scholarly journals Floral Biology and Pollination Efficiency in Yam (Dioscorea spp.)

Agriculture ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 560
Author(s):  
Jean M. Mondo ◽  
Paterne A. Agre ◽  
Alex Edemodu ◽  
Patrick Adebola ◽  
Robert Asiedu ◽  
...  
Keyword(s):  
Pollen Grains ◽  
Floral Biology ◽  
Pollination Efficiency ◽  
Genetic Progress ◽  
Breeding Programs ◽  
Flower Abortion ◽  
Flowering Asynchrony ◽  
Fruit And Seed Set ◽  
The Tropics ◽  
Applied Knowledge

Yam (Dioscorea spp.) is a monocotyledonous herbaceous vine cultivated for its starchy underground or aerial tubers in the tropics and subtropics. It is an allogamous and polyploid species that reproduces by both sexual and asexual mechanisms. However, many of the landrace cultivars, including most of the popular varieties, reproduce exclusively by vegetative propagation (planting the tubers). These varieties are either sterile or produce sparse and irregular flowering with high flower abortion rate, low fruit and seed set. Production of crossbreed seeds for genetic improvement and for maintaining genetic diversity in yams is, therefore, mainly achieved through natural or managed pollination. Flowering in yam is mostly dioecious and, in some instances, monoecious. Flowering asynchrony, sticky nature of the pollen grains, and cross incompatibility are among the challenges in making genetic progress in yam breeding. There are many limitations in basic and applied knowledge of yam flower biology and pollination. This paper, therefore, reviews the flowering biology, pollination, and methods of improving pollination efficiency in yam breeding programs.

scholarly journals Genomic Analysis, Progress and Future Perspectives in Dairy Cattle Selection: A Review

Animals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 599
Author(s):  
Miguel A. Gutierrez-Reinoso ◽  
Pedro M. Aponte ◽  
Manuel Garcia-Herreros
Keyword(s):  
Dairy Cattle ◽  
Production Efficiency ◽  
Association Studies ◽  
Phenotypic Traits ◽  
Progeny Testing ◽  
Genome Wide Association Studies ◽  
Genetic Progress ◽  
Breeding Programs ◽  
Increased Risk ◽  
Selection Of

Genomics comprises a set of current and valuable technologies implemented as selection tools in dairy cattle commercial breeding programs. The intensive progeny testing for production and reproductive traits based on genomic breeding values (GEBVs) has been crucial to increasing dairy cattle productivity. The knowledge of key genes and haplotypes, including their regulation mechanisms, as markers for productivity traits, may improve the strategies on the present and future for dairy cattle selection. Genome-wide association studies (GWAS) such as quantitative trait loci (QTL), single nucleotide polymorphisms (SNPs), or single-step genomic best linear unbiased prediction (ssGBLUP) methods have already been included in global dairy programs for the estimation of marker-assisted selection-derived effects. The increase in genetic progress based on genomic predicting accuracy has also contributed to the understanding of genetic effects in dairy cattle offspring. However, the crossing within inbred-lines critically increased homozygosis with accumulated negative effects of inbreeding like a decline in reproductive performance. Thus, inaccurate-biased estimations based on empirical-conventional models of dairy production systems face an increased risk of providing suboptimal results derived from errors in the selection of candidates of high genetic merit-based just on low-heritability phenotypic traits. This extends the generation intervals and increases costs due to the significant reduction of genetic gains. The remarkable progress of genomic prediction increases the accurate selection of superior candidates. The scope of the present review is to summarize and discuss the advances and challenges of genomic tools for dairy cattle selection for optimizing breeding programs and controlling negative inbreeding depression effects on productivity and consequently, achieving economic-effective advances in food production efficiency. Particular attention is given to the potential genomic selection-derived results to facilitate precision management on modern dairy farms, including an overview of novel genome editing methodologies as perspectives toward the future.

scholarly journals Genetic Variability, Correlation among Agronomic Traits, and Genetic Progress in a Sugarcane Diversity Panel

Agriculture ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 533
Author(s):  
Fernanda Zatti Barreto ◽  
Thiago Willian Almeida Balsalobre ◽  
Roberto Giacomini Chapola ◽  
Antonio Augusto Franco Garcia ◽  
Anete Pereira Souza ◽  
...  
Keyword(s):  
Genetic Parameters ◽  
Mixed Model ◽  
Agronomic Traits ◽  
Average Increase ◽  
Genetic Progress ◽  
Breeding Programs ◽  
Future Studies ◽  
Diversity Panel ◽  
Adjusted Means ◽  
Historical Series

Sugarcane breeding programs require 15 years of experimentation to create more productive cultivars, and estimates of genetic progress can indicate the efficiency of breeding programs. In this study, we used a diversity panel, the Brazilian Panel of Sugarcane Genotypes (BPSG), with the following objectives: (i) to estimate, through a mixed model, the adjusted means and genetic parameters of ten traits evaluated over three harvest years; (ii) to estimate genotypic correlation among those traits; and (iii) to estimate genetic progress over six decades of breeding. The heritabilities ranged from 0.43 to 0.88, and we detected 42 significant correlations, 9 negative and 33 positive. Over six decades, the sucrose-related traits BRIX, POL%C, and POL%J showed an average increase per decade of 0.27 °Brix (0.26% and 0.31%, respectively). Stalk number, height, and weight of the plot, and cane and sucrose yields revealed average increases per decade of 3.27 stalks, 0.06 m, 9.42 kg, 11.22 t/ha, and 2.08 t/ha, respectively. The genetic progress of the main agronomic traits is discussed through a historical series of sugarcane genotypes present in the BPSG. The findings of this study could contribute to the management of new breeding strategies and allow for future studies of associative mapping.

Breeding Programs and Genetic Progress

2017 ◽  
pp. 165-190 ◽  
Author(s):  
Aik Chin Soh ◽  
Sean Mayes ◽  
Jeremy Roberts ◽  
Nicolas Philippe Daniel Turnbull ◽  
Tristan Durand-Gasselin ◽  
...  
Keyword(s):  
Genetic Progress ◽  
Breeding Programs

ARE TODAY’S DAIRY CATTLE BREEDING PROGRAMS SUITABLE FOR TOMORROW’S PRODUCTION REQUIREMENTS?

1980 ◽  
Vol 60 (2) ◽  
pp. 253-264 ◽  
Author(s):  
A. J. McALLISTER
Keyword(s):  
Dairy Cattle ◽  
Genetic Improvement ◽  
Herd Size ◽  
Breeding Program ◽  
Genetic Trend ◽  
Genetic Progress ◽  
Breeding Programs ◽  
Holstein Breed ◽  
Dairy Cattle Breeding ◽  
National Production

In the last decade the dairy cattle population has declined to a level of 1.9 million cows in 1978 with about 56% of these cows bred AI and nearly 20% of the population enrolled in a supervised milk recording program. The decline in cow numbers has been accompanied by an increase in herd size and production per cow. The current breeding program of the dairy industry is a composite of breeding decisions made by AI organizations, breeders who produce young bulls for sampling and all dairymen who choose the sires and dams of their replacement heifers. Estimates of genetic trend from 1958–1975 for milk production in the national milk recorded herd range from 21 to 55 kg per year for the four dairy breeds with Holsteins being 41 kg per year. Both differential use of superior proven sires and improved genetic merit of young bulls entering AI studs contribute to this genetic improvement. Various national production and marketing alternatives were examined. Selection is a major breeding tool in establishing a breeding program to meet national production requirements for milk and milk products once the selection goal is defined. AI and young sire sampling programs will continue to be the primary vehicle for genetic improvement through selection regardless of the selection goal. The current resources of milk-recorded cows bred AI is not being fully utilized to achieve maximum genetic progress possible from young sire sampling indicate that the number of young bulls sampled annually in the Holstein breed could be tripled with the existing milk-recorded and AI bred dairy cow population. Expanded milk recording and AI breeding levels could increase the potential for even further genetic improvement. The potential impact of selection for other traits, crossbreeding and the use of embryo transfer of future breeding programs is highlighted.

scholarly journals Genetic Advance of Durum Wheat Under High Yielding Conditions: The Case of Chile

Agronomy ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 454 ◽  
Author(s):  
Alejandro del Pozo ◽  
Iván Matus ◽  
Kurt Ruf ◽  
Dalma Castillo ◽  
Ana María Méndez-Espinoza ◽  
...  
Keyword(s):  
Durum Wheat ◽  
Grain Quality ◽  
Kernel Weight ◽  
Yield Potential ◽  
High Yield ◽  
Genetic Advance ◽  
Genetic Progress ◽  
Breeding Programs ◽  
Days To Heading ◽  
High Yield Potential

In Chile, durum wheat is cultivated in high-yielding Mediterranean environments, therefore breeding programs have selected cultivars with high yield potential in addition to grain quality. The genetic progress in grain yield (GY) between 1964 and 2010 was 72.8 kg ha−1 per year. GY showed a positive and significant correlation with days to heading, kernels per unit ground area and thousand kernel weight. The gluten and protein content tended to decrease with the year of cultivar release. The correlation between the δ13C of kernels and GY was negative and significant (−0.62, p < 0.05, for all cultivars; and −0.97, p < 0.001, excluding the two oldest cultivars). The yield progress (genetic plus agronomic improvements) of a set of 40–46 advanced lines evaluated between 2006 and 2015 was 569 kg ha−1 per year. Unlike other Mediterranean agro-environments, a longer growing cycle together with taller plants seems to be related to the increase in the GY of Chilean durum wheat during recent decades.

The History of Cacao and Its Diseases in the Americas

2020 ◽  
Vol 110 (10) ◽  
pp. 1604-1619 ◽  
Author(s):  
Jorge R. Díaz-Valderrama ◽  
Santos T. Leiva-Espinoza ◽  
M. Catherine Aime
Keyword(s):  
Latin American ◽  
Smallholder Farmers ◽  
Colonial Period ◽  
Breeding Programs ◽  
Center Of Origin ◽  
Republican Period ◽  
History Of ◽  
Broom Disease ◽  
The Tropics ◽  
Frosty Pod Rot

Cacao is a commodity crop from the tropics cultivated by about 6 million smallholder farmers. The tree, Theobroma cacao, originated in the Upper Amazon where it was domesticated ca. 5450 to 5300 B.P. From this center of origin, cacao was dispersed and cultivated in Mesoamerica as early as 3800 to 3000 B.P. After the European conquest of the Americas (the 1500s), cacao cultivation intensified in several loci, primarily Mesoamerica, Trinidad, Venezuela, and Ecuador. It was during the colonial period that cacao diseases began emerging as threats to production. One early example is the collapse of the cacao industry in Trinidad in the 1720s, attributed to an unknown disease referred to as the “blast”. Trinidad would resurface as a production center due to the discovery of the Trinitario genetic group, which is still widely used in breeding programs around the world. However, a resurgence of diseases like frosty pod rot during the republican period (the late 1800s and early 1900s) had profound impacts on other centers of Latin American production, especially in Venezuela and Ecuador, shifting the focus of cacao production southward, to Bahia, Brazil. Production in Bahia was, in turn, dramatically curtailed by the introduction of witches’ broom disease in the late 1980s. Today, most of the world’s cacao production occurs in West Africa and parts of Asia, where the primary Latin American diseases have not yet spread. In this review, we discuss the history of cacao cultivation in the Americas and how that history has been shaped by the emergence of diseases.

scholarly journals Breeding biology and distyly in Palicourea rigida H. B. & K. (Rubiaceae) in the Cerrados of Central Brazil

2010 ◽  
Vol 24 (3) ◽  
pp. 686-696 ◽  
Author(s):  
Adriana de Oliveira Machado ◽  
Ana Palmira Silva ◽  
Helder Consolaro ◽  
Mariluza A. Granja e Barros ◽  
Paulo Eugênio Oliveira
Keyword(s):  
Reproductive Success ◽  
Fruit Set ◽  
Pollen Grains ◽  
Floral Biology ◽  
Nectar Production ◽  
Central Brazil ◽  
Palicourea Rigida ◽  
Floral Visitors ◽  
Compatible Pollen ◽  
Incompatibility Reactions

Distyly is a floral polymorphism more common among the Rubiaceae than in any other angiosperm group. Palicourea rigida is a typically distylous species of the Rubiaceae widely distributed in the Brazilian Cerrados. This work aimed to study the floral biology and breeding system of P. rigida in order to verify if there wasasymmetry between floral morphs. The work was carried out at Fazenda Água Limpa, Brasília-DF, from 1993 to 1995; and at Serra Caldas Novas State Park-Goias and in Clube Caça e Pesca Itororó de Uberlândia-Minas Gerais in 2005 and 2006. Density, height and pin/thrum ratio were assessed for flowering individuals in all areas. Plants were investigated for differences in floral morphology, nectar production, reproductive success and site of self incompatibility reactions. Blooming period was long and concentrated during the rains. Flowers were clearly distylous and with reciprocal herkogamy. They produced nectar and lasted for a single day. In spite of differences in density and height, populations were mostly isoplethic. Nectar production varied in volume and concentration but the differences could not be associated with floral morphs. The species is self-incompatible but reproductive success was always high and independent of floral morphs. There were differences in the site of incompatibility barriers between floral morphs, which were similar to those observed for other Rubiaceae. The main floral visitors and pollinators were the hummingbirds Colibri serrirostris and Eupetomena macroura. High fruit-set indicates that the pollinators transported enough compatible pollen grains between floral morphs, despite their territorial behavior.

scholarly journals A microsatellite library for Carica papaya L. cv. Sunrise solo

2003 ◽  
Vol 25 (2) ◽  
pp. 263-267 ◽  
Author(s):  
Silvia Correa Santos ◽  
Carlos Ruggiero ◽  
Cristina Lacerda Soares Petrarolha Silva ◽  
Eliana Gertrudes Macedo Lemos
Keyword(s):  
Molecular Markers ◽  
Related Species ◽  
Carica Papaya ◽  
The Self ◽  
Pollination Efficiency ◽  
Breeding Programs ◽  
The Matrix ◽  
Papaya Tree ◽  
Unique Band ◽  
Sexual Form

In experimental areas of the Education and Researches Ilha Solteira and Jaboticabal UNESP/Campus farms were selected and tagged 20 hermaphrodite plants and 20 feminine of cultivar Sunrise Solo, Improved Sunrise Solo cv.72/12 and Baixinho of Santa Amália.The seeds origined of the selected fruits were cropped to be analysed the self-pollination efficiency and frequency of the sex in the progenies. After that, samples of the young leaf of the matrix plants were colected for the extration of the DNA. It was built five library enriched of microsatellite sequencies, using probes (TCA)10, (TC)13, (GATA)4, (CAC)10 e (TGAG)8.It was possible the development of the primers only in the library that has utilized the probe (TCA)10. This probe allowed the design of 32 primer pairs. From these, 31 presented pattern of unique band in agarose Metaphor and in acrilamide. For primer S36 were observed 2 bands, but with no polymorphism to differentiation in the sexual form at papaya tree culture. However, these primers can be tested, in the futures, in the investigation of the others features in segregated populations of this specie and the related species, germoplasm analysis, cultivars identification, parent evolution and molecular markers for the assisted plant breeding programs.

scholarly journals Prolonged Cold Storage Affects Pollen Viability and Germination along with Hydrogen Peroxide and Nitric Oxide Content in Rosa hybrida

2016 ◽  
Vol 44 (1) ◽  
pp. 6-10 ◽  
Author(s):  
Anca MACOVEI ◽  
Matteo CASER ◽  
Mattia DONÀ ◽  
Alberto VALASSI ◽  
Annalisa GIOVANNINI ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Hydrogen Peroxide ◽  
Pollen Viability ◽  
Storage Period ◽  
Pollen Grains ◽  
Rosa Hybrida ◽  
Tube Growth ◽  
Oxide Content ◽  
Breeding Programs ◽  
Wide Range

Roses (Rosa hybrida) are the most important ornamental cut-flowers and breeders’ main focus is to develop new desirable modern cultivars. Rose breeding programs center on the introduction of new flower colors, thornless stems, higher production and good post-harvest performance. The study of the main pollen traits, such as pollen quantity and quality, viability, longevity, morphological homogeneity, germination and tube growth, is important for building suitable breeding programs. Recently, a number of studies have shown that reactive oxygen species, like hydrogen peroxide, and nitric oxide, are involved in a wide range of signaling processes including pollen tube growth and pollen-pistil recognition. Pollen viability after anther dehiscence is crucial for successful crossbreeding. In the present work, pollen grains from 5 hybrid tea rose cultivars were stored at -20 °C up to 12 months. Pollen viability and germination rate was monitored in order to provide useful information about pollen storage length. Additionally, pollen grains were tested for their content in hydrogen peroxide and nitric oxide by using a novel approach where the fluorescence is read in a quantitative RealTime PCR (qRT-PCR) machine. Pollen viability and in vitro pollen germination capacity varied among the rose genotypes, while a progressive decrease was evidenced during 12 months of storage at low temperature. Both hydrogen peroxide and nitric oxide production were found to be genotype-dependent, whilst accumulation of the two molecules was observed during the storage period. A putative detrimental effect of these molecules during pollen conservation is hypothesized.

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