ROLE OF BIO-INOCULANTS AND PLANT GROWTH REGULATORS ON GROWTH, PHYSIOLOGY AND YIELD OF CARROT (DAUCUS CAROTA L.) UNDER HEAT STRESS

Naturally plants exposed to unfavorable environmental conditions which drastically affects the plants. Among all abiotic stress, heat stress is considered a major threat towards the productivity of crops. To understand the effect of heat stress it is necessary to understand the molecular mechanism of heat stress of plants. This study was aimed to ascertain the effects of bioinoculants and plant growth regulators on growth, physiology and yield of different carrot genotypes under heat stress conditions. A field experiment was carried out using randomized complete block design at Noor-Pur-Thal, Punjab during the growing season. The outcomes of recent investigation revealed that elevated temperatures had a detrimental effect on factors that contributed to crops growth, such as RD, RW, RL, LA, and various biochemical parameters. Significant decline was noted during exposure to heat stress, coupled with the increase in the activity levels of antioxidant enzymes. Highly significantly positive strong correlation was observed among the following parameters: RW vs RL, RW vs LA, RL vs RD, RL vs LA, PAL vs RS, PAL vs TS, PAL vs Prot, PAL vs FLA, TS vs RS, TS vs Prot, TS vs FLA, RS vs Prot, RS vs FLA, Prot vs FLA, Prot vs CARO, and FLA vs CARO under all diverse applied treatments of both PGR and BI. The peak specialized potentials of biochemical attributes in mgg-1 of tissue under the applications of HS+BI (T5) were 0.01, 0.11, 10.45, 8.25, and 41.77 for PAL, POD, TS, RS, and Prot, accordingly. The applications of BI and PGR to plants experiencing heat stress enhanced growth, accelerating the development of yield contributing factors and biochemical parameters, thereby ultimately increasing the final crops yield. The utilization of both PGR and bio-inoculants proved advantageous for plant growth in the experiencing of heat stress, with bio-inoculants exhibited a greater impact on plant growth and development than PGR.