Wheat leaf chlorosis controlled by a single recessive gene.

The leaf chlorosis in the wheat genotype AIM9 was demonstrated to be controlled by a single recessive gene, which was designated as CD5. Significant difference in physiological and yield indices between chlorotic and non-chlorotic plants were observed in 10 F3 segregating families of the cross combination CN17/AIM9. Correlation analysis of both chlorotic plants and plants staying green of the F3 populations revealed that there was a significant positive correlation between yield index values and the physiological indices net photosynthetic rate (P(n)), stomatal conductance (G(s)), and chlorophyll (Chl), as well as a significant negative correlation between yield index values and the physiological indices intercellular CO2 concentration (C(i)) and malondialdehyde (MDA). Observation using transmission electron microscopy (TEM) found the irreversible centripetal movement of chloroplasts in chlorotic plants, as a result occurred in three sequential events: (1) chloroplast positions changed from face position (with long axis of chloroplasts at the cell walls perpendicular to light ray) to profile position (with long axis chloroplasts near the cell walls parallel to light ray), (2) chloroplast shapes changed from long elliptical to circular, (3) chloroplasts were separated from the cell wall and moved to the center of the cell.