Articles
Thirty-three half-sib apple clonal rootstocks tolerant to crown rot produced in a 14-year pathology breeding program
Article number
1315_35
Pages
227 – 236
Language
English
Abstract
Dominant challenges of Iranian apple cultivation soils consist of heavy texture, poor organic matter, high alkalinity and so calcium and iron deficiency.
In addition, traditional submerged irrigation systems and superficial manure distribution predispose the apple trees to crown rot disease.
To produce clonal rootstocks the process of parent selection was achieved based on lack of foliar chlorosis, weak vigor, and general adaptness to regional pedoclimatic conditions. Northern Spy was selected as the carrier of resistance gen to <em>Phytophthora cactorum</em> together with other native three native crab apples during 2004-2007. The obtained 5000 progenies of 1-year-old half-sib seedlings were transferred into the thermostatic greenhouse where afterward they were inoculated by the agent of soil disease pathogen in 2008-2010. The screening resulted in the individuation of 99 crown rot tolerant genotypes which were transplanted in the nursery.
After a biennial growth outward till 2012, clonal propagation by layering as second screening led to 33 easy rooting promising clonal apple rootstocks in 2013-2014. Golden Delicious and Red Delicious were grafted on the newly produced rooted shoots of each clone through further layering.
A selection plot was established in an orchard containing rootstock scions combinations besides more gradual dwarfing rootstocks M9, M7, MM111, Support 4, and P22 as planted in Karaj, in the winter of 2013. Promising clonal stocks affected different tree height, rootstock diameter, graft union and trunk diameters, internode length and diameter of annual branches, total branch length, growth habit, number and mean length of root suckers in 2015.
In addition, traditional submerged irrigation systems and superficial manure distribution predispose the apple trees to crown rot disease.
To produce clonal rootstocks the process of parent selection was achieved based on lack of foliar chlorosis, weak vigor, and general adaptness to regional pedoclimatic conditions. Northern Spy was selected as the carrier of resistance gen to <em>Phytophthora cactorum</em> together with other native three native crab apples during 2004-2007. The obtained 5000 progenies of 1-year-old half-sib seedlings were transferred into the thermostatic greenhouse where afterward they were inoculated by the agent of soil disease pathogen in 2008-2010. The screening resulted in the individuation of 99 crown rot tolerant genotypes which were transplanted in the nursery.
After a biennial growth outward till 2012, clonal propagation by layering as second screening led to 33 easy rooting promising clonal apple rootstocks in 2013-2014. Golden Delicious and Red Delicious were grafted on the newly produced rooted shoots of each clone through further layering.
A selection plot was established in an orchard containing rootstock scions combinations besides more gradual dwarfing rootstocks M9, M7, MM111, Support 4, and P22 as planted in Karaj, in the winter of 2013. Promising clonal stocks affected different tree height, rootstock diameter, graft union and trunk diameters, internode length and diameter of annual branches, total branch length, growth habit, number and mean length of root suckers in 2015.
Publication
Authors
H. Hajnajari
Keywords
pathology breeding, clonal rootstock, crown rot, parent selection, easy rooting
Groups involved
- Division Temperate Tree Fruits
- Division Vine and Berry Fruits
- Division Tropical and Subtropical Fruit and Nuts
- Division Ornamental Plants
- Division Plant-Environment Interactions in Field Systems
- Division Postharvest and Quality Assurance
- Division Horticulture for Development
- Division Precision Horticulture and Engineering
- Division Plant Genetic Resources, Breeding and Biotechnology
- Commission Cultivar Registration
- Division Horticulture for Human Health
- Division Greenhouse and Indoor Production Horticulture
- Division Landscape and Urban Horticulture
- Commission Banana
- Division Vegetables, Roots and Tubers
- Division Temperate Tree Nuts
- Commission Agroecology and Organic Farming Systems
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