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#breeding selection

2 public questions tagged with this topic.

Plant Breeding 4

Marker-assisted selection avoids:

Phenotypic selection suffers from confounding effects of environmental variation, microclimate heterogeneity, soil fertility gradients, and developmental stage, which obscure genetic differences especially for low heritability traits governed by many QTLs. DNA markers represent fixed sequence differences that are independent of external environment, plant age, and tissue, expressed constitutively in genome regardless of moisture or pathogen pressure. Therefore selection based on marker genotype is unaffected by seasonal fluctuations, field heterogeneity, or inoculum pressure that may cause esc

Ref: Tanksley et al. 1989; Xu Y. Molecular Plant Breeding – MAS avoids environmental influence

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Plant Breeding 4

Foreground selection in MABC focuses on:

Marker-assisted backcrossing comprises two selection layers that accelerate recovery and ensure gene retention. Foreground selection focuses directly on target locus introgressed from donor, using gene-specific or tightly linked markers less than 2 cM to ensure presence of desired allele in each backcross generation. In early generations BC1F1, BC2F1, individual seedlings genotyped for foreground markers, carriers retained, non-carriers discarded, avoiding waiting for phenotypic expression that may require disease inoculation or recessive homozygosity assessment. This prevents accidental loss

Ref: Hospital F & Charcosset A 1997 Genetics – MABC foreground selection. Collard & Mackill marker review

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