Interactive effect of nitrogen and potassium on dry matter and nutrient partitioning in true potato seed mother plants

Abstract

Field experiments were conducted at Namulonge Agricultural and Animal Production Research Institute and Kalengyere Research Station in Uganda, during 1995-1996 and 1999, to assess the effect of N and K on dry matter yield and nutrient partioning in true potato (Solanum tuberosum) seed (TPS) mother plants. Three N (0, 120, 240 kg ha-1) and K (0, 132.8 and 265.6 kg ha-1) rates were applied to mother plants of three potato genotypes, CIP 800212, CIP 381379.9 (Kisoro) and CIP 381403.1. Potassium application significantly (P<0.05) depressed shoot dry matter yield in all the genotypes. Nitrogen application, however, had no significant effect on shoot dry matter yield although N x genotype interactions were significant (P<0.05) on the parameter. Fresh tuber yield ranged from 21.0 to 37.5 t ha-1, and was significantly (P<0.05) increased by both N and K application. Leaf N concentration varied significantly (P<0.05) among genotypes and K rates higher than 132.8 kg ha-1 increased this parameter in potato genotype CIP 381403. High N and K rates also increased stem N concentration in this genotype. Nitrogen application significantly (P<0.05) increased foliar Ca concentration.



Key Words: Nutrient antagonism, potato genotypes, Solanum tuberosum, tuber yield


(African Crop Science Journal 2001 9(1): 127-146)