An easy way to decrease the chroma (intensity, saturation) of a color is to mix it with Richeson Shiva Series ice blue. Ice blue can be made by mixing cobalt blue with titanium white and a tiny amount of transparent oxide red (or burnt sienna). Look at the wonderful desaturated colors that ice blue can make
This is a beautiful painting by Kenn Backhaus, This painting is used in his educational downloadable, video that describes how to paint the illusion of light. You can find out more at http://www.tucsonartacademyonline.com/kenn-backhaus-dappled-light-video
To understand how to paint the effect of sun dappled light, we closed in on one of these areas and copied it.
To achieve the best "glow", a clean tint (tint is white plus color) of yellow, pink or orange is surrounded by a mid value unsaturated color (a grey blue, or grey lavender).
Note also the lit red flower on the wall that has been painted with a more saturated red in the sunlight.