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<p>Drought stress is a major abiotic stress limiting rice productivity. Forty BC₂F₅ drought QTL pyramided lines (PLs) in the background of DRR dhan 50 cultivar, each carrying combinations of <i>qDTY</i><sub><i>2.1</i></sub>, <i>qDTY</i><sub><i>3.1</i></sub>, <i>qDTY</i><sub><i>1.1</i></sub> and <i>qDTY</i><sub>2.2</sub> were evaluated under drought and irrigated conditions during rabi 2025. The current study aimed to evaluate genetic variability and trait associations through correlation, principal component and cluster analyses among 40 PLs derived from DRR Dhan50*2/ SAB 4 -7-5 cross to identify superior drought tolerant donors. ANOVA revealed highly significant variability across eleven agro-morphological traits under both conditions. Reproductive stage drought stress drastically reduced yield and its components. Five superior PLs (QTV 108-4, 108-3, 189-2, 128-4, and 105-1) exhibited 36–82% yield improvement over DRR dhan 50 and could be utilized in breeding programs to introgress and deploy drought tolerance. High estimates of GCV, PCV, h²b and GAM for total tiller number (TTN), panicle length (PL), fertile grains/ panicle (FGP), grain yield (GY) and Harvest index (HI) indicated additive gene action, suggesting direct selection is effective. Grain yield exhibited strong positive association with productive tiller number (PTN), PL, FGP, SF%, biomass (BM) and HI under drought. PCA indicated that the first two components accounted for 47.95% of the total variance, with PC1 (29.6%) strongly associated with yield-related traits (GY, BM, FGP, HI). Three drought tolerant PLs (QTV 108-4, 128-4 and 105-1) clustered on PC1, reflecting their contribution to enhanced yield performance under drought. Cluster analysis grouped 40 PLs into three clusters: Cluster I lines exhibited high grain yield, grain number, panicle length, spikelet fertility, and shorter flowering duration under stress, making them valuable tolerant donors; Cluster II displayed intermediate trait means; and Cluster III, characterized by high tiller and panicle numbers, appeared suitable donors for pre-breeding and wide crosses to enhance diversity and introduce yield traits. Overall we found high genetic diversity among PLs and detected promising lines suitable for use in drought tolerance breeding.</p>

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Unravelling genetic variation in drought QTL pyramided lines to identify key traits for drought tolerance in rice

  • 期刊论文

  • 发表日期：

    2026年8月5日

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  • M. Gnana Akshaya,
  • C. R. Anusha,
  • G. Padmavathi,
  • S. V. Sai Prasad,
  • Mayank Rai,
  • N. K. Singh,
  • A. Sai Harini

摘要

Drought stress is a major abiotic stress limiting rice productivity. Forty BC₂F₅ drought QTL pyramided lines (PLs) in the background of DRR dhan 50 cultivar, each carrying combinations of qDTY2.1, qDTY3.1, qDTY1.1 and qDTY2.2 were evaluated under drought and irrigated conditions during rabi 2025. The current study aimed to evaluate genetic variability and trait associations through correlation, principal component and cluster analyses among 40 PLs derived from DRR Dhan50*2/ SAB 4 -7-5 cross to identify superior drought tolerant donors. ANOVA revealed highly significant variability across eleven agro-morphological traits under both conditions. Reproductive stage drought stress drastically reduced yield and its components. Five superior PLs (QTV 108-4, 108-3, 189-2, 128-4, and 105-1) exhibited 36–82% yield improvement over DRR dhan 50 and could be utilized in breeding programs to introgress and deploy drought tolerance. High estimates of GCV, PCV, h²b and GAM for total tiller number (TTN), panicle length (PL), fertile grains/ panicle (FGP), grain yield (GY) and Harvest index (HI) indicated additive gene action, suggesting direct selection is effective. Grain yield exhibited strong positive association with productive tiller number (PTN), PL, FGP, SF%, biomass (BM) and HI under drought. PCA indicated that the first two components accounted for 47.95% of the total variance, with PC1 (29.6%) strongly associated with yield-related traits (GY, BM, FGP, HI). Three drought tolerant PLs (QTV 108-4, 128-4 and 105-1) clustered on PC1, reflecting their contribution to enhanced yield performance under drought. Cluster analysis grouped 40 PLs into three clusters: Cluster I lines exhibited high grain yield, grain number, panicle length, spikelet fertility, and shorter flowering duration under stress, making them valuable tolerant donors; Cluster II displayed intermediate trait means; and Cluster III, characterized by high tiller and panicle numbers, appeared suitable donors for pre-breeding and wide crosses to enhance diversity and introduce yield traits. Overall we found high genetic diversity among PLs and detected promising lines suitable for use in drought tolerance breeding.