Abstract

The aim of the experiment is to develop a high-output and low-cost method for propagating elite potato seed in the field from pre-elite seeds. Field experiments were conducted in spring and autumn season of southwestern China (Yucheng in 2010 and Hanyuan in 2011). Randomized-block design was used with 3 seed-size rates, 4 planting densities and 2 cultivars of pre-elite seed from virus-free potato. During potato-growing periods, dry-matter accumulation, number, volume, and dry weight of tubers, and propagation efficiency of pre-elite seed from virus-free potato were measured. The results indicated that medium planting density with large pre-elite potato seed increased tuber volume and dry matter accumulation (per-plant), and prolonged rapid-growth period, resulting in a large amount of final growth. In addition, seed volume, number of plants harvested, rate of seed set per plant, and mass of individual tubers increased, reproductive yield and the coefficient of tuber number and weight increased but the weight coefficient decreased. Per-plant rate of seed set and propagation coefficients of weight, tuber number, and tuber weight decreased with increasing plant density, while number of plants harvested and reproductive output increased. The yields of elite seed of virus-free potato reached a peak in autumn season with large pre-elite seed and high planting density, and in spring season with large seed and medium planting density. Propagation coefficient of tuber numbers and weight reached a peak with large seeds and low planting density, but the highest propagation coefficient of weight was obtained with small pre-elite seeds and low planting density.

Key words: Virus-free potato, pre-elite seed, tuber size, planting density, propagation efficiency.