R ESU M OObjetivou-se, com este trabalho, avaliar o efeito da salinidade da água de irrigação no feijão-caupi e identificar genótipos tolerantes ao estresse salino nos estádios iniciais do seu desenvolvimento. Os níveis de condutividade elétrica da água foram: 0; 2,5; 5,0 e 7,5 dS m -1. A tolerância do feijão-caupi foi avaliada através da redução relativa de matéria seca da parte aérea de cada genótipo. Os resultados foram comparados e analisados pelo teste de Scott-Knott, a 0,05 de probabilidade. Todas as variáveis foram afetadas pelo aumento da salinidade da água de irrigação. O genótipo CE-182 mostrou-se mais tolerante nos níveis 2,5, 5,0 e 7,5 dS m -1 na água salinizada com solução de NaCl. No caso da solução salinizada pela mistura dos sais, os genótipos CE-9 e CE-551 foram mais tolerantes. Palavras-chave: Vigna unguiculata, salinidade, tolerânciaEmergence and seedling vigor of cowpea genotypes under salt stress A B ST R A C T The objective of this study was to evaluate the effect of salinity of irrigation water on cowpea and identify genotypes tolerant to salt stress in the early stages of its development. The levels of electrical conductivity (EC) of irrigation water were 0, 2.5, 5.0 and 7.5 dS m -1 . The tolerance of cowpea was evaluated by the relative reduction in shoot dry matter of each genotype. The results were compared and analyzed by Scott-Knott test at 0.05 level of probability. All variables were affected by increasing salinity of irrigation water. The genotype CE-182 was more tolerant at EC of 2.5, 5.0 and 7.5 dS m -1 of water salinized with NaCl. In the solution containing mixture of salts, the genotypes CE-9 and CE-551 were the most tolerant.

Landraces are sources of genetic variability, especially with respect to alleles that confer tolerance to biotic and abiotic factors and, therefore, can aid breeding programs in the development of promising cultivars. However, it is necessary to know this genetic patrimony at a level that allows its alleged use in breeding programs. In this sense, the objective of this study was: (i) to identify cowpea landraces that present agronomic potential and (ii) to evaluate the genetic diversity for future cross-breeding. For this, two trials (coastal and sertão of the state of Ceará) were carried out in distinct periods for the morphological and agronomic characterization of eight landraces of the state of Ceará plus two control cultivars. Both assays were conducted in a randomized complete block design with four replicates. Additionally, the molecular characterization by ISSR markers was done. Due to the presence of interaction genotypes by environments, it was observed for the conditions of the coast (Fortaleza), the traditional variety Boi Deitado and the conditions of the sertão (Madalena) to Vinagre Barrigudo de Caldo, as the most indicated to be superior in grain yield and in other agronomic characters. In order to increase the genetic base of the cowpea, we suggest crosses between genotypes Boi deitado and Cojó for the generation of segregating populations of future breeding programs.

-The precocity of cowpea is important because it indicates the possibility of increasing and/or stabilizing production in regions with long periods of drought. The aim of this study was to evaluate genetic variability and select extra-early cowpea progenies. Fifteen F 3:6 progenies were evaluated in 2014 while sixty-two F 7 progenies were evaluated in 2015. Two commercial cultivars were used in experiments performed in the irrigated perimeter of Baixo Acaraú, in Marco, CE. The following characteristics were evaluated: number of days for flowering (NDF), number of days for maturity (NDM), plant height (PH), pod length (PL), number of seeds per pod (NSP), number of grains per plant (NGP), weight of 100 grains (W 100 G) and total weight (M TOT ). Data were analyzed in lattice and RBD, according to the methodology of mixed models by the REML/BLUP procedure. Also, the components of variance and genetic values were estimated. Variability among progenies, high heritability and high accuracy were identified for all traits. For NDF and NDM, the progenies presented higher behavior than the controls. The lattice arrangement contributed to a greater gain with the selection of NDF, NDM, PH, NSP, NGP and W TOT

Intercropping is a method of growing plants that assists in rational use of natural resources. Based on this concept, the aim of this study was to evaluate the response of collard green and radish 'Cometo' crops in monoculture and in intercropping under different spatial arrangements through physical production indicators (technical coefficients). The study was conducted in plant beds in a randomized block design (RBD) with 5 treatments and 4 replications. The treatments involved growing the two crops separately and intercropped under different spatial arrangements: (1:2) one row of radish 'Cometo' between two rows of collard green; (2:2) two rows of radish 'Cometo' between two rows of collard green; and (3:2) three rows of radish 'Cometo' between two rows of collard green. The spatial arrangements adopted did not affect the growth and development of radish 'Cometo' and of collard green, and all the arrangements used exhibited high land use efficiency, especially the 3:2 arrangement, which provided the greatest land use efficiency, at 1.69.

ABSTRACT Genotypes can respond differently to environments; thus, studies on adaptability and production stability are important to assist breeders in the identification and recommendation of cultivars. The objective of this work was to determine the adaptability and production stability of cowpea genotypes focused on subsidize recommendations of cultivars for green grain production in the state of Ceará, Brazil. Five assays were conducted in different locations in two climatic regions of the state of Ceará: a tropical mild hot semiarid region encompassing the municipalities of Acaraú, Pentecoste, and Crato, and a tropical hot semiarid region encompassing the municipalities of Mauriti and Madalena. Twenty cowpea genotypes-12 elite lines and 8 cultivars-were evaluated for cultivation value and use, using a randomized block design, with four replications. The results were subjected to analyses of variance and adaptability and green grain yield stability analyses by GGE biplot multivariate analysis. The effects of genotypes, environments, and G×E were significant, denoting different responses of genotypes in different locations. The results of the adaptability and stability analyses by the GGE biplot method showed that the two principal components explained 72.17% of the total variation, allowing reliable bidimensional projections. The municipality of Crato was the ideal location for tests and the lines MNC05-847B-123 and MNC00-595F-27 showed good production, adaptation, and stability, and can be recommended for green grain production in the state of Ceará, Brazil.

Widely grown in diverse regions of Brazil, cowpea has high nutritional value, is easily cultivated, and can fix nitrogen (N) symbiotically. Although there are commercial inoculants for cowpea, it is difficult for small producers to acquire them. A nodule preparation is an inexpensive and easily prepared option for small farmers. The aim of this study was to test a nodule preparation as a low-cost inoculant, increasing cowpea seed grain production. Thus, different cowpea cultivars were compared in two locations, the municipalities of Crato and Madalena, both in Ceará. Two field experiments were performed to evaluate gain derived from this inoculation method. The nodule preparation was created from nodules removed from roots of cowpea grown in the experimental locations. The nodules were macerated and added to water, obtaining a liquid (inoculant) that was applied to the seeds. The experiment was conducted following a randomized block design with four replicates and a 4 × 3 factorial arrangement (N sources × cultivars). Results indicate little interaction between the sources of N and the cultivars because only the shoot dry matter (Crato experiment) exhibited interaction between both. The differences provided by the nodule preparation were more notable among cultivars and between the environments, Crato and Madalena. The nodule preparation differed little from the commercial inoculant; they were comparable. However, gain in relation to the zero control also proved to be reduced, indicating little contribution of the nodule preparation to cowpea under the conditions tested.