Desempenho agronômico da cultivar de gergelim BRS Pérola Negra inoculada com bacilos e submetida à restrição hídrica

Abstract

Sesame (Sesamum indincum L.) is an oleaginous plant cultivated in more than 70 countries, in Brazil, its exploitation has been growing in recent years. It is a crop with wide adaptability to edaphoclimatic conditions of hot weather, however, it can suffer from effects caused by water scarcity. Water deficit can affect plant metabolism, causing, among other factors, inhibition of photosynthesis and a decrease in nutrient absorption, disfavoring plant growth and development. Thus, the use of inoculants based on plant growth-promoting bacteria can be a good management strategy. In this context, this work aims to evaluate the performance of the sesame cultivar BRS Pérola Negra, inoculated with bacilli and subjected to water restriction. The experiment was carried out in the field, experimental design in randomized blocks, being 3 (inoculants) x 2 (chemical nitrogen levels) x 2 (water regime), with 3 replications, totaling 36 treatments. After 35 days of emergence, irrigation was suspended for six days and, on the sixth day, leaves were collected for biochemical analysis. At the end of the crop cycle, the following variables were collected: insertion height of the first fruit; plant height; root length; dry root mass; dry shoot mass; capsule number; counting the number of open capsules; capsule length and diameter; weight of 1000 seeds; total seed weight; nitrogen and phosphorus content. The collected data were submitted to analysis of variance (p≤0.05) and the means compared by the F test (p≤0.05) using the statistical program SISVAR version 5.6. GraphPad version 9.5 was used to generate graphs and Genes for correlation analysis between agronomic and biochemical traits. According to the results, it was possible to observe a positive effect of inoculation in all agronomic variables, mainly in plants under conditions of water restriction. The final grain production had an increase of 15.45% in the treatment inoculated with ESA 402 under water stress, and 151.43% in the treatment inoculated with pant001 in the irrigated condition, in comparison with the treatment without nitrogen. The biochemical analyzes showed that there was an increase in the enzymatic activities of superoxide dismutase (SOD), ascorbate peroxidase (APX) and concentration of photosynthetic pigments in the inoculated treatments. The results obtained for nitrogen and phosphorus in leaves were positive, since their levels increased in the stress condition, in the treatments with nitrogen and inoculated. As for the correlations, the characters that correlated significantly, with high and positive associations, were the number of capsules X number of open capsules (rfe 0.94) and chlorophyll to X total chlorophyll (a+b) (rfe 0.94) and negative between the characters length of capsules X number of capsules (rfe 0.79). Based on these data, it was found that the inoculants for the BRS Pérola Negra sesame plants contributed to their better growth and development even under conditions of water restriction.