Growth, yield and dry matter accumulation of organically grown potatoes

Seven potato genotypes grown and selected from previous studies under organic production were evaluated from November 2007 to February, 2008 at La Trinidad, Benguet. Genotype PHIL 5.19.2.2, CIP 13.1.1 and CP 96-06 had the highest total yield of 4.57kg, 4.21kg and 4.13kg, respectively and corresponding computed marketable yields of 6.33, 5.46 and 5.92 tons/ha. Assimilates partitioned into leaves, stems, roots, stolons, and tubers at 45, 60, 75 and 90 DAP differed among genotypes and at different stages of development. Among the plant organs, the roots and stolons had the highest dry matter contents in genotypes PHIL 5.19.2.2 at 45,60 and 75 DAP. Assimilates partitioned into leaves, stems, roots, stolons and tubers at 45,60,75 and 90 DAP differed among genotypes and at different stages of development. Among the plant organs, the roots and stolons had the highest dry matter contents in genotypes PHIL 5.19.2.2 at 45,60 and 75 DAP. Assimilates partitioned in tubers increased in most of the genotypes at 75 DAP and decreased at 90 DAP except in genotypes 96-06 and 5.19.2.2. Correlation analysis revealed positive significant correlation in: plant vigor with light intensity in genotypes CIP 96-06, 573275, and Ganza; dry matter content of leaves with sunshine duration in Granola, dry matter content of stems with rainfall in genotype CIP 96-06 and with maximum temperature in genotype CIP 573275. Conversely significant negative correlations were ob served in: canopy cover with maximum temperature in genotype CIP 96-06; crop growth rate with rainfall in genotype CIP 13.1.1 and PHIL 5.19.2.2; and leaf area index with minimum temperature. The strong indication that dry matter allocation in the tubers is largely genetic encourages researches to continuously search for genotypes with efficient dry matter partitioning high yield and high harvest index under organic production.