NORTH DAKOTA STATE UNIVERSITY

Plant Propagation PLSC 368

Dr. Chiwon Lee

POTATO PROPAGATION

By

Carina De Luca





Abstract

Potatoes are indigenous to the Andean regions of Peru , Chile and Bolivia , extending northward to the southern Rocky Mountains . Cultivated potato, Solanum tuberosum L., is a highly heterozygous tetraploid (4x = 48), belongs to the Solanaceae family together with other crops like tomato and peppers. Potatoes are adapted to an array of climates and are utilized in many ways. The potato tuber is not only the principal mean for potato propagation, but also a major human food source. Potatoes are mainly propagated by vegetative methods (cloning). Potato tubers have nodes or �eyes� from which the new growth begins. The new stems growing from each �eye� are called sprouts which giver rise to the new plant. Vegetative seed can be either a whole tuber or a cut tuber. Physiological age of seed is influenced by growing conditions, handling, storage and cutting procedures, and it has an impact on how the new crop grows. Sexual propagation occurs by means of botanical or sexual seed. Most potato cultivars produce fruit; each seed will develop into a plant with unique characteristics. This is a process very useful in crop improvements in breeding programs, but its genotypic variation is of little value to growers. Tissue culture is another method which permits a very rapid propagation. This method is used to maintain disease free seed stock, which can be then stored �in vitro� and be used when is needed.

Introduction

Potatoes are indigenous to the Andean regions of Peru , Chile and Bolivia , extending northward to the southern Rocky Mountains . Potatoes purportedly came to North America via Bermuda in 1691. Cultivated potato, Solanum tuberosum L., is a highly heterozygous tetraploid (4x = 48), belongs to the Solanaceae family together with other crops like tomato and peppers. Potato is an annual dicot when grown for botanical seed, but is treated as a perennial because the vegetative propagation from tuber for commercial purposes.

http://oregonstate.edu/potatoes/CSS322WebNotes.html

Potatoes are adapted to an array of climates and are utilized in many ways. There are cultivars developed for different environments and end uses. Because of the wide adaptation and many species, a vast genetic resource can be called upon for introgression of resistance to disease and insect pests, stresses, as well as improvement of quality traits.

Propagation

The tuber is not only the principal mean for potato propagation, but also a major human food source. Potatoes are mainly propagated by vegetative methods (cloning). This is the primary commercial propagation method. Vegetative reproduction ensures a uniform crop, contraire to what would happen with sexual propagation. Sexual propagation of potato is accomplished by planting its �true seed�, but a high variability exist between this seed and that is why is not commonly used. However, sexual seed is becoming more and more popular; especially in places were disease pressure is very high and maintaining disease free seed is becoming a problem.

I. Asexual, vegetative or clonal propagation:

When potato growers talk about �seed� they are talking about the tuber and not the botanical or sexual seed. Potato tubers are actually a modified stem with approximately 70-75% content of water and a remaining 25-30% of dry mater. They have nodes or �eyes� from which the new growth begins. The new stems growing from each �eye� are called sprouts. Sprouts grow from the tuber after a period of dormancy after they are harvested, this varies largely between cultivars. After this dormancy is broken, sprouts grow and when planted, they give rise to the plant stems and from there all the vegetative part of the plant. Underground, lateral shoots called �stolons� are formed, from which the new tubers will be formed.

Vegetative seed can be either a whole tuber or a cut tuber. The standard seed piece used by growers is 2� by 2� or 2 oz.

Potato tuber cut to form seed pieces

Research has shown that a seed piece this size has the adequate amount of carbohydrates levels for shoot initiation and growth. If the tubers are cut, the usual procedure is to let the cut pieces to suberize or cure, for about 10 days. Suberization in tubers allows them to develop a corky layer around the seed piece that prevents the seed piece decay by the entrance of several kinds of pathogens.

Physiological age of seed

Is not the chronological age of the seed piece; instead, is the influence of the growing environment of the seed. Physiological age of seed is influenced by growing conditions, handling, storage and cutting procedures. Physiological age of the seed will have an impact on how the new crop grows.