Produ？？o e desempenho de sementes de cultivares de alface em duas épocas de plantio

studies on lettuce seed production in different seasons may provide a better understanding for growers to use suitable management practices which could increase their production and maximize their profits. environmental conditions during the different stages of plant and seed development may affect lettuce physiological seed quality. the objective of this study was to evaluate the performance of eight lettuce cultivars regarding seed production and seed physiological quality under greenhouse conditions in spring/ summer and in autumn/ winter at lavras - mg region, brazil. plant tasselling, anthesis and seed production were evaluated. after harvesting and processing, seeds were weighed and evaluated for germination, first count, germination rate at 20, 25, 30 and 35 oc, seedling emergence and accelerated aging (41 oc/48 and 72 hours). the highest lettuce seed yield under greenhouse conditions was observed during the autumn/ winter season and higher yield and seed quality were obtained using the 'vera' cultivar. however, seed production of the 'luisa' cultivar during the summer increased germination at high temperatures. the 'lívia' and 'simpson' cultivars grown in the spring/ summer season and the 'elisa' cultivar grown in the autumn/ winter season showed lower seed vigor.