Evaluation of functional stay-green in maize inbred lines and their relationship with agronomic traits

Resumen del póster presentado en el Congreso celebrado en Saint-Malo, Francia, entre el 22 y el 25 de marzo de 2018.The time and rate of senescence in maize affects the duration of photosynthetic activity and the remobilization of nutrients from leaves to grain which has an impact on biomass and grain yield. Various types of late senescence or stay-green have been proposed which can be reduced to two types: functional, when the photosynthesis is active while the plant is green, and cosmetic, when photosynthesis is not working out in spite of the green color of the leaves. Little information has been published about the types of stay-green in inbred lines of temperate maize. We evaluated the functional stay-green of 197 lines developed in different public and private breeding programs. Many of the lines were included in the study because they had visual stay-green according to personal information of breeders or information found in the certification of the lines. Other lines were included because of their relevance in maize breeding, for example B73, PH207, Mo17, etc. We found the reduction in chlorophyll content was always accompanied by a decrease in photosynthetic rate, although, some lines retained small amounts of chlorophyll after losing its photosynthetic activity. Therefore, we concluded that the predominant way of stay-green in inbred lines of temperate maize is functional. There was variation in the duration of photosynthetic activity between the inbred lines. Some lines had active photosynthesis as late as 75 days after flowering, while many others did not. The lines with late photosynthesis had on average the highest grain yield and biomass yield, but also the highest grain filling duration and the highest grain moisture. We conclude that the functional stay-green is favorable for grain yield, but at the cost of increase the grain moisture.Plan Nacional de I+D. Spain, Feder UEPeer reviewe