Drought stress resistance indicators of chickpea varieties grown under deficit irrigation conditions

The aim of this study was to determine the drought stress resistance of three chickpea cultivars (Inci, Hasanbey and Seçkin) grown under water deficit conditions and to discuss the use of yield, crop water stress index and chlorophyll index values as drought stress tolerance indicators in breeding studies. Three drought stress levels, (full irrigation = no stress - I₁₀₀, deficit irrigation = moderate stress - I₅₀, and no irrigation = severe stress - I₀) were used as irrigation treatments. The highest seed yield (1,984 kg ha^-1) in severe stress conditions was recorded for the Inci cultivar with a low crop water stress index (CWSI) (0.50) and high chlorophyll index (33.60 SPAD). The lowest seed yield (1,783.66 kg ha^-1) in I₀treatment was noted for the Seçkin cultivar which had a high CWSI (0.58) and low chlorophyll index (32.88 SPAD). The highest seed yield (2,566.33 kg ha^-1) in full irrigation was recorded for the Inci cultivar which had a low CWSI (0.19) and high chlorophyll index (44.39 SPAD), while the lowest seed yield (2,328.00 kg ha^-1) in I₁₀₀ treatment was recorded for the Seçkin cultivar which had a high CWSI (0.26) and low chlorophyll index (42.12 SPAD). The seed yield of the Hasanbey cultivar in both severe stress (1,893 kg ha^-1) and full irrigation (2,424.00 kg ha^-1) conditions was between Inci and Seçkin varieties. The chlorophyll index and yield had a significant positive (r = 0.877) correlation, while a significant negative (r = -0.90) relationship was determined between CWSI and yield. Seed yield of the Inci cultivar in I₀and I₁₀₀treatments and water use efficiency revealed that the Inci cultivar is resistant to drought stress. Therefore, the Inci cultivar can be used in drought stress tolerance studies. In addition, the CWSI and chlorophyll index values can be employed as resistance indicators in chickpea breeding studies to determine the drought resistant chickpea cultivars.