Abstract

Drought is an important abiotic factor that is affecting crop production worldwide. Cotton (Gossypium hirsutum L.) is an important fibre affected by drought. Identifying cotton lines that are drought  tolerant  is  crucial  for  breeding  for  drought  tolerance  in  cotton,  hence  this  experiment was undertaken to evaluate 12 lines of cotton for drought tolerance, viz: SAMCOT 8, SAMCOT 9, SAMCOT 10, SAMCOT 11, SAMCOT 12, SAMCOT 13, CL-07, LINE 17, LINE 18, LINE 30, MA-1 and MA-15 under in vitro condition using polyethylene glycol (PEG) 6000 at 0, 5, 10 and 15 g/L PEG concentrations.  These were arranged in a 4 × 12 factorial experiment with three replications in a completely randomized design. Data were collected on shoot length (cm), shoot fresh weight (g), seedling fresh weight, root length (cm), root fresh weight (g) and number of roots. Results indicated that the PEG simulated drought stress adversely affected all the traits measured. Significant (P≤0.01) reduction was observed in all the traits as the PEG concentration increases from 0 to 15 g/L PEG.  Result showed that CL-07, SAMCOT 8, SAMCOT 9 and LINE 30 recorded the maximum values for most of the shoot and root traits. Thus, these lines could be considered, having exhibited drought tolerance in vitro.

Key words: Cotton, drought tolerance, in vitro, PEG 6000.