Hydrothermal time analysis of mung bean (Vigna radiata (L.) Wilczek) seed germination at different water potential and temperatures

Abstract

Vigna radiata (L.) Wilczek belongs to the Fabaceae family and it's the third-largest major pulse crop in terms of area (101,566 acres) and yield (36,954 Mt). Over the past few decades, the climate of the planet has changed significantly, affecting all stages of physiological development and plant growth. In the current study, mathematical hydro time model (HT), thermal time model (TT) and hydrothermal time models were used to explore the physiological responses of seed germination to osmotic potential, temperature and their interaction (Osmotic Potential × Temperature). A lab experiment was performed in an incubator using the randomized complete block design (RCBD) at different osmotic potentials (ψs) and temperatures (Ts). Different constant temperatures (20, 25, 30, 35, 40 and 45°C) with five each ψs (0, -0.3, -0.6, 0.9 and -1.2 MPa) were used in the experiment. The results showed that rising the temperature between 25 and 35 °C enhanced the germination rate (GR). Overall, GR seems to be very sensitive to ψ changes than T. The maximum value of GP (germination percentage) is recorded in control (0 MPa) at 30 °C and the lowest was at -1.2 MPa in 45 °C. At each Temperature, the GP decreased as ψ decreased. The θH values were recorded maximum at 30 °C at 0 MPa and minimum in 45 °C at -1.2 MPa. T50% recorded significantly high in 30 °C at 0 MPa and the lowest value showed in 45 °C at (-1.2 MPa). Germination characteristics increased at optimal temperature and reduced as water potential dropped at each temperature. Literature that is currently accessible indicates that no particular seed germination patterns studies utilizing the hydrothermal time model have been published for Vigna radiata var. Ramzan.