The objective of this work was to evaluate the effect of different gibberellin biosynthesis inhibitors on shoot growth above the panicle, as well as on fruit yield, size, and shape of nonirrigated 'Hass' avocado (Persea americana) trees. The experiment was carried out in a randomized complete block design, with five treatments, four replicates, and 40 trees. From 2013 to 2015, the following treatments were applied at full bloom, as foliar sprayings: water (control), 250 mg L-1 prohexadione-calcium, 2,500 mg L-1 trinexapac-ethyl, 1,750 mg L-1 paclobutrazol, and 350 mg L-1 uniconazole; the first two are acylcyclohexanediones and the last two, triazoles. Fruit yield, yield efficiency, and alternate bearing were not affected by the application of plant growth regulators. However, the gibberellin inhibitors increased fruit size and modified the fruit shape of nonirrigated 'Hass' avocado. Uniconazole reduces shoot growth above the panicle, and this effect may vary depending on environmental conditions, especially water supply.

The objective of this work was to evaluate the effects of supplemental irrigation, during winter dry season, on the water status and productivity of 'Hass' avocado (Persea Americana) trees. The experiment was carried out on a clayey Oxisol from 2014 to 2016, when extreme climatic events were recorded in the state of São Paulo, Brazil. The rainfed regime was compared with two irrigation regimes, applied during the whole and half of the irrigation run time defined by the grower, corresponding to 5,091 and 2,545 m3 ha-1 water, respectively. The following variables were evaluated: soil water tension; leaf water potential, color, and chlorophyll content; leaf and fruit abscission rates; tree size; and fruit size and yield. Supplemental irrigation applied during half of the run time increased fruit yield by 18.2%. However, irrigation applied during a fixed-time period and the occurrence of unusual rainfall spells caused soil water logging, negatively affecting tree growth and water status.

Resumen Por ser una especie de polinización cruzada y altamente heterocigótica, la multiplicación del aguacate por semilla origina una progenie altamente variable en relación a las características morfológicas y biológicas. Por ese motivo, se hizo relevante la adopción de métodos de propagación más eficientes, que resulten en plántulas de mejor calidad en términos de producción y resistencia a enfermedades. La injertación es el más utilizado para la propagación comercial de aguacate en los principales países productores. Originalmente, la implementación de plantaciones de aguacate se realizó a partir de plántulas obtenidas de portainjertos provenientes de semillas, siendo ese método de multiplicación el que aún predomina en Brasil. Sin embargo, tal procedimiento confiere en el campo mucha variabilidad y diferencias de productividad, calidad y vigor entre las plantas. En países que adoptan mayor nivel tecnológico, el portainjerto pasó a ser obtenido a partir de métodos clonales (Frolich y Platt, Brokaw, Allesbeste) asociados a otras técnicas como la etiolación y el anillado de los brotes. La presente revisión bibliográfica tiene como objetivo abordar los principales métodos de propagación utilizados en aguacate, sus avances y la importancia del mejoramiento genético y de las nuevas investigaciones en la obtención de cultivares de portainjerto y copa que atiendan las demandas del mercado.

The introduction of new avocado cultivars into producing countries of the Southern Hemisphere may extend the offer period of fresh fruit for export. The ‘Gem’ (‘3-29-5’) avocado is known for extending the marketing period of ‘Hass’-like avocados. This study aimed to evaluate the horticultural performance of ‘Gem’ avocado trees between the 4th and 6th years after planting (2016-2018), in a commercial orchard in the Central-Western region of the State of São Paulo, Brazil. ‘Gem’ avocado trees grafted onto seedling rootstocks were evaluated regarding tree size, shoot growth, flowering, and fruit yield, quality and maturation. In the evaluated biennium, the trees showed a strong upright growth habit and compact tree size. Flowering occurred mainly in indeterminate inflorescences. Fruit yield varied between 106.89 to 116.89 kg tree-1, and 75-91% of the fruit classified within size counts 12 (306 to 365 g/fruit) to 18 (211 to 235 g/fruit), and reached physiological maturity in late June, but could be picked until October, i.e, four to eight months later than ‘Hass’. ‘Gem’ is a new alternative for extending fruit offer of late-maturity avocado cultivars and allowing higher profit to the farmers.