Effect of fruit load of the first coffee harvests on leaf gas exchange

Carlos Andres Unigarro Muñoz,Lina Marcela Díaz Bejarano,José Ricardo Acuña

doi:10.1590/1983-40632021v5169865

Carlos Andres Unigarro Muñoz, Lina Marcela Díaz Bejarano + Show 1 more

Open Access

https://doi.org/10.1590/1983-40632021v5169865

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Abstract

ABSTRACT Coffee production between the first and second harvest presents a difference in the fruit load with the plant age that could affect the leaf gas exchange. This research aimed to evaluate the effect of the increase in fruit load that occurs between the first and second harvest of the Coffea arabica L. production cycle on the measured gas exchange, at the two phenological stages of the fruit. The accessions E057, E318, E338 and E554 were used, as well as a completely randomized design, with three replications, using the accessions as treatments and the harvest measurements during the production cycle as the repeated measures. The variables yield per tree, number of fruits, absolute growth rates for height and stem, leaf area, leaf-to-fruit ratio and leaf gas exchange were measured across the phenological stages of fruit filling and ripening. The increase in the fruit load that occurs with age in the second harvest, if compared to the first harvest, showed a positive and significant effect on the net assimilation rate that was not expected for the obtained leaf-to-fruit ratios. Likewise, the differences in the assimilation rates were higher during the fruit-filling stage. This result suggests that the source-sink relationship may vary with the crop age and fruit phenological stage, and is not entirely depend on the leaf-to-fruit ratio.

Highlights

Coffee is the second most traded commodity in the world after oil, and its cultivation constitutes a source of income for 26 million people in 56 countries (Davis et al 2012, Castro-Tanzi et al 2014)
In Colombia, the area dedicated to the commercial cultivation of Arabic coffee is 911 thousand hectares, with varieties resistant to rust grown in 76.3 % of the territory (FNC 2017)
The present study aimed to evaluate the effect of the increase in fruit load that occurs between the first and second harvest of the C. arabica production cycle on the gas exchange measured during two phenological stages of the fruit

Summary

Introduction

Coffee is the second most traded commodity in the world after oil, and its cultivation constitutes a source of income for 26 million people in 56 countries (Davis et al 2012, Castro-Tanzi et al 2014). The commercial production of canephora coffees in the country is incipient and limited to investigative, experimental lots In fruit trees such as mango (Urban et al 2004), citrus (Rivas et al 2007), peach (Duan et al 2008) and coffee (Franck et al 2006, Vaast et al 2006), the fruit load (sink) affects the production of dry matter, carbon partitioning and leaf photosynthetic activity (source). In this context, by reducing the sink demand for carbohydrates, there is a decrease in the net photosynthetic rate, mainly in response to the.

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