Genetic parameters for agronomic characteristics. I. Early and intermediate breeding populations of true potato seed

Abstract

The original variation in the source population as well as the selection method may influence the genetic variation in further cycles of genetic improvement. Therefore, the objectives of this research were to determine genetic parameters (variance components and heritability) in source and intermediate stages of a true potato seed (TPS) breeding population and to calculate the genetic and phenotypic correlations in this breeding material developed by the Centro Internacional de la Papa (CIP). The intermediate stage was derived from a source population adapted to the warm lowland tropics plus introduction of exotic germplasm from North America and Europe. Non-additive genetic variation was almost nil for plant survival, tuber yield and tuber shape uniformity in both stages of the breeding population and no quantitative genetic variation for uniformity of tuber color was observed in both source and intermediate breeding materials. Heritability was higher in the intermediate stage than in the source population for plant survival (0.86 vs 0.66), tuber yield (0.30 vs 0.14) and tuber shape (0.77 vs 0.51), but it was the reverse for tuber uniformity (0.11 vs 0.72). These results suggest that potato breeders at CIP were able to keep enough genetic variation for most important characteristics for potato production from true seed in their intermediate breeding materials by adding new sources of variation to the original breeding population. Additive genetic and phenotypic correlations were significant and positive between plant vigor after transplanting and tuber yield, and tuber shape and tuber uniformity, which suggest that high yielding offspring result from early vigorous growth, and that tuber uniformity could depend on tuber shape uniformity in this breeding material.

Genetic analyses for bioactive potential in tetraploid potato (Solanum tuberosum L.)

“…A significant additive × year interaction suggests the need of selecting stable parental lines. Conversely, the non‐additive variance components accounted for the negligible h 2 estimates for tuber colour uniformity in different populations of tetraploid potatoes suggest that dominance genetic effects are prevalent for this qualitative trait (Ortiz & Golmirzaie, ; Thompson, Mendoza, & Plaisted, ).…”

“…As stated by Killick and Malcolmson (1973), traits subjected to directional selection show lower additive components and higher dominant and epistatic genetic effects. This is the case of yield, tuber uniformity and other agronomic characters, which are major goals for potato breeders (Ortiz & Golmirzaie, 2003, 2004Tai, 1976).…”

“…The experimental design was adapted from Ortiz and Golmirzaie (, ). True potato seeds of each offspring were sown in flats at a glasshouse nursery in April 2014, and a total of 45 seedlings were transferred after four weeks to individual pots and grown on peat substrate in glasshouse conditions.…”

Challenges and Way-forward in Selection of Superior Parents, Crosses and Clones in Potato Breeding

“…1). Ortiz and Golmirzaie (2003) too had found significant and positive correlations between plant vigour after transplanting the seedlings and their tuber yield. In order to define the selectability of visible traits, Love et al (1997) evaluated 27 traits through three clonal generations.…”

Phenotypic and genetic variation in an Apios americana breeding collection; and characterization of the HD-Zip gene family, involved in abiotic stress responses in Glycine max

“…Identification of aboveground traits that can serve as a proxy for belowground yield will aid in early identification of high-yielding genotypes. In the current evaluations, stem Golmirzaie, 2003). This will eventually aid in short-listing two traits that can be used during emergence and elongation of the vine, for selection of high-yielding plants.…”