Abstract

This study determined the effect of phosphorus application rates on quality of potato tubers. Field experiments were set up at Egerton University, Njoro and Kenya Agricultural Livestock and Research Organization (KARLO), Molo. A randomized complete block design with split plot arrangement and three replicates were used. Main plot factors were varieties (Shangi, Dutch Robyjn, Unica and Wanjiku). Sub plot factors were phosphorus levels (0, 30, 60, 90 kg P ha-1). Data collected was subjected to analysis of variance (ANOVA) using SAS software version 9.3. Application of 0 and 60 kg P ha-1 at KALRO Molo resulted in significantly higher (P<0.05) tuber dry matter contents of 23.49 and 25.76%, respectively. Unica variety at Egerton site and Dutch Robyjn and Wanjiku at KARLO, Molo site recorded significantly higher (P<0.001) dry matter and starch contents of 24.70, 25.52, and 23.45%, respectively. Wanjiku variety and application of 60 kg P ha-1 resulted in significantly higher (P<0.05) tuber starch content of 22.07%. Shangi with 0 and 60 kg P ha-1, Dutch Robyjn and Unica with 0, 30, 60 and 90 kg P ha-1 and Wanjiku with 0, 30, and 60 kg P ha-1 recorded significantly higher (P<0.001) specific gravity of tubers. Application of phosphorus is recommended for improvement in quality of potato propagated from rooted apical cuttings.

Key words: Dry matter, potato, rooted apical cuttings, specific gravity, starch content.