Characterization of Leaf Senescence in E-gene Near Isogenic Lines.

The current study explores the impact of a group of developmental genes, known as the E gene series, on the rate of soybean leaf senescence. The experiment was conducted in a split-plot design with three replications.  The main plots were two photoperiods imposed following R1; i) natural day length (Amb) and ii) incandescent day length extension of 3 hours (Amb+3). The split plots were five E-gene near-isogenic lines (NILs), planted on different dates to obtain synchronous flowering. Cultivars with the dominant E1 allele maintained functional photosynthesis for longer, such that full senescence was delayed by 10-15 days in these cultivars. This phenomenon was observed under both photoperiod treatments and irrespective of the genetic background (‘Clark’ and ‘Harosoy’) in which the alleles appeared. The dominant E allele may delay leaf senescence directly or indirectly, through its delay of reproductive development.