Citation
Abdulrahman, Abbas Lateef
(2018)
Performance of crosses and development of doubled haploid lines in wheat (Triticum aestivum L.) for salt tolerance.
Doctoral thesis, Universiti Putra Malaysia.
Abstract
Wheat (Triticum aestivum L.) is an important staple food crop for the world
population. Despite its importance, the crop productivity is often affected by salinity
stress. This study aimed to develop sodium chloride (NaCl) tolerant doubled haploid
wheat using anther culture technique. The effect of different concentrations of NaCl
(0, 50, 100, 150 and 250 mM) on seed germination and selected seedling growth traits
of eight wheat genotypes was evaluated. The G1, G2, G6, G8, and G10 were classified
as salt tolerant while Abo- Graib, Forat and, Dijla genotypes were salt susceptible.
Increasing concentration of NaCl solution led to the gradual reduction in the seed
germination percentage, and seedling growth traits. The three salt susceptible and one
high salt tolerant genotypes (G8) were selected for crossing to obtain a total of six
crosses. The agronomic performance of the six F1 crosses was investigated under 0,
50, 100, 150 mM of NaCl. For all, grain yield exhibited positive correlation with
spikes number/plant, grains number per spike and weight of 1000 grain. Abo-
Graib×G8, Forat×G8, and Dijla×G8 showed superiority in grain yield (7.3 g/plant, 7.4
g/plant and 6 g/plant, respectively) under high concentration of NaCl (100 mM)
related to the spikes number/plant, grains number per spike and the 1000 grain weight.
Investigation on callus induction from anther culture of the F1 progenies was
performed. All F1 produced a high percentage of callus (47.9%) when subjected to
33°C + chemical pre-treatment for 48 hours followed by culturing on CHB3 induction
medium containing Myo-inositol (300 mg/L), L-glutamine (993.5 mg/L) and 2 mg/L
of both 2, 4-D and kinetin. The F1 produced good percentage (45.6%) of green plants
and the lowest percentage (6.8%) of albino plants after growing on R9 regeneration
medium containing 0.076 mg/L CuSO4.5H2O and 90000 mg/L maltose following the
pre-treatment of the anther with heat + chemical and culturing on CHB3 callus
induction medium. Abo-Graib×G8 displayed the highest ability for callus induction
and green plants production (82.3% and 81.3%, respectively) and the lowest percentage of albino plants (2%). The 883 regenerated plants from the F1, 646 were
green and 237 were albino plants. Among the green plants, 281 grew to maturity.
Thirty-nine lines were fertile and their seeds were grown for developing salt tolerant
doubled haploid lines. Haploid plant's chromosomes were doubled under colchicine
treatment (0.2%) with dimethyl sulfoxide (DMSO) (2%) and 2-3 drops of Tween-20
for 4 hours at room temperature. The doubling of chromosomes was validated using
a fluorescent microscope. Thirty-nine doubled haploid lines were evaluated under 0,
50, 100 and 150 mM of NaCl in the greenhouse. The doubled haploid lines DH6
obtained from (Abo-Graib×G8), DH8 (Forat×G8) and DH6 (Dijla×G8) showed a high
performance due to their superiority in leaves K+ content, K+/Na+ ratio, the spikes
number, grains number, and the decrease in leaves Na+ content. Taken together, it can
be concluded that through anther culture, doubled haploid lines that displayed high
yielding trait were developed for future exploitation.
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