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RESUMO -Objetivou-se avaliar a produtividade, o rendimento e a qualidade de fibras de cultivares de algodoeiro herbáceo submetidas a diferentes lâminas de irrigação. Durante dois anos consecutivos foi conduzido um experimento de campo na região de Apodi (RN) disposto em parcelas subdivididas com quatro lâminas de irrigação (130, 100, 70 e 40% da evapotranspiração da cultura -ETc) e quatro cultivares de algodoeiro (FiberMax 993, BRS 286, BRS 336 e BRS 335), em delineamento de blocos casualizados com quatro repetições. Foram avaliadas a produtividade, a percentagem e a qualidade das fibras do algodoeiro. Houve diferença significativa para as características avaliadas entre as cultivares e as lâminas de irrigação. A rega com déficit (70 e 40% ETc) ocasionou declínio na produtividade de algodão em caroço, na percentagem e qualidade das fibras. As cultivares FiberMax 993 e BRS 286 apresentaram as maiores produtividades e percentagem de fibras entre as cultivares avaliadas. Com a lâmina de 40% da ETc as cultivares de fibra média (FiberMax 993, BRS 286 e BRS 335) apresentaram fibras curtas, e a cultivar de fibra longa (BRS 336) apresentou fibra média. De forma geral, a redução na qualidade da fibra não foi severa, haja vista a fibra produzida está dentro da faixa de qualidade aceitável pela indústria têxtil nacional, mesmo em condições de déficit hídrico. Dessa forma, a decisão em irrigar o algodoeiro com ou sem déficit hídrico dependerá dos custos da irrigação e do valor de mercado do produto.Palavras-chave: Déficit hídrico. Algodão. Semiárido. EFFECT OF IRRIGATION ON YIELD AND FIBER QUALITY IN COTTON CULTIVARSABSTRACT -This study was conducted to evaluate seed cotton yield, fiber yield, and fiber quality traits of cotton cultivars grown under different irrigation levels in Brazil. The experiment was conducted over two years in the region of Apodi -RN, with sprinkler irrigation. Treatments comprised of 4 irrigation levels i.e., 130, 100, 70 and 40 % of the crop evapotranspiration (ETc) and 4 cotton cultivars i.e., FiberMax 993, BRS 286, BRS 336 and BRS 335. The experimental design was factorial with randomized complete block design and four replicates. Yield, lint percent and fiber quality traits determined were evaluated. Different responses were observed for cultivars at various irrigation levels. Cultivars grown under limited irrigation exhibited a decline in the seed cotton yield, lint percent, and fiber quality. Cultivars with the highest yield and lint percent were FiberMax 993 and BRS 286. Within irrigation level of 40 % ETc, the medium fiber cultivars produced short fibers whereas the long fiber cultivar, BRS 336, produced medium fiber length. Overall, the different levels of water deficits did not significantly affect fiber quality of the four cultivars tested as all fiber quality traits remained acceptable for the domestic textile industry.

SUMMARYField-based soil moisture measurements are cumbersome. Thus, remote sensing techniques are needed because allows field and landscape-scale mapping of soil moisture depth-averaged through the root zone of existing vegetation. The objective of the study was to evaluate the accuracy of an empirical relationship to calculate soil moisture from remote sensing data of irrigated soils of the Apodi Plateau, in the Brazilian semiarid region. The empirical relationship had previously been tested for irrigated soils in Mexico, Egypt, and Pakistan, with promising results. In this study, the relationship was evaluated from experimental data collected from a cotton field. The experiment was carried out in an area of 5 ha with irrigated cotton. The energy balance and evaporative fraction (Λ Λ Λ Λ Λ) were measured by the Bowen ratio method. Soil moisture (θ θ θ θ θ) data were collected using a PR2 -Profile Probe (Delta-T Devices Ltd). The empirical relationship was tested using experimentally collected Λ Λ Λ Λ Λ and θ θ θ θ θ values and was applied using the Λ Λ Λ Λ Λ values obtained from the Surface Energy Balance Algorithm for Land (SEBAL) and three TM -Landsat 5 images. There was a close correlation between measured and estimated θ θ θ θ θ values (p<0.05, R 2 = 0.84) and there were no significant differences according to the Student t-test (p<0.01). The statistical analyses showed that the

RESUMO -O cultivo da pitangueira no Nordeste vem crescendo rapidamente devido à utilização do seu fruto pelas indústrias de polpas e sucos; no entanto, a ausência de cultivares adaptadas às condições irrigadas constitui atualmente um dos principais problemas da cultura. O presente trabalho foi conduzido com o objetivo de estudar o comportamento de dez dentre os 85 acessos da Coleção de Germoplasma de Pitangueira do IPA, sob irrigação, em Ibimirim, na região semi-árida de Pernambuco. Foram avaliadas características de crescimento, rendimento e qualidade do fruto de plantas oriundas de "pé-franco" e enxertadas. A pitangueira conduzida sob irrigação mostrou boa adaptação às condições do Vale do Rio Moxotó, tanto para as características de crescimento como de produção e qualidade do fruto. Os acessos mostraram grande variabilidade em relação às características físicas e químicas do fruto. Foram identificados dois acessos promissores ¯ IPA-13.2 e IPA-1.1E ¯, os quais reuniram as melhores características de produção e de qualidade do fruto. Termos para indexação: Pitanga, seleção, irrigação, adaptação regional, cultivar. PERFORMANCE OF SURINAM CHERRY (Eugenia uniflora L.) UNDER IRRIGATION IN THE MOXOTÓ VALLEY, PERNAMBUCO STATE, BRAZILABSTRACT -Surinam cherry crop is growing fastly in the Northeast region of Brazil due to its fruit uses by the industry in processing juice and pulp. However, one of the main problems of this crop is the lack of an apropriated cultivar adapted to such climate environments and irrigated conditions. This work was carried out aiming to study the performance of ten among 85 Surinam cherry accesses of IPA's germplasm collection cultivated under drip irrigation at the semi-arid region of Pernambuco State. The following characteristics were evaluated: growth, yield and fruit quality of plants originated from seedlings as well as from grafting. Surinam cherry trees have shown good adaptability to such environmental conditions, both in respect to plant growth characteristics as well as to yield and fruit quality. Accesses have shown great variability in relation to physical-chemical characteristics of fruits. Two promising materials were identified ¯ IPA-13.2 and IPA-1.1E, with better yielding and fruit quality characteristics.

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