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ABSTRACT
Peanut is one of the most cultivated oily in the world. For countries of semi-
arid climate, as Brazil, for example, the peanut is an important alternative to farming
due to the low water requirement during the cycle and adaptation to environments of
high temperature and solar radiation. Despite the tolerance to low water availability,
peanuts’ requirements are not the same over the cycle. Water shortage during the
reproductive phase directly affects the formation and filling of pods, even in cultivars
notoriously resistant to water deficit. According to some authors, which makes the
peanut plant tolerant to environmental adversities are the morphological and
physiological mechanisms that maintain the plant turgidity, even under low water
availability conditions. Among those are cited changes in water ratios (stomatal
behavior and osmotic adjustment) and the expansion of the root system for deeper
and wetter soil areas. Faced with this adaptability, understanding the role of water
deficit during the production cycle of culture is essential for adopting management
strategies that enable secure production in areas prone to drought. In this work, four
peanut genotypes of different growth habits were subjected to 21 days of water
stress in a greenhouse. The planting was performed in pots containing sandy-loam
texture soil, previously limed and fertilized. The experimental design was randomized
with a bi-factorial 4x2 scheme (4 genotypes x 2 water treatments) with 10 repetitions.
the water treatment were control (daily irrigation) and stress (irrigation suspension).
The variables evaluated were difusive resistance, transpiration, leaf water potential,
relative water content, proline content, chlorophyll content, root length, dry weight of
pods, harvest index and stress tolerance index (STI). Under stress conditions,
stomatal behavior was changed from the second week, when all genotypes
significantly increased abaxial surface diffusive resistance and reduced sweating,
highlighting the isoline LBM Branco Moita/08. The water potential of all genotypes
was significantly reduced, being more expressive in isolines LBM-Branco Moita/08
and LBR-Branco Rasteiro/08 reaching more negative values. The LBM-Branco
Moita/08 also had higher levels of proline and along with a BR 1 had the greatest
expansion of the root system as adaptive way. In the production aspect, the LBM-
Branco Moita/08 revealed the lowest reductions in weight of pods and harvest index
when subjected to water deficit. Regarding the STI, values obtained with the cv. BR1
confirm its suitability for management in semi-arid environments; the strains LBR-