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Diversification of rootstock varieties, with consequent reduction in phytosanitary risks, has great importance to the sustainability of citrus cultivation in the south of Brazil. This study evaluated the performance of 42 rootstocks in the nursery phase to generate ‘Valencia Late’ sweet orange seedlings. Therefore, nucellar seedlings from the rootstocks under study were analyzed in relation to plant height, stem diameter, mortality rate and percentage of bud set after grafting. The experimental design was completely randomized with four replications of 20 sample units. Not adapted genotypes had high mortality rates, and the ones of both hybrids LCR x CTSW - 009 and LVK x LCR - 038 were 100% and 90%, respectively. Other 13 genotypes had mortality rates above 30%, and ‘Sunki’ mandarin was the female genitor of ten of them. ‘Swingle’ citrumelo was the rootstock with the highest development (plant height and stem diameter), associated with low mortality rate. In relation to the other rootstocks, the best results were the fast grafting diameter, associated with low mortality rate obtained by hybrids HTR - 053, LRF x (LCR x TR) - 005, CLEO x TRBN - 245, CLEO x TRSW - 287, and citrandarins ‘Indio’, ‘Riverside’ and ‘San Diego’, as well as Trifoliate orange and ‘Rangpur’ lime. In addition to Trifoliate orange, which is widely used in Rio Grande do Sul, these rootstocks have great potential in citriculture in the south of Brazil. RESUMO: A diversificação do uso de variedades porta-enxerto, com a consequente redução de riscos fitossanitários, é de fundamental importância para a sustentabilidade da citricultura do Sul do Brasil. O objetivo deste trabalho foi avaliar o comportamento de 42 porta-enxertos na formação de mudas de laranjeira ‘Valência Late’ em fase de viveiro. Nesse sentido, seedlings (plantas oriundas da germinação de sementes) nucelares dos porta-enxertos estudados foram avaliados relativamente aos caracteres altura da planta, diâmetro do caule, taxa de mortalidade e percentagem de pegamento de borbulhas após a enxertia. O delineamento experimental foi inteiramente casualizado, com quatro repetições de 20 unidades amostrais. Genótipos não adaptados tiveram altas taxas de mortalidade, os híbridos LCR x CTSW - 009 e LVK x LCR - 038 apresentaram 100% e 90% de mortalidade, respectivamente. Mais 13 genótipos apresentaram mortalidade superior a 30%, destes, dez têm como parental feminino a tangerineira ‘Sunki’. O citrumelo ‘Swingle’ foi o porta-enxerto que apresentou maior desenvolvimento (altura da planta e diâmetro do caule), associado a uma baixa taxa de mortalidade. Quanto aos demais porta-enxertos, destacaram-se por atingir rapidamente o diâmetro de enxertia, associado a baixa taxa de mortalidade, os híbridos HTR - 053, LRF x (LCR x TR) - 005, CLEO x TRBN - 245, CLEO x TRSW - 287, citrandarins ‘Indio’, ‘Riverside’ e ‘San Diego’, assim como o limoeiro ‘Cravo’ e o Trifoliata. Além do Trifoliata, amplamente utilizado no Rio Grande do Sul, estes porta-enxertos são promissores para a citricultura do Sul do Brasil.

El duraznero es un cultivo de gran importancia económica y social dentro de los países del Cono Sur de Sudamérica. La evolución de este frutal se ha visto condicionada tanto por las particularidades edafoclimáticas, como por las culturales y las económicas de cada país. Sintetizar en un solo documento la situación actual y los distintos aspectos que caracterizan al cultivo de durazneros en Uruguay, Brasil y Argentina fue el objetivo en este trabajo. La incorporación de tecnología en todos los sentidos ha permitido una mejora en los rendimientos, por lo que la producción se ha mantenido a pesar de la reducción del área de plantación. Últimamente se ha dado un proceso de crecimiento en escala y concentración de la producción, aunque las características del cultivo lo siguen haciendo muy apto para el pequeño productor. Grandes esfuerzos de investigación canalizados a través de universidades e institutos especializados han permitido generar información local y regional de alto valor e impacto. La importancia del material genético para el éxito del sistema productivo es clave y la estrategia de generar cultivares con adaptación local ha sido tomada por la región, siendo creciente la disponibilidad de nuevos cultivares generados por los programas de mejoramiento locales. El enfoque de producción integrada ha tomado gran impulso y son cada vez más las alternativas productivas que se desarrollan buscando prescindir de los agroquímicos, principalmente en lo que respecta al control de plagas y enfermedades. La densidad de plantación se ha ido incrementando y los sistemas de conducción y poda están evolucionando hacia formas más simples y pasibles de ser mecanizadas. Numerosos son los desafíos que hay por delante, pero a su vez es grande la convicción, entre los equipos de investigación, de poder seguir aportando para una mayor y mejor disponibilidad de frutos de Prunus en las mesas de los consumidores. / Peach production is of great economic importance in the Southern Cone of South America, having gone through great technological changes since its introduction during the time of Spanish and Portuguese colonies. The evolution of this crop has been determined by edaphoclimatic peculiarities, as well as by the culture and econ-omy of each country. The aim of this work is to summarize in one document the current situation and the specific characteristics of peach growing in Uruguay, Brazil, and Argentina. Technology incorporation, in all its different aspects, has made it possible to increase yields, so production has remained at the same level despite the reduction of the planted area. Also, a process of upscaling and concentration has been taking place, even though peach production characteristics keep making it especially suited for small growers. Great efforts have been made through universities and research institutes to develop local knowledge useful for growers and with poten-tial of great impact not only for them, but at regional level as well. The importance of genetic material for the success of the production system is paramount and strategies of developing cultivars with adaptation to local conditions have been embraced by the region, thus having a growing offer of new cultivars generated by local breeding programs. The integrated production approach is being generally applied, and alternative production systems that minimize or don’t use synthetic agrochemicals at all are being developed in many production areas. The planting density has been increased and the training and pruning systems are evolving towards simpler ones and prone to mechanization. Challenges to improve sustainability are many, but the belief among research groups on the capability to continue generating and making available technology and solutions for a broader and better availability of Prunus fruits on the consumers’ table is also high. O pessegueiro é uma cultura de grande importância econômica e social nos países do Cone Sul da América do Sul. A evolução desta espécie frutífera tem sido condicionada tanto pelas características edafoclimáticas como culturais e econômicas de cada país. Sintetizar em um único documento a situação atual e os diferentes aspectos que caracterizam o cultivo do pessegueiro no Uruguai, Brasil e Argentina foi o objetivo abordado neste trabalho. A incorporação de tecnologia em todos os sentidos tem permitido uma melhora na produtividade para que a produção seja mantida apesar da redução da área de plantio. Ultimamente tem ocorrido um processo de crescimento em escala e concentração da produção, embora as características da cultura continuem a torná-la muito adequada para pequenos produtores. Grandes esforços de pesquisa canalizados através de Universidades e Institutos especializados têm permitido gerar informações locais e regionais de alto valor e impacto. A importância do material genético para o sucesso do sistema de produção é fundamental e a estratégia de geração de cultivares com adaptação local tem sido adotada pela região, com a disponibilidade de novas cultivares geradas por meio de programas de melhoramento locais. A abordagem da produção integrada vem ganhando grande impulso e cada vez mais alternativas produtivas vêm sendo desenvolvidas, visando a dispensar os agroquímicos, principalmente para o controle de pragas e doenças. A densidade de plantio tem aumentado e os sistemas de condução e poda estão evoluindo para formas mais simples e mecanizáveis. São muitos os desafios pela frente, mas também a convicção, entre as equipes de pesquisa, de poder continuar contribuindo para uma maior e melhor disponibilidade de frutos de Prunus nas mesas dos consumidores. EEA San Pedro Fil: Dini, Maximiliano. Instituto Nacional de Investigación Agropecuaria (INIA). Estación Experimental «Wilson Ferreira Aldunate»; Uruguay Fil: Raseira, Maria do Carmo Bassols. Empresa Brasileira de Pesquisa Agropecuária (Embrapa). Embrapa Clima Temperado; Brasil Fil: Valentini, Gabriel Hugo. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria San Pedro; Argentina Fil: Zoppolo, Roberto. Instituto Nacional de Investigación Agropecuaria (INIA). Estación Experimental «Wilson Ferreira Aldunate»; Uruguay

The use of grapevine minicutting is an alternative for the production of quality plants. This technique has been gaining ground as one of the most used forms of vegetative propagation. The objective of this study was to evaluate the rooting of herbaceous minicuttings of Chardonnay grapevine and SO4 grapevine rootstock by using different concentrations of indolebutyric acid (IBA) to form a clonal mini-garden. The experimental design was randomized blocks with four levels of IBA concentrations (0, 500, 1000 and 1500 mg L-1). The minicuttings remained in trays containing vermiculite and kept in a micro sprinkler chamber. After 60 days, the percentage of survival, rooting and callus formation, root number and average length, shoot number and average length were evaluated. For Chardonnay, the means of survival and rooting varied between 93 and 100% in all treatments. In relation to SO4, the IBA concentration of 1500 mg L-1 negatively affected the minicuttings survival and rooting. It is possible to propagate Chardonnay grapevine and SO4 grapevine rootstock through herbaceous minicutting, with no need of apply IBA for the rooting.

The aim of this study was to evaluate the effect of different aminoethoxyvinilglycine (AVG), thidiazuron (TDZ) and prohexadione calcium (P-Ca) rates sprayed at different timings on fruit set, yield, and fruit quality of ‘Rocha’ pear trees in different climatic conditions of Southern Brazil. The study was performed in two commercial orchards located in Sao Joaquim, SC (2015/2016) and Antonio Prado, RS (2016/2017). Plant material consisted of ‘Rocha’ pear trees grafted onto Pyrus calleryana and quince rootstock ‘BA29’ in Sao Joaquim and Antonio Prado, respectively. Treatments consisted of AVG, TDZ and P-Ca sprayed at different rates and timings. Trunk cross-sectional area increase, fruit set, thinned fruit, fruit per tree, yield, average fruit weight, projected yield, yield efficiency, fruit length, fruit diameter, L/D ratio, seed number, flesh firmness, and soluble solids content were assessed. Fruit set and yield were consistently increased by AVG in all experiments. Fruit set was not affected by P-Ca and was significantly decreased by TDZ. However, yield was positively affected by P-Ca 100 mg L–1 sprayed at full bloom + 7 days after full bloom and TDZ 10 mg L–1 at full bloom. Fruit size was consistently increased by TDZ.

Peach is a temperate fruit species that is cultivated under various edaphoclimatic conditions all over the world. In Brazil, in the early 1950s, peaches were planted only in Sao Paulo state and in the Southern states, and the harvest period was restricted to 15 days. Currently, mainly due to peach breeding programs, it is cultivated in subtropical areas and even in high altitude tropical areas, with a harvest period of over 100 days. Knowledge of genetic, phenotypic and environmental parameters that influence characters of economic importance is crucial for guiding breeding programs. The objectives of this study were to estimate the heritability of phenological characters, to evaluate their distribution within populations, to test the possible existence of maternal effect and to evaluate the relationship of these traits with brown rot incidence (Monilinia fructicola). The study was performed in Pelotas, RS, Brazil during 2015-2016 to2017-2018 seasons. Sixteen first generation (F1) progenies were evaluated, 10 of them being reciprocal crosses. All genotypes were cultivated in the same area, under the same cultural practices (without fungicide application). Full bloom was considered when more than 50% of flowers were open, and the harvest, when more than 10 fruits reached commercial maturity, the fruit development period being calculated by the difference between full bloom and harvest dates. Brown rot incidence was estimated by the percentage of fruits with symptoms. Broad-sense heritability estimates for full bloom date, harvest date, and fruit development period were high (95 to 98%), and narrow-sense heritabilities were medium to high (65 to 72%). A segregation study of these traits suggests a maternal effect on their heritability, mainly for full bloom and harvest date. The three phenological characters were significantly correlated, and only harvest date had a negative and significant correlation (-0.12) with brown rot incidence.

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The adaptation of a temperate climate fruit cultivar to a certain area depends mainly on its chilling requirement and the chilling accumulation in such places. Several attempts have been made to estimate these two conditions, using different models. The great variation among the models to calculate chilling requirement makes it necessary to determine their efficiency in a given location. Aiming to estimate the chilling requirement of ten peach cultivars, including Bonão, Pepita, Maravilha, Precocinho, Turmalina, Diamante, BR-3, Marfim, Coral, and Cambará do Sul, seven models were tested: Utah, Positive Utah, Low Chill, Taiwan, Chilling Hours (≤7.2°C), Chilling Hours (≤11°C), and Dynamic. The results showed that the estimation of chilling accumulation for all the studied cultivars in all the tested models showed a large variability. None of the tested models was perfect for estimating the chilling requirement, especially considering the variable climatic conditions of southern Brazil. Except for the Utah model, any of the others can be used to provide a rough estimate of the chilling requirement of the cultivars; however, the Taiwan and Low Chill models seem to be more suitable. The chilling requirement, which was estimated based on the average over the 11 years of the study, overestimated the real need, when compared to the yields over those years. There are differences among the studied cultivars; however, with the exception of Cambará do Sul, all the others can yield good crops and show good adaptation to the climatic conditions of the southern Rio Grande do Sul.© Copyright 2010-Till Date, Journal of Experimental Agriculture International. All rights reserved.

Gala Fult is the first Uruguayan apple cultivar, originated by spontaneous somatic mutation of ‘Royal Gala’, identified and evaluated by nurseryman Fernando Rocca and INASE. The fruits have a complete red-blushed skin without streaks and matures more precociously than the other ‘Gala’ clones, but with the same range of edaphoclimatic adaptation.

Chilling requirement is a characteristic that limits temperate fruit crops cultivation under subtropical climate. Several mathematic models, differing on the relative value of chilling units have been developed, in order to estimate the chilling accumulation on a given site. The present work compared eight of these models using data from hourly temperatures from May to August, from a period of 11 years, collected in Pelotas, RS, Brazil, aiming to characterize the region regarding the chilling accumulation for the cultivation of deciduous fruit trees and it also had as objective to check if a model using average temperatures is suitable enough to be used when hourly temperatures were not available. The eight tested models were: Chilling Hours (≤7.2°C); Chilling Hours (≤11°C); Utah; Low Chill; Dynamic; Mean Temperatures; Positive Utah and Taiwan. The results showed large differences between years, regardless of the used model. However, the Taiwan and Low Chill models seemed more suitable for the estimation of the accumulation of cold in the Pelotas region. The Medium Temperatures model can be used as a valid option since it has a high correlation with the other models and easy data availability. Chilling requirement is a characteristic that limits temperate fruit crops cultivation under subtropical climate. Several mathematic models, differing on the relative value of chilling units have been developed, in order to estimate the chilling accumulation on a given site. The present work compared eight of these models using data from hourly temperatures from May to August, from a period of 11 years, collected in Pelotas, RS, Brazil, aiming to characterize the region regarding the chilling accumulation for the cultivation of deciduous fruit trees and it also had as objective to check if a model using average temperatures is suitable enough to be used when hourly temperatures were not available. The eight tested models were: Chilling Hours (≤7.2°C); Chilling Hours (≤11°C); Utah; Low Chill; Dynamic; Mean Temperatures; Positive Utah and Taiwan. The results showed large differences between years, regardless of the used model. However, the Taiwan and Low Chill models seemed more suitable for the estimation of the accumulation of cold in the Pelotas region. The Medium Temperatures model can be used as a valid option since it has a high correlation with the other models and easy data availability.

Brown rot caused by Monilinia spp. provokes dramatic losses of peach in all production regions. In this context, the general objective of our work is to develop sustainable ways to fight against this damaging disease. This study explored phenolic and triterpenoid diversity of fruit skin together with brown rot resistance. A Brazilian peach collection and an interspecific cross between P. davidiana and P. persica, each of 120 genotyped individuals, have been screened for 3 years, for susceptibility to M. fructicola and to M. laxa respectively. Some genotypes of the two populations showed low or null infection the 3 years. Secondary compounds of fruit skin of all genotypes were analyzed two years by HPLC-DAD. Depending on the genotypes, 30 to 40 compounds including triterpenoids, hydroxycinnamic derivatives and flavonoids, were quantified and around 20 were identified by mass spectrometry. Among these, phenolic esters of triterpenoids were identified for the first time in peach fruit. The correlation of quantitative data between years showed their robustness. A large diversity in contents of the compounds was observed. The association and QTL analyses proved to be complementary and led to assumptions about the co-locations of loci controlling different traits, especially for compounds with differential levels in the skin of peaches and nectarines. These analyses will help deciphering the genetic control of fruit skin phenolics and triterpenoids and pave the way to the identification of the underlying genes. Detection of loci related to resistance will provide tools for the implementation of marker assisted selection. Correlations between compounds and infection traits led us to hypothesize that some compounds from peach skin could play a role in the brown rot control. The fungicide activity of these compounds is being tested in vitro.

The fact that Brazilian citriculture has focused on few rootstocks poses several phytosanitary risks to the culture and has made genetic improvement programs develop hybrid genotypes to be used as novel alternatives. This study aimed at evaluating the behavior of 42 different rootstocks regarding their emergence percentage and speed in weather conditions experienced in the extreme south of Brazil. Seeds of hybrids developed by the Citrus Genetic Improvement Program (PMG Citros) at the Embrapa Mandioca e Fruticultura (PMG Citros) and cultivars from other citrus growing regions were sown in conical tubes filled with commercial substrate in May 2017. A thoroughly randomized design with 4 replicates, each composed of 45 sampling units, was employed. Emergence percentage and emergence speed of every genotype were evaluated and the ones with the highest emergence percentage of seedlings and the ones with the most precocious emergence were identified. All genotypes completed seedling emergence 98 days after sowing. Seeds of Trifoliata, TSKC × CTSW-041 and TSKC × CTSW-025 had the highest values of seedling emergence whereas the highest emergence speed indexes were exhibited by genotypes Trifoliata and lemon tree ‘Cravo’.

A cultura do pessegueiro [Prunus persica (L.) Batsch] vem crescendo em todo o mundo, devido ao aumento no consumo de frutas in natura e de seus produtos industrializados. No Brasil, em parte, o crescimento deve-se ao melhoramento genético. Essa área de pesquisa, visando a obtenção de novas cultivares que produzam frutos de qualidade, tenham alta produção, adaptação climática, e apresentem resistência às principais doenças é de muita importância para a expansão da cultura. O conhecimento dos parâmetros genéticos, fenotípicos e ambientais que influenciam direta ou indiretamente nos caracteres de importância econômica em pessegueiro são de fundamental importância para o delineamento dos programas de melhoramento desta frutífera, permitindo antever a possibilidade de sucesso com a seleção de diferentes genótipos em diferentes ambientes. O objetivo central deste trabalho foi buscar fontes de resistência à podridão-parda; estudar a segregação; estimar a herdabilidade e verificar a possível existência de efeito materno em alguns caracteres de importância econômica no pessegueiro. Foi constatada variabilidade fenotípica e segregação transgressiva, para os caracteres fenológicos estudados nas populações avaliadas. A herdabilidade para o período de desenvolvimento do fruto, data de plena floração e data de maturação, é alta a muito alta, permitindo um rápido ganho genético para estes caracteres fenológicos. A herança desses caracteres fenológicos estudados é predominantemente aditiva, e os desvios podem ser atribuídos a um possível efeito materno ou a genes de efeito maior. Foi observada a presença de segregação transgressiva para os parâmetros referentes à tonalidade da cor da polpa (ângulo Hue, croma e luminosidade), e a herdabilidade estimada foi alta, possibilitando rápido avanço genético também para este caráter. A herança da tonalidade da cor da polpa é predominantemente aditiva, e os desvios podem ser atribuídos a genes de efeito menor, sem constatar-se indícios de efeitos maternos. O ângulo Hue é o parâmetro correto para classificar e estudar a tonalidade de pêssegos e nectarinas de polpa amarela, e o parâmetro luminosidade pode ser uma opção para o estudo dos frutos de polpa branca. O uso dos três parâmetros em conjunto possibilita melhor representação deste caráter. Para os caracteres de resistência à podridãoparda em flores e frutos, nas populações estudadas, foi verificada alta variabilidade genética. As cultivares Maciel e Cerrito foram os genitores de maior resistência à podridão-parda nas flores, e transmitiram essa característica a suas progênies. As seleções Conserva 947 e Conserva 1600 foram os genitores de maior resistência à podridão-parda nos frutos, com um nível de resistência similar a ‘Bolinha’, transmitindo essa característica a suas progênies. A herdabilidade da resistência à podridão-parda nas flores (incidência e severidade) e nos frutos (diâmetro da lesão e esporulação), no pessegueiro, é média. A seleção dos genitores, baseada no fenótipo, possibilita um médio avanço genético para esta característica. Agencia Nacional de Investigación e Innovación