Occurrence of rice blast on and grain quality of irrigated rice fertilized with nitrogen and silicates

Lillian Matias De Oliveira,Bruno Behenck Aramburu,Isabel Schlegel Werle,Ricardo De David,Ivan Francisco Dressler Da Costa,Anelise Lencina Da Silva,Gabriel Donato,Enio Marchesan

doi:10.1590/s1678-3921.pab2019.v54.00295

Lillian Matias De Oliveira, Bruno Behenck Aramburu + Show 6 more

Open Access

https://doi.org/10.1590/s1678-3921.pab2019.v54.00295

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Abstract

Abstract: The objective of this work was to evaluate the effects of fertilization with nitrogen topdressing and silicates, as well as of the use of fungicides, on the occurrence of rice blast on panicles, milling yield, and whole grains, vitreous grains, and chalky kernels in a flood-irrigated rice cultivar sensitive to the disease. Two experiments were conducted in a randomized complete block design, in a 4×4×2 factorial arrangement, with four replicates: in experiment 1, four doses of nitrogen × four doses of calcium and magnesium silicate on soil × with and without fungicides; and, in experiment 2, four doses of nitrogen × four doses of potassium silicate applied on leaves x with and without fungicides. At the doses above 60 kg ha-1 nitrogen without fungicides, there was an increase of rice blast severity on panicles, a decrease in the percentage of whole and vitreous grains, and an increase in chalky kernels and chalky area. The greatest effects of silicates occurred without fungicides. Fungicide use reduced the severity of rice blast on panicles. Milling yield ranged from 60 to 70% in both experiments. The control of rice blast with fungicides maintains high rice grain quality, milling yield, and percentages of whole and vitreous grains.

Highlights

Rice (Oryza sativa L.) is one of the most important cereals for the world population and much of its consumption is in the form of whole milled kernels
The objective of this work was to evaluate the effects of fertilization with nitrogen topdressing and silicates, as well as of the use of fungicides, on the occurrence of rice blast on panicles, milling yield, and whole grains, vitreous grains, and chalky kernels in a flood-irrigated rice cultivar sensitive to the disease
Two experiments were conducted in a randomized complete block design, in a 4×4×2 factorial arrangement, with four replicates: in experiment 1, four doses of nitrogen × four doses of calcium and magnesium silicate on soil × with and without fungicides; and, in experiment 2, four doses of nitrogen × four doses of potassium silicate applied on leaves x with and without fungicides

Summary

Introduction

Rice (Oryza sativa L.) is one of the most important cereals for the world population and much of its consumption is in the form of whole milled kernels. The physical quality of the grain, expressed by milling yield, whole grains, and grain dimensions and characteristics, steers the commercialization process (Mingotte et al, 2012). According to the Brazilian legislation, milling yield is considered as the percentage of milled rice or of milled and polished rice, resulting from the rice milling process (Brasil, 2009). In the Brazilian market, the preference is for grains with a high milling yield of over 70%, without defects and with a high whole grain yield above 60% (Reunião Técnica..., 2018). The characteristics of whole grains, vitreous grains, and chalky kernels, as well as staining defects, are affected by physiological disturbances caused by biotic or abiotic factors and result in the depreciation of the final product (Streck et al, 2018). The improvement of grain quality is one of the main selection criteria in breeding programs

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