Inheritance and Stability of Earliness in Solanum Potato

Potato is an important food and cash crop in Uganda. Recent climatic variability characterised by erratic rainfall and elevated temperatures have been recognised as a major threat to potato production and productivity. Breeding for adaptation to these conditions will be imperative to sustain potato productivity. This will require developing high yielding, short growth cycle genotypes with in both high and low elevations. Breeding strategies to guide development of such genotypes require understanding the mode of inheritance of earliness and its impact on potato tuber yield and quality. In order to address this, five late-maturing potato clones with partial resistance to late blight were crossed with five early-maturing but low yielding lines using a North Carolina 2 (NC2) design, F1 plants are being evaluated for the combining abilities of parents and the relative importance of additive and non-additive gene effects. In addition, nine advanced potato clones are being evaluated across three sites located at different altitudes, from 1400 m to 2450 m above sea level for 2 seasons to determine the magnitude of genotype by environment interactions for early maturity and tuber yield. Studies are on-going and preliminary data suggest that there is a strong G x E interaction for growth and yield, implying that there will be location specific selection programmes for potato.