Optimization of Temperature Regime to Screen Cold Tolerant Rice Seedlings

Abstract

This is an Open-Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/4.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. ABSTRACT Low temperature stress at the seedling stage of rice is an important factor causing the leaf discoloration, wilting and consequently leads to non-uniform crop maturation. In order to screen the cold tolerance elite lines efficiently, the five cold treatment conditions with different water and air temperature were designed and treated at seedling stage. For the evaluation of seedling tolerance, the injury was scored by visual rate and measured by Soil and Plant Analyzer Development (SPAD) meter. In the reactions of varieties for each treatment, the treatment 'B' condition, 12 o C mean water with 24 o C mean air, shows clear discoloration, so it's correlation coefficient was highest (r=−0.9, P＜0.0001) among the treatments. In the treatment condition for screening the cold-tolerance elite line, the cultivar, treatment and their interaction significantly affect the SPAD value. The 'A' treatment, 12 o C mean water with 34 o C mean air, was the best way to observe the variation between the elite lines. On the basis of the Duncan's test for SPAD value of cultivars, Keumo (moderate tolerant), Saetbyeol (sensitive) and Seolak (tolerant) were selected as check varieties. To study its impacts at the paddy field, the changes of crop characteristics such as height, panicle length, number of tiller and heading were investigated. In later growth period, the seedling treatment impact at the paddy field leads to heading delay. Due to the low temperature stress at the seedling stage induced by 12 o C mean cold water, Japonica and Tongil group shows the heading delay 4 to 7 and 8 to 11 days respectively.

Temporal Changes of Leaf Spectral Properties and Rapid Chlorophyll—A Fluorescence under Natural Cold Stress in Rice Seedlings

“…The average temperature was close to the point where rice damage begins, at about 15 • C [34,35]. The germination and seedling growth rates of the cold-sensitive cultivars were low, as described in earlier studies [38,[46][47][48]. Therefore, this kind of long-term cold stress leads to greater differences among the genotypes than autumn screening (Figures 3 and 4).…”

Efficient Cold Tolerance Evaluation of Four Species of Liliaceae Plants through Cell Death Measurement and Lethal Temperature Prediction

“…Visual inspection reported more stable results when mixed with other methods [38]. Visual inspection by the SPAD method or measurement of chlorophyll or photosynthesis rate was more reliable than visual inspection alone [40].…”

“…However, since the experiential knowledge of the observer judges the visual measurement method, it is not an objective judgment. Nonetheless, low-temperature plant damage generally leads to changes in color [38], and these changes have been used as a critical indicator of cold tolerance [39]. The visual inspection showed that S. scilloides was more tolerant, followed by H. longipes, H. plantaginea, and H. fulva.…”

Estimating the genotype by environment interaction among diverse rice genotypes identified under artificial conditions

“…On the other hand, cold sensitive genotypes had high proportion of saturated fatty acids than unsaturated fatty acids resulting in high transition temperature (Sudesh, 2010). IRRI ( 2013) developed a standard evaluation system (SES) scale to distinguish tolerant and susceptible rice genotypes, which has been used by several studies for cold tolerance evaluation (Andaya and Mackill, 2003;Kim and Tai, 2011;Hyun et al, 2016). Leaf growth/leaf wilting score is one of an essential measurement for cold stress damage.…”