Quantitative Genetics

Having a little trouble if you could help me answer the question or point me in the right direction I would really appreciate it!

The F1 generation of a cross between two inbred strains of maize has a standard deviation in mature plant height of 30 cm.  When grown under the same conditions, the F2 generation produced by the F1 x F1 cross has a standard deviation in plant height of 50 cm.  What is the genotypic variance and broad sense heritability of mature plant height in the F2 population ? (assume that G X E interactions are absent)