Rapid Screening of Small Millet Varieties for Seedling Stage Drought Stress Tolerance

Abstract

Aim: Drought is one of the most important abiotic stresses that affect the yield of crops globally. The present investigation was conducted to identify small millet genotypes tolerant to seedling stage drought stress.
 Study Design: The experiment was laid out in Completely Randomized Design (CRD) with three replications with genotypes and stress treatments as factors.
 Place and Duration of Study: It was carried out at Department of millets, Centre for plant breeding and genetics, Tamil Nadu Agricultural University, Coimbatore, during 2019.
 Methodology: Ten varieties of various small millets, CO 7 (foxtail millet), CO 4 and ATL 1 (little millet), CO 15 and CO 9 (finger millet), ATL 1 and CO (PV) 5 (proso millet), MDU 1 and CO 2 (barnyard millet) and CO 3 (kodo millet), were used for the study. In vitro screening of the seedlings in Polyethylene Glycol (PEG)-induced water stress at four levels (0, -3, -5 and -7 bars) were carried out based on germination percent, shoot and root length, plant height stress tolerance index (PHSI), root length stress tolerance index (RLSI) and seedling vigour index (SVI).
 Results: Analysis of variance of the genotypes and PEG treatments revealed significant variation for genotypes, treatments and genotype x treatment interactions at P< 0.001. A declining trend for germination percent, shoot length and root length was observed as the stress levels were increased. However, at mild and moderate stress root length was slightly increased. Under mild (-3 bars) and high stress (-7 bars), CO 7 (foxtail millet) recorded the highest SVI percent over control values (165% and 65% respectively). Under moderate stress CO 4 (little millet) recorded the highest SVI (191%). The lowest SVI values under high stress, 4% and 8%, were recorded for ATL 1 (little millet) and CO 3 (kodo millet) respectively.
 Conclusion: Based on invitro screening of small millet varieties for seedling stage water stress, foxtail millet variety CO 7 and kodo millet variety CO 3 can be concluded as the tolerant and susceptible varieties respectively. Further a controlled field experiment may be carried out to understand the field level tolerance of the varieties and their growth stages to drought.