STM Article Repository

An investigation was undertaken to assess the effect of moisture stress during the reproductive initiation stage on the quality and quantity of pollen grains produced in eight inbred lines (UASBM22, UASBM13, UASBM09, UASBM11, UASBM06, UASBM14, UASBM02 and UASBM10) under greenhouse conditions in three blocks viz., well-watered, stress I (for 21 days from 28 days after sowing) and stress II (for 22 days from 32 days after sowing). Moisture stress significantly affected the number of pollen grains per anther and other plant growth-related traits. The moisture stress effect was not uniform across inbred lines. The inbred lines UASBM22, UASBM13, UASBM09 and UASBM11 recorded a significant reduction in the total number of pollen grains per anther and an increase in pollen sterility while in inbred lines, UASBM06, UASBM14, UASBM02 and UASBM10, the moisture stress effect was not significant. The changes in the DNA methylation pattern in leaves and immature anthers under moisture stress of the contrasting inbred lines (UASBM06 and UASBM13) were studied through methylation- sensitive random amplification polymorphism. An increase in total DNA methylation level in both leaves and anthers was observed in drought tolerant inbred line, UASBM06 under stress while the increase was only in the leaves of the susceptible inbred line UASBM13. Leaves and anthers of UASBM06 showed hypermethylation compared to UASBM13 in moisture-stress conditions. In maize, increased DNA methylation seems to be an important mechanism associated with drought responses which probably regulates the methylation-sensitive gene expression and acclimation responses in maize.