Produção e qualidade de sementes de girassol (Helianthus annuus L.) influenciadas pela densidade de semeadura e pelo vigor das sementes

Abstract

The objective of this work was to compare different procedures of the accelerated aging and controlled deterioration tests to evaluate sunflowers achenes vigour, correlate the results of tests conducted in the laboratory with the emergence of sunflower seedlings in the field, evaluate the influence of sunflower achenes vigour on the seedlings establishment and plant performance, evaluate the effect of achenes vigour and sowing density on the sunflower plants growth, evaluate the effect of achenes vigour and sowing density on the nutrients of accumulation and the oil of yield in sunflower plants. For this were installed six experiments. The results showed that the accelerated aging test and controlled deterioration were efficient to classification the sunflowers achenes lots. Under adverse conditions, the achene vigour evaluated by accelerated aging, controlled deterioration and electrical condutivity presented a higher correlation with sunflower plant emergence in field. Sunflower achene vigour improved the development of plants beyond 60 DAS and this effect may persist until the final production, at initial population ausence. Plants originated from smaller achenes vigour showed the lower total dry matter and leaf area index to 80 and 100 DAS, as well as lower culture growth rate in the period from 60 to 100 DAS. The plants conducted under the lower density had higher total dry matter and leaf area index at 40 and 60 DAS, as well as higher culture growth rate and relative growth rate in the period from 20 to 40 DAS. To the 60 days, at flowering high accumulation of dry mater, N, P K and Ca in stem, leaves and total at density of 45,000 seeds.ha-1. The sunflower achenes oil yield and dry mater and nutrients harvest index not affected by the achenes vigour and sowing density to