Evaluation of physiological traits associated with abiotic stress tolerance in Gossypium hirsutum L. genotypes under rainfed conditions in black cotton soils

摘要

A field experiment was laid out in a strip plot design with 2 irrigation levels as main treatments (need based irrigation and rainfed conditions) and 20 cotton entries viz; CPD 231, NH 635, GBHv 164, ARBH 813, GISV 218,BS 30, H1452, CPD 168, F2228, GJHv 358, HBB 101, BS 279, ARBH 2004, GSHv 97/612, Sahana, LRA 5166, MR 786, AKH0205, RCR 102 and H1353 as sub treatments to know the relative tolerance of the entries under moisture stress conditions in black cotton soils under natural conditions. Relative water content (RWC), specific leaf weight (SLW), chlorophyll stability index (CSI), SPAD chlorophyll meter reading (SCMR), leaf temperature, photosynthetic rate, seed cotton yield and per cent reduction in photosynthetic rate, dry matter production andseed cotton yield under rainfed conditions in comparison with irrigated conditions were examined and found significant variation among the entries tested. Significantly higher seed cotton yield was recorded in F 2228 (3909 kg/ha) followed by NH 635 (3061 kg/ha), H 1452 (2972 kg/ha ), CPD231 (2954 kg/ha), MR 786 (2761kg/ha), GISV 218 (2721 kg/ha) and the higher yield was associated with higher boll number and weight. The entries viz., H 1252, F2228, NH 635 GBHv 164, GISV 218 and ARBH 813 have shown goodperformance under rainfed conditions with their inbuilt tolerance to drought. Higher chlorophyll stability index was recorded in AKH0205, GBHv 164, ARBH 813, MR 786 and LRA 5166. Higher photosynthetic rate was recorded in MR 786 followed by LRA 5166, ARBH 813, RCR 102, F 2228 and H 1353. The entry F 2228 recorded significantly higher RWC followed by RCR 102, CPD 168 and GJHv 358. The experimental results indicated that the entries having higher productivity under rainfed conditions were associated with more than one drought tolerance parameters viz., RWC, SLW and CSI in addition to less reduction in photosynthetic rate and dry matter production.