scholarly journals Maize Breeding in the Highlands of Ecuador, Peru, and Bolivia: A Review

Agronomy ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 212
Author(s):  
José Luis Zambrano ◽  
Carlos F. Yánez ◽  
Carlos A. Sangoquiza
Keyword(s):  
Agricultural Research ◽  
Public Institutions ◽  
Human Consumption ◽  
Participatory Plant Breeding ◽  
Maize Breeding ◽  
Andean Region ◽  
Breeding Programs ◽  
Maize Cultivars ◽  
Maize Varieties ◽  
Breeding Techniques

Maize is one of the most important staple crops in the highlands of the Andean region of Ecuador, Peru, and Bolivia. Most seeds come from landraces, with their own kernel characteristics. The kernels are used for the elaboration of traditional dishes and other elaborates for human consumption. In this region, maize breeding is conducted mainly by public institutions. In this review, we outline the methodology that has been used by the maize breeding programs (MBPs) of the National Institutes for Agricultural Research and other institutions in the highlands of Ecuador, Peru, and Bolivia during the last 20 years. The main objective of MBPs in the region has been to develop more uniform and productive open-pollinated varieties (OPVs) of floury maize (Zea mays L. var. Amylacea), which is the most important type of maize in the area. Participatory plant breeding, combined with half-sib, has been used to breed new maize varieties. At least 18 OPVs of floury maize have been released into the Andean region in the last 20 years. Breeding this type of maize has been very important to conserve diversity and promote consumption in the region, but they have had very little impact on yield. The yield of floury maize is around three times below that of dent or semident maize grown in the region. Therefore, there is a need to apply new breeding techniques in the region to accelerate the development of more productive floury-maize cultivars.

scholarly journals Genetic progress, adaptability and stability of maize cultivars for value of cultivation and use trials

2019 ◽  
Vol 41 (1) ◽  
pp. 42624
Author(s):  
Joaquim Vicente Uate ◽  
Joel Jorge Nunvuga ◽  
Carlos Pereira da Silva ◽  
Lauro Jose Moreira Guimarães ◽  
Renzo Garcia Von Pinho ◽  
...  
Keyword(s):  
Low Cost ◽  
Yield Potential ◽  
Joint Analysis ◽  
Stability Estimates ◽  
Maize Breeding ◽  
Genetic Progress ◽  
Breeding Programs ◽  
Growing Seasons ◽  
Maize Cultivars ◽  
Maize Genotypes

Maize breeding programs conduct multi-environment trials every year to assess the performance of new cultivars in pre-releasing tests. The data are combined across sites and seasons to perform a joint analysis in order to obtain information that will help breeders to select the best cultivars for different environments. Beyond this, it is essential to understand the different factors that can hamper the selection and genetic progress (i.e., genetic variability, selection intensity and genotype-by-environment interactions). In this study, the genetic progress (GP) was estimated and the adaptability and stability of 81 maize genotypes were evaluated in a series of trials for the value of cultivation and use (VCU) between the 2010/11 and 2014/15 growing seasons. The genotypes were composed of open-pollinated varieties, topcross hybrids, intervarietal hybrids, and single, double and three-way cross hybrids and were assessed in 117 environments in the central region of Brazil, from which 22 presented environmental stresses. For grain yield, an annual GP of 331.5 kg ha-1 was observed, thus showing efficiency in the selection of superior cultivars. Additionally, it was observed that some low-cost seed cultivars showed yield potential, adaptability and stability estimates that were compatible with commercial hybrids, thus making them quite attractive for cultivation in environments with or without abiotic stresses.

scholarly journals Adaptability and stability of maize varieties using mixed model methodology

2012 ◽  
Vol 12 (2) ◽  
pp. 111-117 ◽  
Author(s):  
Flávia Ferreira Mendes ◽  
Lauro José Moreira Guimarães ◽  
João Cândido Souza ◽  
Paulo Evaristo Oliveira Guimarães ◽  
Cleso Antônio Patto Pacheco ◽  
...  
Keyword(s):  
Mixed Models ◽  
Mixed Model ◽  
Relative Performance ◽  
Environment Interaction ◽  
Maize Breeding ◽  
Breeding Programs ◽  
Genotype X Environment ◽  
Growing Seasons ◽  
Maize Varieties ◽  
Harmonic Means

The objective of this study was to evaluate the performance, adaptability and stability of corn cultivars simultaneously in unbalanced experiments, using the method of harmonic means of the relative performance of genetic values. The grain yield of 45 cultivars, including hybrids and varieties, was evaluated in 49 environments in two growing seasons. In the 2007/2008 growing season, 36 cultivars were evaluated and in 2008/2009 25 cultivars, of which 16 were used in both seasons. Statistical analyses were performed based on mixed models, considering genotypes as random and replications within environments as fixed factors. The experimental precision in the combined analyses was high (accuracy estimates > 92 %). Despite the existence of genotype x environment interaction, hybrids and varieties with high adaptability and stability were identified. Results showed that the method of harmonic means of the relative performance of genetic values is a suitable method for maize breeding programs.

Estimation of Yield traits & Correlation in Zea Mays

1970 ◽  
pp. 27-32
Author(s):  
Maysoun M. Saleh ◽  
Zakia Hajjar, Rima Koudsieh ◽  
Fattima Al- Sadek
Keyword(s):  
Zea Mays ◽  
Agricultural Research ◽  
Grain Weight ◽  
Yield Traits ◽  
Thousand Grain Weight ◽  
Maize Breeding ◽  
Grain Number ◽  
Breeding Programs ◽  
Research Centres

Seven Zea mays genotypes were planted at two sites Aleppo and Edleb which are research centres belongs to the General Commission of Scientific Agricultural research GCSAR northern Syria. Yield traits (ear diameter, ear length, row number per ear-1, grain number per ear-1, thousand grain weight) were studied in order to estimate the variation between genotypes and to between sites and to select the best genotypes concerning studied yield  traits to be applied in maize breeding programs. Results showed that all Studied genotypes of maize had significant differences in yield traits in which both genotypes (Z 263, Z 67) were remarkable in all studied traits like thousand grain weight (391.7, 390.7) g for each of them respectively. Results also revealed that most studied traits were significantly superior in Aleppo comparing to Edleb. Results of correlation showed positively and significantly relations between all studied traits except between each of row number per ear-1 and grain number per ear-1 with thousand grain weight.

INCREASING THE CLIENT ORIENTATION OF MAIZE BREEDING USING FARMER PARTICIPATION IN EASTERN INDIA

2005 ◽  
Vol 41 (4) ◽  
pp. 413-426 ◽  
Author(s):  
D. S. VIRK ◽  
M. CHAKRABORTY ◽  
J. GHOSH ◽  
S. C. PRASAD ◽  
J. R. WITCOMBE
Keyword(s):  
Breeding Programme ◽  
Mass Selection ◽  
Participatory Plant Breeding ◽  
Research Station ◽  
Eastern India ◽  
Maize Breeding ◽  
Maize Varieties ◽  
Resource Poor ◽  
On Farm ◽  
Oriented Approach

A maize-breeding programme was targeted at resource-poor farmers of eastern India using a client-oriented approach (often called participatory plant breeding). Farmers tested a range of varieties in a participatory varietal selection programme but none proved to be very popular. Information from these trials was used in a breeding programme to develop a broadly-based population from three yellow- and three white-grained maize varieties that were either identified in the trials or had traits liked by farmers. The population was subjected to several cycles of random mating. In the C3, C4 and C6 cycles, subpopulations were extracted and subjected to mass selection over several generations in environments that represented well the target population of environments of resource-poor farmers' fields in eastern India for traits identified by farmers. To identify better the required traits, in some generations the selection was carried out by farmers on a research farm under fertility levels that approximated farmers' practice. The improvement of the subpopulations resulted in several varieties that performed well in research station and on-farm trials. One of them, BVM 2, was released in Jharkhand state, India. In multilocational research station trials, it yielded more than the control variety BM 1 but silked earlier. In the less favourable environments of on-farm trials, its yield superiority, in percentage terms, was higher. Farmers perceived BVM 2 to have better grain quality and stover yield than the local varieties. BVM 2 was specifically bred to meet the needs of the clients (resource-poor farmers with no access to irrigation) and has earlier maturity combined with higher grain yield. The returns were higher from this highly client-oriented approach, than by classical breeding, mainly because uptake was faster as a result of research and extension being done in tandem.

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 INOVATION AND SPECIALTY MAIZE BREEDING FOR MARKET NICHES IN THE STATE OF SÃO PAULO

2020 ◽  
Vol 19 ◽  
pp. 19
Author(s):  
MARIA ELISA A. G. ZAGATTO PATERNIANI ◽  
CRISTINA FACHINI ◽  
CINTHIA SOUZA RODRIGUES
Keyword(s):  
Animal Feed ◽  
Sao Paulo ◽  
Human Consumption ◽  
São Paulo ◽  
Maize Breeding ◽  
Maize Production ◽  
Genetic Breeding ◽  
Industrial Processing ◽  
Maize Cultivars ◽  
Maize Genetic

Maize is one of the most harvested cereals on the planet. In Brazil, it is the country’s second largest grain production after soybean, with a large portion of production destined for animal feed. During the 2019/2020 harvest, 35% of total maize production was exported, 9.5% was destined for industrial processing and only 1.1% for human consumption. Specialty maize are those grains that are not destined for the dry grain commodities market, but have various other uses and are destined exclusively for human consumption. Specialty maize are also considered as an alternative profit source for farmers. From a plant breeding standpoint, maize is greatest example of success when it comes to the exploitation of heterosis and therefore most of the investment in genetic breeding done by private companies is in the development of simple GMO single-cross hybrids. In today’s market, there are rarely any specialty maize cultivars available, creating a niche for public funded research and development centers to exploit with their conventional type cultivars. This article discusses the relevance of the specialty maize market niches and the role of the Maize Genetic Breeding Program of Instituto Agronomico (IAC) in the development of innovations in São Paulo through the launch of conventional cultivars aimed at small and medium producers and niches of specialty maize.

Assessing farmer interest in participatory plant breeding: Who wants to work with scientists?

2008 ◽  
Vol 23 (03) ◽  
pp. 177-187 ◽  
Author(s):  
Julie C. Dawson ◽  
Jessica R. Goldberger
Keyword(s):  
Plant Breeding ◽  
Agricultural Research ◽  
Developed Countries ◽  
Wheat Breeding ◽  
Breeding Program ◽  
Rural Sociology ◽  
Farm Size ◽  
Participatory Plant Breeding ◽  
Wheat Varieties ◽  
Breeding Programs

AbstractParticipatory research, particularly participatory plant breeding (PPB), can increase the relevance of public-sector research to the agricultural community. PPB has mostly been used in developing countries with resource-poor farmers, but there is increasing interest among farmers in developed countries who are dissatisfied with the performance of available varieties. In 2006, scientists associated with the winter and spring wheat breeding programs in the Department of Crop and Soil Sciences and the Department of Community and Rural Sociology at Washington State University (WSU) conducted a survey of members of the Washington Association of Wheat Growers. Through analysis of the survey results, we sought to understand (1) whether or not farmers want to work with scientists in PPB programs and (2) the determinants of PPB interest. Results indicated that 52% of Washington wheat growers were interested in working with WSU scientists in a participatory breeding program. Interested farmers tended to be younger and college educated with fewer years of farming experience. Moreover, PPB interest appeared to be related positively to farm size, the number of wheat varieties planted, use of and interest in alternative production and marketing practices (e.g., seed saving, organic agriculture), and prior experience with WSU. Based on this analysis and ongoing discussions with farmers, we hope to develop a participatory wheat breeding program where farmers are able to choose their level of involvement with the breeding process based on their interest and needs. This new program will increase the relevance of WSU's wheat breeding programs to farmers in the state and could serve as a model for other public agricultural research programs seeking to increase farmer involvement and, thereby, democratize agricultural research.

Population Structure And Diversity Among Improved Cowpea Varieties From Senegal Based On Microsatellite Markers

2021 ◽  
pp. 7
Author(s):  
◽  
◽  
◽  
Keyword(s):  
Genetic Diversity ◽  
Population Structure ◽  
Microsatellite Markers ◽  
Agricultural Research ◽  
Human Consumption ◽  
Breeding Programs ◽  
Cowpea Varieties ◽  
Total Variability ◽  
Varietal Variation ◽  
Set Up

Cowpea (Vigna unguiculata) is used in West Africa for both human consumption and animal feeding. Despite its importance, the production of the crop is hampered by biotic and abiotic constraints. To overcome these constraints, the Senegalese Institute of Agricultural Research (ISRA) has set up a breeding program since 1960 leading to the release of productive varieties. Information of the genetic diversity for these varieties could improve the effectiveness of further breeding programs. The objectives of this study was to assess the genetic diversity and the population structure of 11 cowpea improved varieties from ISRA collection. Twelve (12) polymorphic microsatellite markers were used and the analysis of genotypic data showed a total of 39 alleles ranging from 2 (SSR6288, SSR6311 and SSR6827) to 6 (SSR6807) per locus. Polymorphism rate ranged from 8.33% (Mougne and Kelle) to 58.33% (Mouride) with an average of 31.06%. Intra varietal genetic diversity was very weak (0.012 to 0.091). The genetic similarity revealed that Melakh and Pakau varieties were genetically the closest while Bambey 21 and Sam were the most distant. These results are confirmed by the dendrogram, which also showed that Thieye, Leona, Kelle, Sam, Mougne and Yacine varieties have a higher genetic stability than Lisard, Melakh, Pakau, Mouride and Bambey 21. Eighty-seven percent (87%) of the total variability was attributed to inter varietal variability while 17% was due to intra varietal variation. These results provide a better knowledge of genetic resources of cowpea varieties released and held by ISRA and constitute important input for further cowpea breeding programs.

scholarly journals Analytical assessment of maize kernels for Fe, Zn, and β-carotene dense cultivars with low phytate contents

2020 ◽  
Vol 49 (1) ◽  
pp. 40-48
Author(s):  
A. Sharma ◽  
S. Prasad ◽  
R. Arun Kumar ◽  
S. Jaiswal ◽  
P.K. Agrawal ◽  
...  
Keyword(s):  
Molar Ratio ◽  
Lower Amount ◽  
Maize Breeding ◽  
Breeding Programs ◽  
Maize Cultivars ◽  
Maize Genotypes ◽  
Analytical Assessment ◽  
Maize Kernels ◽  
Hill Agriculture ◽  
Β Carotene

The present paper reports that significant genetic variability was evident in Fe, Zn, β-carotene, and phytic acid (phytate, PA) contents in a set of 39 diverse maize genotypes collected from maize breeding programme of hill agriculture, India. The Fe, Zn, β-carotene, and PA concentrations were found to be in the range 19.31–50.64 mg kg−1, 12.60–37.18 mg kg−1, 0.17–8.27 µg g−1, and 6.59–7.13 g kg−1, respectively. The genotypes V335, V420, V393, V416, V414, V372, and V351 were identified to have higher concentration of β-carotene, Fe, and Zn but lower amount of PA. Possible availability of the minerals Fe and Zn was determined using molar ratio between PA as inhibitor and β-carotene as promoter for their absorption. The micronutrient molar ratio showed that Fe and Zn traits could be dependent of each other. Low R2 value revealed relation between β-carotene and kernel colour. The selected genotypes could be considered as potential sources of favourable genes for further breeding programs to develop micronutrient enriched maize cultivars.

scholarly journals HANDY: a device for assessing resistance to mechanical crushing of maize kernel

Plant Methods ◽  
2021 ◽  
Vol 17 (1) ◽  
Author(s):  
Yuan Su ◽  
Yang Xu ◽  
Tao Cui ◽  
Xiaojun Gao ◽  
Guoyi Xia ◽  
...  
Keyword(s):  
Moisture Content ◽  
Goodness Of Fit ◽  
Function Analysis ◽  
Physical Damage ◽  
Maize Kernel ◽  
Rotating Speed ◽  
Maize Cultivars ◽  
Maize Varieties ◽  
New Perspective ◽  
Mechanical Crushing

Abstract Background How to control the physical damage during maize kernel harvesting is a major problem for both mechanical designers and plant breeders. A limitation of addressing this problem is lacking a reliable method for assessing the relation between kernel damage susceptibility and threshing quality. The design, construction, and testing of a portable tool called “HANDY”, which can assess the resistance to mechanical crushing in maize kernel. HANDY can impact the kernel with a special accelerator at a given rotating speed and then cause measurable damage to the kernel. These factors are varied to determine the ideal parameters for operating the HANDY. Results Breakage index (BI, target index of HANDY), decreased as the moisture content of kernel increased or the rotating speed decreased within the tested range. Furthermore, the HANDY exhibited a greater sensitivity in testing kernels at higher moisture level influence on the susceptibility of damage kernel than that in Breakage Susceptibility tests, particularly when the centrifugation speed is about 1800 r/min and the centrifugal disc type is curved. Considering that the mechanical properties of kernels vary greatly as the moisture content changes, a subsection linear (average goodness of fit is 0.9) to predict the threshing quality is built by piecewise function analysis, which is divided by kernel moisture. Specifically, threshing quality is regarded as a function of the measured result of the HANDY. Five maize cultivars are identified with higher damage resistance among 21 tested candidate varieties. Conclusions The HANDY provides a quantitative assessment of the mechanical crushing resistance of maize kernel. The BI is demonstrated to be a more robust index than breakage susceptibility (BS) when evaluating threshing quality in harvesting in terms of both reliability and accuracy. This study also offers a new perspective for evaluating the mechanical crushing resistance of grains and provides technical support for breeding and screening maize varieties that are suitable for mechanical harvesting.

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