Banca de QUALIFICAÇÃO: RENATO OLIVEIRA DE SOUSA

Uma banca de QUALIFICAÇÃO de MESTRADO foi cadastrada pelo programa.
DISCENTE: RENATO OLIVEIRA DE SOUSA
DATA: 31/01/2024
HORA: 14:30
LOCAL: Google meet (meet.google.com/szn-zcka-vxo)
TÍTULO: Osmotic adjustment and photosynthetic machinery efficiency are determinant for performance of cotton cultivars (Gossypium hirsutum L.) under water deficit
PALAVRAS-CHAVES: Cotton crop, photosynthetic performance, water restriction, stress tolerance, semiarid.
PÁGINAS: 19
GRANDE ÁREA: Ciências Agrárias
ÁREA: Agronomia
SUBÁREA: Fitotecnia
ESPECIALIDADE: Fisiologia de Plantas Cultivadas
RESUMO:

Water deficit severely restricts the metabolism and development of numerous plant species, with potential impacts on global agricultural production. This study aimed to identify cotton cultivars with high performance under water restriction and elucidate the stress tolerance mechanisms. The trials were carried out using a completely randomized design (CRD) in a 6 × 4 factorial scheme, consisting of six cotton cultivars (FM 911 GLTP, FM 912 GLTP RM, FM 970 GLTP RM, FM 974 GL, FM 978 GLTP RM FM 985 GLTP) under four water levels (100, 80, 60, and 40% of field capacity - FC). At 20 days after drought imposition, growth parameters, physiological and biochemical aspects were evaluated. Plants subjected to water restriction (60 and 40% FC) exhibited reductions in almost all growth parameters compared to well-irrigated plants (100 and 80% FC), irrespective of studied cultivars, with more pronounced effects in 40% FC-treated plants. The data highlight the varying responses of cotton cultivars to water restriction, with a high sensitivity to a 40% FC. Under the 60% FC, FM 978 and FM 985 cultivars demonstrated superior growth performance, exibithing higher values of stem, leaf and total dry mass, and leaf area. In contrast, cultivars FM 970 and FM 985 exhibited superior drought tolerance indexes. Under drought (60 and 40% FC), cultivars FM 911, FM 912, and FM 978 showed increased rates of CO₂ assimilation, transpiration, and stomatal conductance, a response associated with reductions in internal CO₂ concentration, photosynthetic pigments, and an increase in MDA. In parallel, cultivars FM 911, FM 970, and FM 974 displayed the lowest osmotic potential values under water deficit. Taken together, our findigns evidence that the 80% FC water level proves to be a crucial strategy for water-saving cotton cultivation, especially for cultivars FM 970, FM 974, and FM 985. Water levels of 60 and 40% FC are characterized as moderate and severe drought for cotton plants, respectively. Superior performace of FM 970, FM 978, and FM 985 is attributed to pigment accumulation and photosynthetic efficiency, emerging as promising genetic materials for cotton cultivation in regions affected by drought or water scarcity.

MEMBROS DA BANCA:
Interno - 1342777 - RAFAEL DE SOUZA MIRANDA
Externo ao Programa - 1553560 - FRANCISCO DE ALCANTARA NETO
Externo à Instituição - HUMBERTO HENRIQUE DE CARVALHO - UFC