Screening and Variability Studies in Rice Genotypes for Drought Tolerance and Yield

In the present investigation, laboratory and field screening of nine rice genotypes, namely, TM 12061, TM 12077, TM 12012, TM 14035, TM 16017, Senthuram, Vandhana, TKM 12 and Anna (R) 4 was taken up to assess their drought tolerance potential. For laboratory screening, the effect of different levels of PEG concentration namely, -0.2, -0.4, -0.6 and -1.0 MPa on germination, shoot length and root length were studied. There was a considerable decrease in the germination potential among all the genotypes with increase in PEG concentration. The culture, TM 12077 showed higher level of tolerance to PEG induced drought stress showing 30.8% germination with 3.2 cm and 8.85 cm shoot and root length, respectively at higher level of PEG concentration (1.0 MPa). In field screening under managed stress condition, the cultures, TM 12077 and TM 12012 showed higher accumulation of proline (4.15 mg/g). Chlorophyll stability index was more than 80% in the genotypes, TM 12012, TM 12077, and TM 12061. The culture TM 14035, the varieties Anna (R) 4 and Vandhana matured early in 115 days. Plant height was found to be moderate in Vandhana (103.3 cm), TM 12077(105.4 cm), TM 12061 (108.2 cm) and TM 12012 (110.5 cm) under managed stress condition. The number of tillers per plant, number of panicles/sqm and yield/hectare were maximum in the culture, TM 12077 under managed stress condition. Based on laboratory and field screening, the cultures TM 12077, TM 12012, and TM 12061 were found promising for water stress environment and can be utilized as donors in the breeding programs for drought tolerance in rice. High heritability coupled with moderate to high GA as per cent of mean was recorded for plant height, tillers per plant, chlorophyll Stability index and total chlorophyll content indicating the presence of additive gene effects and scope for their improvement through direct selection.