The Relationship Between Morphological and Molecular Characterizations of Roots and the Ability of Drought Tolerance for Some Durum Wheat Lines

Abdul Razaak Al-Soud
General Commission for Scientific Agricultural Research-
Deraa Research Center
Faculty of AgricultureDamascus University,
2009

Abstract

One hundred and twelve sister lines of durum wheat derived from the cross (Cham1 X Lahen) were studied to determine the correlation between root length and root system distribution, to identify the effect of root length and distribution on drought resistance, and to study genetic characterization and genetic variance for some lines that show drought resistance by using molecular markers.
The study was carried out under 2nd agro-ecological zone conditions (Izraa Research Station, Deraa, Southern Syria). The augmented design was used with five checks where every check replicated at least twice at every block. Adams Brais method with some personal modification was also used for counting the number of roots at each depth 10, 20, 30, 40, 50 and 60 cm. To calculate correlation values between the studied traits and the root system, the statistical program (STAT 7) was used. The statistical program (TASSEL) was used to analyze the correlation between primers and traits.
The results showed that the highest root density was concentrated at 0-50 cm deep but it decreased at 60 cm deep. There was a significant negative correlation between root depth 10, 20, 30, 40 and 50 cm and grain yield, number of seeds per spike and plant height. Otherwise, a significant positive correlation was found between number of roots on depth 60 cm and grain yield, number of seed per spike, number of spikes per square meter (m²), biological yield, harvest index, plant height, dry weight and green weight. The results have demonstrated significant positive correlation between root length and grain yield, number of seeds per spike, number of spikes per square meter (m²), biological yield harvest index, plant height, dry weight and green weight.
The dry weight of roots has positively correlation with number of seeds per spike, number of spikes per square meter (m²), biological yield, harvest index, plant height, dry weight and green weight, However the highest correlation was between grain yield and root length (0.917) A strong correlation was found between root length and number of roots on depth 60 cm (0.608).
Consequently, we can say that the lines with root average length more than 80 cm gave average yield 845.5 kg/ha, while those with average root length less than 65 cm gave average yield of 292.5 kg/ha. Lines which with high root density on depth 0-50 cm) had no increase in their own number of roots on depth 60 cm and their root length was not higher than those of  high root density on depth  0-50 cm.   For Molecular study of some lines, the study showed that some primers correlated positively with some root traits but others were negative.