Initial development of upland rice plants inoculated with the MAY12 strain of Azospirillum spp.

Marivaine Da Silva Brasil,Matheus Wimkler Alvarenga Batistela,Mayara Silva Torres De Souza,Salomão Lima Guimarães,Sergio Luiz Koswoski Junior

doi:10.1590/0103-8478cr20200824

Marivaine Da Silva Brasil, Matheus Wimkler Alvarenga Batistela + Show 3 more

Open Access

https://doi.org/10.1590/0103-8478cr20200824

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Abstract

ABSTRACT: The purpose of this study was to evaluate the contribution of the inoculation of the strain Azospirillum MAY12 to the development of rice plants of the cultivar BRS Esmeralda. A completely randomized experiment was performed in a greenhouse, with 8 treatments and 6 repetitions, namely, commercial inoculant (CI) containing strains of Azospirillum brasilense ABV5 and ABV6 (T1), MAY12 (T2), nitrogen control with 50 mg of N or full dose (T3), CI + 30% of N (percentage referring to full dose) (T4), CI + 60% N (T5), MAY12 + 30% N (T6), MAY12 + 60% N (T7) and absolute control (T8). There was a significant increase in the fresh and dry mass of the shoot and roots, height, root volume, and the number of tillers and leaves of plants with the MAY12 inoculation (with and without N added) compared to T8. Treatments containing MAY12 + N increased the total dry mass by ~920% compared to T8, matching the T3 yield. The inoculation of MAY12 in isolation was as efficient as the application of the full dose of N, resulting in an increase of ~115% in height and 373% in root volume of the plants compared to T8. The MAY12 strain demonstrated good performance in the development of the cultivar, which was comparable to the CI in the variables tested. Therefore, inoculation with the MAY12 strain is promising for the partial reduction of nitrogen fertilizers in upland rice cultivation.

Highlights

Rice (Oryza sativa) originated in Asia and is one of the most widely produced cereals in the world, responsible for feeding ~50% of the world’s population (KUMAR & LADHA, 2011)
This study evaluated the contribution of inoculation of the Azospirillum MAY12 strain in the development of rice plants of the cultivar BRS Esmeralda, in a greenhouse experiment
Nitrogen treatments (T3, T4, T5, T6 and T7) presented the highest mean chlorophyll content; in the fourth and fifth Falker chlorophyll index (FCI) readings, there was no significant difference between any of the nitrogen-containing treatments compared to the absolute control (Table 1)

Summary

Introduction

Rice (Oryza sativa) originated in Asia and is one of the most widely produced cereals in the world, responsible for feeding ~50% of the world’s population (KUMAR & LADHA, 2011). Brazil is one of the leading rice producers, with production representing ~1.6% of the world total, ranking 9th, only behind Asian countries (SILVA, 2014). ARANTES (2013) reported that upland rice, commonly known as dryland rice, is grown using only water from rainfall, and is the reality for small farmers in poor regions of the world such as Asia, Africa and Latin America. This is because of a lack of resources for irrigated planting and because of the high demand for rice.

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