Marker-Assisted Selection in Breeding for Fruit Trait Improvement: A Review

Abstract

Breeding fruit species is time-consuming and expensive. With few exceptions, trees are likely the worst species to work with in terms of genetics and breeding. Most are characterized by large trees, long juvenile periods, and intensive agricultural practice, and environmental variability plays an important role in the heritability evaluations of every single important trait. Although vegetative propagation allows for the production of a significant number of clonal replicates for the evaluation of environmental effects and genotype × environment interactions, the spaces required for plant cultivation and the intensity of work necessary for phenotypic surveys slow down the work of researchers. Fruit breeders are very often interested in fruit traits: size, weight, sugar and acid content, ripening time, fruit storability, and post-harvest practices, among other traits relevant to each individual species. The translation of trait loci and whole-genome sequences into diagnostic genetic markers that are effective and affordable for use by breeders, who must choose genetically superior parents and subsequently choose genetically superior individuals among their progeny, is one of the most difficult tasks still facing tree fruit geneticists. The availability of updated sequencing techniques and powerful software tools offered the opportunity to mine tens of fruit genomes to find out sequence variants potentially useful as molecular markers. This review is devoted to analysing what has been the role of molecular markers in assisting breeders in selection processes, with an emphasis on the fruit traits of the most important fruit crops for which examples of trustworthy molecular markers have been developed, such as the MDo.chr9.4 marker for red skin colour in apples, the CCD4-based marker CPRFC1, and LG3_13.146 marker for flesh colour in peaches, papayas, and cherries, respectively.

Essential oil composition, morphological characterization, phenolic content and antioxidant activity of Iranian populations of Hymenocrater longiflorus Benth. (Lamiaceae)

“…Moreover, these morphological traits showed a positive correlation with compound 24 of EO (BL = 0.40, BW = 0.46), while displaying a negative correlation with compounds 1 and 5. These correlations with phytochemical traits can contribute to cost-effective analysis in the selection process of these plants and serve as valuable indicators for marker-assisted selection (MAS) 28 . The negative correlation observed between DPPH leaf (DPPH L) IC50 and TFC (-0.73), TPC (-0.63), compound 20 (-0.90), EO (-0.85), and compound 9 (-0.73) suggests that these compounds exert a significant influence on the antioxidant activity of the leaves.…”

Molecular Markers for Marker-Assisted Breeding for Biotic and Abiotic Stress in Melon (Cucumis melo L.): A Review

“…Multiple factors, including the complexity of the desired trait and proximity of the genetic marker to the target characteristic influence the efficiency of MAS. MAS is becoming increasingly important for improving plant breeding efficiency by enabling the precise transfer of genomic regions of interest and accelerating the recovery of genome segments bearing the desired characteristics [ 28 ].…”

Multiple-Genome-Based Simple Sequence Repeat Is an Efficient and Successful Method in Genotyping and Classifying Different Jujube Germplasm Resources

“…Similarly, molecular markers used for species classification, such as RAPD, RFLP, AFLP, SRAP, and Simple Sequence Repeat (SSR), offer advantages over morphological classification approaches [8][9][10][11][12]. These markers, having high levels of polymorphism and reproducibility, are evenly distributed in the genome, and are not influenced by factors such as tissue type, developmental stage, or environment [13]. Among them, SSR is the most favored due to its ease of detection, abundant quantity, and high level of polymorphism.…”