E. APARNA*, Y. AMARAVATHI, N.P. ESWARA REDDY, R.P. VASANTHI AND A.R. NIRMAL KUMAR

Dept. of Molecular Biology and Biotechnology, S.V. Agricultural College, ANGRAU, Tirupati – 517 502, Chittoor Dt., Andhra Pradesh

ABSTRACT

Maximum yield losses under drought situation coincide with pegging, pod formation and pod development stages in groundnut. Among the eleven genotypes analyzed under midseason drought, TCGS 1157 and MLTG 4 were found to be most drought tolerant and Narayani and Kadiri 6 were found to be highly sensitive to moisture stress. Prominent leaf folding was observed in drought tolerant genotypes such as TCGS 1157 and MLTG 4 to reduce the evapotranspiration losses within 15 days after mois-ture stress imposition. In contrast, drought sensitive genotypes like Kadiri 6 and Narayani did not exhibit leaf folding phenom-enon resulted in withering and drooping of leaves at 65 DAS. TCGS 1157 and MLTG 4 displayed better ability to expand their roots than Narayani and Kadiri 6 under moisture stress situation. The extent of increase in root shoot ratio is more in drought tolerant genotypes (79-103%) when compared to susceptible genotypes (31-53%). The increase in proline content was more in Kadiri 6 and Narayani than in TCGS 1157 and MLTG 4 at 20 days and 30 days after stress imposition. Sensitive genotypes were subjected to severe stress at early stages as they did not show any water saving mechanisms like leaf folding which was prominent in drought tolerant genotypes. This leads to increased evapotranspiration rates in Kadiri 6 and Narayani and thereby synthesizes more proline to maintain osmotic potential. Therefore, the increased levels of proline under drought stress can be better consid-ered as a stress indicator in plants.

KEYWORDS:

Genetic variability, PCV, GCV, heritability, genetic advance, pod yield, groundnut.