Altogether, CCA1 coordinates heterosis for both defense and growth by enhancing the disease resistance ability of hybrids at the exact time that precedes the burst of SA to avoid the growth consumption caused by the constitutive activation of CCA1 at dawn of all infection day; and rhythmically improving the growth vigor of hybrids when the light-requiring step in chlorophyll biosynthesis could be activated and maintaining this growth enhancement in a diurnal manner. Here, TRNT1 is linked to infection.