4 research outputs found
Phenotypic diversity of Tunisian durum wheat landraces
Tunisia is considered as a diversification centre of durum wheat (
Triticum durum Desf.) and barely ( Hordeum vulgare ). It is
characterised by large genetic diversity; however, several genotypes
are in the process of disappearance. The safeguard and rehabilitatation
of this genetic inheritance requires genetic characterisation,
evaluation and in-situ and ex-situ conservation. In this context, a
local collection of thirty durum wheat accessions was evaluated using
agronomical traits. Three other phenological traits: days to maturity,
days to heading and filling period were evaluated. The phenotypic
diversity was determined by the Shannon-Weaver diversity Index (H')
revealing that number of kernel/spike (H'=0.91), yield (H'=0.89), plant
height (H'=0.87) and thousand kernel weight (H'=0.86) had the highest
diversity index. Flag leaf area (H'=0.32) showed the weakest index.
This germplasm presented average diversity (0.77) showing a large
genetic variability. Correlations between traits showed a significant
positive relation between yield and spikeless tillers/plant (0.90),
thousand kernel weight (0.39), plant height (0.35) and flag leaf area
(0.36), suggesting the usefulness of these parameter for selecting for
improving grain yield. The components analysis explained 59.61% of
total variability and led to identification of a group of accessions
Jeneh kotifa 1, Jeneh kotifa 2, Jeneh kotifa 3, Sbei glabre, Hamira 1,
Hamira 2, Biskri glabre, Mahmoudi, Biskri glabre AP2, Swabaa Elgia,
Sbei, and Mahmoudi glabre showing the best agronomical characteristics.
These genotypes can, therefore, be used as parents for the improvement
of durum wheat.La Tunisie est un centre de diversité génétique du
blé dur ( Triticum durum Desf.) et de l'orge ( Hordeum vulgare
). En dépit de la large diversité génétique au
niveau du germoplasme local, plusieurs génotypes sont en voie de
disparition. La sauvegarde et la réhabilitation de ce patrimoine
génétique nécessitent sa caractérisation, son
Ă©valuation ainsi que sa conservation in situ et ex situ. Dans ce
contexte une collection locale de trente genotypes de blé dur a
été évaluée utilisant des paramÚtres
agronomiques. Trois autres paramĂštres phĂ©nologiques Ă
savoir jours de maturation, jours de rétablissement et
période de remplissage étaient aussi évaluées. La
diversité phénotypique determinée par l'index de
diversité de Shannon-Weaver (H') a révélé que le
nombre de grains par Ă©pi (H'=0.91), rendement (H'=0.89), hauteur
des plants (H'=0.87) et le poids de 1000 grains (H'=0.86) avaient un
index de diversité le plus élevé. La surface foliare
(H'=0.32) a montré un index le plus faible. Ce germplasm
presentait un index de diversité moyen de 0.77 montrant ainsi une
large variabilité génétique. Les corrélations entre
les paramÚtres a montré une relation positive significative
entre le rendement et le nombre de talles d'Ă©pillets par plant
(0.39), le poids de 1000 grains (0.35) et la surface foliaire (0.36),
suggérant ainsi l'utilité de ces paramÚtres de
sélection pour l'amélioration du rendement en grains.
L'analyse des composants a expliqué 59.61% de la variabilité
totale et a conduit Ă identifier un groupe de genotypes entre
autre kotifa 2, Jeneh kotifa 3, Sbei glabre, Hamira 1, Hamira 2, Biskri
glabre, Mahmoudi, Biskri glabre AP2, Swabaa Elgia, Sbei, Mahmoudi
glabre montrant les meilleures caractéristiques agronomiques. Ces
gĂ©notypes peuvent donc ĂȘtre utilisĂ©s comme parents pour
l'amélioration de blé dur
Genetic variation of salt-stressed durum wheat (Triticum turgidum subsp. durum Desf.) genotypes under field conditions and gynogenetic capacity
Agriculture has new challenges against the climate change: the preservation of genetic resources and the rapid creation of new varieties better adapted to abiotic stress, specially salinity. In this context, the agronomic performance of 25 durum wheat (Triticum turgidum subsp. durum Desf.) genotypes (nineteen landraces and six improved varieties), cultivated in two semi-arid regions in the center area of Tunisia, were assessed. These sites (Echbika, 2.2âŻgâŻlâ1; Barrouta, 4.2âŻgâŻlâ1) differ by their degree of salinity of the water irrigation. The results showed that most of the agronomic traits (e.g. spike per meter square, thousand kernels weight and grain yield) were reduced by salinity. Durum wheat landraces, Mahmoudi and Hmira, and improved varieties, Maali and Om Rabia showed the widest adaptability to different quality of irrigation water. Genotypes including Jneh Kotifa and Arbi were estimated as stable genotypes under adverse conditions. Thereafter, salt-tolerant (Hmira and Jneh Khotifa) and the most cultivated high-yielding (Karim, Razzak and Khiar) genotypes were tested for their gynogenetic ability to obtain haploids and doubled haploid lines. Genotypes with good induction capacity had not necessarily a good capacity of regeneration of haploid plantlets. In our conditions, Hmira and Khiar exhibited the best gynogenetic ability (3.1% and 2.9% of haploid plantlets, respectively). Keywords: Durum wheat, Genetic variation, Salinity, In vitro gynogenesi