scholarly journals Assessment of Genetic Gain Trends for Yield in IRRI Rice Varieties in the Philippines Using “era” Trial Studies and Implications for Future Rice Breeding

2021 ◽  
Author(s):  
Shoba Venkatanagappa ◽  
Bertrand C. Y Collard ◽  
Alaine Gulles ◽  
Mohammad Rafiq Islam ◽  
Vitaliano Lopena ◽  
...  
Keyword(s):  
Genetic Gain ◽  
The Philippines ◽  
Population Increase ◽  
Rice Varieties ◽  
Breeding Programs ◽  
Genetic Characteristics ◽  
Yield Increase ◽  
Genetic Gains ◽  
Realized Genetic Gains ◽  
Staple Crop

Abstract Rice is a staple crop for 3.5 billion people in the world. To meet the challenges of the rice production for food security and demand due to population increase, yield improvement due to a rice variety’s genetic characteristics is imperative. Two studies presented in this paper were undertaken at the International Rice Research Institute (IRRI) in the Philippines, to assess genetic gains for yield in rice varieties bred over the past 50 years. These studies are called as “Era” studies as the varieties used for trials were released during long and distinct periods. Due to the differences in time periods of studies, varieties and locations, the studies were treated separately so as to not to compromise the data analyses. The studies demonstrated that IRRI developed varieties have achieved genetic gains and levels of genetic gains were dependent on correction or otherwise for maturities. In Study 1, the highest level of genetic gain was 0.70% at about a 23 kg ha-1 annual yield increase when not corrected for maturity followed by a genetic gain of 0.62% when corrected for maturity. In Study 2, the highest level of genetic gain was 0.74% at about a 19 kg ha-1 annual yield increase when corrected for maturity followed by 0.66% genetic gain when not corrected for maturity. Implications for breeding programs are discussed, however, the studies were not intended to compare genetic gains achieved through different breeding methods nor to compare genetic gains achieved using plot trials versus realized genetic gains for crops grown under farmers’ management.

scholarly journals Dynamic Insertion of Pot3 in AvrPib Prevailing in a Field Rice Blast Population in the Philippines Led to the High Virulence Frequency Against the Resistance Gene Pib in Rice

2019 ◽  
Vol 109 (5) ◽  
pp. 870-877 ◽  
Author(s):  
Toluwase Olukayode ◽  
Berlaine Quime ◽  
Yin-Chi Shen ◽  
Mary Jeannie Yanoria ◽  
Suobing Zhang ◽  
...  
Keyword(s):  
Resistance Gene ◽  
Rice Blast ◽  
Indica Rice ◽  
The Philippines ◽  
Avirulence Gene ◽  
Rice Varieties ◽  
Breeding Programs ◽  
Genome Wide ◽  
A Genome ◽  
Polymerase Chain

The Magnaporthe oryzae avirulence gene AvrPib is required for the resistance mediated by its cognate resistance gene Pib, which has been intensively used in indica rice breeding programs in many Asian countries. However, the sequence diversity of AvrPib among geographically distinct M. oryzae populations was recently shown to be increasing. Here, we selected a field population consisting of 248 rice blast isolates collected from a disease hotspot in Philippine for the analysis of AvrPib haplotypes and their pathogenicity against Pib. We found that all of the isolates were virulent to Pib and each of them contained an insertion of Pot3 transposon in AvrPib. Moreover, Pot3 insertion was detected in different genomic positions, resulting in three different AvrPib haplotypes, designated avrPib-H1 to H3. We further conducted a genome-wide Pot2 fingerprinting analysis by repetitive element palindromic polymerase chain reaction (PCR) and identified seven different lineages out of 47 representative isolates. The isolates belonging to the same lineage often had the same AvrPib haplotype. In contrast, the isolates having the same AvrPib haplotypes did not always belong to the same lineages. Both mating types MAT1-1 and MAT1-2 were identified in the population in Bohol and the latter appeared dominant. On the host side, we found that 32 of 52 released rice varieties in the Philippines contained Pib diagnosed by PCR gene-specific primers and DNA sequencing of gene amplicons, suggesting that it was widely incorporated in different rice varieties. Our study highlights the genetic dynamics of rice blast population at both the AvrPib locus and the genome-wide levels, providing insight into the mechanisms of the mutations in AvrPib leading to the breakdown of Pib-mediated resistance in rice.

scholarly journals Genetic gain and relationship of yield and yield attributes of mutant and cross-bred stevia (Stevia rebaudiana) genotypes

2021 ◽  
Vol 22 (8) ◽  
Author(s):  
Suseno Amien ◽  
Haris Maulana ◽  
Dedi Ruswandi ◽  
Sarifah Nurjanah
Keyword(s):  
Plant Breeding ◽  
Genetic Gain ◽  
Genetic Parameters ◽  
Field Experiments ◽  
Stevia Rebaudiana ◽  
Breeding Programs ◽  
Yield Attributes ◽  
Genetic Gains ◽  
High Heritability ◽  
Relationship Of

Abstract. Amien S, Maulana H, Ruswandi D, Nurjanah S. 2021. Genetic gain and relationship of yield and yield attributes of mutant and cross-bred stevia (Stevia rebaudiana) genotypes. Biodiversitas 22: 3119-3126. Plant breeding programs involved many traits and genetic parameters in the selection process. The information on genetic parameters on yield and other related traits provided an overview for breeders and farmers in selecting new superior genotypes. The purpose of this study was to estimate genetic parameters including heritability and genetic gains in yield and other traits, to determine the relationship between various traits, and to select superior stevia (Stevia rebaudiana Bertoni) genotypes for each trait. Field experiments were carried out in two planting environments, namely, the highlands and the medium plains employing a randomized completed block design and each genotype was three replicates. The results showed that the yield had high heritability and genetic gains  ??in mutant populations, whereas cross-bred populations had moderate heritability and low genetic gains. Stem weight (SW) and number of leaves (NoL) traits were identified as having high heritability and genetic gains in both populations. The GT biplot measurement showed that the yield was identified to have a significant and positive correlation with SW (p<0.05). H4 was correlated with Number of branches (NoB), Yield, SW, and chlorophyll content (Chl) traits in the cross-bred populations. H9 excelled on and was correlated with NoL and plant height (PH). M11 was identified to be highly correlated with NoL, PH, NoB, and Chl traits in the mutant populations, while M15 excelled on and was correlated with yield and SW. The results of this study revealed that there was a potential for improvement in the traits tested of stevia through cross-bred and mutant populations in different environmental conditions. The selected genotypes can be developed in a suitable environment and used for further stevia plant breeding programs.  

scholarly journals GENETIC GAINS AND SELECTION ADVANCES OF THE UENF-14 POPCORN POPULATION

2018 ◽  
Vol 31 (2) ◽  
pp. 271-278 ◽  
Author(s):  
AMANDA GONÇALVES GUIMARÃES ◽  
ANTÔNIO TEIXEIRA DO AMARAL JÚNIOR ◽  
VALTER JÁRIO DE LIMA ◽  
JHEAN TORRES LEITE ◽  
CARLOS ALBERTO SCAPIM ◽  
...  
Keyword(s):  
Grain Yield ◽  
Genetic Gain ◽  
Recurrent Selection ◽  
Selection Index ◽  
Economic Importance ◽  
Average Height ◽  
Breeding Programs ◽  
Genetic Gains ◽  
Full Sibling ◽  
Selection Of

ABSTRACT Recurrent selection can generate successive gains for characters of economic interest without causing genetic narrowing in the population. However, it has rarely been used in breeding programs in popcorn, especially when using full-sibling progenies to generate more expressive gains. The objective of this study was to estimate the genetic gain of the UENF-14 popcorn population through recurrent selection, and verify the evolution of the gains between the selection cycles four and eight. A total of 200 full-sibling progenies were evaluated in randomized blocks arranged in eight sets within three replicates in two environments; each set containing twenty-five progenies and six controls (selection cycles 4, 5, 6 and 7 of the UENF-14, BRS-Angela and IAC-125). The average height, prolificacy, 100-grain weight, ear weight, grain yield, and grain popping expansion of the plants were evaluated. In the selection of the thirty superior progenies for the eighth cycle, the Mulamba and Mock selection index was used, which generated estimated genetic gains of 4.60 for grain yield and 3.61% for popping expansion. The grain yield increased 111.99 kg ha-1 and the popping expansion increased 1.75 mL g-1 per cycle. The evolution of the cycles resulted in an accumulated genetic gain for the main characters of economic importance, allowing the prediction of success in the continuity of the recurrent selection.

scholarly journals Breeding of High Cooking and Eating Quality in Rice by Marker-Assisted Backcrossing (MABc) Using KASP Markers

Plants ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 804
Author(s):  
Me-Sun Kim ◽  
Ju-Young Yang ◽  
Ju-Kyung Yu ◽  
Yi Lee ◽  
Yong-Jin Park ◽  
...  
Keyword(s):  
Genetic Background ◽  
Amylose Content ◽  
Yield Potential ◽  
Eating Quality ◽  
Breeding Cycle ◽  
Recurrent Parent ◽  
Rice Varieties ◽  
Breeding Programs ◽  
Genome Wide ◽  
Cooking And Eating Quality

The primary goals of rice breeding programs are grain quality and yield potential improvement. With the high demand for rice varieties of premium cooking and eating quality, we developed low-amylose content breeding lines crossed with Samgwang and Milkyqueen through the marker-assisted backcross (MABc) breeding program. Trait markers of the SSIIIa gene referring to low-amylose content were identified through an SNP mapping activity, and the markers were applied to select favorable lines for a foreground selection. To rapidly recover the genetic background of Samgwang (recurrent parent genome, RPG), 386 genome-wide markers were used to select BC1F1 and BC2F1 individuals. Seven BC2F1 lines with targeted traits were selected, and the genetic background recovery range varied within 97.4–99.1% of RPG. The amylose content of the selected BC2F2 grains ranged from 12.4–16.8%. We demonstrated the MABc using a trait and genome-wide markers, allowing us to efficiently select lines of a target trait and reduce the breeding cycle effectively. In addition, the BC2F2 lines confirmed by molecular markers in this study can be utilized as parental lines for subsequent breeding programs of high-quality rice for cooking and eating.

scholarly journals Reproductive, pathogenic and genotypic characterisation of five Meloidogyne graminicola populations from the Philippines on susceptible and resistant rice varieties

Nematology ◽  
2018 ◽  
Vol 20 (4) ◽  
pp. 299-318
Author(s):  
Ma. Teodora Nadong Cabasan ◽  
Arvind Kumar ◽  
Stéphane Bellafiore ◽  
Dirk De Waele
Keyword(s):  
Phenotypic Variability ◽  
The Philippines ◽  
Growth And Yield ◽  
Oryza Glaberrima ◽  
Rice Varieties ◽  
Single Nucleotide ◽  
Nematode Reproduction ◽  
Rdna Genes ◽  
Meloidogyne Graminicola ◽  
Disease Induction

Summary Five populations of Meloidogyne graminicola isolated from different rice-growing areas in the Philippines were characterised. The populations showed little phenotypic variability of second-stage juveniles and female perineal pattern. Differences in reproduction among M. graminicola populations were not observed on mature resistant Oryza glaberrima varieties ‘TOG5674’, ‘TOG5675’, ‘RAM131’ and ‘CG14’, or on susceptible O. sativa varieties ‘IR64’ and ‘UPLRi-5’. In all infected rice varieties, plant growth and yield-contributing traits showed no differences among the populations. A search on M. graminicola populations from the Philippines for single-nucleotide polymorphism on the sequences of Internal Transcribed Spacer (ITS) of rDNA genes and mtDNA indicated only few points of heteroplasmy. Nematode reproduction and disease induction of the five M. graminicola populations in the Philippines exerted the same level of aggressiveness and virulence. The absence of resistance-breaking populations of M. graminicola is important for the maintenance of durability of resistance to this important rice pathogen.

scholarly journals Genetic gains under three methods of selection

1962 ◽  
Vol 3 (3) ◽  
pp. 417-423 ◽  
Author(s):  
D. J. Finney
Keyword(s):  
Linear Function ◽  
Genetic Gain ◽  
Index Selection ◽  
Genetic Gains ◽  
Independent Culling

Results obtained by Young for the expectation of genetic gain in an arbitrary linear function of several traits under selection by independent culling levels, under tandem selection, and under index selection have been obtained in slightly more general form and their dependence on basic genetic and phenotypic parameters exhibited. A warning is given about the effects of selection in modifying the distribution of traits; when the distribution has become appreciably non-normal, any calculation of genetic gains from formulae based on normality will tend to overestimation.

scholarly journals Genetic parameters and estimated genetic gains in young rubber tree progenies

2013 ◽  
Vol 48 (4) ◽  
pp. 411-416 ◽  
Author(s):  
Cecília Khusala Verardi ◽  
Erivaldo José Scaloppi Junior ◽  
Guilherme Augusto Peres Silva ◽  
Lígia Regina Lima Gouvêa ◽  
Paulo de Souza Gonçalves
Keyword(s):  
Genetic Gain ◽  
Genetic Parameters ◽  
Block Design ◽  
Rubber Tree ◽  
First Year ◽  
Genetic Gains ◽  
Selection Gain ◽  
Randomized Block Design ◽  
Using Data ◽  
Selection Of

The objective of this work was to assess the genetic parameters and to estimate genetic gains in young rubber tree progenies. The experiments were carried out during three years, in a randomized block design, with six replicates and ten plants per plot, in three representative Hevea crop regions of the state of São Paulo, Brazil. Twenty-two progenies were evaluated, from three to five years old, for rubber yield and annual girth growth. Genetic gain was estimated with the multi-effect index (MEI). Selection by progenies means provided greater estimated genetic gain than selection based on individuals, since heritability values of progeny means were greater than the ones of individual heritability, for both evaluated variables, in all the assessment years. The selection of the three best progenies for rubber yield provided a selection gain of 1.28 g per plant. The genetic gains estimated with MEI using data from early assessments (from 3 to 5-year-old) were generally high for annual girth growth and rubber yield. The high genetic gains for annual girth growth in the first year of assessment indicate that progenies can be selected at the beginning of the breeding program. Population effective size was consistent with the three progenies selected, showing that they were not related and that the population genetic variability is ensured. Early selection with the genetic gains estimated by MEI can be made on rubber tree progenies.

scholarly journals Breeding Temperate Japonica Rice Varieties Adaptable to Tropical Regions: Progress and Prospects

Agronomy ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 2253
Author(s):  
Myrish Pacleb ◽  
O-Young Jeong ◽  
Jeom-Sig Lee ◽  
Thelma Padolina ◽  
Rustum Braceros ◽  
...  
Keyword(s):  
The Philippines ◽  
Tropical Region ◽  
Japonica Rice ◽  
Rice Varieties ◽  
Temperate Japonica ◽  
Tropical Regions ◽  
Tropical Environments ◽  
Increasing Demand ◽  
Northeast Asian ◽  
The Tropics

Temperate japonica rice is mainly cultivated in temperate regions. Many temperate japonica varieties have a superior grain quality that is preferred in Northeast Asian countries such as Japan, Korea, and China. The changes in consumers’ preferences in Southeast Asia and Western countries has contributed to increasing the demand for temperate japonica. Most temperate japonica varieties developed in temperate regions typically exhibit extra-early flowering under the short-day conditions in the tropics, which usually results in severely reduced yields. Since 1992, we have been developing temperate japonica varieties that can adapt to tropical environments to meet the increasing demand for temperate japonica rice, having released six varieties in the Philippines. Especially, the yield of one of the temperate japonica varieties, Japonica 7, was comparable to the yields of leading indica varieties in the Philippines. Here, we discuss the current breeding initiatives and future plans for the development of tropical-region-bred temperate japonica rice.

scholarly journals Genetic Gains in Pearl Millet in India: Insights Into Historic Breeding Strategies and Future Perspective

2021 ◽  
Vol 12 ◽  
Author(s):  
Om Parkash Yadav ◽  
S. K. Gupta ◽  
Mahalingam Govindaraj ◽  
Rajan Sharma ◽  
Rajeev K. Varshney ◽  
...  
Keyword(s):  
Pearl Millet ◽  
Pennisetum Glaucum ◽  
Sub Saharan Africa ◽  
Hybrid Breeding ◽  
Future Perspective ◽  
Yield Increase ◽  
Genetic Gains ◽  
Parental Lines ◽  
Sub Saharan ◽  
Periodic Replacement

Pearl millet (Pennisetum glaucum R. Br.) is an important staple and nutritious food crop in the semiarid and arid ecologies of South Asia (SA) and Sub-Saharan Africa (SSA). In view of climate change, depleting water resources, and widespread malnutrition, there is a need to accelerate the rate of genetic gains in pearl millet productivity. This review discusses past strategies and future approaches to accelerate genetic gains to meet future demand. Pearl millet breeding in India has historically evolved very comprehensively from open-pollinated varieties development to hybrid breeding. Availability of stable cytoplasmic male sterility system with adequate restorers and strategic use of genetic resources from India and SSA laid the strong foundation of hybrid breeding. Genetic and cytoplasmic diversification of hybrid parental lines, periodic replacement of hybrids, and breeding disease-resistant and stress-tolerant cultivars have been areas of very high priority. As a result, an annual yield increase of 4% has been realized in the last three decades. There is considerable scope to further accelerate the efforts on hybrid breeding for drought-prone areas in SA and SSA. Heterotic grouping of hybrid parental lines is essential to sustain long-term genetic gains. Time is now ripe for mainstreaming of the nutritional traits improvement in pearl millet breeding programs. New opportunities are emerging to improve the efficiency and precision of breeding. Development and application of high-throughput genomic tools, speed breeding, and precision phenotyping protocols need to be intensified to exploit a huge wealth of native genetic variation available in pearl millet to accelerate the genetic gains.

scholarly journals Genomic Selection for Any Dairy Breeding Program via Optimized Investment in Phenotyping and Genotyping

2021 ◽  
Vol 12 ◽  
Author(s):  
Jana Obšteter ◽  
Janez Jenko ◽  
Gregor Gorjanc
Keyword(s):  
Genomic Selection ◽  
Genetic Gain ◽  
Breeding Program ◽  
Progeny Testing ◽  
Initial Training ◽  
Training Population ◽  
Breeding Programs ◽  
Use Of Resources ◽  
Dairy Cattle Breeding ◽  
Close Relatives

This paper evaluates the potential of maximizing genetic gain in dairy cattle breeding by optimizing investment into phenotyping and genotyping. Conventional breeding focuses on phenotyping selection candidates or their close relatives to maximize selection accuracy for breeders and quality assurance for producers. Genomic selection decoupled phenotyping and selection and through this increased genetic gain per year compared to the conventional selection. Although genomic selection is established in well-resourced breeding programs, small populations and developing countries still struggle with the implementation. The main issues include the lack of training animals and lack of financial resources. To address this, we simulated a case-study of a small dairy population with a number of scenarios with equal available resources yet varied use of resources for phenotyping and genotyping. The conventional progeny testing scenario collected 11 phenotypic records per lactation. In genomic selection scenarios, we reduced phenotyping to between 10 and 1 phenotypic records per lactation and invested the saved resources into genotyping. We tested these scenarios at different relative prices of phenotyping to genotyping and with or without an initial training population for genomic selection. Reallocating a part of phenotyping resources for repeated milk records to genotyping increased genetic gain compared to the conventional selection scenario regardless of the amount and relative cost of phenotyping, and the availability of an initial training population. Genetic gain increased by increasing genotyping, despite reduced phenotyping. High-genotyping scenarios even saved resources. Genomic selection scenarios expectedly increased accuracy for young non-phenotyped candidate males and females, but also proven females. This study shows that breeding programs should optimize investment into phenotyping and genotyping to maximize return on investment. Our results suggest that any dairy breeding program using conventional progeny testing with repeated milk records can implement genomic selection without increasing the level of investment.

Sign in / Sign up

Export Citation Format

Share Document