Reaction of Sour Passion Fruit Lineages and Hybrids to Bacterial Spot Caused by Xanthomonas axononopodis pv. passiflorae Under Protected Cultivation and Field Conditions

Passion fruit is infected by many plant pathogens, including Xanthomonas axonopodis pv. passiflorae, causing bacterial spot disease. This disease has been impaired orchards all over Brazil, resulting in low yield and production. In addition, it results in premature death of plants in the field. This study aimed to analyze the reaction of sour passion fruit genotypes to bacterial spot in leaves under protected cultivation (Experiment 1) and the bacterial spot severity in fruits under field conditions (Experiment 2). Experiment 1 was carried out as a randomized block design (RBD) with subdivided plots, composed of 24 treatments (genotypes), three replications, five plants per plot, and five evaluation dates. Bacterial spot incidence and severity were evaluated using a 0 to 5 grading scale. Evaluations were carried out at a 7-day interval after disease symptoms first appeared. Genotypes differed for mean disease severity and incidence. The bacterial spot disease evaluations showed that genotypes MAR20#46 P3 R4 X Rosa Claro R4 and MD 16 P3 X MAR20#39 P1 R4 presented the lowest scores for the disease incidence in the leaves. S2L AP R1, MAR20#19 ROXO R4 X ECRAM P3 R3, and MD 16 P3 X MAR20#39 P1 R4 were the genotypes with the lowest disease severity scores. Experiment 2 consisted of a RBD with 24 treatments, three replications, and seven plants per plot. Severity assessments were monthly performed on five fruits per plot, totaling three evaluation dates. In this experiment, the percentage of total fruit area with necrotic lesions was measured using a 1 to 4 grading scale. Bacterial spot severity assessments in fruits identified interactions between genotypes and evaluation dates (p ≤ 0.05). The lineages S2L MAR 20#15 R4 and S2L MAR20#19 R2 showed the lowest mean severity scores of bacterial spot in fruit. The genotypes with the lowest mean scores were selected to continue the breeding program.

Potassium and irrigation water salinity on the formation of sour passion fruit seedlings

HIGHLIGHTS Potassium does not attenuate the deleterious effects of salt stress on the formation of seedlings of sour passion fruit. Water salinity increases the percentage of cell membrane damage in sour passion fruit seedlings. Salt stress inhibits growth of sour passion fruit but water with up to 3.5 dS m-1 can be used for formation of its seedlings.

Foliar application of H2O2 as salt stress attenuator in ‘BRS Rubi do Cerrado’ sour passion fruit

Irrigation with saline water causes a reduction in yield, especially in semi-arid regions. Cultivation strategies have been developed to mitigate salt stress on plants, such as the use of hydrogen peroxide. The objective of this study was to evaluate the attenuating effect of hydrogen peroxide on the gas exchange and growth of ‘BRS Rubi do Cerrado’ sour passion fruit cultivated under irrigation with saline water. The design was completely randomized in split-plot plots, with water salinity levels ECw (0.6, 1.2, 1.8, 2.4, and 3.0 dS m-1) considered the plots and the concentrations of hydrogen peroxide H2O2 (0, 15, 30, and 45 μM) considered the subplots, with three replicates. Gas exchange (stomatal conductance, transpiration, CO2 assimilation rate, intercellular CO2 concentration, instantaneous water use efficiency, and instantaneous carboxylation efficiency), and absolute and relative growth rates in stem diameter were evaluated. An increase in irrigation water salinity from 0.6 dS m-1 reduced gas exchange, and exogenous application of hydrogen peroxide did not promote a significant effect on gas exchange. However, foliar application of hydrogen peroxide at 15 μM increased the growth of ‘BRS Rubi do Cerrado’ sour passion fruit.

Growth, photosynthetic pigments, and photochemical efficiency of sour passion fruit as a function of the cationic nature of water

The objective of this study was to evaluate the growth, photosynthetic pigments, and photochemical efficiency of sour passion fruit cv. BRS Rubi do Cerrado irrigated with waters of different cationic natures. The experiment was carried out from March 2019 to January 2020 in a protected environment belonging to the Academic Unit of Agricultural Engineering of the Federal University of Campina Grande (UFCG), Campina Grande, PB, Brazil. The treatments consisted of eight combinations of irrigation water with different cationic natures: S1 - Control; S2 - Na+; S3 - Ca2+; S4 - Mg2+; S5 - Na+ + Ca2+; S6 - Na+ + Mg2+; S7 - Ca2+ + Mg2+, and S8 - Na+ + Ca2+ + Mg2+. Plants in the control treatment (S1) were irrigated using water with an electrical conductivity (ECw) of 0.4 dS m-1, while the other treatments (S2; S3; S4; S5; S6; S7; and S8) were subjected to an ECw of 3.5 dS m-1. Sour passion fruit growth was affected by variations in the level of electrical conductivity, regardless of the cationic nature of irrigation water. The use of salinized water with sodium favored the synthesis of chlorophyll a, chlorophyll b, and carotenoids of passion fruit plants at 180 days after transplanting. The distinct cationic natures of irrigation water did not influence the fluorescence variables of sour passion fruit.

Genotypic selection of multispecific hybrids obtained through crosses between commercial Passiflora edulis and wild passiflora species

The interspecific introgression of resistance genes to diseases in commercial varieties through interspecific crosses has been adopted as a strategy in breeding programs of sour passion fruit. This work aimed to evaluate 11 progenies of multispecific hybrids obtained from crosses involving seven Passiflora species, in addition to four commercial cultivars, using the REML/BLUP method. The experiment was carried out as a randomized block design with six repetitions and three plants per plot. Ten fruit traits were evaluated. The additive, multiplicative, and sum of ranks indexes were applied to determine the most appropriate selective strategy in the simultaneous increase of fruit weight, number of fruits, and yield. Plants from the 325 x VAO progeny showed a lower bacterial defoliation index and better means predicted for the traits number of fruits and productivity. The progenies 325 x LD4, PL3 x LD4, and the controls CSB-Marília and BRS-Gigante Amarelo showed plants with better-predicted means for traits related to fruit quality. The genetic gains demonstrated good prospects for the use of wild species in sour passion fruit genetic breeding.

DANO CELULAR E PIGMENTOS FOTOSSINTÉTICOS DO MARACUJAZEIRO-AZEDO EM FUNÇÃO DA NATUREZA CATIÔNICA DA ÁGUA

DANO CELULAR E PIGMENTOS FOTOSSINTÉTICOS DO MARACUJAZEIRO-AZEDO EM FUNÇÃO DA NATUREZA CATIÔNICA DA ÁGUA GEOVANI SOARES DE LIMA1; WESLLEY BRUNO BELO DE SOUZA2; LAURIANE ALMEIDA DOS ANJOS SOARES3; FRANCISCO WESLEY ALVES PINHEIRO4; HANS RAJ GHEYI5 E VALESKA KAROLINI NUNES OLIVEIRA6 1 Unidade Acadêmica de Engenharia Agrícola, Universidade Federal de Campina Grande, UFCG, Rua Aprígio Veloso, 882 - Universitário, Campina Grande, PB, Brasil. E-mail: geovani.soares@p q.cnpq.br. 2 Unidade Acadêmica de Ciências Agrárias, Universidade Federal de Campina Grande, UFCG, Rua Jario Vieira Feitosa, 1770, Bairro dos Pereiros, Pombal, PB, Brasil. E-mail: [email protected]. 3 Unidade Acadêmica de Ciências Agrárias, Universidade Federal de Campina Grande, UFCG, Rua Jario Vieira Feitosa, 1770, Bairro dos Pereiros, Pombal, PB, Brasil. E-mail: [email protected]. 4 Unidade Acadêmica de Engenharia Agrícola, Universidade Federal de Campina Grande, UFCG, Rua Aprígio Veloso, 882 - Universitário, Campina Grande, PB, Brasil. E-mail: [email protected]. 5Unidade Acadêmica de Engenharia Agrícola, Universidade Federal de Campina Grande, UFCG, Rua Aprígio Veloso, 882 - Universitário, Campina Grande, PB, Brasil. E-mail: [email protected]. 6 Unidade Acadêmica de Ciências Agrárias, Universidade Federal de Campina Grande, UFCG, Rua Jario Vieira Feitosa, 1770, Bairro dos Pereiros, Pombal, PB, Brasil. E-mail: [email protected]. 1 RESUMO Este trabalho teve como objetivo de avaliar o dano celular e os teores de pigmentos fotossintéticos do maracujazeiro-azedo em função da natureza catiônica da água de irrigação. O experimento foi desenvolvido sob condições de casa-de-vegetação em Pombal-PB. O delineamento experimental foi o de blocos casualizados, sendo os tratamentos constituídos de seis natureza catiônica da água (S1-Testemunha; S2 - Na+; S3 - Ca2+; S4 - Na+ + Ca2+; S5 - Mg2+ e S6 - Na+ + Ca2+ + Mg2+), distribuídos em delineamento de blocos ao acaso com quatro repetições, sendo a parcela constituída de duas plantas. As plantas do tratamento testemunha (S1) foram irrigadas com água de condutividade elétrica (CEa) de 0,3 dS m-1 e as demais (S2; S3; S4; S5 e S6) foram cultivadas com CEa de 3,0 dS m-1. A irrigação com água de composição Na+ e Na+ + Ca2+ resultou em maior dano celular nos tecidos foliares. A síntese de clorofila a foi inibida pela salinidade de natureza Mg2+ e Na+ + Ca2+ + Mg2+. A salinidade da água afetou negativamente os teores de clorofila b do maracujazeiro-azedo. O uso de água com composição sódica induziu aumento na síntese de carotenoides em plantas de maracujazeiro-azedo. Palavras-chave: Passiflora edulis Sims, estresse salino, semiárido. LIMA, G. S. de; SOUZA, W. B. B. de; SOARES, L. A. dos A.; PINHEIRO, F. W. A.; GHEYI, H. R.; OLIVEIRA, V. K. N. CELL DAMAGE AND PHOTOSYNTHETIC PIGMENTS OF THE SOUR PASSION FRUIT IN FUNCTION OF THE CATIONIC NATURE OF WATER 2 ABSTRACT This study had the objective of evaluating the cellular damage and the levels of photosynthetic pigments of the sour passion fruit in function of the cationic nature of the irrigation water. The experiment was conducted under greenhouse conditions in Pombal -PB. The experimental design was randomized blocks, with treatments consisting of six cationic nature of water (S1 - Control; S2 - Na+; S3 - Ca2+; S4 - Na++ Ca2+; S5 - Mg2+ and S6 - Na++ Ca2++ Mg2+), distributed in a randomized block design with four replications, and each plot consisting of two plants. The plants of the control treatment (S1) were irrigated with water of electrical conductivity (ECw) of 0.3 dS m-1 while those of the other (S2; S3; S4; S5 and S6) were cultivated with ECw of 3.0 dS m-1. Irrigation with Na+ and Na++ Ca2+ water resulted in greater cellular damage in the leaf tissues. The synthesis of chlorophyll a was inhibited by salinity of Mg2+ and Na++ Ca2++ Mg2+. The salinity of the water negatively affected the chlorophyll b content of the sour passion fruit. The use of water with sodium composition induced an increase in the synthesis of carotenoids in sour passion fruit plants. Keywords: Passiflora edulis Sims, saline stress, semiarid.