The root-knot nematode, Meloidogyne javanica, is one of the most damaging plant-parasitic nematodes, affecting chickpea and causing substantial yield losses worldwide. The damage potential and population dynamics of this nematode in chickpea in Ethiopia have yet to be investigated. In this study, six chickpea cultivars were tested using 12 ranges of initial population densities (Pi) of M. javanica second-stage juveniles (J2): 0, 0.125, 0.25, 0.5, 1, 2, 4, 8, 16, 32, 64 and 128 J2 (g dry soil)-1 in a controlled glasshouse pot experiment. The Seinhorst yield loss and population dynamics models were fitted to describe population development and the effect on different measured growth variables. The tolerance limit (TTFW) for total fresh weight ranged from 0.05 to 1.22 J2 (g dry soil)-1, with corresponding yield losses ranging from 31 to 64%. The minimum yield for seed weight (mSW) ranged from 0.29 to 0.61, with estimated yield losses of 71 and 39%. The 'Haberu' and 'Geletu' cultivars were considered good hosts, with maximum population densities (M) of 16.27 and 5.64 J2 (g dry soil)-1 and maximum multiplication rate (a) values of 6.25 and 9.23, respectively. All other cultivars are moderate hosts for M. javanica; therefore, it is crucial to initiate chickpea-breeding strategies to manage the tropical root-knot nematode M. javanica in Ethiopia.

Drought stress induces a range of physiological changes in plants, including oxidative damage. Ascorbic acid (AsA), commonly known as vitamin C, is a vital non-enzymatic antioxidant capable of scavenging reactive oxygen species and modulating key physiological processes in crops under abiotic stresses like drought. Chickpea (Cicer arietinum L.), predominantly cultivated in drought-prone regions, offers an ideal model for studying drought tolerance. We explored the potential of AsA phenotyping to enhance drought tolerance in chickpea. Using an automated phenomics facility to monitor daily soil moisture levels, we developed a protocol to screen chickpea genotypes for endogenous AsA content. The results showed that AsA accumulation peaked at 30% field capacity (FC)-when measured between 11:30 am and 12:00 noon-coinciding with the maximum solar radiation (32 degrees C). Using this protocol, we screened 104 diverse chickpea genotypes and two control varieties for genetic variability in AsA accumulation under soil moisture depletion, identifying two groups of genotypes with differing AsA levels. Field trials over two consecutive years revealed that genotypes with higher AsA content, such as BDNG-2018-15 and PG-1201-20, exhibited enhanced drought tolerance and minimal reductions in yield compared to standard cultivars. These AsA-rich genotypes hold promise as valuable genetic resources for breeding programs aimed at improving drought tolerance in chickpea.

A new sustainable approach was aimed to explore the damage caused to legume grown in cadmium (Cd) polluted soil. Owing to the importance of chickpea (Cicer arietinum L.) as a source of protein which is exposed to Cd that imposes severe health hazards. A greenhouse pot experiment was designed to evaluate the potential of Rhizobium application in the amelioration of cadmium stress (Cd; 50 and 100 mg kg(- 1) soil) on chickpea cultivar namely Pusa-BG372 on growth (plant length; plant dry biomass; leaf area; and nodule number), photosynthetic pigments (total chlorophyll and carotenoids), stress biomarkers (malondialdehyde, MDA; superoxide radicles; cell viability), defense (proline, superoxide dismutase, SOD; peroxidase, POD; catalase, CAT; stomatal behaviour), and the major enzymes involved in nitrate assimilation (nitrate reductase; NR) and Calvin Cycle (carbonic anhydrase; CA). Among the different tested concentrations, 100 mg kg(-1) of Cd reduced the growth, photosynthetic variables, biochemical enzymes activity and increased oxidative stress under Cd stress. However, chickpea plants supplemented with Rhizobium-inoculation under the Cd toxicity revealed significantly increased chlorophyll, carotenoid, and proline contents, activity of CA, NR, and antioxidant enzymes. Aside from improved antioxidant enzyme performance and lower lipid peroxidation, cell viability and stomatal functioning were also improved in Rhizobium-inoculated plants. These observations depicted that application of Rhizobium inoculation to seeds could be useful approach to assist stress tolerance against Cd in crop plants grown in Cd contaminated sites.