Evaluation of varieties, planting date and polyethylene mulch for spring and summer sweet potato production in south-east Queensland.

Abstract

Three sweet potato (lpomoea batatas (L) Lam.) varieties LO-323, Beerwah Gold and Red Abundance were tested for spring and summer harvests in coastal south-east Queensland. Experiments were established in March (Experiment 1), May (Experiment 2) and August (Experiment 3) of 1984. Three harvests per experiment at monthly intervals commencing in October, November and December, respectively, monitored rate of maturity with and without black polyethylene mulch. Polyethylene mulch significantly increased total yield in all experiments and saleable yield in Experiments1 and 2 (P<0.05). Total and saleable yields increased significantly from sequential harvests in all experiments (P<0.05). There were significant differences between varieties for total and saleable yields and percentage saleable in all experiments (P<0.05). L0-323 was superior for total yield in all experiments and for saleable yield in Experiments 2 and 3. Red Abundance produced the highest saleable yield in Experiment 1. Beerwah Gold was superior for percentage saleable in Experiments 1 and 2, and exhibited much less cracking and malformation than LO-323. Interaction of variety X polyethylene mulch X time of harvest occurred in Experiment 3. Beerwah Gold produced a significantly higher saleable yield under mulch than with no mulch at second time of harvest in
January (P<0.05). L0-323 produced a significantly lower marketable yield with mulch than without mulch at the final harvest in February as a result of losses from soil rot (Streptomyces ipomoea).