Field estimate with NDVI of grain yield and quality of wheat flour¹

Estimativa de campo com NDVI da produtividade de grãos e qualidade da farinha de trigo

HIGHLIGHTS:

The active optical sensor was sensitive to the variation of nitrogen fertilization.

It was possible to estimate the flour quality using an active optical sensor at the vegetative stage of the wheat crop.

The wheat cultivar should be considered to adjust the grain yield and flour quality prediction equations.

ABSTRACT

Nitrogen fertilization is essential for wheat yield and quality but needs more accuracy, and the use of proximal optical sensors in the field can assist in this goal. This study aimed to verify if it is possible to use the normalized difference vegetation index (NDVI) obtained throughout the wheat growth phase to estimate the grain yield and the technological quality of the flour from cultivars submitted to nitrogen doses. The experiment was conducted at field conditions in Ponta Grossa, PR, Southern Brazil. The experimental design was randomized blocks in a 4 × 6 factorial scheme with four replicates. The cultivars Quartzo, Gralha Azul, Sinuelo, and Toruk, combined with six doses of N (0, 40, 80, 120, 160, and 200 kg ha^-1 of N), were evaluated. The NDVI values were sensitive to both nitrogen doses and the different cultivars. There was a relationship between NDVI and grain yield, protein, and gluten concentration of flour. The NDVI estimated the gluten strength, stability, tenacity, extensibility of the mass, and tenacity/extensibility ratio of the flour obtained at the beginning of the cycle, but not for all cultivars. The determinations of NDVI with active optical sensor GreenSeeker in wheat are efficient to estimate the grain yield and the flour quality under field conditions, allowing to generate models for estimation of these variables separately for each cultivar.

Key words:
Triticum aestivum; vegetation index; wheat genotype; wheat flour quality; precision agriculture