Sustainable Potato Production - Guidelines for - FAO.org

Seed production and seed qualityAreliable supply of good quality seedis crucial to the development of thepotato subsector. Availability of seedremains one of the mainconstraints to the large scale adoption ofresearch-bred or research-derived improvedvarieties.Good quality seed is essential to highyields and is usually the most costly input topotato cultivation, accounting for 30-50percent of production costs. Theimprovement of seed quality will contributeto enhancing farmer efficiency andcompetitiveness. The most important seedquality characteristics are variety purity,physiological stage, seed size, seed healthand physical aspect.Good practicesSeed production3Supply seeds that meet strict quantity,timing, and quality-control requirements.3Grow seed in the best and coolest areas ortime of the year in order to avoid insectpopulations that can transmit diseases.3Where potatoes can be grown year-round,encourage farmers in a seed productionarea to include a “potato-free” period inthe farming calendar in order to breakcycles of insects that act as vector for virusdiseases.Purity of varietyThe use of varieties with better quality andgreater adaptability to marginalenvironments will help to enhance potatoproduction and ensure the sustainabilityand competitiveness of potato-basedfarming and utilization systems.3Seed should be of the same variety as thatby which it is sold.3Use varieties that are adapted and stable interm of yields.Where appropriate and where farmerscurrently use mixes of different varieties,ensure the added benefits of such mixturesin terms of tolerance to diseases and ensurethat farmers have adequate knowledge,infrastructure and guidelines to apply bestpractices for seed production.Physiological stagePhysiological development of a seed tuber iscategorized as follows:3Phase I = dormant period;3Phase II=apical sprouting;3Phase III=period of normal sprouting;3Phase IV=period of thin sprouts;3Phase V= incubated – too old seed tubers.As the physiology of the seed is a majorfactor in seed quality, storage systems andstorage duration are critical aspects to beconsidered. To obtain a high yielding crop,seed should be at the correct physiologicalage and sprouting stage at planting,depending on the purpose of the crop. Inprinciple, seed should be at least threemonths old before it is planted, and no olderthan 5-11 months (depending on variety,storage system and temperature).37KEY INDICATORSOFSUSTAINABILITY