Cluster heatmap for detection of good tolerance trait on doubled-haploid rice lines under hydroponic salinity screening

Abstract

Abstract The development of salinity tolerant varieties can be done by using doubled haploid technology. In the determination of the salinity tolerance trait, hydroponic screening at the seedling stage is the most common screening method. However, it needs improvement on the assignment of the tolerance traits. Cluster heatmap analysis has been reported to select lines by combining various data. The objective of the study was to select tolerant doubled-haploid rice lines to salinity stress at the seedling phase and evaluate the use of cluster heatmap analysis by combining tolerance score and growth characters. The study was conducted in a greenhouse using a nested factorial design (repetition nested in NaCl concentrations), with 3 replications. The plant materials used consisted of 62 genotypes and NaCl concentration levels consisted of 0 (1 dS/m) and 120 mM (13.3 dS/m). Hydroponic cultures used a Yoshida solution. Each container contained 14 experimental units and 2 units of check i.e. sensitive and tolerant controls. Observations was carried out on tolerance scoring and growth parameters. The results showed that tolerant and moderate genotypes have a lower pattern of decline than sensitive genotypes, especially in shoot-related characters. Based on the cluster heatmap analysis, there were 38 doubled haploid rice lines considered good tolerance traits under saline condition. The cluster heatmap assignment was considered more selective than only focused on tolerance score, especially in negative selection to sensitive lines.