Identifying the selection criteria for evolving high-yielding rapeseed genotypes (Brassica napus L.) for water stress conditions

Water scarcity is one of the main constraints for the cultivation of many field crops, including rapeseed. Water-stress resistant in rapeseed cultivars is an efficient and productive approach to face the challenge of water shortage. Therefore, the current study regarding correlation analysis was carried out under water stress in order to identify the yield enhancing characters, which are evolving in high yielding rapeseed genotypes under water stress conditions. The experiment was conducted in a randomized complete block design with factorial arrangements having twenty rapeseed genotypes at Botanical Garden, Sindh Agriculture University Tandojam during the growing season of 2019-20. For the estimation of correlation, two treatments were used, such as, well-watered (WW) with four normal irrigations at several growth stages and water stress (WS) with only two irrigations, imposing at silique formation stage. The values of mean squares of genotypes, treatments and genotype × treatment interactions were differed significantly ( P ≤0.05) for many studied traits, signifying that breeding materials used in the present research has worth to be used in future rapeseed improvement programs. Most of the investigated characters exhibited positive and significant ( P ≤0.05) correlations with seed yield plant -1 under well-watered and water stress conditions, such as, plant height (WW= 0.60 ** ; WS= 0.61 ** ), branches plant -1 (WW= 0.51 ** ; WS= 0.46 ** ), silique plant -1 (WW= 0.49 ** ; WS= 0.33 ** ), seeds silique -1 (WW= 0.74 ** ; WS= 0.71 ** ), silique length (WW= 0.86 ** ; WS= 0.88 ** ), seed yield silique -1 (WW= 0.77 ** ; WS= 0.80 ** ), seed index (WW= 0.85 ** ; WS= 0.86 ** ), relative water content (WW= 0.60 ** ; WS= 0.61 ** ), chlorophyll (WW= 0.77 ** ; WS= 0.81 ** ) and oil content (WW= 0.51 ** ; WS= 0.55 ** ). Besides that, scientists and farmers can be used such characteristics as selection criteria to develop high-yielding rapeseed varieties water stress tolerant condition.