GENOTYPIC VARIATION FOR BIOCHEMICAL CHARACTERS AND SEED QUALITY PARAMETERS UNDER DROUGHT STRESS CONDITIONS IN CHICKPEA
Acharya N G Ranga Agricultural University, Guntur
The present investigation was carried out in the Department of Seed Science and Technology, Advanced Post Graduate Centre, Lam, Guntur during 2018-19 to study the genotypic variation among the chickpea genotypes for biochemical and seed quality parameters under drought stress conditions. Biochemical characters such as nitrogen content, protein, proline, soluble sugars and MDA content along with activity of peroxidase, esterase and acid phosphatase were estimated in the seed of thirty three chickpea genotypes. Significant variation in biochemical composition was noticed among the genotypes. Correlation studies revealed highly significant positive association among all the biochemical characters except MDA content which exhibited highly significant negative association with the remaining characters. Acid phosphatase exhibited positive correlation with the biochemical characters under study Seed of thirty three different chickpea genotypes were subjected to various levels (-0.3, -0.6, -0.9, -1.2 MPa) of PEG induced drought stress and tested for germination and seedling growth along with control and hydration treatments. Differential influence of PEG 6000 induced drought stress was noticed among the genotypes. With the increase in drought stress, germination, root length, shoot length, seedling length and seedling vigour index decreased gradually. In most of the genotypes complete inhibition of germination was observed at -1.2 MPa. JG 11 followed by NBeG 3 exhibited comparatively higher germination and seedling quality parameters even at higher levels of drought indicating their tolerance towards drought, while NBeG 723 and NBeG 833 did not perform better even under lower levels of drought stress. The biochemical composition and enzymatic activities of JG 11 and NBeG 3 was found to be significantly superior to that of all the remaining chickpea genotypes under study, while reverse was noticed with NBeG 723 and NBeG 833. xv Based on the data on biochemical composition of seed and seed quality parameters, two genotypes with tolerance (JG 11 and NBeG 3), three genotypes with moderate response (KAK 2, NBeG 868 and NBeG 801) and two genotypes susceptible (NBEG 723 and NBeG 833) to drought stress were selected to further study the trend of variation among the genotypes for germination and seedling quality parameters under water deficit and also the contribution of biochemical characters and enzymatic activities in the seedlings in imparting drought stress Germination, seedling growth and vigour declined significantly and progressively with increase in the level of drought stress in all the seven genotypes. However, the negative impact of drought stress was found to be more pronounced in the sensitive genotypes than the tolerant genotypes. Increased levels of drought stress showed gradual reduction in all the biochemical characters studied except for MDA content. Among the seven chickpea genotypes under study, comparatively lower reduction in nitrogen, protein, proline, soluble sugars, peroxidase, acid phosphatase and esterase activity along with a slight increase in MDA content was observed in JG 11 and NBeG 3. NBeG 723 and NBeG 833 exhibited higher levels of MDA content and greater reduction in all the remaining biochemical parameters studied indicating their susceptibility towards PEG induced drought stress. Correlation studies revealed highly significant positive association of protein, proline, soluble sugars and peroxidases with germination and seedling quality parameters, while highly significant negative correlation of MDA content was noticed with seed quality. Based on the results obtained from the above studies, the chickpea genotypes JG 11 and NBeG 3 were considered as tolerant and NBeG 723 and NBeG 833 were categorized as susceptible to PEG induced drought stress during germination and early seedling growth. These genotypes need to be further tested for their reaction to drought stress in the field. Biochemical characterization for protein, proline, soluble sugars, MDA contents and peroxidase activity can be considered as a suitable assay for screening of chickpea genotypes for drought stress.