Factors Influencing Potato Emergence

Managing potato seed to encourage rapid emergence is essential to the establishment of a healthy crop. Rapid emergence is desirable because seed tubers are the only source of energy for the early stages of plant development. Potato plants should emerge 3 weeks after planting, but several factors influence the length of time between planting and emergence:

Soil Moisture. Sprouts grow faster in soils that are close to field capacity than in drier soils.

Soil Temperature. Sprout development and elongation occur more rapidly at 17-19°C than at 10-15°C.

Seed Warming. Seed tubers warmed (10-15°C) prior to planting will emerge more rapidly and uniformly. The warming period needs to be controlled carefully so that the seed has sprouts just emerging (white points). Longer sprouts are tender and susceptible to mechanical damage.

Physiological Age of Seed. Temperature is the main factor that determines the physiological age of a seed tuber. The physiological age of a potato tuber is determined not from harvest but from tuber initiation. Seed grown during a season with stressful weather conditions, will be physiologically older at harvest than tubers from a more favorable growing season. It is possible to determine the physiological age of a seed lot by taking a representative sample of tubers from cold storage and warming them to 15-17°C in the dark. The length of time required for sprout emergence (white point stage) will provide an estimate of the amount of time and warming that will be required in storage for that particular variety and seed lot. If the seed is physiological old the sprouts are weak and form branches. This results in weak plants that will mature before maximum yield. This results in a lot of small sized tubers

Diseases. Developing sprouts are susceptible to Rhizoctonia canker and soft rot. Rhizoctonia can be reduced by applying Quadris in-furrow. Soft rot bacteria cause serious problems when soils become saturated after heavy rains. Cold seed is highly susceptible to seed-piece decay when planted in warm soil or in light, sandy soil that warms quickly. When a cold seed piece is surrounded by warm, moist soil, water will condense on the seed piece. This creates the anaerobic environment that favors soft rot.

The 3 principles of potato planting are to select high quality seed,handle it carefully and encourage quick emergence.

How seed tubers are handled and planted is just as important as the quality of the seed itself