RESUMEN
Global climatic instabilities have become the main reason for drastic yield losses in chickpea. This shift in climate could be a great threat in the future for food security in developing countries. Chickpea production is badly hampered by heat stress coupled with drought stress, and these factors can reduce yields by 40-45%. To mitigate yield losses due these abiotic factors, irrigation supplementation could be the best strategy. The present study aimed to (i) investigate the tolerance response of 9 desi chickpea genotypes against heat stress (H), irrigation (I), and a combination of both (I+H) through morphophysiological and biochemical indices at early growth stage, and (ii) assess yield performance across multiple locations of the country. Results revealed that under irrigation treatment, all genotypes perform well, but the genotypes D-09027 and D-09013 showed best performance because, as compared to control, they retained root length, seedling fresh weight, root fresh weight, root dry weight, esterase activity, Malondialdehyde (MDA) content, total chlorophyll, and total carotenoids. Shoot length and total phenolic contents (TPC) increased in both genotypes. Superoxide dismutase (SOD) and peroxidase (POD) increased in D-09027 and retained in D-09013. Catalase activity increased in D-09013 and retained in D-09027. Protease activity, total water potential and osmotic potential decreased in both genotypes and depicted high yield potential with 27 and 30% increase in yield over Bhakhar-2011 (check), respectively. In case of heat stress, maximum tolerance was found in genotypes CH104/06 and D-09013 with no change in shoot and root length, seedling dry weight, shoot fresh and dry weight, root dry weight, relative water content, turgor water potential, catalase (CAT) activity, esterase activity, increased root fresh weight, peroxidase activity (POD), ascorbate peroxidase activity (APX), and lycopene with low accumulation of protease and Malondialdehyde content (MDA). Both genotypes depicted high yield potential with 30 and 43% increase in yield over check across multiple locations of the country. Under the combined treatment, most genotypes showed good performance, while CH104/06 was selected as best performer genotype because significant of its increased root fresh weight, lycopene content, chlorophyll b, total carotenoids, total chlorophyll, retained shoot length, root length, seedling fresh and dry weight, total water potential, osmotic potential, relative water content, peroxidase activity (POD), catalase, esterase, and its ascorbate peroxidase (APX) activity and total soluble proteins (TSP) showed highest yield potential with 43% increase over check. Identified best performing and tolerant genotypes can further be employed for breeding climate-smart chickpea genotypes for sustainable production under changing climate.
RESUMEN
In Pakistan, chickpeas (Cicer arietinum L.) are the largest grown legume crops, especially in desert areas. Along with an excellent source of nutrition, chickpea seeds have discernible medicinal and antioxidant characteristics. The diverse set of 90 chickpea genotypes (66 desi and 24 kabuli) were collected from different research zones in Pakistan, and seed flour was used for biochemical profiling. Genotypes were significantly different (Tukey HSD test, P < 0.05) for the traits under investigation. In non-enzymatic antioxidants, highest seed total phenolic contents (TPC) (34725 ± 275 µM/g s. wt.) was found in CM-98 (desi), ascorbic acid (AsA) (69.23 ± 2.25 µg/g s. wt.) in WH-3 (desi), and total flavonoid content (TFC) (394.98 ± 13.06 µg/mL sample) was detected in WH-11 (desi). In the class of enzymatic antioxidants, the highest seed ascorbate peroxidase (APX) (1680 ± 40 Units/g s. wt.) was detected in Tamman-2013 (kabuli), peroxidases (POD) (2564.10 ± 233.10 Units/g s. wt.) activity in CM1235/08 (desi), and superoxide dismutase (SOD) (279.76 ± 50 Units/g s. wt.) was detected in CH24/11 (desi). Highest seed catalase activity (CAT) (893 ± 50 Units/g s. wt.) and proline content (272.50 ± 20.82 µg/g s. wt.) was detected in an ICC-4951 (desi). In hydrolytic enzymes, the highest activity of esterase (37.05 µM/min/g s. wt) was found in, CH56/09(Kabuli), protease (11080 ± 10 Units/g s. wt.) in Karak-2 (desi), and α-amylase (213.02 ± 3.20 mg/g s. wt.) was observed in CH74/08 (kabuli). In other biochemical parameters, the highest seed total oxidant status (TOS) (356 ± 17.50 µM/g s. wt.) was detected in CM3457/91 (desi); malondialdehyde (MDA) content (295.74 ± 3.097 uM/g s. wt.) was observed in CM-2008 (kabuli), and total antioxidant capacity (TAC) (8.36 ± 0.082 µM/g s. wt.) was found in CM-72 (desi). In case of pigment analysis, Sheenghar-2000 (desi) depicted highest lycopene (12.579 ± 0.313 µg/g s. wt.) and total carotenoids (58.430.23 ± 0.569 µg/g s. wt.) contents. For seed therapeutic potential, the highest seed α-amylase inhibition (82.33 ± 8.06%) was observed in CM-88 (desi), while WH-1, WH-6, and ICCV-96030 (desi) depicted the highest value for seed anti-inflammatory potential (78.88 ± 0.55%). Genotypes with the highest antioxidant and therapeutic potential can be utilized as a natural antioxidant source and in breeding programs aimed at improving these traits in new breeding lines.
