Prohexadione calcium on shoot growth of 'Starkrimson' pear trees

Abstract

-The objective of this work was to evaluate the fruiting and vegetative growth of 'Starkrimson' pear in response to the application of prohexadione calcium (P-Ca). P-Ca (250 mg L -1 ) was sprayed to scaffold limbs and to whole trees in commercial orchards. A randomized complete block design was used to minimize declivity effects. Vegetative growth (length and number of shoots, increment in limb and trunk cross-sectional area, number of nodes, and internode length), production (fruit number, yield, yield efficiency, and fruit size), and return bloom were evaluated from 2010 to 2013. P-Ca efficiently controlled shoot growth in all growing seasons, when applied early in the season, due to the reduction in internode length. Production was not negatively affected by the application of P-Ca in all years and at both sites, and fruit size and return bloom were not reduced. Fruit quality attributes were also little affected by P-Ca, except for total soluble solids content, which was lower than that of the control. This shows that P-Ca is efficient to manage tree vigor in high-density 'Starkrimson' pear orchards.Index terms: Pyrus communis, modern orchard, plant growth regulator, vigor control. Prohexadiona cálcio no crescimento de ramos de pereiras 'Starkrimson'Resumo -O objetivo deste trabalho foi avaliar a produção e o crescimento vegetativo de peras 'Starkrimson' em resposta à aplicação de prohexadiona cálcio (P-Ca). Aplicou-se P-Ca (250 mg L -1 ) em ramificações laterais e em plantas inteiras, em pomares comerciais. Utilizou-se o delineamento experimental de blocos ao acaso, para minimizar os efeitos da declividade do terreno. O crescimento vegetativo (comprimento e número de ramos, incremento da área da secção transversal dos ramos laterais e do tronco, número de nós e comprimento de entrenós), a produção (número de frutos, produtividade, eficiência produtiva e tamanho de fruto) e o retorno da floração foram avaliados de 2010 a 2013. P-Ca foi eficiente no controle do crescimento de ramos em todas as safras, quando aplicada no início do ciclo de crescimento, devido à redução no comprimento dos entrenós. A produção não foi afetada negativamente pela aplicação de P-Ca em todos os anos e em ambos os locais, e o tamanho de fruto e o retorno da floração não foram reduzidos. Os atributos de qualidade dos frutos também foram pouco afetados por P-Ca, exceto o teor de sólidos solúveis totais, que foi menor que o do controle. Assim, P-Ca é eficiente no manejo do vigor em pomares de alta densidade de peras 'Starkrimson'.Termos para indexação: Pyrus communis, pomares modernos, reguladores vegetais, controle de vigor.

Effect of the application of prohexadione-calcium on the growth of ‘Packham’s Triumph’ and ‘Hosui’ pears (Pyrus communis L.)

“…This behavior is the same observed in the previous experiments with the 'Packham's Triumph' pears, suggesting that both cultivars respond similarly to the application of PCa. Other authors reported similar trends for 'Le Conte', 'Starkrimson', and 'Smith' pear trees, whose fruit yield and quality were not affected by the application of PCa in the range of 100-400 mg•L -1 (Carra et al, 2016(Carra et al, , 2017aPasa and Einhorn, 2017). The only exception was the 'Shinseiki' pear trees, whose fruit quality parameters were not influenced by the application of PCa, but the fruit yield was reduced when the trees were treated with PCa 600 mg•L -1 (Carra et al, 2017b).…”

“…Carra et al (2017a), who evaluated the application of PCa in 'Smith' pear trees at the doses of zero, 100, 200, 300, and 400 mg•L -1 , reported a linear inverse trend between the PCa dose and the length of the plant branches. Pasa and Einhorn (2017) also reported a reduction of average branch length for 'Starkrimson' pear trees, from 55.1 cm in the control to 38.9 cm in trees treated with 250 mg•L -1 PCa.…”

“…This behavior is similar to the one of 'Packham's Triumph' for the second measurement but was distinct from the first measurement, in which the PCa dose of 330 mg•L -1 differed from the control. This may indicate that the sensibility of the pear trees to PCa may differ with the cultivar, as can be seen when comparing the works of Carra et al (2016Carra et al ( , 2017aCarra et al ( , 2017b, who studied 'Le Conte', 'Smith', and 'Shinseiki' pear trees, and Pasa and Einhorn (2017), who worked with 'Starkrimson' pear trees.…”

Influence of prohexadione-calcium on temperate fruit crops – A Review

“…Double spray of prohexadione-calcium (200 ppm) resulted in higher fruit weight (82.85 g), fruit length (6.81 cm) and fruit diameter (6.44 cm) as compared to control plants (Lal et al, 2018). Pasa and Einhorn (2017) also noted good result in terms of fruit weight (205.78 g) with pro-ca spray at 250 mg/l as compared to untreated Starkrimson pear trees. An averaged fruit weight (230.96 g) in Passe Crassane pear plants was observed greater in 150-ppm prohexadione-calcium spray (Shehaj et al, 2015).…”

“…The double spray of prohexadione-calcium @ 200 ppm, one at the complete petal fall stage and one at four weeks after the first spray, increased the return bloom percentage by about 24.04 in Clapp's Favorite pear plants. Pasa and Einhorn (2017) reported that prohexadione-calcium was found to be best for return bloom in stark crimson pear trees as it produces more number of flowering spurs (14.80%) and flowering shoots (8.60%) in second year of application. Shehaj et al (2015) reported that the application of prohexadione-calcium (100 and 150 ppm) showed significant effect on return bloom of treated pear plants.…”