Quantitative Traits of Interest in Apple Breeding and Their Implications for Selection

Abstract

Apple breeding is a laborious and long-lasting process that requires qualified resources, land, time, and funds. In this study, more than 5000 F1 apple hybrids from direct and testcrosses were analyzed. The results revealed how the phenotypic expression of the main quantitative traits of interest assessed in five half-sib families was controlled by the additive genetic effects and by non-additive effects of dominance and epistasis. The statistical number of hybrids required to ensure efficient selection increased exponentially with the number of desirable traits. The minimum number of progenies required to obtain a hybrid with associated quantitative traits of agronomic interest was highly variable. For two independent traits essential in selection (fruit size and quality), but incorporated together in the same hybrid, the statistical number was between about 30 and 300. If three more cumulative traits were added (a large number of fruits per tree, resistance/tolerance to apple scab, and powdery mildew attack), the limits increased to between 1500 and 18,000. The study highlighted the need for new apple varieties due to the narrowing of the genetic diversity of the cultivated species and how the choice of parents used in hybridizations (as well as the objectives pursued in the selection) can increase the efficiency of apple breeding.

The use of genetic resources in rose breeding and creation of new rose cultivars through hybridization and selection

“…The new cultivars obtained are primarily intended for use in parks, gardens, and as cut flowers, and they offer a wide range of colour, form, scent, recurrent blooming and hardiness combinations. Even though there are various methods of inducing artificial variability, the primary breeding method used for all species, was artificial hybridization, followed by selection, which resulted in positive outcomes for both rose and other Rosaceae species (Wagner et al, 2000;Sestras and Sestras, 2023).…”

Climate Potential for Apple Growing in Norway—Part 1: Zoning of Areas with Heat Conditions Favorable for Apple Growing under Observed Climate Change

“…Humidity depends on precipitation, temperature, local terrain characteristics (soil type or slope-impact infiltration rate of precipitation in soil), and the vicinity of the sea. These, and other, limitations are considered as risks, and in some cases could be manageable using agrotechnical measures and selection of more resistant varieties [43,44]. In [13] it is shown that the significant increase in temperature conditions, expansion of growing season, but also the increase in precipitation will happen in the future in Norway.…”

Comparative Analysis of Phenotypic and Molecular Data on Response to Main Pear Diseases and Pest Attack in a Germplasm Collection

“…Nak., and P. sinkiangensis T.T.Yu have been recorded in China. In addition, just like with apples [ 30 ], vegetative multiplication and the extension of different clones, heirlooms, and mutations of the same cultivar, each with its own unique local or regional names, synonyms, and homonyms [ 4 , 12 , 31 , 32 ], are likely to make the total number of cultivated forms considerably higher than has been thought.…”

“…The Horticulture Research Station in Cluj-Napoca, Romania, situated in the country’s northwest, achieved remarkable results in fruit tree breeding, releasing many cultivars [ 27 , 46 ]. However, breeding cultivars with a desired associated response to the attack of different biotic stress agents is extremely difficult in fruit trees [ 27 , 30 , 47 ].…”

“…In turn, the variability produced by artificial hybridization is determined by the available gene resources and their compatibility with the fruit tree breeding goals [ 48 , 49 , 50 ]. The more compatible the parents with the desired characteristics that are used, the higher the chance of effective selection [ 13 , 30 , 51 ]. In this regard, the current study investigated the phenotypic and genetic diversity related to the response of various pear genotypes from a germplasm collection to biotic stress factors frequent in the Carpathian region, including significant diseases and pests.…”