Thidiazuron (TDZ) increases fruit set and yield of 'Hosui' and 'Packham's Triumph' pear trees.

The low fruit set is one of the main factors leading to poor yield of pear orchards in Brazil. The exogenous application of thidiazuron (TDZ) and aminoethoxyvinilglycine (AVG) has shown promising results in some pear cultivars and other temperate fruit trees. The objective of this study was to evaluate the effect of TDZ and AVG on fruit set, yield, and fruit quality of 'Hosui' and 'Packham's Triumph' pears. The study was performed in a commercial orchard located in São Joaquim, SC. Plant material consisted of 'Hosui' and 'Packham's Triumph' pear trees grafted on Pyrus calleryana. Treatments consisted on different rates of TDZ (0 mg L-1, 20 mg L-1, 40 mg L-1 and 60 mg L-1) sprayed at full bloom for both cultivars. An additional treatment of AVG 60 mg L-1 was sprayed one week after full bloom in 'Hosui'. The fruit set, number of fruit per tree, yield, fruit weight, seed number, and fruit quality attributes were assessed. Fruit set and yield of both cultivars are consistently increased by TDZ, within the rates of 20 to 60 mg L-1. Besides, its application increased fruit size of 'Hosui' and did not negatively affect fruit quality attributes of both cultivars.

Thidiazuron (TDZ) increases fruit set and yield of 'Hosui' and 'Packham's Triumph' pear trees

ABSTRACT The low fruit set is one of the main factors leading to poor yield of pear orchards in Brazil. The exogenous application of thidiazuron (TDZ) and aminoethoxyvinilglycine (AVG) has shown promising results in some pear cultivars and other temperate fruit trees. The objective of this study was to evaluate the effect of TDZ and AVG on fruit set, yield, and fruit quality of 'Hosui' and 'Packham's Triumph' pears. The study was performed in a commercial orchard located in São Joaquim, SC. Plant material consisted of 'Hosui' and 'Packham's Triumph' pear trees grafted on Pyrus calleryana. Treatments consisted on different rates of TDZ (0 mg L-1, 20 mg L-1, 40 mg L-1 and 60 mg L-1) sprayed at full bloom for both cultivars. An additional treatment of AVG 60 mg L-1 was sprayed one week after full bloom in 'Hosui'. The fruit set, number of fruit per tree, yield, fruit weight, seed number, and fruit quality attributes were assessed. Fruit set and yield of both cultivars are consistently increased by TDZ, within the rates of 20 to 60 mg L-1. Besides, its application increased fruit size of 'Hosui' and did not negatively affect fruit quality attributes of both cultivars.

Aumento da produção de pereira asiática pelo uso de fitorreguladores / Fruit production increase in Asian pear trees by use of plant growth regulators

A baixa frutificação de pereiras nas condições do Sul do Brasil é um dos limitantes à produção da cultura no país, podendo o problema ser minimizado pelo uso de fitorreguladores. Objetivou-se avaliar a efetividade de diferentes fitorreguladores e a combinação dessas substâncias no aumento da frutificação de pereira asiática 'Shinseiki. A aplicação dos fitorreguladores foi realizada quando as pereiras atingiram o estádio de plena floração. O delineamento experimental foi em blocos casualizados, com quatro repetições de uma planta, sendo avaliados os seguintes tratamentos: 1. testemunha (sem aplicação); 2. thidiazuron (TDZ) 20mg L-1; 3. ácido giberélico (AG) 20mg L-1; 4. proexadione cálcio (PCa) 600mg L-1; 5. PCa 600mg L-1 + TDZ 20mg L-1; 6. PCa 600mg L-1 + AG 20mg L-1; e 7. AG 20mg L-1 + TDZ 20mg L-1. Os fitorreguladores thidiazuron e ácido giberélico, e a combinação dessas substâncias, ambos na concentração de 20mg L-1, quando aplicados na floração, determinam aumento significativo da frutificação e da produção de peras 'Shinseiki'. A utilização do proexadione cálcio na floração, tanto isoladamente quanto associado ao thidiazuron e ao ácido giberélico, não repercutiu no aumento da frutificação.

The low fruit set in the Southern Brazil conditions is one of the limiting factors to pear production in the country. The use of plant growth regulators may minimize this problem. This study was carried out aiming to evaluate the effectiveness of different growth regulators and the combination of these substances on fruit set increase of 'Shinseiki Asian pears. The application of growth regulators was performed when the pears have reached the full bloom stage. The experimental design was randomized blocks with four replications of one tree, with the following treatments: 1. control (no application); 2. thidiazuron (TDZ) 20mg L-1; 3. gibberellic acid (GA) 20mg L-1; 4. prohexadione calcium (PCa) 600mg L-1; 5. PCa 600mg L-1 TDZ + 20mg L-1; 6. PCa 600mg L-1 + AG 20mg L-1; and 7. AG 20mg L-1 + TDZ 20mg L-1. When sprayed on full bloom stage, thidiazuron and gibberellic acid, and combinations of these substances, both at a concentration of 20mg L-1, increased significantly the fruit set and the fruit production of 'Shinseiki' pears. The use of prohexadione calcium, single or in combination with thidiazuron and gibberellic acid, did not increase the fruit production.