R E S U M OA berinjela tem grande importância nutricional e socioeconômica, sendo cultivada e comercializada em vários países, principalmente em ambiente protegido; sua produção, assim como a de inúmeros cultivos agrícolas, é dependente de fatores como água, nutrientes e luz; propôs-se, assim, com este trabalho, avaliar as trocas gasosas, fluorescência da clorofila a e temperatura foliar de berinjela cultivada em ambiente protegido em diferentes lâminas de irrigação. O estudo foi realizado em casa de vegetação utilizando-se delineamento inteiramente casualizado, com 5 tratamentos e oito repetições, totalizando 40 unidades experimentais. Os tratamentos constaram de cinco lâminas de irrigação: 33, 66, 100, 133 e 166% da ETc, as quais corresponderam a 133, 266, 403, 536, 669 mm planta -1 ciclo -1 , respectivamente. A taxa fotossintética das plantas de berinjela aumenta com o acréscimo da reposição hídrica. Os valores mais expressivos de trocas gasosas (A, E, gs, Ci, EiUA e EiC) nas plantas de berinjela, de forma geral, foram observados quando se utilizaram, na irrigação, lâminas estimadas entre 123,52 e 166% da ETc. A fluorescência da clorofila aumentou com o aumento das lâminas de irrigação e a temperatura foliar diminuiu em função do aumento da água. Gas exchange and chlorophyll fluorescence of eggplant grown under different irrigation depths A B S T R A C TEggplant has a nutritional, social and economic importance in the world, being grown and marketed in several countries, normally in protected environment. Its production, as a lot of crops, is dependent on factors such as water, light and nutrients. Thus, it was proposed with this study to evaluate leaf gas exchange, chlorophyll fluorescence and leaf temperature in eggplant grown in greenhouse under different irrigations levels. The study was accomplished in a greenhouse, using a completely randomized experimental design with five treatments and eight replications, totaling 40 experimental units. The treatments were consisted of five irrigation depths: 33, 66, 100, 133 and 166% of ETc, which amounted to 133, 266, 403, 536, , respectively. Photosynthetic rate of eggplant increases with the addition of water depth. The higher values of gas exchange (A, E, gs, Ci, EiUA e EiC) in eggplants, in general, were observed in irrigation, water depths estimated between 123,52 and 166% ETc were used. The chlorophyll fluorescence increased with increasing water depths and leaf temperature decreased with the increase in water depth. Palavras-chave:Solanum melongena L. reposição hídrica fotossíntese eficiência fotoquímica

The introduction of genes from wild species is a practice little adopted by breeders for the improvement of commercial crops, although it represents an excellent opportunity to enrich the genetic basis and create new cultivars. In peanut, this practice is being increasingly adopted. In this study we present results of introgression of wild alleles from the wild species Arachis duranensis and A. batizocoi improving photosynthetic traits and yield in a set of lines derived from the cross of an induced allotetraploid and cultivated peanut with selection under water stress. The assays were carried out in greenhouse and field focusing on physiological and agronomic traits. A multivariate model (UPGMA) was adopted in order to classify drought tolerant lines. Several lines showed improved levels of tolerance, with values similar to or greater than the tolerant control. Two BC1F6 lines (53 P4 and 96 P9) were highlighted for good drought-related traits, earliness and pod yield, having better phenotypic profile to the drought tolerant elite commercial cultivar BR1. These lines are good candidates for the creation of peanut cultivars suitable for production in semiarid environments.

Core Ideas Performance of salicylic acid to reduce the effects of water deficit in cowpea seedlings. Oxidative protection in cowpea seedlings under water deficit. Salicylic acid improve the biochemical metabolism in cowpea seedlings. The cowpea cultivar BRS Itaim is suitable for semiarid regions by its tolerance to water deficit. Drought stress is one of the greatest problems facing agriculture and a critical factor affecting the success or failure of agricultural activity. Application of an elicitor substance to plants, such as salicylic acid (SA), might be a strategy to induce tolerance to water deficit by acting especially on the regulation of stress‐responsive mechanisms. This study aimed to evaluate the antioxidant activity of cowpea [Vigna unguiculata (L.) Walp.] seedlings as a function of water deficit and exogenous application of SA. Six cowpea cultivars were subjected to three seed treatments before sowing (WS = without soaking; SPW = soaking seeds in purified water, and SSA = soaking seeds in SA) and five water potentials induced by polyethylene glycol 6000 solution (–1.0, –0.8, –0.6, –0.4, and 0.0 MPa) during germination and early growth. Increase in the activity of superoxide dismutase (SOD), catalase (CAT), and ascorbate peroxidase (APX) improved the growth of cowpea seedlings under water deficit. Antioxidant activity of cowpea seedlings increased after seeds were soaked in SA, especially for cultivar BRS Itaim. BRS Itaim was more tolerant under low water potential after SA treatment and showed increase in SOD, CAT, and APX activities. Soaking seeds in SA solution (10−5 M) can be used as a strategy to induce tolerance to water deficit during seed germination and early growth of cowpea seedlings.

Cowpea is a crop with great economic, social and food importance in semi-arid regions, but its production is drastically reduced by the water deficit in these regions, requiring better management strategies that allow the crop’s production. This study therefore aimed to evaluate the photosynthetic efficiency and production of cowpea cultivars under deficit irrigation replacement levels. The experiment tested three cowpea genotypes (G1 = ‘BRS Aracé’, G2 = ‘BR 17 Gurguéia’ and G3 = ‘BRS Marataoã’) and four irrigation depths (40, 60, 80 and 100% of ETc), resulting in a 3 x 4 factorial scheme, arranged in randomized complete blocks design with four replicates. During the experiment, the gas exchanges, chlorophyll a fluorescence and production of the cowpea genotypes under deficit irrigation were evaluated. Carbon fixation in the photosynthetic metabolism of cowpea plants was reduced by accentuated water deficit, regardless of the genotype. The low stress severity was indicated by the lack of effects on chlorophyll fluorescence, indicating that the reduction in the rate of carbon assimilation was due to the stomatal effects. The irrigation with 80% of ETc can be used in the cultivation of the respective cultivars, but with small losses in the production. Among the genotypes, ‘BRS Marataoã’ stands out with respect to yield, with higher values for weight of pods and green beans.

-Characterizing genetic diversity based on evaluations involving germination and seed vigor, is a fundamental stage in starting the development of a cultivation system for Calotropis procera. Thus, this study aimed to estimate genetic diversity among 35 C. procera genotypes based on germination and vigor of seeds stored for 1 year. The genotypes, which originated from areas in Paraíba (Brazil), where they occur naturally, were collected and stored in March 2014. In order to evaluate the physiological potential of the seeds, two experiments were conducted between March and April 2015. The first involved a propagation test conducted in a germination chamber, while the second involved an emergence test in washed sand, performed in polyethylene trays in a screened environment under uncontrolled conditions. In both experiments, an entirely randomized design was used, with four repetitions of 25 seeds per genotype. The characteristics evaluated were germination, average daily germination, daily germination speed, the speed of germination index, the plantlet vigor index, emergence, the speed of emergence index, total length, and total dry mass. The results showed that genetic variability exists among the C. procera genotypes for variables involving germination and vigor of seeds stored for 1 year. Also, emergence, total dry plantlet mass, and germination characteristics contribute most to the genetic divergence among C. procera genotypes.

-This study aimed to characterize and select silk blossom genotypes (Calotropis procera) with forage potential. Between April and July 2014, we cultivated 89 genotypes in plastic tubes arranged in a randomized block design with three replications; each experimental plot was composed of 8 plants. The following characteristics were evaluated: plant height (PH), stem diameter (SD), number of leaves (NL), total leaf area (TLA), leaf fresh mass (LFM), stem fresh mass (SFM), root fresh mass (RFM), leaf dry mass (LDM), stem dry mass (SDM), and root dry mass (RDM). Significant differences (p < 0.05) among genotypes were observed for all characteristics, except for NL at 45 and 60 days after sowing (DAS) and for RFM at 60 DAS. Broad-sense heritability estimates and genotype means had medium and high values for most characteristics. Genetic variability among C. procera genotypes was observed. High gain selection was found for the characteristics TLA, PH, SFM, LFM, SDM, and LDM as the genotypes 79, 65, 48, 12, 51, 35, 63, 25, 1, and 46 are suitable for future breeding works to improve forage production.

Genotypic values and selection gains were estimated in peanut lines derived from backcrossing with synthetic amphidiploid (A. batizocoi x A. duranensis)4x and a commercial cultivar, based on agronomical traits. Thirteen BC1F3 lines were grown in the field and submitted to 21 d of water suppression. Two earliness and drought tolerant cultivars (BR 1 and Senegal 55 437) were used as controls. Eight agronomic traits were adopted to characterize the lines. The estimates were based on mixed models (REML/BLUP) and Sum of Ranks Selection Index. We found that residual variance was greater than genotypic one, indicating the existence of variability within the families. Most traits showed high accuracy values. Three families showed an increased number of pods/plant, pod length and several seeds/pod. Negative gains were achieved for time for blooming and full pod maturation. As these traits are used as criteria for selection for earliness, these results favour the identification of short-cycle plants and prone to tolerate dry environments.

Salinization leads to several worldwide damages in agricultural regions, mainly in semiarid regions where leaching of salt is poor due to limited and erratic rainfall. Cotton (Gossypium hirsutum L.) is a Malvaceae with wide genetic variability to salt stress. The identification of salinity tolerant genotypes is a dynamic target in a breeding program, and the selection is often based on plant phenotypes. Molecular markers are reliable tools to aid in these selection procedures. Aquaporin (AQPs) are channel proteins that play fundamental role in water relations and tolerance to environmental stresses. Plants have fine regulation of water transport through AQPs activities. In order to evaluate the AQP expressions of different cotton cultivars submitted to salt stress, we use molecular and physiological tools, based on RT-qPCR and gas exchange assays. Seven cultivars were submitted to 95 mM NaCl, started at V3 stage (21 days after emergence), during 72 h. At the end of stress treatment, root tissues were used to total RNA extraction, followed by cDNA synthesis and RT-qPCR analyzes. Three sets of specific primers were used, drawn from AQP accessions deposited in NCBI. Additionally, full expanded leaves were used to gas exchange assays and to estimate the relative water content. The dry matter of the shoots was also evaluated. Based on pattern of AQPs transcripts, we found that all semiarid tolerant cultivars (BRS Seridó, 7MH, CNPA MT 2009 152 and BRS 416) showed downregulation of AQP subtypes, mainly GhPIP1;1 and GhTIP2;1 whose action is characterized as tolerant to salinity. The results of gas exchanges, relative water content and dry matter were consistent with the molecular findings in these cultivars, confirming that GhPIP1;1 and GhTIP2;1, located at plasma membrane and vacuoles, respectively, could be adopted as AQP markers for identification of cotton tolerant to salt stress.