Banca de QUALIFICAÇÃO: GABRIELA GONÇALVES COSTA

Uma banca de QUALIFICAÇÃO de MESTRADO foi cadastrada pelo programa.
STUDENT : GABRIELA GONÇALVES COSTA
DATE: 28/09/2024
TIME: 09:00
LOCAL: sala virtual do google meet
TITLE:

DEVELOPMENT OF PITAYA (Hylocereus costaricensis) UNDER
BIOSALINE CULTIVATION AND SHADING CONDITIONS IN SEMI-ARID REGIONS

KEY WORDS:

Dragon Fruit; Abiotic Stress; Fruit Growing

PAGES: 53
BIG AREA: Ciências Agrárias
AREA: Agronomia
SUMMARY:

Agriculture in the Brazilian semiarid region faces challenges due to high temperatures and low precipitation, requiring adapted crops and efficient agricultural practices to ensure sustainability and productivity. Pitaya (Hylocereus costaricensis), a cactus resistant to drought and poor soils, emerges as a promising alternative for agricultural diversification in the region. Studies show that pitaya can thrive in adverse conditions, such as salinity and high radiation, with adequate management and techniques such as shading to reduce abiotic stress. This study evaluated the effect of different salinity levels on pitaya development in two solar exposure environments: shading and full sun. The specific objectives included comparing plant development in shading and full sun, evaluating the influence of salinity in each environment, and analyzing Na and K levels as indicators of saline stress at 6 and 12 months. The experiment was conducted in the experimental area of the CCAB of UFCA, Crato, Ceará. Pitayas were propagated from 20- to 30-cm cuttings collected from adult plants, totaling 80 seedlings. The cuttings were cured in the laboratory for 15 days and then rooted in polypropylene bags (15 x 25 cm) with a substrate of washed sand and coconut fiber (1:1), in a greenhouse with 50% shade and alternating irrigation for 90 days. The seedlings were transplanted into 12 dm3 pots with a substrate of sand and manure (1:1), two per pot, with 1 cm of gravel drainage. The pots were arranged in shaded areas (A1) and full sun (A2), with 40 plants in each environment and stakes measuring 1.80 m above the ground. The 50% PVC shaded area was fixed with wire to posts, and the experiment occupied an area of 28 x 11 m. Salinity treatments were applied via irrigation with levels: no salt (T0), 2.5 dS m−1 (T1), 5 dS m−1 (T2), 7.5 dS m−1 (T3) and 10 dS m−1 (T4). Water was stored in 500 L tanks, with solutions prepared and verified by conductivity meter, and replenished when the level fell below 10%. Irrigation occurred on alternate days, with 3 L per pot. Fertilization with macro and micronutrients was performed every 30 days, starting 60 days after transplanting, with potassium applied every 15 days from 180 days. Biometric analyses were performed 90 days after the start of treatments and repeated every 3 months, with the last one scheduled for 365 days. The following parameters were evaluated: Number of Cladodes (NC), Sum of Cladode Length (SCC), Mean Cladode Diameter (MDC) and Mean Rib Diameter (MDCOS). After 365 days, the Terminal Cladode Diameter (TCD) and Terminal Cladode Thickness (ECT) were also measured. Destructive analyses, except for Na and K contents, which was also performed at 6 months, included the collection, drying and grinding of cladode samples for analysis of Na and K contents by flame spectrophotometry. The experiment was conducted in a completely randomized design (CRD) with a 2x5 factorial scheme and analyzed by ANOVA and PCA, using F and Tukey tests at 5% probability. The shaded environment (A1) favored growth at low and moderate salinities, improving NC and SCC, but full sun (A2) was more stable at high salinities. PCA revealed more homogeneous responses among treatments over time. Management should consider salinity and sun exposure; shading is effective at moderate salinities, while in extreme conditions, it is necessary to select salt-tolerant varieties and adopt techniques to reduce sodium accumulation.

COMMITTEE MEMBERS:
Externa à Instituição - MILENA MARIA TOMAZ DE OLIVEIRA - UFC
Externo à Instituição - ANTÔNIO MOREIRA BARROSO NETO - UFC
Presidente - ANA CELIA MEIRELES OLIVEIRA
Interno - CARLOS WAGNER OLIVEIRA