Multivariate analysis and vigor tests to determine the quality of Brachiaria decumbens seeds

Givanildo Zildo Da Silva,Riselane De Lucena Alcântara Bruno,Cibele Chalita Martins,Tatiane Sanches Jeromini,Francisco Elder Carlos Bezerra Pereira

doi:10.5935/1806-6690.20190034

Abstract

This study aimed to verify the efficiency of multivariate analysis in the identification of promising vigor tests for the evaluation of the physiological quality of seed lots of Brachiaria decumbens cv. Basilisk. Seeds of B. decumbens cv. Basilisk were tested for the following parameters: water content, germination, first germination count, cold test, electrical conductivity, seedling growth, seedling dry mass, first count and emergence percentage of seedlings in laboratory substrate, and seedling emergence in the field. The data obtained in each test—all completely randomized experimental designs—were analyzed separately by means of analysis of variance, Scott-Knott’s test, and multivariate analysis. Principal component analysis is efficient to discriminate vigor and seed germination tests capable of identifying the top performance batch in the field. Germination, first germination count, emergence of seedlings in sand, first seedling emergence count in sand, shoot length, and the cold test are promising in the evaluation of the physiological quality of seed lots of B. decumbens cv. Basilisk, providing similar information to that from the emergence of field seedlings.

Highlights

In Brazil, there are approximately 172 million ha of pasture grown in extensive livestock systems (TIMBÓ et al, 2014), placing the country as the world’s largest producer, consumer, and exporter of grass seed (VIGNA et al, 2011).Brachiaria decumbens Stapf. is the oldest species of forage grass and continues to have high demand, ranking second in terms of importance in the forage grass seed market
The tests applied to the seeds to determine emergence in the field were used as reference for the selection of vigor tests, as described below: Seedling emergence in the field was evaluated by sowing four subsamples of 50 seeds per treatment in beds in the field in lines of 1.5 m in length, with rows spaced 0.2 m apart, at a depth of 2 cm, with counts performed at 21 days after sowing and results expressed as percentages (SILVA et al, 2017)
The seedling emergence in the field was used as a reference for the selection of vigor tests, and it was possible to classify the performance of the batches in decreasing order of vigor from 1-13 and to group them into two vigor classes: high and low

Summary

Introduction

In Brazil, there are approximately 172 million ha of pasture grown in extensive livestock systems (TIMBÓ et al, 2014), placing the country as the world’s largest producer, consumer, and exporter of grass seed (VIGNA et al, 2011).Brachiaria decumbens Stapf. is the oldest species of forage grass and continues to have high demand, ranking second in terms of importance in the forage grass seed market. The seed quality of Brachiaria spp. is not always satisfactory, and research in this area is necessary (CARDOSO et al, 2014; PEREIRA et al, 2011). Germination and vigor tests are used to evaluate the physiological quality of seed batches for the identification of those with the best field or storage potential (GRZYBOWSKI; VIEIRA; PANOBIANCO, 2015; MARCOS FILHO, 2015a). This information may assist in the internal decision-making of companies about the best destination of the seed, the geographical area to be targeted, whether it can be conveniently stored, or if it is necessary for them to be quickly sold (MARCOS FILHO, 2015a)

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