Genetic mapping of morpho-physiological traits involved during reproductive stage drought tolerance in rice.

Saumya Ranjan Barik,Sharat Kumar Pradhan,Elssa Pandit,Trilochan Mohapatra,Shakti Prakash Mohanty,Ajay Kumar

doi:10.1371/journal.pone.0214979

Saumya Ranjan Barik, Sharat Kumar Pradhan + Show 4 more

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https://doi.org/10.1371/journal.pone.0214979

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Abstract

Reproductive stage drought stress is an important yield reducing factor in rainfed rice. Genetic mapping of morpho-physiological traits under the stress will help to develop cultivars suitable for drought prone environments through marker-assisted breeding (MAB). Though various yield QTLs under reproductive stage drought tolerance are available for MAB, but no robust markers controlling different morho-physiological traits are available for this stress tolerance. QTLs linked to morpho-physiological traits under drought stress were mapped by evaluating 190 F7 recombinant inbred lines (RIL) using bulk segregant analysis (BSA) strategy. Wide variations were observed in the RILs for eleven morpho-physiological traits involved during the stress. A total of 401 SSR primers were surveyed for parental polymorphism of which 77 were detected to be polymorphic. Inclusive composite interval mapping detected a total of five consistent QTLs controlling leaf rolling (qLR9.1), leaf drying (qLD9.1), harvest index (qHI9.1), spikelet fertility (qSF9.1) and relative water content (qRWC9.1) under reproductive stage drought stress. Another two non-allelic QTLs controlling leaf rolling (qLR8.1) and leaf drying (qLD12.1) were also detected to be linked and found to control the two traits. QTL controlling leaf rolling, qLR8.1 was validated in this mapping population and may be useful in MAB programs. Out of these five consistent QTLs, four (qLR9.1, qLD9.1, qHI9.1 and qRWC9.1) were detected to be novel QTLs and useful for MAB for improvement of reproductive stage drought tolerance in rice.

Highlights

Rice is the staple food for more than half of the global population
The morpho-physiological parameters estimates viz., percentage of panicle emergence, harvest index, 1000-grain weight, percentage of spikelet fertility, relative water content, cell membrane stability and grain yield were observed to be high in tolerant parent, CR 143-2-2 than susceptible parent Krishnahamsa except plant height, leaf rolling, leaf drying and panicle length
Plant height of the studied recombinant inbred lines (RIL) showed high variation ranging from 45.67cm to 117.92cm

Summary

Introduction

Rice is the staple food for more than half of the global population. This crop provides livelihood security to the majority of rural people in Asia and South-east Asia. The crop is cultivated in about 160.8 million hectares with annual production of more than 725.5 million tons of paddy [1]. The food production need to be increased even from the drought-prone areas with an increase of 40% from the difficult ecosystem to meet the targeted food production by 2025 [2].

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