Abstract
Low temperature stress severely hampers rice productivity, and hence elaborating chilling-mediated physiochemical alterations and unravelling cold tolerance pathways will facilitate cold resilient rice breeding. Various cold tolerant Near-isogenic lines (NILs) selected at the booting stage through backcrossing of a japonica landrace Lijing2 (cold tolerant) with cold sensitive Towada (a japonica cultivar). The cold tolerance attributes of NILs was validated over two years by evaluating the spikelet fertility followed by correlation of nineteen morphological traits with the rate of seed setting (RSS). Results revealed BG, FG, 1-2IL, RSLL, and UIL were significantly correlated with RSS and had nearer marker interval distance with cold tolerance in QTL analysis. Two QTLs, qCTB-7-a and qCTB-7-b, were found for RSS based on a mixed linear model. Alleles of two QTLs were contributed by Lijing2 and genetic distances between the peaks were 0.00 and 0.06cM, which explained 5.70% and 8.36% variation, respectively, One QTL for 1-2IL, RSLL, and ILBS, while two QTLs for FG, BG, and UIL were also identified. These findings can be exploited to engineer low temperature stress tolerant rice in times of climate change.
Highlights
Plant metabolic processes and life functions are used to work in optimum condition of prevailing environment, i.e., optimum temperature and light, but diversions from the optimum condition imparts severe damages in a plants life, owing to excessive production and accumulation of reactive oxygen species (ROS), obstruction in the process of photosynthesis, disturbance of ion and nutrient uptake, Agronomy 2019, 9, 40; doi:10.3390/agronomy9010040 www.mdpi.com/journal/agronomyAgronomy 2019, 9, 40 and declines plant growth and yield [1,2,3]
We conjectured that lower temperature at booting stage could affect more morphological traits; a similar conclusion has been drawn previously by Cui et al [26]
Internode Length (1-2IL), Panicle Length (PaL), Full Grains (FG), Blighted Grains (BG), and Number of Grain Per Panicle (NOGP), with cold stress tolerance indicator, rate of seed setting (RSS), of Near-isogenic lines (NILs) population grown at Kunming (K), and Aziying (A)
Summary
Plant metabolic processes and life functions are used to work in optimum condition of prevailing environment, i.e., optimum temperature and light, but diversions from the optimum condition imparts severe damages in a plants life, owing to excessive production and accumulation of reactive oxygen species (ROS), obstruction in the process of photosynthesis, disturbance of ion and nutrient uptake, Agronomy 2019, 9, 40; doi:10.3390/agronomy9010040 www.mdpi.com/journal/agronomyAgronomy 2019, 9, 40 and declines plant growth and yield [1,2,3]. Plant metabolic processes and life functions are used to work in optimum condition of prevailing environment, i.e., optimum temperature and light, but diversions from the optimum condition imparts severe damages in a plants life, owing to excessive production and accumulation of reactive oxygen species (ROS), obstruction in the process of photosynthesis, disturbance of ion and nutrient uptake, Agronomy 2019, 9, 40; doi:10.3390/agronomy9010040 www.mdpi.com/journal/agronomy. Cereals are more prone to environmental clues and they experience diverse environmental conditions during their growth cycle. Cold stress severely influences the growth and productivity of rice (Oryza sativa L.) and affects its distribution around the globe [5,6]. 4.5 million hectares of rice are grown per year all over the world including tropical and subtropical areas, especially in some areas of moderate climatic zones, which experience unpredicted chilling stresses [7,8].
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