International Biometric Society
Genetic analysis of salt tolerance in a segregant population of citrus
rootstocks
Raga, V, Bernet, GP, Intrigliolo, DS, Roca, D, Carbonell, EA, Asins, MJ
Instituto Valenciano de Investigaciones Agrarias, Valencia, Spain
A genotyped reference population of 151 hybrids between Citrus reshni (Cleopatra
mandarin) and Poncirus trifoliata (salt tolerant and sensitive genotypes, respectively)
was used for 2 salt tolerance experiments. Nucellar plants of each hybrid were used
as repetitions and distributed randomly to set up a control (no NaCl) and a saline
irrigation regimen at each experiment. Final NaCl concentration was 25 mM in
experiment 1 (three years under a screenhouse) and 30 mM in experiment 2 (one
year in a greenhouse). Salt tolerance was evaluated considering traits related to the
vegetative growth (leaf and root system), leaf and root ion (Cl-, Na+, K+ and Ca2+)
concentrations and leaf water potential. Year effects were significant for all traits in
experiment 1. Trait heritabilities under control were generally higher than under
salinity condition in the experiment 2, while in the experiment 1, it was the opposite.
Regarding GxE interaction, some hybrids behaved differently for leaf [Cl -] and for
[Na+] and [K+] distribution between leaf and root tissues when comparing control and
salinity conditions. A total of 169 putative QTLs were detected. Most relevant ones to
improve citrus rootstocks were found on linkage groups 3 (plant vigour and leaf Clexclusion) and 4c (exclusion of toxic ions). Salt tolerance candidate genes SOS 1
and SOS 2 were found significantly associated with the difference between leaf and
root [Na+] under salinity and leaf [Na+] under control condition, respectively. SOS 2
was also associated with the leaf water potential after 7 days of salt treatment.
International Biometric Conference, Florence, ITALY, 6 – 11 July 2014