Answer:
ST and St genetic combinations
Explanation:
This is a dihybrid pea plant i.e. a pea plant with two genes (S and T). The pea plant is homozygous for gene S i.e it possesses same alleles of the gene while it is heterozygous for gene T i.e. possesses different alleles for the gene.
This pea plant will undergo meiosis in order to produce its reproductive cells (gametes) which are borne in the pollen grain.
According to Mendel's law of segregation and independent assortment, the alleles of each gene get separated into gametes independently of one another i.e. alleles S and S get sorted into the gametes without affecting the sorting of alleles T and t.
The parent pea plant produces four possible gametes after meiosis: ST, St, ST, and St.
From the observation of the genotypic content of the above gametes, it is clear that there are only two distinct genotype i.e. ST and St.
Hence, ST and St are the two possible genetic combinations of gamete (pollen grain) that can be produced by pea, SSTt.