ABSTRACT Anatomical, physiological, and biochemical analyses have been performed to predict graft compatibility. We analyzed if the concentrations of auxins, jasmonic acid, gibberellins, 1-aminocyclopropane-1-carboxylic acid, zeatin (cytokinin), salicylic acid, and abscisic acid could be used as predictors of compatibility between the rootstocks FOX1 and FOX4 (resistant to Fusarium wilt) and the scion of cherry tomatoes Sweet Heaven (SH). Self-grafted (SH/SH) and ungrafted SH plants (SH) were used as controls. Hormonal analyses were performed on leaves, at 20 and 70 days after grafting (DAG), and roots, at 20 DAG. No expressive concentrations of auxins, gibberellins, or jasmonic acid were detected. The concentrations of 1-aminocyclopropane-1-carboxylic acid, the immediate precursor of ethylene, and zeatin were altered at 20 DAG, but they stabilized at 70 DAG. Salicylic acid levels were reduced in the leaves of grafted plants at 70 DAG. The concentration of abscisic acid (ABA) in the leaves of SH grafted onto FOX1 was higher than in ungrafted and self-grafted plants at 70 DAG, suggesting some degree of incompatibility between these genotypes. The concentration of ABA in the combination FOX4/SH was similar to that in the self-grafted plants. Abscisic acid might be used as a reference phytohormone to predict graft compatibility among tomato genotypes.

Abstract Few commercial genotypes of tomato are resistant to Fusarium wilt (Fusarium oxysporum f. sp. lycopersici [FOL]), especially to race 3. We developed five intraspecific hybrids of Solanum lycopersicum (FOX1 to FOX5) and assessed them for agronomic traits and resistance to FOL races 1, 2, 3, and a mixture of these races. FOX1 and FOX4 were resistant to all races and the race mixture but did not have the desired agronomic traits. Next, FOX1 and FOX4 were assessed as rootstocks of the cherry tomato Sweet Heaven. The grafting of Sweet Heaven on FOX4 did not reduce growth, gas exchange, yield, or fruit quality. When FOX1 was used as a rootstock, the fruits exhibited a reduction in firmness, fruit pulp pH, and total soluble solids by 14.3%, 1.2%, and 6.75%, respectively. Thus, the hybrid FOX4 can be used as a rootstock for Sweet Heaven to manage Fusarium wilt.

RESUMO O objetivo deste estudo foi caracterizar e avaliar populações híbridas e segregantes, provenientes de cruzamentos entre acessos de Cucurbita moschata, com potencial oleaginoso, e cultivares que apresentam o gene para crescimento do tipo moita (Bush), visando à obtenção de genótipos com elevado teor de óleo nas sementes e com crescimento da planta do tipo moita. O delineamento experimental utilizado foi o de blocos casualizados, com três repetições. Cada repetição foi constituída por cinco plantas dos acessos BGH-7319 e BGH-7765, dos cultivares Piramoita e Tronco Verde e dos híbridos F1 (BGH-7319 x Piramoita, BGH-7319 x Tronco Verde, BGH-7765 x Tronco Verde), sendo consideradas as três plantas centrais das parcelas como úteis. Para cada uma das três populações F2 (‘População 1 F2’, ‘População 2 F2’, ‘População 3 F2’), 30 plantas foram avaliadas. Foram utilizados 28 descritores fenotípicos, sendo nove relativos à fase vegetativa das plantas, 12 referentes aos frutos e sete às sementes. Os dados foram submetidos à análise de variância e as médias dos tratamentos contrastadas com as médias das testemunhas, a 5% de probabilidade, pelo teste Dunnett. Na predição do potencial das populações para obtenção de linhagens superiores, foi utilizada a metodologia de Jinks & Pooni (1976). O híbrido BGH-7319 x Tronco Verde destaca-se para os caracteres massa de sementes por fruto, massa de cem sementes, comprimento, largura e espessura da semente, sendo considerada promissora quanto ao teor de óleo nas sementes. A ‘População 2 F2’ derivada do cruzamento entre os genitores BGH-7319 e Tronco Verde foi considerada a mais promissora para planta com crescimento do tipo moita.

ABSTRACT The objective of this study was to characterize and evaluate hybrid and segregating populations of crosses between accessions of Cucurbita moschata, with oil potential, and cultivars that possess the gene of dwarfism (bush), aiming at obtaining genotypes with high seed oil yield and reduced plant architecture. The experimental design was in randomized blocks with three replicates. Each replicate consisted of five plants of the BGH-7319 and BGH-7765 accessions, of the cultivars Piramoita and Tronco Verde and the F1 hybrids (BGH-7319 × Piramoita, BGH-7319 × Tronco Verde, BGH-7765 × Tronco Verde), considering the three central plants of the plots as useful. Thirty plants for each of the three F2 populations ('Population 1 F2', 'Population 2 F2', 'Population 3 F2') were evaluated. Twenty-eight phenological descriptors were applied, nine of which were related to the vegetative phase of the plants, 12 referring to the fruits, and seven to the seeds. The data were subjected to analysis of variance and the means of the treatments were compared with the means of the controls at 5% of probability by Dunnett’s test. In predicting the potential of populations to obtain superior strains, the methodology of Jinks & Pooni (1976) was used. The hybrid BGH-7319 × Tronco Verde stood out for the characteristics of seed mass per fruit, mass of 100 seeds, and seed length, width, and thickness, being promising for the oil content of the seeds. The 'Population 2 F2', derived from the crossbreeding between BGH-7319 and Tronco Verde was to the most promising for plant with shrub-type growth.

ABSTRACT Germplasm classification by species requires specific knowledge on/of the culture of interest. Therefore, efforts aimed at automation of this process are necessary for the efficient management of collections. Automation of germplasm classification through artificial neural networks may be a viable and less laborious strategy. The aims of this study were to verify the classification potential of Capsicum accessions regarding/ the species based on morphological descriptors and artificial neural networks, and to establish the most important descriptors and the best network architecture for this purpose. Five hundred and sixty-four plants from 47 Brazilian Capsicum accessions were evaluated. Neural networks of multilayer perceptron type were used in order to automate the species identification through 17 morphological descriptors. Six network architectures were evaluated, and the number of neurons in the hidden layer ranged from 1 to 6. The relative importance of morphological descriptors in the classification process was established by Garson's method. Corolla color, corolla spot color, calyx annular constriction, fruit shape at pedicel attachment, and fruit color at mature stage were the most important descriptors. The network architecture with 6 neurons in the hidden layer is the most appropriate in this study. The possibility of classifying Capsicum plants regarding/ the species through artificial neural networks with 100 % accuracy was verified.

RESUMO O desenvolvimento do sistema radicular do cafeeiro é alterado quando submetido à irrigação localizada e fertirrigação. Este trabalho foi desenvolvido com o objetivo de avaliar os efeitos de diferentes doses de fertirrigação sobre o desenvolvimento do sistema radicular do cafeeiro irrigado por gotejamento na região Oeste da Bahia. Realizou-se o trabalho na fazenda Café do Rio Branco, localizada em Barreiras - BA, em cafeeiros de aproximadamente 3,5 anos de idade, da variedade Catuaí IAC 144. O experimento foi montado em um esquema fatorial 3 x 3, sendo três níveis de adubação nitrogenada e potássica (900/800, 600/500 e 300/250 kg ha-1 ano-1 de N e K2O), em 3 parcelamentos mensais de fertirrigação (2, 4 e 8 vezes). Após a quarta safra, o sistema radicular do cafeeiro foi avaliado e a densidade de comprimento radicular (DCR) e densidade radicular (DR) em diferentes camadas amostradas foram determinadas. A maior concentração de raízes, densidade de comprimento radicular (DCR) e densidade radicular (DR) foi obtida nas camadas superficiais (0-20 cm) e sob a linha lateral (30 e 70 cm de distância do ramo ortotrópico). As menores doses de N e K2O propiciaram maior desenvolvimento (DCR e DR) do sistema radicular do cafeeiro.

ABSTRACT The development of coffee plant root system changes when subjected to drip irrigation and fertigation. This work aimed to evaluate the effects of different levels of fertigation on the development of coffee root system by drip irrigation in western Bahia. The experiment was carried out with Catuaí Vermelho IAC 144 coffee plants, of about 3.5 years of age, in the “Café do Rio Branco” farm, located in Barreiras - BA, and consisted of a complete randomized blocks design with 3 replicates. Treatments consisted of three levels of nitrogen and potassium fertilization (900/800, 600/500 and 300/250 kg ha-1 year-1 N and K2O), weekly distributed, by means of fertigation, throughout the process. After the fourth harvest, coffee root system was evaluated, and root length density (RLD) and root density (RD) were determined at different sampled layers. The highest root concentration, root length density (RLD), and root density (RD) were observed in the superficial layers of soil (0-20 cm), and under the dripline (30 and 70 cm from the orthotropic branch). Results showed that the lower the N and K2O levels, the higher was the development (RLD and RD) of the coffee root system.