ASSESSMENT OF DROUGHT TOLERANCE ABILITY OF SIX TEA GENOTYPES IN RESPECT OF BANGLADESH

Drought stress significantly limits the growth, physiology, and yield of tea (Camellia sinensis), creating the necessity of the identification of drought-tolerant genotypes for sustainable cultivation in Bangladesh. This study evaluated the drought performance of six tea genotypes i.e. BT2, BT4, BT10, BT21, BT23 and B/8/93 based on 14 morpho-physiological and biochemical traits to assess their tolerance levels under water-deficit conditions (Maintaining 18% soil moisture content-T1) with control condition (T0). Traits analyzed included plant height (PH), base diameter (BD), vertical root length (VRL), root dry weight (RDW), shoot dry weight (SDW), total dry weight (TDW), chlorophyll stability index (CSI), proline content (PRL), relative water content (RWC), stomatal conductance (gs), rate of photosynthesis (A), transpiration rate (E), water use efficiency (WUE) and green leaf per plant (GL) after 30, 60, 90, 120, 150 and 180 days of drought imposition. All the traits significantly affected the growth and development of tea under drought condition. A clustering heatmap based on trait performances grouped the genotypes by tolerance levels, allowing for a ranked sequence from most to least tolerant: B/8/93 > BT2 > BT21 > BT23 > BT4 > BT10. The integration of multiple traits provided a reliable framework for evaluating drought responses and identified key physiological markers for future selection. These findings offer valuable insights for tea breeding programs aimed at developing drought-resilient cultivars to ensure productivity under changing climatic conditions.