Articles
PEACH GERMPLASM EVALUATION AND CONSERVATION AT HIGH ALTITUDES IN CENTRAL MEXICO
Article number
565_8
Pages
59 – 62
Language
English
Abstract
Efficiency of germplasm conservation and use is determined by climate: chilling accumulation, frost risks at blossom, soil fertility, light intensity, and rainfall.
Site selection for germplasm conservation in representative fruit growing regions should also be based on experience and motivation of growers (Pérez-González, 2000). The objective of this work was to introduce a wide range of variability to a high altitude site and describe their performance.
Local and introduced selections, hybrids between local and foreign germplasm, F2 seedlings and cultivars.
Variables recorded included: vigor, resistance to oidium (Sphaeroteca pannosa), time of defoliation, resistance to winter frosts, budbreak-blossom season, intensity of budbreak and fruit set during the second and third season.
For most trees, vigor was not related to genetic origin during the first five months.
However, some seedlings and budded trees did not grow well after transplanting, a probable effect of the sudden change in temperature from the hot humid nursery, to the cool or even chilling temperatures of the planting site.
As nights became cooler during fall, most budded trees and seedlings derived from parents with high chilling requirement, stopped their growth and defoliated.
While most local selections and hybrids derived from low chilling requirement parents, continued to grow until the first frost occurred.
Winter frost damage was directly related to growth activity, but there were large differences associated with genetic origin.
Blossom season ranged from mid-January to early April, with early blooming materials exhibiting higher blossom density.
Late blooming trees had: extended blossom periods, poor set and fruits had double pistils, low resistance to powdery mildew was low, probably due to higher inoqulum densities during budbreak and early leaf development, when they are more susceptible.
Site selection for germplasm conservation in representative fruit growing regions should also be based on experience and motivation of growers (Pérez-González, 2000). The objective of this work was to introduce a wide range of variability to a high altitude site and describe their performance.
Local and introduced selections, hybrids between local and foreign germplasm, F2 seedlings and cultivars.
Variables recorded included: vigor, resistance to oidium (Sphaeroteca pannosa), time of defoliation, resistance to winter frosts, budbreak-blossom season, intensity of budbreak and fruit set during the second and third season.
For most trees, vigor was not related to genetic origin during the first five months.
However, some seedlings and budded trees did not grow well after transplanting, a probable effect of the sudden change in temperature from the hot humid nursery, to the cool or even chilling temperatures of the planting site.
As nights became cooler during fall, most budded trees and seedlings derived from parents with high chilling requirement, stopped their growth and defoliated.
While most local selections and hybrids derived from low chilling requirement parents, continued to grow until the first frost occurred.
Winter frost damage was directly related to growth activity, but there were large differences associated with genetic origin.
Blossom season ranged from mid-January to early April, with early blooming materials exhibiting higher blossom density.
Late blooming trees had: extended blossom periods, poor set and fruits had double pistils, low resistance to powdery mildew was low, probably due to higher inoqulum densities during budbreak and early leaf development, when they are more susceptible.
Authors
S. Perez-Gonzalez, J.C. Merlin
Keywords
vigor, growth habit, harvest season, low chilling requirement
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