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This article in CS

  1. Vol. 52 No. 2, p. 644-653
     
    Received: Apr 14, 2011


    * Corresponding author(s): kalmesh@gmail.com
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doi:10.2135/cropsci2011.04.0206

Direct Selection for Grain Yield under Moisture Stress in Oryza sativa cv. IR58025B × Oryza meridionalis Population

  1. P. Kalmeshwer Gouda *a,
  2. C. Mohan Kumar Varmaa,
  3. S. Saikumara,
  4. B. Kirana,
  5. Vinay Shenoya and
  6. H. E. Shashidharb
  1. a Barwale Foundation, Barwale Chambers, #3-6-666, Street No. 10, Himayathnagar, Hyderabad 500 029, India
    b Professor, Department of Biotechnology, University of Agricultural Sciences, GKVK, Bangalore 560 065, India

Abstract

Rice (Oryza sativa L.) is one of the important food crops drastically affected by drought. Considering the low heritability of grain yield under water stress, several secondary traits associated with drought tolerance have been used, but the success achieved in deriving cultivars with high yield potential under stress is less compared to irrigated conditions. Hence, objective of the experiment was to estimate heritability for grain yield under lowland stress and select for grain yield per se using wild species Oryza meridionalis Ng and also to identify physio-morphological traits responsible for withstanding water stress. A population derived from O. sativa cv. IR58025B × O. meridionalis (BC2F3) was evaluated under control and stress conditions. Variability observed for yield and component traits indicated O. meridionalis to be a good source of useful alleles for drought tolerance. Broad-sense heritability (h2) of grain yield under stress, although only 33.1%, was comparable to control 59.4%, indicating direct selection for grain yield per se can be practiced. Twenty high-yielding selected lines and 40 random lines were evaluated under control and stress conditions to estimate selection response. Yield of selected lines outperformed random lines and checks under stress. Furthermore, 10 lines (5 high yielding and 5 low yielding) selected from the population were characterized for root morphological traits. Maximum root length (MRL) and root volume (RV) of selected high-yielding lines recorded maximum compared with checks and low-yielding lines indicating positive influence of drought avoidance root traits on grain yield under stress. Hence, O. meridionalis can be a good source of root traits contributing to stress tolerance and selection for grain yield under stress is an effective strategy in deriving drought tolerant lines in rice.

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