increased by saline and low P stress while the activities inhibited in combined stress. Similar results were found for ascorbate peroxidase (APX), glutathione peroxidase (GR), and dehydroascorbate reductase (DHAR) activities in both genotypes. However, monodehydroascorbate reductase (MDHAR) activity was inhibited in all the stresses. Interestingly, Tre enhanced CAT, APX, GPX, GR, MDHAR, and DHAR activities suggesting the amelioration of ROS scavenging in maize under all the stresses. Conversely, increased glyoxalase activities in saline and low P stress in BHM-9 suggested better MG detoxification system because of the down-regulation of glyoxalase-I (Gly-I) activity in BHM-7 in those stresses. Tre also increased the glyoxalase activities in both genotypes under all the stresses. Tre improved the growth in maize seedlings by decreasing Na+/K+, ROS, MDA, and MG through regulating antioxidant and glyoxalase systems.

Hybrid maize breeding with doubled haploids. IV. Number versus size of crosses and importance of parental selection in two-stage selection for testcross performance

2008 ◽  
Vol 117 (2) ◽  
pp. 251-260 ◽  
Author(s):  
Thilo Wegenast ◽  
C. Friedrich H. Longin ◽  
H. Friedrich Utz ◽  
Albrecht E. Melchinger ◽  
Hans Peter Maurer ◽  
...  
Keyword(s):  
Doubled Haploids ◽  
Maize Breeding ◽  
Two Stage ◽  
Parental Selection ◽  
Testcross Performance ◽  
Selection For ◽  
Hybrid Maize

scholarly journals Identification of Associations between SSR Markers and Quantitative Traits of Maize (Zea mays L.)

Agronomy ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 182
Author(s):  
Jan Bocianowski ◽  
Kamila Nowosad ◽  
Barbara Wróbel ◽  
Piotr Szulc
Keyword(s):  
Zea Mays ◽  
Ssr Markers ◽  
Marker Assisted Selection ◽  
Quantitative Traits ◽  
Zea Mays L ◽  
Fresh Weight ◽  
Multiple Traits ◽  
Good Tool ◽  
Maize Varieties ◽  
Hybrid Maize

Microsatellite or simple sequence repeat (SSR) markers have wide applicability for genetic analysis in crop plant improvement strategies. Marker-assisted selection is an important tool for plant breeders to increase the efficiency of a breeding process, especially for multigenic traits, highly influenced by the environment. In this paper, the relationships between SSR markers and 26 quantitative traits of hybrid maize varieties (Zea mays L.) were analyzed. Association analyses were performed based on 30 SSR primers in a set of thirteen hybrid maize varieties. A total of 112 SSR markers were detected in these genotypes. The number of alleles per locus ranged from 1 to 17, with the average number of alleles per locus equal to 3.7. The number of molecular markers associated with observed traits ranged from 1 (for the number of kernels in row, ears weight and fresh weight of one plant) to 14 (for damage of maize caused by P. nubilalis) in 2016 as well as from 1 (for soil plant analysis development—SPAD, the number of grains in ear and fresh weight of one plant) to 12 (for carotenoids content) in 2017. The sum of statistically significant associations between SSR markers and at least one trait was equal to one hundred sixty in 2016 as well as one hundred twenty-five in 2017. Marker trait associations (MTAs) were found on the basis of regression analysis. The proportion of the total phenotypic variances of individual traits explained by the marker ranged from 24.4% to 77.7% in the first year of study and from 24.3% to 77.9% in 2017. Twenty-two SSR markers performed a significant effect on at least one tested trait in both years of experiment. The three markers (phi021/4, phi036/3, and phi061/2) can be a good tool in marker-assisted selection because they allow simultaneous selection for multiple traits in both years of study, such as the number of kernels in row and the number of grains in ear (phi021/4), the number of plant after germination, the number of plants before harvest, and the number of ears (phi036/3), as well as moisture of grain and length of ears (phi061/2).

Contextualizing private sector-based seed system development: The case of sorghum in Eastern Africa

2021 ◽  
pp. 003072702110563
Author(s):  
Caroline Hambloch ◽  
Jane Kahwai ◽  
John Mugonya
Keyword(s):  
Rural Development ◽  
Private Sector ◽  
New Technologies ◽  
System Development ◽  
Sub Saharan Africa ◽  
Eastern Africa ◽  
Improved Varieties ◽  
Seed System ◽  
Political Economic ◽  
Farming Households

Private sector-based seed system development remains a key development intervention in Sub-Saharan Africa. Seed system interventions promoting the adoption of improved varieties through the private sector generally follow a linear, market-oriented technological adoption logic. A qualitative case study of the sorghum seed system in Kenya, Uganda, and Tanzania demonstrates that this model may not be able to drive the broad-scale adoption of improved sorghum varieties and to generate significant benefits for small sorghum-farming households. The findings suggest that the agro-ecological, social, and political-economic contexts critically determine the role improved varieties and the private sector can play in rural development. Improved sorghum varieties promoted by both the public and private sectors may not suit the needs, preferences and contexts of farming households. Seed companies hold sorghum as an add-on in their portfolio, investing less resources and research into sorghum compared to more profitable crops such as vegetable and maize seeds. Significant political-economic obstacles exist that favor the support of cash crops such as maize and rice, limiting the growth and development of the private sector in the sorghum seed system. We conclude that future interventions should build on approaches that aim to develop more diverse channels of seed delivery in both the formal and informal seed systems, adopt a livelihoods perspective to evaluate the costs, benefits, and risks associated with the adoption of new technologies, and acknowledge that seed system interventions are only one out of a portfolio of interventions to generate rural development.

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