Stay-Green Trait As a Tool for Wheat Breeding.

The future scenario of agriculture requires a new vision from plant breeders. The increase in yield will have to be supported by physiological efficiency and abiotic stress adaptation, regarding shortage of natural resources and water as well a global changes. The stay-green trait is caused by a delayed senescence of photosynthetically active tissues and has been proposed as an important trait for stress adaptation and phenotypical stability. Based on the importance of this trait, the objective of this work was to analyse the performance of sister lines with and without the stay-green trait under different years in Southern Brazil. Lines originating from two parents contrasting for the trait stay-green were selected for high yield and divided into stay-green and synchronized maturation type. After reaching homozigozity, lines were compared for three years in Capão do Leão County,  Rio Grande do Sul State, Brasil. A randomized block design with three replications was used , and 5 m² plots were evaluated for weight of a thousand grains, number of fertile tillers and number of grains per ear. Lines containing the stay-green trait were superior for grain yield but differences between years were observed. Also, the trait seems to favor increases in number of grains per year. However, no influence on number of fertile tillers was observed. Other associations between traits are discussed.