Response of Boll Development to Macronutrients Application in Different Cotton Genotypes

Irshad Ahmad,Yousaf Jamal,Guanglong Zhu,Muhi Eldeen Hussien Ibrahim,Zahoor Ahmad,Xudong Song,Nimir Eltyb Ahmed Nimir,Guisheng Zhou

doi:10.3390/agronomy9060322

Abstract

Combined application of nitrogen (N), phosphorus (P), and potassium (K) is a valuable practice to improve the growth and physiological activities of cotton, especially during a boll setting. The main purpose of this research was to investigate the effects of the different combined ratios of nitrogen (N), phosphorus (P), and K (potassium) on morpho-physiological activities of Bacillus thuringiensis (Bt) cotton genotypes Siza 1 and Sikang 1 during the cotton boll development stage. A two-year (2016–2017) field experiment was performed in which the total amount of combined N, P, and K were applied at different levels, B1 = 150 N, 0 P2O5, and 0 K2O kg ha−1 (control), B2 = 150 N, 45 P2O5, and 90 K2O kg ha−1, B3 = 150 N, 90 P2O5, and 135 K2O kg ha−1, and B4 = 150 N, 135 P2O5, and 180 K2O kg ha−1. Results revealed that combined application of N, P, and K significantly increased boll length by 5.8% and 2.3%, fresh boll weight by 12.2% and 16.4%, dry lint weight by 15.2% and 1.7%, number of seeds boll−1 by 15.2% and 2.5% as well as dry boll shell weight by 11.0% and 4.9% as compared with the treatment without P and K (1:0:0) across two growing seasons. Furthermore, superoxide dismutase activity was improved by 2.3% and 15.6% and soluble protein by 5.1% and 14.1% as compared with the control, respectively. Our study indicated that combined application of N, P, and K at appropriate ratios enhanced morpho-physiological activities (boll length, boll width, boll weight, protein content, sugar content, and superoxide dismutase) of cotton during boll development and generally the ratio of 150:135:180 considerably performed best amongst all treatments during two growing seasons in this study.

Highlights

Cotton is one of the most important cash crops, cultivated for fiber and oilseed production
The main purpose of this work was to investigate the effect of ratio of N, P, and K on cotton boll development and to compare the morpho-physiological characteristics of two Bacillus thuringiensis (Bt) cotton genotypes
The boll length was affected by cultivar, ratio of N, P, and K, and their combination at 3, 10, 17, 38, and 52 days after flowering (DAF) during the first year and at 17 to 52 DAF during the second year (Table 1), but no significant differences were observed for boll length at 24, 31, and 45 DAF in 2016 and at 3 and 10 DAF in 2017

Summary

Introduction

Cotton is one of the most important cash crops, cultivated for fiber and oilseed production. In the past two decades, Bacillus thuringiensis (Bt) cotton has been widely extended in Agronomy 2019, 9, 322; doi:10.3390/agronomy9060322 www.mdpi.com/journal/agronomy. China is one of the leading Bt cotton producers in the world with an average lint yield level of 1438 kg ha−1. There is a stagnancy of cotton production in terms of both quality and quantity in the past decade [3]. There are many field management aspects responsible for this stagnancy in China, such as inappropriate sowing method and time, unbalanced fertilization, inappropriate irrigation, poor pest management, and so on. Of all these aspects, the unbalanced application of fertilizer is certainly a major factor [4]

Objectives

Methods

Results

Discussion

Conclusion