Direct and indirect selection for drought tolerance in alien tetraploid wheat x durum wheat crosses |
| |
Authors: | A Al Hakimi P Monneveaux MM Nachit |
| |
Institution: | (1) Faculty of Agriculture, Sana'a University, Yemen;(2) ENSA-INRA, Montpellier, France;(3) CIMMYT/ICARDA, P.O. Box 5466, Aleppo, Syria |
| |
Abstract: | After the evaluation of numerous accessions of primitive wheats for yield components and morphophysiological traits related
to drought tolerance (e.g., maintenance of high relative water content, RWC; photochemical quenching of chlorophyll fluorescence,
qQ; and chlorophyll loss, chl, under moisture stress conditions), several accessions belonging to three species (Triticum
dicoccum, T. polonicum, and T. carthlicum) were crossed with the improved durum wheat varieties Cham 1 and Om Rabi 5. A direct
selection (F2 progeny) for yield and an indirect physiological trait were applied on interspecific T. durum x T. dicoccum, T. durum x T.
polonicum, and T. durum x T. carthlicum populations. Divergent selection was applied to validate the possible use of morphophysiological
traits (root parameters, RWC, photochemical quenching, proline content, and carbon isotope discrimination) in selection, and
to evaluate the resulting effects on yield. Heritability and selection response of these traits has been evaluated, and the
impact of divergent selection for morphological and agronomic characters was studied under field conditions. The divergent
populations were evaluated under different environmental conditions in France, Syria, and Yemen. Selection for morphophysiological
traits related to moisture stress, such as root parameters, RWC and carbon isotope discrimination was possible due to high
h2 values and effective, resulting in high genetic gains. However, the effect of selection for these traits on yield stability
needs to be further studied. Furthermore, a modified bulk method (F2 'progeny method') was developed. Direct selection for grain yield per plant in F2 was carried out and yield per line in F3 was evaluated under contrasting environmental conditions in France, Syria, and Tunisia. Results revealed that some F3 lines were higher yielding than the improved durum wheat varieties Cham 1 and Om Rabi 5 under both stressed (Aleppo) and
favourable (Montpellier) environmental conditions. Lines were evaluated in preliminary yield trials at Montpellier (France),
Aleppo (Syria), and Constantine (Algeria). Results indicated that the use of related species combined with the use of the
modified bulk breeding method is promising not only for increasing durum wheat yield in drought prone environments, but also
for improving durum wheat yield stability across contrasting environments. Results of both breeding strategies are presented,
and the potential advantages of using related tetraploid species in durum wheat breeding for drought tolerance are discussed.
This revised version was published online in August 2006 with corrections to the Cover Date. |
| |
Keywords: | |
本文献已被 SpringerLink 等数据库收录! |
|