Water relations, growth and yield of tall and short wheat cultivars irradiated with X-rays

• Published in: Environmental and experimental botany 1979-01, Vol.19 (4), p.349-356
• Main Authors: Erickson, P.I., Kirkham, M.B., Adjei, G.B.
• Format: Article
• Language: English
• ISSN: 0098-8472; 1873-7307
• DOI: 10.1016/0098-8472(79)90038-8

Irradiated seeds of two cultivars of winter wheat ( Triticum aestivum L. em. Thell.), one tall (‘Scout 66’) and one short (‘Sturdy’), were planted in the field to determine the effect of seed irradiation on plant water relations, growth and yield. Seeds were exposed to 0, 150, 250, 450, 650, 750, 850, 950, 1000, 1500 or 2000 rad of X-rays. On day 21, 56, 70, 174, 189 and 224 after planting, stomatal resistance, plant water potential and height were measured. At harvest (day 246), yield was determined. Stomatal resistance was decreased by 150 rad compared to 0 rad, even though the difference was significant only for the short cultivar. For both cultivars, stomatal resistance increased with increasing exposure between 950 and 2000 rad. At 0, 1500 and 2000 rad, the tall cultivar had a lower stomatal resistance than the short cultivar. Between 150 and 950 rad, the tall and short cultivars had similar stomatal resistances. At 150 rad, the plant water potential of both cultivars was higher than that of the control, even though differences were not significant. Between 250 and 2000 rad, plant water potential of both cultivars dropped with increasing dose level. Potentials of the two cultivars at each exposure level were similar. Height differences between the cultivars became apparent after culm elongation in the spring. On day 189, plants from seeds treated with 150 rad were taller, although not significantly, than the control plants. Height and yield were variable, but height tended to decrease, and yield increase, with increasing dose rate. The results suggested that stimulation of plant growth at low exposures of radiation (150 rad in this study), which has been reported in the literature, may be due, in part, to decreased stomatal resistance.