Pre-selection for juvenile period, flowering and picking time in apple seedlings

Abstract

The length of the juvenile period was found to be associated with the degree of juvenility (degree to which seedlings show juvenile symptoms) and with the time leaf buds break in spring . The time of bud break was also related to time of flowering ; bud break and juvenility were not interrelated . The observations suggest that preselection on the basis of a low degree of juvenility and early bud break together would substantially increase the proportion of early-bearing and, to a smaller extent, that of early-flowering seedlings in the selected material . The shift towards earlier flowering was not accompanied by an advance of the date at which flowering ended, at least when the selection limit is based on the progeny mean .The degree of leaf fall (colour) during autumn appeared to be closely related to the time the fruits become picking ripe ; no significant relation existed between this parameter and juvenility or bud break . The degree or time of leaf fall (colour) is a possible pre-selection criterion of the time of picking .

Relationship between Clone Age and Selection Trait Expression in Mature Walnuts

“…Schaffalitzky de Muckadell (17) reported that trees grafted with juvenile wood (leafy epicormics) of beech leafed out later than those grafted with more mature wood (leafless tops). He cites a similar phenomenon reported by Fritsche (7) for apple and pear, but Visser (19,21) found a very low correlation (0.07) between degree of juvenility and time of bud break in apples. An improved correlation (0.37) was found between the length of the juvenile period and bud break.…”

“…Breeding, selection, and release of new cultivars is a lengthy process in tree crop species. The prolonged juvenile period before reproductive maturity accounts for much of the time consumed, and most of the literature on age-related changes in trees has focused on this period (8,19,20,21,22). Changes in trait expression after a tree has reached reproductive maturity is another factor that requires investigation because it influences the number of years required to assess adequately the expected commercial performance of potential releases.…”

The Length of the Juvenile Period in Olive as Influenced by Vigor of the Seedlings and the Precocity of the Parents

“…The length of the juvenile period has been traditionally one of the main drawbacks of fruit tree breeding (Hackett, 1985;Visser and Schaap, 1967). In fact, "a long juvenile period tries breeder's patience and weights on his orchard budget" (Visser et al, 1976).…”

Inheritance of foliage characteristics in (Annona cherimola Mill. × A. squamosa L.) × A. reticulata L. hybrids

“…As the flowers appear on the current seasons growth (Venkatratnam 1959) it should be possible to develop early, mid and late fruiting varieties by genetically altering time of leaf fall. Visser and Schaap (1967) observed that the time of leaf fall could be a possible pre-selection criterion of the time of picking in apple as leaf fall during autumn appeared to be closely related to the time fruits attaining picking ripe.…”