Banca de DEFESA: ELIENE ARAUJO FERNANDES

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
STUDENT : ELIENE ARAUJO FERNANDES
DATE: 21/03/2025
TIME: 14:00
LOCAL: Sala de aula do PPGF
TITLE:

Response of cowpea cultivars subjected to water restriction

KEY WORDS:

Vigna unguiculata, drought; tolerance, productivity

PAGES: 105
BIG AREA: Ciências Agrárias
AREA: Agronomia
SUBÁREA: Fitotecnia
SPECIALTY: Fisiologia de Plantas Cultivadas
SUMMARY:

Cowpea Vigna unguiculata (L.) Walp is a legume widely cultivated in tropical and subtropical regions, and is an important source of low-cost protein for human nutrition in marginal areas. Although it is considered tolerant to water deficit, water shortage continues to be one of the main limiting factors for its productivity, especially in areas subject to irregular rainfall. This study aimed to compare the physiological responses and productivity of six cowpea genotypes (EPACE 10, BRS Novaera, BR-17 Gurguéia, Paulistinha, Pingo de Ouro 1-2 and BRS Sempre
Verde) grown under water deficit, conducted in a greenhouse in the Plant Science sector of the Federal Rural University of Rio de Janeiro (UFRRJ). The water deficit was applied at the pre-flowering stage, considered the most sensitive phase for cowpea. Leaf water potential, relative water content, protoplasmic tolerance, leaf area and shoot dry mass were evaluated. Collections were performed on hydrated plants (day 0), every two days during the water deficit period and two days after rehydration. The content of leaf proteins, starch, soluble sugars and free amino acids in the leaves were evaluated at three times: before stress (day 0), last day of stress, and two days after rehydration. At the end of the cycle, the production components were evaluated
in continuously irrigated plants and those subjected to water deficit. Cowpea showed rapid recovery of physiological characteristics after moderate and severe stress. The genotypes EPACE 10, Paulistinha, Pingo de Ouro 1-2 and BRS Sempre verde showed higher Ψa values than the other genotypes during water deficit, suggesting greater stomatal control. Among the genotypes studied under water deficit conditions, EPACE 10 and Pingo de Ouro 1-2 were the least sensitive to drought, presenting lower electrolyte release values and consequently less damage to membrane integrity, in addition to lower accumulation of soluble sugars and free
amino acids. The genotypes BRS Novaera and BRS Gurguéia were the most sensitive to drought, with greater reduction in water status favoring greater damage to membrane integrity. Water deficit reduced leaf area and biomass accumulation for all genotypes evaluated. However, the genotypes BRS Novaera and BR-17 Gurguéia, although significantly affected by water stress, presented higher productivity and, therefore, can be recommended for agriculture in regions subject to water shortage. In addition, the genotype EPACE 10 showed promise for genetic improvement programs, due to its high protoplasmic tolerance. These results reinforce the importance of combining different physiological, morphological and phenological characteristics to identify drought-tolerant genotypes, contributing to the development of more resilient cultivars adapted to conditions of low water availability.

COMMITTEE MEMBERS:
Presidente - 387258 - CARLOS PIMENTEL
Interno - 1905333 - AROLDO FERREIRA LOPES MACHADO
Interno - 2181674 - LEONARDO OLIVEIRA MEDICI
Externo à Instituição - JEAN LUIZ SIMÔES DE ARAÚJO - EMBRAPA
Externa à Instituição - NORMA GOUVÊA RUMJANEK - EMBRAPA