Abstract
Improving drought resistance in crops is imperative under the prevailing erratic rainfall patterns. Drought affects the growth and yield of most modern rice varieties. Recent breeding efforts aim to incorporate drought resistance traits in rice varieties that can be suitable under alternative irrigation schemes, such as in a (semi)aerobic system, as row (furrow-irrigated) rice. The identification of quantitative trait loci (QTLs) controlling grain yield, the most important trait with high selection efficiency, can lead to the identification of markers to facilitate marker-assisted breeding of drought-resistant rice. Here, we report grain yield QTLs under greenhouse drought using an F2:3 population derived from Cocodrie (drought sensitive) × Nagina 22 (N22) (drought tolerant). Eight QTLs were identified for yield traits under drought. Grain yield QTL under drought on chromosome 1 (phenotypic variance explained (PVE) = 11.15%) co-localized with the only QTL for panicle number (PVE = 37.7%). The drought-tolerant parent N22 contributed the favorable alleles for all QTLs except qGN3.2 and qGN5.1 for grain number per panicle. Stress-responsive transcription factors, such as ethylene response factor, WD40 domain protein, zinc finger protein, and genes involved in lipid/sugar metabolism were linked to the QTLs, suggesting their possible role in drought tolerance mechanism of N22 in the background of Cocodrie, contributing to higher yield under drought.
Highlights
The onset of widespread climate change is causing erratic rainfall patterns, leading to limited availability of surface water for irrigation in field crops, creating a water deficit or drought scenario in arid and semi-arid regions [1]
The population used in the present mapping study included 190 F2:3 progeny lines derived from the F1 s between a US-bred drought-sensitive variety ‘Cocodrie’ [26] and an “Aus”-type Indian-origin drought-resistant Nagina 22 (N22)
The recent shifts in climate have challenged rice researchers to devise scientific strategies to address this issue, such as to breed new rice varieties that can adapt to periodic dry spells even in areas where water availability for irrigation is considered to be abundant
Summary
The onset of widespread climate change is causing erratic rainfall patterns, leading to limited availability of surface water for irrigation in field crops, creating a water deficit or drought scenario in arid and semi-arid regions [1]. Rice is life to billions of people who depend on it as their primary source of calories. Rice production needs to be doubled in the decade to meet the demand of the ever-increasing rice-consuming population. This has to be achieved with less land and without exhausting natural resources, including water [2]. Drought is considered the most devastating abiotic stress for rice, causing up to 50% yield loss worldwide [3].
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