Seed treatment with growth regulators and crop productivity. II. Response of critical growth stages of wheat (Triticum aestivum L.) under salinity stress.

Laboratory experiments were conducted to study the effect of different conc entrations of some plant growth hormones (GA(3), IAA, and IBA) on germinati on of wheat (Triticum aestivum L.) seeds and seedling vigour under saline c onditions. The hormones were administered through seed soaking in aqueous s olutions of different concentrations. As expected, germination of seeds dec reased with the soil salinity. Negative effects of soil salinity on seed ge rmination were significantly mitigated by hormone treatment. At 200 ppm, GA (3) caused 100% seed germination at an electrical conductivity of 13.11 dSm (-1). Auxins (IAA and IBA) also enhanced the germination at moderate salini ty (E.C. 8.44 dSm(-1)) but were unable to cause 100% germination. In normal soil, GA3 and IBA at 100 and 150 ppm, respectively, caused an increase of 10 and 22% in total dry weight of seedling, while IAA treatment had no sign ificant effect. At low (5.41 dSm(-1)) and moderate (8.44 dSm(-1)) salinity, IAA at 50 and IBA at 10 ppm enhanced the seedling dry matter yield by 17-2 8%, whereas the increase was only 5-9% with GA(3) at 10 ppm. Seed soaking i n 10ppm GA(3) and 50 ppm IAA solutions caused 36 to 43% increase in dry wei ght at E.C. 13.11 dSm(-1).