Priming treatments for improvement of germination and emergence of cotton seeds at low temperature

摘要

Early sowing in cotton is important for obtaining a high and qualiy yield. Since cotton prefers high temperatures to have a good stand establisment, this work is important to determine better performing genotypes or to promote germination and emergence at low temperatures (G. hirsutum L. species (Aydin-110 and Paymaster-2379) were primed with PEG-6000 (200, 300, 400 g/L), KNO₃ (2, 3, 4%), KH₂PO₄ (0.3, 0.4, 0.5 M), NaCl (2, 3, 4%) or Mannitol (2, 4, 6%) to determine the best priming medium and its best amount. After priming, seeds were germinated in germination cabin at cold (18°C) and warm (30°C) temperatures and some characteristics (germination rates, radicle length, hypocotyl length and seedling length) were analyzed. Priming with KNO₃ (4% or 2%) was found to result in the highest germination rates in both cotton genotypes. The seeds of the genotypes were also primed with 5-aminolevulinic acid (ALA) (1, 10, 25 mg/L), gibberellic acid (GA₃) (100, 250, 500 μM), methyl jasmonate (MeJA) (1, 3, 5 μM), acetylsalicylic acid (ASA) (1, 10, 100 μM) or kinetin (1, 5, 10 mg/L) added to KNO₃ (4%) medium to choose the most effective plant growth regulator (PGR) application and its dose. PGRs were observed to have reverse effects on germination rate. Finally, emergence test was conducted with KNO₃ (4%) and KNO₃ (2%) using metabolic chill test, and some traits (radicle length, radicle weight, hypocotyl length, hypocotyl weight, seedling length, seedling fresh weight and seedling dry weight) were examined. Our results suggested that priming with KNO₃ (2%) might be an effecient way to have vigourous cotton plants under the cold stress.