The present study was conducted at Genetic Engineering Department in Agricultural
Research Directorate in Ministry of Science and Technology/Iraq in 2013, to evaluate
the effectiveness of aqueous extract of cogon grass at concentrations of (0.0 ,0.
25,
0.5, 1, 1.5 and 2%) and Kinetin (0.0, 1.5, 3, 5) mg/L on microtuberization of two
potato varieties; Daimond and Desire, in two separate experiments. All cultures
were placed in a growth room chamber at temeratures of 18-20 °C with darkness
for 90 days, until microtubers harvest. Data of microtuber per plant, diameters and
weights were investigated. Results showed a positive effect of cogon grass extract
at 2% on the number of microtubers and fresh weight (2.1, 104.41 mg, respectively)
and at 1% on the diameter (5.52 mm). Desiree cultivar was the best in fresh weight
of microtubers (188.41mg). The results of kinetin showed a significant effect on
all of the studied traits. The superior kinetin concentration was 5.0 mg/L which
gave the highest number of microtubers 2.22, while the concentrations 3.0 and 1.5
mg/L gave the highest values of diameter and weight ( 6.95 mm and 388.38 mg,
respectively). The two cultivars did not differ significantly in number of microtubers,
while Diamond cultivar was significantly higher in diameter and weight (6.86 mm
and 363.45 mg, respectively).
Experiments were conducted to study effect of radiation and salt levels on plant
regeneration from callus for two cultivars of potato i.e. Riviera and Burren, under
in vitro condition. Results showed that the efficiency of radiation in induced
reg
eneration from callus in Riviera cultivar at salt level of (10 dS m-1) and Burren
cultivar at salt levels (8, 12 dS m-1). For the purpose of making sure inheritance
of salinity tolerant, mutant clones (plants induced from salt tolerant calli, which
planted at salt levels of 8, 10, 12 dS m-1 and plants induced from non salt tolerant
calli, which planted at salt level of 6 dS m-1) and their parental cultivars (Riviera
and Burren) by exposing to salt stress conditions and comparing them with control
(6 dS m-1). Results revealed that the lowest percentage of reduction in plant height,
number of nods per plant and tuberization were observed in salt tolerant mutants.
Plant height and number of nodes/plant can be considered as selective morphological
markers for in vitro salt tolerance .
