Journal of Environmental Biology

Effect of temperature regimes, seed priming and priming duration on germination and seedling growth on American cotton

K. Singh¹*, N. Gupta² and M. Dhingra³

¹Punjab Agricultural University Regional Research Station, Faridkot - 151 203, India

²Department of Plant Breeding and Genetics, Punjab Agricultural University, Ludhiana - 141 004, India

³Department of Soil Science, Punjab Agricultural University, Ludhiana - 141 004, India

*Corresponding Author E-mail: kulvir@pau.edu

Key words

Bt cotton hybrid

Seed priming

Hydropriming

Seedling growth

Publication Data

Paper received : 30.08.2016

Revised received : 05.01.2017

Re-revised received : 11.05.2017 Accepted : 24.06.2017???????? ??

Abstract

Aim: High temperature during sowing of cotton results in poor emergence and high seedling mortality, thus leading to poor crop stand and reduced yield. Improvement in germination by seed priming may combat this problem as this physiological technique results in faster and synchronous seed germination. Hence, in vitro studies were conducted to evaluate the effect of different temperature regimes, seed priming and also duration of priming on germination and seedling growth to determine and exploit their usefulness in improving cotton seed germination for better seedling establishment.

Methodology: Seeds of Bt cotton hybrid (Ankur 3028 BGII) were primed separately with water and KNO₃ at different concentrations (2.5, 5.0, 7.5 & 10.0%) for 2, 4 and 6 hrs. Non-primed seeds and hydro primed seeds for 4 hrs were considered as control. Seeds for each set of treatment were placed on moistened filter paper in petri dish. Each treatment was then divided into two sub-sets for assessment of seedling response at two temperature regimes i.e., at 25^?C and at ambient temperature of 32-38.5^?C. After 7 days, final germination percentage, root length, shoot length and fresh weight of seedling were measured at both temperature regimes. Germination count was recorded on daily basis and was used to calculate speed of germination. ????

Results: Primed seeds exhibited an increase in germination by 43% and 34% than control (non-primed seeds) at ambient temperature (32-38.5?C) and 25?C respectively. Germination speed also improved by 61% and 67% respectively at ambient temperature and 25?C over control. Hydropriming resulted in highest germination (75.5 and 79.2%), germination speed (5.13 and 6.63 days), root length (4.68 and 6.30 cm) and shoot length (2.59 and 3.40 cm) than control at 25?C and ambient temperature respectively. Contrarily, increase in KNO3 concentration caused deleterious effects on root and shoot length. ????

Interpretation: Cotton seed germination was higher at ambient temperature (32^?-38.5^?C) than 25^?C and priming improved germination potential of seeds. Hydropriming was more effective than KNO₃ for enhancing germination percentage, germination speed and seedling growth at both temperature regimes. Studies concluded that hydro priming of cotton seeds improved germination, a key factor for better crop stand having positive effect on crop survival, and consequently improved cotton productivity.

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