*Article* **Effect of K and Zn Application on Biometric and Physiological Parameters of Different Maize Genotypes**

**Hafiz Muhammad Ali Raza <sup>1</sup> , Muhammad Amjad Bashir 1,2 , Abdur Rehim 1,2,\*, Qurat-Ul-Ain Raza <sup>1</sup> , Kashif Ali Khan <sup>2</sup> , Muhammad Aon <sup>1</sup> , Muhammad Ijaz <sup>2</sup> , Shafeeq Ur Rahman <sup>3</sup> , Fiaz Ahmad <sup>4</sup> and Yucong Geng 5,\***


**Abstract:** Potassium (K) and zinc (Zn) are mineral nutrients required for adequate plant growth, enzyme activation, water retention and photosynthetic activities. However, Pakistani soils are alkaline and have serious problems regarding Zn deficiency. The current study aims at finding the nutrient–nutrient interaction of K and Zn to affect maize plants' (i) physiological processes and (ii) productivity. For this purpose, a pot experiment was conducted at the research area of the Department of Soil Science, Faculty of Agricultural Science and Technology, Bahauddin Zakariya University, Multan. Two maize genotypes, DK-6142 (hybrid) and Neelam (non-hybrid), were used with three K fertilizer doses, i.e., 0, 60 and 100 kg ha−<sup>1</sup> in all possible combinations with three Zn fertilizer doses, i.e., 0, 16 and 24 kg ha−<sup>1</sup> . The treatments were replicated under a completely randomized block design. The results elucidated that the combined application of K and Zn with K60 + Zn16 treatment significantly increased agronomic, productive, and physiological attributes. It has improved fresh biomass (89%), dry biomass (94%), membrane stability index (142%), relative water content (200%) and chlorophyll contents (191%) as compared to the control. Moreover, the mineral uptake of K and Zn was significantly improved with their maximum fertilization rate in hybrid genotype compared to non-hybrid and CK.

**Keywords:** potassium; zinc; maize; physiological attributes
