Abstract
Drought is a major abiotic factor restricting rice yield; therefore, to cope with this stress, 2030 japonica rice accessions from China and other countries were evaluated in Beijing in 2017 and 2018. This was the first time six agronomic traits in the large-scale germplasm of rice under lowland and upland conditions with an augmented randomized complete block design (ARCBD) were analysed. The genotypes revealing drought resistant grade (DRG) scores of 1, 1–3, 3 and 3–5 were considered drought-tolerant and comprised 10% of the assessed germplasm. These findings were consistent with the agglomerative hierarchical cluster (AHC) analysis that classified germplasm in nine clusters. The generated clusters were further grouped in A, B, C and D classes based on the stress response. Approximately half of the genotypes with an upland ecotype were distributed in drought-resistant class A (cluster VII and VI) and moderately resistant class B (VIII and IX). The majority of the genotypes from China, Korea and Japan fall in drought-susceptible classes C and D. Genotypes of DRG 1, 1–3 and 3 belonged to the clusters VII and VI. Finally, we screened out 42 elite genotypes including seven improved upland rice lines (D78, LB37-13, NSU77, Handao 385, Handao 306, SF83 and HF6-65-119), three upland released varieties (Liaogeng 27, Hanfeng 8 and IRAT109) and three traditional lowland cultivars (Hongmaodao, Weiguo 7 and Xiaohongbandao). These genotypes might be used as priority parents in drought-tolerant rice breeding programmes and some of them could be recommended directly to farmers in water-deficient rice areas of China.
Highlights
Published: 30 August 2021Drought is a direct result of water scarcity, in particular the long-term lack of precipitation that could result in low soil moisture content, reduced crop yields, and increased water demand for irrigation and groundwater extraction [1]
Augmented randomized complete block design (ARCBD) is widely used for the phenotyping of large populations under lowland and upland conditions in maize crops [27,28,29,30], in this article we report for the first time on the application of the augmented randomized complete block design (ARCBD)
A large-scale germplasm of 2030 rice (Oryza sativa L. ssp. japonica) genotypes was subjected to augmented randomized complete block design (ARCBD) under lowland and upland conditions, which resulted in significant differences for days to flowering (DF), plant height to leaf (PHL), plant height to panicle (PHP), aboveground biomass plant−1 (ABP−1 ), grain yield plant−1 (GYP−1 ) and harvest index (HI)
Summary
Published: 30 August 2021Drought is a direct result of water scarcity, in particular the long-term lack of precipitation that could result in low soil moisture content, reduced crop yields, and increased water demand for irrigation (low runoff) and groundwater extraction [1]. Rice (Oryza sativa L.), a major food crop for over half of the world’s population, is cultivated worldwide in over 95 countries, with around 90% of the world’s rice being produced and consumed in Asia, providing 35% to 60% of the dietary calories for more than 3 billion people [3]. Due to industrial and urban development, declining supply because of resource depletion, pollution and population growth, water is becoming readily shorter in supply [4], and its supply for rice production is becoming limited. There is a need for another production system for rice, especially for the areas with reduced labour resources and supply of water. Germplasm banks are warehouses of the crop plants, and its pools characterize a large capability for resources of stress tolerance.
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