Differential Biochemical Response of Wheat Genotypes Under Temperature Stress

Abstract

Background Changes under temperature induction response has been shown as a potential tool for empirical assessment for plant cell tolerance. By this technique, thermotolerant lines were identified from crop wheat, which showed better performance than the original population under high temperature. The present investigation ten days old seedlings of six wheat genotypes released by DR. PDKV, Akola ,Maharashtra, India viz., PDKV Sardar, AKAW-381, PDKV-Washim, AKAW-3722, WSM-109-4, AKAW-4627 compared with Raj-4083 (National check) by exposing to gradual increase of high temperature and duration (control 25°C to 30°C 1 hr, 34°C 1 hr, 38°C 2 hr and 42°C 3 hr) in order to investigate its effect on some physiological and biochemical parameters to provide the basic information to wheat breeder for improvement targeted to heat tolerant cultivar. Results Increase of temperature induced the proline accumulation in all genotypes till a temperature threshold 34°C 1 hr (it depended on genotype), while above the proline content declined. However, the level was dropped at 38°C 2 hr PDKV-washim, AKAW-3722 and PDKV Sardar and 42°C 3 hr in all seven wheat genotypes. The relative leaf water content (RLWC), chlorophyll ‘b’ content significantly declined with steady increase in hydrogen peroxide (H2O2) content. High temperature and duration of exposure induces the activity of Superoxide dismutase (SOD), Ascorbate peroxidase (APX) and peroxidase enzymes. However, it was observed that, at lethal temperature stress (42°C 3 hr) levels majority of biochemical parameters studied in this experiment found to be declined. Conclusion In our investigation, a positive association between rising temperatures, H2O2 levels and SOD, APX and peroxidase levels in all wheat genotypes was found. The fact that AKAW-4627 maintains greater RLWC and Chlorophyll a and b content as well as other biochemical parameters may be contributing to their minor rise in H2O2 content. A steady rise in high temperature with duration of their exposure an increase in the activity of superoxide dismutase, APX and peroxidase and carotenoids were observed. Among the seven-wheat genotype pre-released WSM-109-04 and AKAW4627 and PDKV Sardar genotypes followed by AKAW-381 showed better adaptability at higher temperature stress when compared with national check Raj-4083. The information generated on biochemical basis is useful for wheat breeder for further improvement in wheat for thermotolerance.