Genotypic Variation of Sweetpotatoes Grown Under Low Potassium Stress

Abstract

Ninety‐four sweetpotato (Ipomoea batatas L.) genotypes were compared under low potassium (K) stress (35 mg kg⁻¹ dry soil) over two growing seasons. Potassium utilization efficiency ratio (KER), defined as the dry matter weight/K content, was significantly different among genotypes. Genotypes were divisible into four KER categories: high efficient, efficient, fairly efficient and inefficient with most of the genotypes falling in the efficient and fairly efficient groups. The K contents varied significantly within individual plants. Potassium concentration on a dry weight basis was greatest in the petioles followed by leaves, stems, and roots. On a total plant basis, K content in roots was greatest followed by stems, leaves, and petioles. Several genotypes (including 602 × 81‐3, Zhe15‐47 and Xushu18) were selected as most suitable for growth on soils low in available K due to their appreciable yields and higher KER under low K stress.

Keywords:

• Potassium utilization efficiency ratio (KER)
• Ipomoea batatas L

Acknowledgments

The authors would like to thank Prof. Ye Yanfu, Mr. Wu Lianhong, and Ms. Ji Zhixian of the Zhejiang Academy of Agricultural Sciences for providing most of the sweetpotato cultivars used in this study. The research was supported by the grant from National Foundation Committee of Natural Sciences and from Department of Zhejiang Province's Sciences and Technology.