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Genetic mechanisms underlying alternate cropping in apple (Malus x domestica) (AlternApp)
Project
Project code: JKI-ZGO-08-4181
Contract period: 01.03.2015
- 28.02.2018
Purpose of research: Applied research
In AlternApp, we will investigate new avenues on the genetic and environmental control of flower induction (FI) to open perspectives for innovative material selection. In apple tree, FI, the time at which meristems become committed to develop flowers, is the critical developmental stage for the intensity of alternate bearing in a given year. The existence of a genetic determinism, suspected since a long time, has been recently demonstrated in an apple segregating population. First candidate genes (CGs) were revealed which support the assumption of hormonal control of FI, involving developing fruits. But the role of nutritional competition between reproductive and vegetative growth, must also be considered. These two assumptions will be examined by genetic and genomics approaches. Two segregating populations will be studied for FI and bearing behavior, in order to identify genomic regions associated to regular phenotypes. Phenotypes, as well as genotypes, years and climatic effects will be quantified by specific statistical developments. Transcriptome of varieties contrasted in their bearing behavior and artificially set into high or low cropping conditions will be explored by New Generation Sequencing Technology (NGS) to identify new CGs and allelic variation of interest. Apical meristem tissues will be collected on shoots which are micro-climatically, morphologically and physiologically characterized in order to correlate transcriptome with the heterogeneity of meristem flowering behaviors within the trees. By this project, we expect new and high standing results on FI in apple tree in relation to their alternate bearing behavior and more applied results linked to the discovery of allelic variation in key genes that could be used in breeding programs.
The AlternApp project aimed at increasing the understanding of the physiological and molecular mechanisms involved in the control of alternate bearing in apple. The genetic determinism was studied using a segregating F1-population, which was phenotyped over five years and genotyped using a 20K apple SNP array. First QTLs for the number of seeds per fruit could be detected. Microscopic studies, large-scale proteomic and metabolic profiling as well as RNA sequencing were applied to study the effects of physiological processes. 225 proteins, 23 compunds and 10.905 genes were found to be significantly different between trees with different bearing behaviour.
Section overview
Subjects
- Plant Breeding
- Arboriculture
Framework programme
Funding programme
Excutive institution
Institute for Breeding Research on Horticultural Crops (JKI-ZG)