Evaluation of cotton (Gossypium hirsutum L.) seed longevity and deterioration: Physiological and biochemical aspects in relation to moisture contents during storage in different module systems

Abstract

During Storage, deterioration is an undesirable and unalterable attribute that leads to reduction of stored seeds quality in result of it viability and vigour are ultimately affected. Seed moisture plays an important role in seed deterioration process during post-harvest. In storage, oily seeds are extremely vulnerable to moisture conditions during storage. Moreover, seed with higher moisture are also disposed to mechanical damages during whole processing. This study was conducted to examine the effectiveness of hermetic and cloth bag packaging to store cotton seed for 12 months at different seed moisture contents (6, 8, 10 and 12%) at Dera Ghazi Khan, Punjab, Pakistan. The effectiveness of packaging material was assessed on the bases of physiological and biochemical attributes at different moistures. Seed stored at 6 and 8% in hermetic bags maintained maximum germination (71.6 and 42.3%) respectively as compared to initial 76.1%. Similarly, this storage material also equipped seed with more concentration of antioxidants to control deterioration process. In hermetic bag, seeds at high moisture (10 and 12%) were deteriorated and experienced almost complete loss in germination. Because of low ambient relative humidity (<39% RH) conditions of storage environment, the moisture of seed (5.5%) stored in cloth bags equilibrate with environmental RH. In cloth bags, the recorded germination was from 53 to 42% at all moisture levels of storage. Results of cotton seeds moisture sorption isotherm at varying RH (40–90%) levels and constant temperature (25°C) are helpful to predict the safe RH limit for cotton seeds storage. At the end, the role of the temperature (°C) during storage cannot be neglected, because the temperature was recorded up to 46°C during storage period. Thus, cotton seed can be securely stored at low moisture (6%) in hermetic bags but high moisture cause in loss in viability and vigour as well to accelerate deterioration.