Water Stress Is Differently Tolerated by Fusarium-Resistant and -Susceptible Chickpea Genotypes During Germination

Abstract

Chickpea is a legume that grows in most parts of the world. It is negatively affected by abiotic and biotic factors like drought and fungal diseases, respectively. One of the most important soil-borne pathogens affecting chickpeas is Fusarium oxysporum f.sp. ciceris (Foc). Its population dynamics in the soil are affected by fluctuations in soil water content and host characteristics. For the last three decades, drought has been common in most areas of the world due to global warming. Drought stress decreases the quality and quantity of the chickpeas, particularly where soil-borne pathogens are the main stress factor for plants. The use of both drought-tolerant and disease-resistant cultivars may be the only option for cost-effective yield production. In this study, we screened the seeds of twelve chickpea genotypes WR-315, JG-62, C-104, JG-74, CPS-1, BG-212, ANNIGERI, CHAFFA, BG-215, UC-27, ILC-82, and K-850 for drought tolerance at increasing polyethylene glycol (PEG) concentrations (0-, 5-, 7.5-, 10-, 15-, 20-, 25-, 30- and 50%) to create drought stress conditions at different severities. The performances of genotypes that were previously tested in Foc resistance/susceptibility studies were assessed in terms of percentage of germination, radicle and hypocotyl length, germination energy, germination rate index, mean germination time, and vigor index in drought conditions. We determined the genotypes of C-104, CPS-1, and WR-315 as drought-susceptible, moderately drought-tolerant, and drought-tolerant, respectively. We then elucidated the stress levels of selected genotypes (20-day-old seedlings) at 0-15% PEG conditions via measuring proline and malondialdehyde (MDA) contents. Our findings showed that genotypes that were resistant to Foc also exhibited drought tolerance. The responses of chickpea genotypes infected with Foc under drought conditions are the next step to assess the combined stress on chickpea genotypes.

Keywords: chickpea; combined stress; drought stress; fusarium wilt; germination.

Figure 1

Post-germination stages of the drought-tolerant (WR-315), moderate drought-tolerant (CPS-1), and drought-susceptible (C-104) genotypes to water stress under 0-, 5-, 10-, and 15% of PEG6000 concentrations. The white bar in the upper right corner of each photograph represents 1 cm.

Figure 2

Proline contents of WR-315, CPS-1, and C-104 chickpea genotypes at different PEG6000 doses. Different letters in bars show significant differences at the p < 0.05 level; results were expressed as mean ± SE of bars.

Figure 3

MDA contents of WR-315, CPS-1, and C-104 chickpea genotypes at different PEG6000 doses. Different letters in bars show significant differences at the p < 0.05 level; results were expressed as mean ± SE of bars.