Effects of Different Growth Regulators on Agronomic Characters and Grain Yield of Maize Varieties

Abstract

In order to screen the sweet corn varieties with strong cadmium tolerance and explore the differences in response to cadmium stress, 12 sweet corn varieties mainly selected in South China were used to study the effects of cadmium treatment. The seedling grew in sand culture until they initiated three leaves in total with two leaves expanded and treated with cadmium ion (Cd 2+ ) solution, and then phenotypic investigation of seedling height, main root length, total root number, fresh weight, dry weight, and SPAD value of the first leaf. The results showed that there were significant differences under cadmium tolerance to those sweet corn varieties with different genetic backgrounds, and most of the eight characters measured had significant correlations between cadmium tolerance indices. A comprehensive index obtained by principal component analysis can effectively evaluate the cadmium tolerance of different varieties of sweet corn, and its contribution rate is 73.42%. Cluster analysis was used to classify 12 sweet corn varieties into sensitive (one variety), intermediate (eight varieties) and tolerant (three varieties). Among them, three varieties including ‘Zhongxiantian 102’, ‘Zhuyutian 1’ and ‘Fotian 10’ had strong cadmium tolerance, which could be further screened for low-cadmium-accumulating varieties to be used in agricultural production. At the same time, by comparing and analyzing the phenotypic variation between two varieties with different response to cadmium stress, it was found that cadmium stress would break the stability of chlorophyll in the leaves of sensitive sweet corn seedlings, affecting photosynthesis, and then reducing the accumulation of biomass and inhibiting growth and development. This study provides reference for further analysis of cadmium-resistant response mechanism of sweet corn.