scholarly journals PHENOTYPIC AND GENETIC PARAMETERS ESTIMATED FOR FRESH CORN UNDER DIFFERENT NUTRIENT AVAILABILITY1

2021 ◽  
Vol 34 (4) ◽  
pp. 752-762
Author(s):  
CECÍLIA LEÃO PEREIRA RESENDE ◽  
JULIANA BEZERRA MARTINS ◽  
FELIPE RIBEIRO ILARIA ◽  
CARLA MARIANE MACHADO DOS SANTOS ◽  
FABRICIO RODRIGUES
Keyword(s):  
Nutrient Availability ◽  
Nitrogen Availability ◽  
Genetic Parameters ◽  
Recurrent Selection ◽  
P Availability ◽  
Breeding Programs ◽  
Low Phosphorus ◽  
P Rate ◽  
Selection For ◽  
Low Nitrogen

ABSTRACT The objective of this work was to estimate and compare phenotypic and genetic parameters after three cycles of intrapopulation recurrent selection for fresh corn grown under three nutrient availability conditions. Three experiments derived from the same population (MV-003) were conducted to assess the ability of progenies to absorb nutrients, one under adequate fertilization (control; MV-006), one under low nitrogen availability (N; MV-006N), and one under low phosphorus availability (P; MV-006P). The experiments were carried out in randomized blocks, with 64 half-sib progenies and three replications for each nutritional condition. Chlorophyll index, plant height, ear insertion, ear diameter, ear length, unhusked ear yield, and marketable husked ear were evaluated. The populations showed variability for the three nutrient availability conditions. The variability reduced after only three selection cycles; thus, evaluating a higher number of half-sib progenies, above 64, under low N and P availability is indicated. The rates used to identify the most efficient progenies in breeding programs should be close to the appropriate one, with a slow reduction after the selection cycles. The variability will be thus maintained, with a greater possibility of identifying more promising progenies. In addition, the frequency of favorable alleles increases more gradually and effectively. The N and P rate of 60 kg ha-1 is not indicated as a critical level for the initial phase of the program.

scholarly journals Recurrent Selection for Improved Germination under Water Stress in Russian Dandelion

2017 ◽  
Vol 142 (2) ◽  
pp. 85-91 ◽  
Author(s):  
Katrina J.M. Hodgson-Kratky ◽  
Olivier M. Stoffyn ◽  
David J. Wolyn
Keyword(s):  
Polyethylene Glycol ◽  
Water Stress ◽  
Recurrent Selection ◽  
Field Experiments ◽  
Phenotypic Selection ◽  
Bare Soil ◽  
Promising Candidate ◽  
Breeding Programs ◽  
Selection For

Russian dandelion [Taraxacum kok-saghyz (TKS)] is a promising candidate for introducing natural rubber production into North America. Seeds normally germinate in a humid microenvironment, such as the thatch layer of a lawn or under a canopy of grass; however, 5% to 15% establishment is often observed on bare soil, presumably due to water stress. Phenotypic selection and half-sib family recurrent selection were conducted for three cycles to improve germination in vitro, under low osmotic potential (Ψs), using a polyethylene glycol (PEG) solution. Populations were then tested for establishment on bare soil in the greenhouse and field. Germination under water stress in vitro increased from 5.8% for the cycle 0 (C0) population to 40.8% and 47.8% for the C3-phenotypic and C3-half-sib family populations, respectively. Soil establishment in the greenhouse and field was improved up to two- and 4-fold, respectively, compared with the C0, in two of four greenhouse experiments and three of eight field experiments. Overall, recurrent selection for germination under water stress in vitro has potential to improve establishment in the field and can be incorporated into current breeding programs to support the overall goal of creating cultivars with high-rubber yield.

scholarly journals Marker-assisted selection for quantitative traits

2011 ◽  
Vol 11 (spe) ◽  
pp. 50-55 ◽  
Author(s):  
Ivan Schuster
Keyword(s):  
Molecular Markers ◽  
Cost Reduction ◽  
Marker Assisted Selection ◽  
Quantitative Traits ◽  
Large Scale ◽  
Recurrent Selection ◽  
Phenotypic Selection ◽  
Breeding Programs ◽  
The Subject ◽  
Selection For

Although thousands of scientific articles have been published on the subject of marker-assisted selection (MAS) and quantitative trait loci (QTL), the application of MAS for QTL in plant breeding has been restricted. Among the main causes for this limited use are the low accuracy of QTL mapping and the high costs of genotyping thousands of plants with tens or hundreds of molecular markers in routine breeding programs. Recently, new large-scale genotyping technologies have resulted in a cost reduction. Nevertheless, the MAS for QTL has so far been limited to selection programs using several generations per year, where phenotypic selection cannot be performed in all generations, mainly in recurrent selection programs. Methods of MAS for QTL in breeding programs using self-pollination have been developed.

scholarly journals Genetic control of traits related to phosphorus use efficiency in tropical maize

2015 ◽  
Vol 15 (2) ◽  
pp. 59-65 ◽  
Author(s):  
Flávia Ferreira Mendes ◽  
Lauro José Moreira Guimarães ◽  
Cláudia Teixeira Guimarães ◽  
João Cândido Souza ◽  
Paulo Evaristo Oliveira Guimarães ◽  
...  
Keyword(s):  
Genetic Control ◽  
Agronomic Traits ◽  
P Availability ◽  
Phosphorus Use Efficiency ◽  
P Efficiency ◽  
Breeding Programs ◽  
P Use Efficiency ◽  
Selection Strategies ◽  
Low Phosphorus ◽  
Use Efficiency

Knowing the inheritance of traits is essential to establish selection strategies in breeding programs. The aim of this study was to determine the genetic control of traits related to the phosphorus use efficiency in maize. A total of 280 progenies were developed according to design III, which were evaluated in the field under high and low phosphorus (P) availability. The genetic variance components were estimated for the agronomic traits and indices that define P use efficiency. The results indicated that the additive and dominance effects were important in explaining the genetic variability for the flowering time, grain yield and P efficiency indices. However, dominance effects prevailed, indicating that breeding efforts should be made to develop hybrids exploiting the heterosis for traits related to P use efficiency.

scholarly journals PSVIII-37 Estimation of genetic parameters for novel meat quality and carcass traits in Duroc pigs

2019 ◽  
Vol 97 (Supplement_3) ◽  
pp. 265-265
Author(s):  
Hannah E Willson ◽  
Hinayah Oliveira ◽  
Allan Schinckel ◽  
Daniela Grossi
Keyword(s):  
Meat Quality ◽  
Genetic Parameters ◽  
Carcass Traits ◽  
Genetic Selection ◽  
Relationship Matrix ◽  
Breeding Programs ◽  
Genetically Improved ◽  
Selection Indexes ◽  
Selection For ◽  
Terminal Sire

Abstract In recent years, swine breeding programs have turned their selection attentions from focusing mostly on growth, feed efficiency and percent fat towards including meat quality and carcass traits with aims to efficiently produce nutritious and tasty meat to attend a growing demand for pork. In this context, the success of genetic selection for such traits relies on several factors, especially the heritability (h2) of the traits included in the selection indexes. Therefore, this study aimed to estimate genetic parameters for seven meat quality and carcass traits in Duroc pigs, including: meat lightness (L*), loin pH (pH), marbling (MARB), untrimmed belly weight (UBLW), untrimmed ham weight (UHW), untrimmed loin weight (ULW), and untrimmed shoulder weight (USW). Phenotypic measurements were collected on 2,857 purebred Duroc gilts from a Terminal Sire line. The pedigree-based relationship matrix included 5,316 animals and genetic parameters were estimated using univariate models under the REML approach. The traits studied here were shown to be moderately to highly heritable (h2 estimates were 0.32, 0.42, 0.47, 0.35, 0.24, 0.28, and 0.28 for L*, pH, MARB, UBLW, UHW, ULW, and USW, respectively). Our findings suggest that these traits are under genetic control, and thus, they can be genetically improved if included in selection schemes. The next step will be to estimate the genetic correlation between those traits (among themselves and with other traits), as well as alternatives to efficiently incorporate these traits in the selection indexes.

RESPONSE TO SELECTION FOR STEM LENGTH IN RED CLOVER EVALUATED AT WIDE AND NARROW SPACINGS

1984 ◽  
Vol 64 (4) ◽  
pp. 925-934 ◽  
Author(s):  
S. R. BOWLEY ◽  
N. L. TAYLOR ◽  
P. L. CORNELIUS ◽  
C. T. DOUGHERTY
Keyword(s):  
Recurrent Selection ◽  
Trifolium Pratense ◽  
Red Clover ◽  
Stem Length ◽  
Yield Response ◽  
Response To Selection ◽  
Breeding Programs ◽  
Herbage Yield ◽  
Trifolium Pratense L ◽  
Selection For

Six cycles of phenotypic recurrent selection for stem length were conducted in a 91-cm-spaced planted population of red clover (Trifolium pratense L.) as a means of increasing herbage yield. The objectives of this investigation were (1) to compare the effectiveness of selection for stem length tested in transplants at wide (91 cm) and narrow (7 cm) spacings, and in row seedings and (2) to determine the effect of selection for stem length on herbage yield. Response to selection for stem length was obtained under all plantings; however, greater gains were observed at the wide transplant spacing (3.3 cm∙cycle−1) compared to the narrow transplant spacing (0.7 cm∙cycle−1) and row seeding (0.8 cm∙cycle−1). Densely spaced transplants gave performance similar to row seedings and may be of value to forage crop breeders in situations where yield or quality assessment is desired but seed supplies are insufficient for the establishment of seeded plots, such as in the early stages of breeding programs. Selection for stem length was effective in increasing herbage yield at first harvest but was associated with reduced persistance, decreased regrowth yields, and increased partitioning of dry matter towards the shoot rather than the root during seedling development. Selection for stem length in the regrowth or in the second year, rather than in the primary (seedling) growth, might have avoided the declines in persistence and regrowth yields.Key words: Trifolium pratense L., red clover, recurrent selection, stem length, density, herbage yield

Improvement of effectiveness in maize breeding

2006 ◽  
Vol 54 (3) ◽  
pp. 351-358 ◽  
Author(s):  
P. Pepó
Keyword(s):  
Recurrent Selection ◽  
Genetic Manipulation ◽  
Field Testing ◽  
Tissue Cultures ◽  
Maize Breeding ◽  
Breeding Programmes ◽  
Speed Up ◽  
Selection For

Plant regeneration via tissue culture is becoming increasingly more common in monocots such as maize (Zea mays L.). Pollen (gametophytic) selection for resistance to aflatoxin in maize can greatly facilitate recurrent selection and the screening of germplasm for resistance at much less cost and in a shorter time than field testing. In vivo and in vitro techniques have been integrated in maize breeding programmes to obtain desirable agronomic attributes, enhance the genes responsible for them and speed up the breeding process. The efficiency of anther and tissue cultures in maize and wheat has reached the stage where they can be used in breeding programmes to some extent and many new cultivars produced by genetic manipulation have now reached the market.

ESTIMASI NILAI HERITABILITAS BOBOT IKAN MAS VARIETAS PUNTEN DALAM PROGRAM SELEKSI INDIVIDU

2016 ◽  
Vol 11 (3) ◽  
pp. 217
Author(s):  
Estu Nugroho ◽  
Budi Setyono ◽  
Mochammad Su’eb ◽  
Tri Heru Prihadi
Keyword(s):  
Body Weight ◽  
Selection Response ◽  
Base Population ◽  
Breeding Programs ◽  
Male And Female ◽  
Body Weight Trait ◽  
Population Selection ◽  
Selection For ◽  
Weight Trait ◽  
Selection Of

Program pemuliaan ikan mas varietas Punten dilakukan dengan seleksi individu terhadap karakter bobot ikan. Pembentukan populasi dasar untuk kegiatan seleksi dilakukan dengan memijahkan secara massal induk ikan mas yang terdiri atas 20 induk betina dan 21 induk jantan yang dikoleksi dari daerah Punten, Kepanjen (delapan betina dan enam jantan), Kediri (tujuh betina dan 12 jantan), Sragen (27 betina dan 10 jantan), dan Blitar (15 betina dan 11 jantan). Larva umur 10 hari dipelihara selama empat bulan. Selanjutnya dilakukan penjarangan sebesar 50% dan benih dipelihara selama 14 bulan untuk dilakukan seleksi dengan panduan hasil sampling 250 ekor individu setiap populasi. Seleksi terhadap calon induk dilakukan saat umur 18 bulan pada populasi jantan dan betina secara terpisah dengan memilih berdasarkan 10% bobot ikan yang terbaik. Calon induk yang terseleksi kemudian dipelihara hingga matang gonad, kemudian dipilih sebanyak 150 pasang dan dipijahkan secara massal. Didapatkan respons positif dari hasil seleksi berdasarkan bobot ikan, yaitu 49,89 g atau 3,66% (populasi ikan jantan) dan 168,47 g atau 11,43% (populasi ikan betina). Nilai heritabilitas untuk bobot ikan adalah 0,238 (jantan) dan 0,505 (betina).Punten carp breeding programs were carried out by individual selection for body weight trait. The base population for selection activities were conducted by mass breeding of parent consisted of 20 female and 21 male collected from area Punten, eight female and six male (Kepanjen), seven female and 12 male (Kediri), 27 female and 10 male (Sragen), 15 female and 11 male (Blitar). Larvae 10 days old reared for four moths. Then after spacing out 50% of total harvest, the offspring reared for 14 months for selection activity based on the sampling of 250 individual each population. Selection of broodstock candidates performed since 18 months age on male and female populations separately by selecting based on 10% of fish with best body weight. Candidates selected broodstocks were then maintained until mature. In oder to produce the next generation 150 pairs were sets and held for mass spawning. The results revealed that selection response were positive, 49.89 g (3.66%) for male and 168.47 (11.43%) for female. Heritability for body weight is 0.238 (male) and 0.505 (female).

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