Influence of Variety and Location on Flesh Color in Potato

Abstract

Studies were conducted to evaluate metolachlor for weed control and crop tolerance in sweet potatoes. Metolachlor was applied posttransplant at rates of 0.5, 1.0, or 2.0 lb/A. Tank-mix combinations of metolachlor + clomazone were also evaluated. Clomazone was the standard herbicide used for comparison. Metolachlor alone or in combination with clomazone did not cause any serious reduction in sweet potato plant vigor when applied posttransplant. Metolachlor provided excellent control of Brachiaria platyphylla, Cyperus iria, Cyperus esculentus, and Amaranthus hybridus. Tank-mixes with clomazone did not improve the weed control of metolachlor alone. Yields of No. 1 and marketable roots from metolachlortreated plots were equal to or greater than yields from plots treated with clomazone. RESISTANCE IN SWEETPOTATO TO ROOT-KNOT NEMATODE: ITS VALUE AND OTHER BENEFITS A root-knot nematode (Meloldogyne incognita) project was initiated in a field of infested sandy loam (EREC) in 1991 and continued. There were ten sweetpotato entries consisting of six cultivars (Beauregard. Excel, Georgia Jet, Jewel, Red Jewel, and Sumor), three advanced lines (W-270, W-274, and W-279) and PI 399161 which were selected for their diversity in disease reactions and other traits. Each entry was planted in the same plots each year to monitor effects of continuous cropping, disease reactions, yield and population shifts of the pathogen. Marketable yields were reduced each year for Georgia Jet and Red Jewel, but not for Beauregard. Internal necrosis in the storage roots was most severe for Beauregard. Several of the highly resistant entries, especially Sumor and W-279, performed well each year, including high yields, good quality. and little or no nematode reproduction. This study demonstrates the considerable economic benefits of a high level of durable resistance to root knot in sweetpotato.

Effect of iron and nitrogen on the development ofHelminthosporium solaniand potato silver scurf

“…The toxic effect of NO 2 − seems to be related to its transformation to NO (nitric oxide), which exhibits antifungal, antibacterial, antiviral and antiparasitic activity (De Groote & Fang, 1995). Nitric oxide can be generated from nitrite more efficiently in the presence of reducing agents like polyphenols or ascorbic acid (Gago et al, 2007), and antioxidants are present in high quantity in tuber periderm (Al-Saikhan et al, 1995). Iron exerts antimicrobial action by catalysing the generation of hydroxyl radicals, under aerobic conditions, that will strongly react with several kinds of molecules leading to the oxidation of proteins, peroxidation of membrane lipids and modification of nucleic acids (Papanikolaou & Pantopoulos, 2005).…”