Abstract
Germination and seed vigor may be influenced by several factors, such as water stress during production, which affect crops differently according to the phenological stage of the plant. The aim of this study therefore was to evaluate the physiological quality of sesame seeds from plants subjected to water stress at different phenological stages. To this end, sesame plants were subjected to water stress at the following stages: I - germination to the start of vegetative growth (T1); II - vegetative growth to flowering (T2); III - flowering to pod formation (T3); IV - fruit maturation (T4); also for stress at all stages (T5) and full irrigation (T6). By weighing and daily irrigation of the containers, levels were kept at 50% of pot capacity (CV) for treatments with water deficit, and at 100% CV for treatments with no deficit. At 90 days after planting, the plants were harvested. The seeds were evaluated by germination test, first germination count, germination speed index, mean germination time, accelerated aging, electrical conductivity, seedling emergence, emergence speed index, mean time of emergence, seedling length and seedling dry weight. Sesame seeds from plants grown under water deficit display lower physiological quality. Between germination and the start of vegetative growth, and between flowering and fruit formation, the sesame is more sensitive to water stress, so that water limitation during these periods results in the production of seeds of low physiological quality.
Highlights
Sesame is a crop that is adapted to deep soils which have a loamy texture, are well drained and of good natural fertility
Tavares et al (2013) concluded that a water deficit from 20 days after sowing, causes a reduction in the physiological quality of the seeds, being more severe in plants originating from seeds of low vigor. Because it is a species which is often recommended as an alternative for generating income in the Brazilian semi-arid region, it is extremely important to know the response to water availability during the different phenological stages of the plant
The aim of this study was to evaluate the physiological quality of sesame seeds from plants which were subjected to water stress at different phenological stages
Summary
Sesame is a crop that is adapted to deep soils which have a loamy texture, are well drained and of good natural fertility. Despite having an optimal range of between 500 and 650 mm of water during its production cycle (GRILO JÚNIOR, AZEVEDO, 2013), the species is considered resistant to drought and is productive with a rainfall of up to 300 mm, if this is well distributed throughout its development. Water deficiency is caused by the transpiration of water exceeding the rate of absorption, thereby acting directly on the water balance in plants (COSTA et al, 2008). It is known that in addition to suitable climatic conditions, for a successful crop, it is necessary to use seeds of high physiological quality, as this contributes to high productivity, whereas seeds of low quality compromise an adequate stand of plants, directly affecting productivity. The most vigorous seeds are generally more resistant to such abiotic stresses as a soil water deficit, for example (MAGALHAES et al, 2013; OLIVEIRA; GOMES-FILHO, 2011)
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