Banca de DEFESA: LIZETTE DANIANA MENDEZ FASABI

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
DISCENTE: LIZETTE DANIANA MENDEZ FASABI
DATA: 31/07/2023
HORA: 14:00
LOCAL: Ambiente virtual Google Meet
TÍTULO:

PHYSIOLOGICAL AND YIELD RESPONSES TO DROUGHT IN UPLAND RICE

PALAVRAS-CHAVES:

Water stress; Split roots; Proline, Yield of grains; Oryza sativa L.

PÁGINAS: 141
GRANDE ÁREA: Ciências Agrárias
ÁREA: Agronomia
RESUMO:

Drought stress during the development phases of rice cultivation is a major production challenge
worldwide. The development of drought-tolerant genotypes has been slow due to the lack of accurate
high-throughput phenotyping tools to assess drought stress-induced traits. In this experiment it was
decided to evaluate the cultivation of rice because it is a crop of economic importance at a national and
international level. In this sense, our research has consisted of three experiments with the objective of
evaluating the response of highland rice cultivation under hydric conditions due to lack of water. In the
first experiment, the objective was to study the impact of the CMG-2085 genotype on partial root zone
drying (PRD) on water status, carbon balance and growth of rice plants. Using a split root design,
differential irrigation was imposed on the left and right sides of the root system, in two water cycles
(C1/C2), totaling four treatments. The parameters of relative water content, leaf water potential, gas
exchange and biomass allocation were evaluated. Water treatments affected leaf water potential, water
use efficiency, and plant growth. Treatment T3 presented higher water potential after noon than
treatments T2 and T4 and greater efficiency in water use than treatments T2 and T1, but also lower
aerial biomass than the last two. The results may be related to root-to-shoot signaling, which places
PRD as a feasible water-saving technique for upland rice. In the second experiment, the objective was
to evaluate the effects of stress due to lack of water and the beneficial role of foliar application of proline

on the physiological characteristics and compounds of biochemical characteristics of the drought-
tolerant rice genotype CMG-2085. Three water regimes were carried out according to the treatments,

that is, 100%, 80% and 65% at field capacity and two levels of exogenous proline, without proline (N)
and with proline (P=0.36 mM) applied before the bloom. In biomass yield parameters, water stress was
significantly reduced. Likewise, in antioxidant enzymes, superoxide dismutase was the only one that
increased its activity both in the aerial part and in the root compared to catalase and ascorbate
peroxidase. Finally, in our third experiment, the objective was to evaluate the adaptive capacity of
rainfed rice genotypes to overcome water stress in terms of adjustment of their stress-associated
morphophysiology and yield characteristics. For this, the experiment was carried out in a greenhouse
with highland rice genotypes, CMG-2085, CMG-2162, CMG-2168, CMG-2093 and BRS-Esmeralda
planted in pots, under two water conditions, at field capacity ( WS) and water deficit (S) in 2021 and
2022. The genotypes showed significant differences in production, biomass and production, which were
influenced differently by water conditions, both under water deficit and at field capacity.

MEMBROS DA BANCA:
Externo à Instituição - FERNANDO HENRIQUE SILVA GARCIA - UNIFAP (Membro)
Externo à Instituição - JOÃO PAULO PENNACCHI - UFLA (Membro)
Externo ao Programa - MARCIO ANDRE STEFANELLI LARA - DZO/FZMV (Suplente)
Interno - VITOR DE LAIA NASCIMENTO (Suplente)
Interno - JOYCE PEREIRA ALVARENGA - UFLA (Suplente)
Interno - FERNANDA CARLOTA NERY - UFSJ (Membro)
Interno - PAULO EDUARDO RIBEIRO MARCHIORI (Membro)
Presidente - JOAO PAULO RODRIGUES ALVES DELFINO BARBOSA (Membro)